# Changes and Influencing Factors of Cognitive Impairment in Patients with Breast Cancer

Authors: Huixia Cui; Xusheng Shi; Xiaoxiu Song; Wenlu Zhang
Journal: Evidence-Based Complementary and Alternative Medicine
 (2021)

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## Abstract

Objective. To investigate the changes in cognitive function and its influencing factors in patients with breast cancer after chemotherapy, to provide a scientific basis for further cognitive correction therapy. Methods. In this study, general information on age, marital status, and chemotherapy regimen was collected from 172 breast cancer chemotherapy patients. 172 patients with breast cancer undergoing chemotherapy were investigated by convenience sampling method, and the subjects were tested one-on-one using the Chinese version of the MATRICS Consensus Cognitive Battery (MCCB) computer system. Results. The mean value of standardized t-value of cognitive function and its abnormal dimensions in breast cancer patients undergoing chemotherapy were MCCB total cognition (66.3%, 36.99 ± 13.06, abnormal), working memory (73.3%, 36.84 ± 10.25), attention and alertness (70.3%, 37.20 ± 12.50), social cognition (65.1%, 39.54 ± 10.17), and visual memory (61.6%, 42.19 ± 9.38). A comparison of cognitive function among breast cancer chemotherapy patients with different demographic characteristics showed that differences in place of residence, educational level, monthly income, timing of chemotherapy, chemotherapy regimen, and chemotherapy times may be associated with abnormal cognitive function. Further multiple linear regression analysis was performed and the results showed that there was a linear regression between literacy, number of chemotherapy sessions, monthly personal income, and cognitive function. Conclusion. Cognitive impairment is common in patients with breast cancer after chemotherapy. Nurses should pay attention to the cognitive function changes and intervention of patients with breast cancer after chemotherapy, to prevent the changes of cognitive function and promote the rehabilitation of patients.


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## Body

## 1. Introduction

Breast cancer is already the most common malignant tumor in women with the highest incidence [1]. In 2018, it is estimated that there are about 2.1 million new cases of breast cancer worldwide, accounting for 25% of all new cases of malignant tumors [2]. In recent years, the incidence and mortality of female breast cancer in China has increased year by year, and the disease burden of breast cancer patients has also increased year by year. At present, surgery combined with postoperative chemotherapy is still the first choice for the treatment of breast cancer, but chemotherapy drugs are used in the treatment of diseases. At the same time, there are many adverse reactions, which brings great pain to patients [3]. Studies have shown that chemotherapy will cause not only leukocytosis, nausea, vomiting, loss of appetite, bone marrow suppression, hair loss, and so on, but also severe cognitive decline [4]. Chemotherapy-related cognitive impairment [5] (chemotherapy-related cognitive impairment, CRCI), also known as chemotherapy brain (chemobrain) or chemotherapy fog (chemofog), is refered to the memory of patients with malignant tumors during or after chemotherapy and the decline of cognitive functions such as power, executive ability, language ability, reasoning ability, and visual space ability [6]. The pathogenesis of CRCI is not yet clear. Studies have confirmed that it is related to a variety of factors, including changes in estrogen levels, inflammation, and DNA factors.The occurrence of CRCI not only affects the frequency of social interaction and the efficiency of work for breast cancer patients but also has a serious impact on the patient’s ability to perform daily activities, which can be physically and mentally devastating and have a negative impact on family harmony. Currently, most of the studies on cognitive impairment in China focus on elderly patients, stroke patients, and other populations, and there are fewer studies on cognitive impairment and its influencing factors in breast cancer chemotherapy patients [7]. This study, therefore, investigates breast cancer chemotherapy patients, using a neuropsychological test as a research tool and a computerized measurement platform to enable the implementation of computer-assisted data for brain function tests and the implementation of validated cognitive function sets for patients in hospitals. This is to provide a clearer understanding of the current status of CRCI in breast cancer chemotherapy patients and to analyze its influencing factors, to provide a scientific basis for further cognitive remediation treatment.


## 2. Objects and Methods

### 2.1. Object

Convenience sampling was used to investigate the subjects who met the inclusion criteria in the First and Third Affiliated Hospitals of Jinzhou Medical University from October 2018 to March 2020. Inclusion criteria: (1) patients with histopathologically diagnosed breast cancer and undergoing chemotherapy; (2) no hearing, vision, language, and other dysfunctions and having certain expression and reading ability; and (3) voluntarily participating in the research of this subject. Exclusion criteria: (1) patients with advanced cachexia; (2) patients with cognitive impairment prior to receiving chemotherapy treatment; (3) patients with obvious anxiety, depression, and other mental illnesses; (4) patients taking drugs related to cognitive function; (5) patients with intracranial abnormalities and intracranial metastases on MRI or CT examination of the head; (6) combined with severe heart, liver, kidney, brain, and hematopoietic system diseases. 206 breast cancer chemotherapy patients participated in this study, of whom 34 did not complete this study, for a final sample size of 172. The general information is shown in Table1.Table 1
General demographic data of breast cancer chemotherapy patients (n = 172, %).
FactorGroupAmount of people (n)Composition ratio (%)Age (years)Scope26–68Average value (mean ± SD)49.38 ± 9.20MarriageUnmarried2313.37Married14986.63OccupationWork in city9253.49Work in rural or unemployed8046.51EducationElementary school and below5230.23Junior high school3319.19High school6537.79University and above2212.79Monthly income (yuan)<1000158.721000–30005431.403001–50008750.58>5000169.30Family history of breast cancerYes4023.26No13276.74Types of breast cancer pathologyCarcinoma in situ2011.63Invasive carcinoma12673.25Other2615.12Clinical stageI3419.76II4425.58III6135.47IV3319.19RadiotherapyYes5431.40No11868.60SurgeryYes14584.30No2715.70Surgery typeRadical mastectomy5632.56Modified radical mastectomy5632.56Breast conservation3319.18No surgery2715.70MetastasisYes10158.72No7141.28Time to receive chemotherapyBefore operation5531.98After operation11768.02Current chemotherapy regimenCEF4928.49CET4928.49TP2112.21TCH and others5330.81Number of chemotherapy sessions (times)1–94425.5810–182916.8619–366236.05≥373721.51


### 2.2. Method

#### 2.2.1. Survey Tools

1. The general information survey form was designed by the research themselves according to a large amount of literature, mainly including age, marital status, education level, personal monthly income, surgical method, disease stage, chemotherapy regimen, chemotherapy cycle, etc. 2. The Chinese version of the computer system for MATRICS Consensus Cognitive Battery (MCCB) was introduced from the United States in 2009 by Beijing Huilongguan Hospital. After translation and back translation, the Chinese version of MCCB was revised and completed. Later, Beijing Huilongguan Hospital organized experts to conduct tests, standardization, and computerization. In all MCCB subtests, except for the visual memory test, which is subjectively scored by the rater, other subtests are automatically scored by computer programs. As long as the main tester operates according to the regulations, there is no need for the main tester to score by time. The MCCB is an individual cognitive function test, which requires one-to-one testing between the examiner and the subject. The examiner needs to have certain qualifications and undergo a rigorous training before the evaluation. According to the results of the cognitive function test, the number of standard deviations compared with the norm is used to determine the degree of cognitive deficits.


#### 2.2.2. Survey Method

This study was reviewed and approved by the Ethics Committee of Jinzhou Medical University. Convenience sampling was used to investigate the subjects who met the inclusion criteria in the First and Third Affiliated Hospitals of Jinzhou Medical University from October 2018 to March 2020 and solicited the test subjects. After the participants and their family members agree, the researchers explained the test procedures and requirements in detail to the subjects and conducted one-to-one computer system tests on the subjects.


#### 2.2.3. Statistical Methods

The data was checked by two persons and entered into SPSS 21.0, and statistical analysis was carried out. The statistical data were expressed as rates and composition ratios (n, %) using the chi-square test, while the measurement data were expressed as mean ± standard deviation (mean ± SD), using t-test between two groups and one-way variance (F) test between multiple groups. Pearson’s model was used for correlation analysis and the multiple linear regression model for multifactor analysis; P<0.05 was considered statistically significant.


## 2.1. Object

Convenience sampling was used to investigate the subjects who met the inclusion criteria in the First and Third Affiliated Hospitals of Jinzhou Medical University from October 2018 to March 2020. Inclusion criteria: (1) patients with histopathologically diagnosed breast cancer and undergoing chemotherapy; (2) no hearing, vision, language, and other dysfunctions and having certain expression and reading ability; and (3) voluntarily participating in the research of this subject. Exclusion criteria: (1) patients with advanced cachexia; (2) patients with cognitive impairment prior to receiving chemotherapy treatment; (3) patients with obvious anxiety, depression, and other mental illnesses; (4) patients taking drugs related to cognitive function; (5) patients with intracranial abnormalities and intracranial metastases on MRI or CT examination of the head; (6) combined with severe heart, liver, kidney, brain, and hematopoietic system diseases. 206 breast cancer chemotherapy patients participated in this study, of whom 34 did not complete this study, for a final sample size of 172. The general information is shown in Table1.Table 1
General demographic data of breast cancer chemotherapy patients (n = 172, %).
FactorGroupAmount of people (n)Composition ratio (%)Age (years)Scope26–68Average value (mean ± SD)49.38 ± 9.20MarriageUnmarried2313.37Married14986.63OccupationWork in city9253.49Work in rural or unemployed8046.51EducationElementary school and below5230.23Junior high school3319.19High school6537.79University and above2212.79Monthly income (yuan)<1000158.721000–30005431.403001–50008750.58>5000169.30Family history of breast cancerYes4023.26No13276.74Types of breast cancer pathologyCarcinoma in situ2011.63Invasive carcinoma12673.25Other2615.12Clinical stageI3419.76II4425.58III6135.47IV3319.19RadiotherapyYes5431.40No11868.60SurgeryYes14584.30No2715.70Surgery typeRadical mastectomy5632.56Modified radical mastectomy5632.56Breast conservation3319.18No surgery2715.70MetastasisYes10158.72No7141.28Time to receive chemotherapyBefore operation5531.98After operation11768.02Current chemotherapy regimenCEF4928.49CET4928.49TP2112.21TCH and others5330.81Number of chemotherapy sessions (times)1–94425.5810–182916.8619–366236.05≥373721.51


## 2.2. Method

### 2.2.1. Survey Tools

1. The general information survey form was designed by the research themselves according to a large amount of literature, mainly including age, marital status, education level, personal monthly income, surgical method, disease stage, chemotherapy regimen, chemotherapy cycle, etc. 2. The Chinese version of the computer system for MATRICS Consensus Cognitive Battery (MCCB) was introduced from the United States in 2009 by Beijing Huilongguan Hospital. After translation and back translation, the Chinese version of MCCB was revised and completed. Later, Beijing Huilongguan Hospital organized experts to conduct tests, standardization, and computerization. In all MCCB subtests, except for the visual memory test, which is subjectively scored by the rater, other subtests are automatically scored by computer programs. As long as the main tester operates according to the regulations, there is no need for the main tester to score by time. The MCCB is an individual cognitive function test, which requires one-to-one testing between the examiner and the subject. The examiner needs to have certain qualifications and undergo a rigorous training before the evaluation. According to the results of the cognitive function test, the number of standard deviations compared with the norm is used to determine the degree of cognitive deficits.


### 2.2.2. Survey Method

This study was reviewed and approved by the Ethics Committee of Jinzhou Medical University. Convenience sampling was used to investigate the subjects who met the inclusion criteria in the First and Third Affiliated Hospitals of Jinzhou Medical University from October 2018 to March 2020 and solicited the test subjects. After the participants and their family members agree, the researchers explained the test procedures and requirements in detail to the subjects and conducted one-to-one computer system tests on the subjects.


### 2.2.3. Statistical Methods

The data was checked by two persons and entered into SPSS 21.0, and statistical analysis was carried out. The statistical data were expressed as rates and composition ratios (n, %) using the chi-square test, while the measurement data were expressed as mean ± standard deviation (mean ± SD), using t-test between two groups and one-way variance (F) test between multiple groups. Pearson’s model was used for correlation analysis and the multiple linear regression model for multifactor analysis; P<0.05 was considered statistically significant.


## 2.2.1. Survey Tools

1. The general information survey form was designed by the research themselves according to a large amount of literature, mainly including age, marital status, education level, personal monthly income, surgical method, disease stage, chemotherapy regimen, chemotherapy cycle, etc. 2. The Chinese version of the computer system for MATRICS Consensus Cognitive Battery (MCCB) was introduced from the United States in 2009 by Beijing Huilongguan Hospital. After translation and back translation, the Chinese version of MCCB was revised and completed. Later, Beijing Huilongguan Hospital organized experts to conduct tests, standardization, and computerization. In all MCCB subtests, except for the visual memory test, which is subjectively scored by the rater, other subtests are automatically scored by computer programs. As long as the main tester operates according to the regulations, there is no need for the main tester to score by time. The MCCB is an individual cognitive function test, which requires one-to-one testing between the examiner and the subject. The examiner needs to have certain qualifications and undergo a rigorous training before the evaluation. According to the results of the cognitive function test, the number of standard deviations compared with the norm is used to determine the degree of cognitive deficits.


## 2.2.2. Survey Method

This study was reviewed and approved by the Ethics Committee of Jinzhou Medical University. Convenience sampling was used to investigate the subjects who met the inclusion criteria in the First and Third Affiliated Hospitals of Jinzhou Medical University from October 2018 to March 2020 and solicited the test subjects. After the participants and their family members agree, the researchers explained the test procedures and requirements in detail to the subjects and conducted one-to-one computer system tests on the subjects.


## 2.2.3. Statistical Methods

The data was checked by two persons and entered into SPSS 21.0, and statistical analysis was carried out. The statistical data were expressed as rates and composition ratios (n, %) using the chi-square test, while the measurement data were expressed as mean ± standard deviation (mean ± SD), using t-test between two groups and one-way variance (F) test between multiple groups. Pearson’s model was used for correlation analysis and the multiple linear regression model for multifactor analysis; P<0.05 was considered statistically significant.


## 3. Results

### 3.1. Analysis of the Current Status of Various Dimensions and Subtest Results of Cognitive Function in Patients with Breast Cancer Chemotherapy

#### 3.1.1. Analysis of the Current Status of Various Dimensions of Cognitive Function  in Patients with Breast Cancer Chemotherapy

The processing speed score of breast cancer chemotherapy patients is (48.83 ± 10.73), the working memory score is (36.84 ± 10.25), and the speech learning score is (44.67 ± 10.90) as shown in Table2.Table 2
Analysis of T-scores of various dimensions and subtests of MCCB (n = 172,%).
Cognitive dimensionSubtestScope (scores)Average value (scores, mean ± SD)ResultProcessing speedScore21–7248.83 ± 10.73NormalCategory fluency29–8262.50 ± 14.79ExtraordinaryTrail making test26–8052.72 ± 12.48NormalSymbolic coding test10–6133.31 ± 13.53AbnormalWorking memoryScore11–5936.84 ± 10.25AbnormalNumber sequence test15–6744.85 ± 9.95NormalSpatial span test10–4931.75 ± 12.02AbnormalSpeech learningVerbal memory test12–6544.67 ± 10.90NormalVisual learningVisual memory14–6442.19 ± 9.38AbnormalReasoning and problem solvingMaze test29–7050.06 ± 9.08NormalAttention/alertnessContinuous operation test10–6837.20 ± 12.50AbnormalSocial cognitionEmotion management test20–7239.54 ± 10.17AbnormalMCCB10–6336.99 ± 13.06Abnormal


#### 3.1.2. Ratio Analysis of the Current Status of Various Dimensions and Subtest Results of Cognitive Function in Patients with Breast Cancer

Chemotherapy among the 172 breast cancer patients undergoing chemotherapy: the percentages of cognitive impairment in various dimensions, from high to low, were working memory (73.3%), attention/alertness (70.3%), social cognition (65.1%), and visual memory (61.6%), verbal memory (34.3%), processing speed (27.3%), reasoning and problem-solving ability (23.3%), and MCCB cognitive total score (66.3%), as shown in Table3.Table 3
Ratio analysis of the current status of cognitive dimensions and subtests in patients with breast cancer chemotherapy (n = 172,%).
Subtests/dimensionsResultFrequencyPercentage (%)Cumulative percentage (%)MCCBAbnormal11466.2866.28Normal4023.2689.54Extraordinary1810.46100.00In total172100.00Working memoryAbnormal12673.2673.26Normal4425.5898.84Extraordinary21.16100.00In total172100.00Attention/alertnessAbnormal12170.3570.35Normal4325.0095.35Extraordinary84.65100.00In total172100.00Social cognitionAbnormal11265.1265.12Normal5531.9897.10Extraordinary52.90100.00In total172100.00Visual memoryAbnormal10661.6361.63Normal5029.0790.70Extraordinary169.30100.00In total172100.00Verbal memoryAbnormal5934.3034.30Normal9052.3386.63Extraordinary2313.37100.00In total172100.00Processing speedAbnormal4727.3327.33Normal8147.0974.42Extraordinary4425.58100.00In total172100.00Reasoning and problem-solvingAbnormal4023.2623.26Normal8650.0073.26Extraordinary4626.74100.00In total172100.00Trail making testAbnormal4526.1626.16Normal5531.9858.14Extraordinary7241.86100.00In total172100.00Symbolic coding testAbnormal13679.0779.07Normal3017.4496.51Extraordinary63.49100.00In total172100.00Category fluency testAbnormal2313.3713.37Normal4023.2636.63Extraordinary10963.37100.00In total172100.00Number sequence testAbnormal5733.1433.14Normal9354.0787.21Extraordinary2212.79100.00In total172100.00Spatial span testAbnormal13980.8180.81Normal3218.6099.41Extraordinary10.59100.00In total172100.00


### 3.2. Comparison of Cognitive Function of Breast Cancer Patients Undergoing Chemotherapy with Different Demographic Characteristics

The results of the comparison of cognitive function in breast cancer chemotherapy patients with different demographic characteristics showed that differences in place of residence, literacy, monthly income, timing of chemotherapy, chemotherapy regimen, and chemotherapy times may be associated with abnormal cognitive function (p<0.05). See Table 4 for details.Table 4
Comparison of scores of various dimensions of cognitive function in breast cancer patients with different characteristics.
FactorCase (n)Score (mean ± SD)t/FpMarital statusUnmarried2332.09 ± 10.99−1.9460.053Married14937.99 ± 13.89Place of residenceCity9239.85 ± 13.592.7770.006Rural8034.16 ± 13.18Educational levelElementary school and below5225.50 ± 9.3773.322≤0.001Junior high school3329.12 ± 8.95High school6547.09 ± 7.60University and above2247.77 ± 12.10Monthly income (yuan)<10001532.47 ± 8.449.085≤0.0011000–30005430.61 ± 12.273001–50008741.32 ± 13.87>50001641.50 ± 11.34Pathological typeCarcinoma in situ2039.55 ± 16.760.3340.717Invasive carcinoma12636.93 ± 13.52Metastatic cancer and others2636.73 ± 11.99Clinical stageI3440.12 ± 17.611.9790.119II4439.16 ± 13.75III6136.48 ± 11.29IV3332.94 ± 12.26Surgical approachRadical mastectomy5633.84 ± 12.991.7850.152Modified radical mastectomy5638.21 ± 13.87Breast conservation3339.67 ± 12.00No surgery2739.07 ± 15.76Timing of chemotherapyBefore surgery5533.89 ± 13.14−2.2050.029After surgery11738.76 ± 13.68Chemotherapy regimenCEF4939.49 ± 14.012.9450.035CET4938.49 ± 12.81TP2129.48 ± 14.45TCH5336.96 ± 13.04Chemotherapy times1–94448.16 ± 10.5623.659≤0.00110–182941.10 ± 14.1519–366232.23 ± 11.76≥373729.46 ± 10.00


### 3.3. Multiple Linear Regression Analysis of Cognitive Function in Patients with Breast Cancer Chemotherapy

The MCCB score of patients with breast cancer chemotherapy was used as the dependent variable, and the statistically significant variables in the univariate analysis were used as independent variables to perform multiple linear stepwise regression analysis (αin = 0.05, αout = 0.10). The analysis revealed that education level, chemotherapy times, and personal monthly income (see Table 5 for assignments) were risk factors for cognitive function in breast cancer chemotherapy patients (p<0.05), as shown in Table 6.Table 5
Assignment for multivariate analysis of factors.
FactorsAssignmentMonthly income1 = <1000, 2 = 1000–3000, 3 = 3001–5000, 4 = >5000Education level1 = elementary school and below, 2 = junior high school, 3 = high school, 4 = university and aboveChemotherapy times1 = 1–9, 2 = 10–18, 3 = 19–36, 4 = ≥37Table 6
Multiple linear regression analysis of cognitive function in patients with breast cancer chemotherapy (n = 172).
ModelBSEBetatp95.0% CILower limitUpper limitConstant term21.7645.3430.0164.073≤0.00111.21332.315Monthly income3.4860.9850.1983.541≤0.0011.5425.431Education level6.7180.8020.5138.378≤0.0015.1358.301Chemotherapy times−3.8610.708−0.309−5.455≤0.001−5.259−2.464Note:R2 = 0.599, adjust R2 = 0.579, F = 30.455, p<0.001. B is the regression coefficient, SE is the standard error, and 95% CI is the 95% confidence interval.


## 3.1. Analysis of the Current Status of Various Dimensions and Subtest Results of Cognitive Function in Patients with Breast Cancer Chemotherapy

### 3.1.1. Analysis of the Current Status of Various Dimensions of Cognitive Function  in Patients with Breast Cancer Chemotherapy

The processing speed score of breast cancer chemotherapy patients is (48.83 ± 10.73), the working memory score is (36.84 ± 10.25), and the speech learning score is (44.67 ± 10.90) as shown in Table2.Table 2
Analysis of T-scores of various dimensions and subtests of MCCB (n = 172,%).
Cognitive dimensionSubtestScope (scores)Average value (scores, mean ± SD)ResultProcessing speedScore21–7248.83 ± 10.73NormalCategory fluency29–8262.50 ± 14.79ExtraordinaryTrail making test26–8052.72 ± 12.48NormalSymbolic coding test10–6133.31 ± 13.53AbnormalWorking memoryScore11–5936.84 ± 10.25AbnormalNumber sequence test15–6744.85 ± 9.95NormalSpatial span test10–4931.75 ± 12.02AbnormalSpeech learningVerbal memory test12–6544.67 ± 10.90NormalVisual learningVisual memory14–6442.19 ± 9.38AbnormalReasoning and problem solvingMaze test29–7050.06 ± 9.08NormalAttention/alertnessContinuous operation test10–6837.20 ± 12.50AbnormalSocial cognitionEmotion management test20–7239.54 ± 10.17AbnormalMCCB10–6336.99 ± 13.06Abnormal


### 3.1.2. Ratio Analysis of the Current Status of Various Dimensions and Subtest Results of Cognitive Function in Patients with Breast Cancer

Chemotherapy among the 172 breast cancer patients undergoing chemotherapy: the percentages of cognitive impairment in various dimensions, from high to low, were working memory (73.3%), attention/alertness (70.3%), social cognition (65.1%), and visual memory (61.6%), verbal memory (34.3%), processing speed (27.3%), reasoning and problem-solving ability (23.3%), and MCCB cognitive total score (66.3%), as shown in Table3.Table 3
Ratio analysis of the current status of cognitive dimensions and subtests in patients with breast cancer chemotherapy (n = 172,%).
Subtests/dimensionsResultFrequencyPercentage (%)Cumulative percentage (%)MCCBAbnormal11466.2866.28Normal4023.2689.54Extraordinary1810.46100.00In total172100.00Working memoryAbnormal12673.2673.26Normal4425.5898.84Extraordinary21.16100.00In total172100.00Attention/alertnessAbnormal12170.3570.35Normal4325.0095.35Extraordinary84.65100.00In total172100.00Social cognitionAbnormal11265.1265.12Normal5531.9897.10Extraordinary52.90100.00In total172100.00Visual memoryAbnormal10661.6361.63Normal5029.0790.70Extraordinary169.30100.00In total172100.00Verbal memoryAbnormal5934.3034.30Normal9052.3386.63Extraordinary2313.37100.00In total172100.00Processing speedAbnormal4727.3327.33Normal8147.0974.42Extraordinary4425.58100.00In total172100.00Reasoning and problem-solvingAbnormal4023.2623.26Normal8650.0073.26Extraordinary4626.74100.00In total172100.00Trail making testAbnormal4526.1626.16Normal5531.9858.14Extraordinary7241.86100.00In total172100.00Symbolic coding testAbnormal13679.0779.07Normal3017.4496.51Extraordinary63.49100.00In total172100.00Category fluency testAbnormal2313.3713.37Normal4023.2636.63Extraordinary10963.37100.00In total172100.00Number sequence testAbnormal5733.1433.14Normal9354.0787.21Extraordinary2212.79100.00In total172100.00Spatial span testAbnormal13980.8180.81Normal3218.6099.41Extraordinary10.59100.00In total172100.00


## 3.1.1. Analysis of the Current Status of Various Dimensions of Cognitive Function  in Patients with Breast Cancer Chemotherapy

The processing speed score of breast cancer chemotherapy patients is (48.83 ± 10.73), the working memory score is (36.84 ± 10.25), and the speech learning score is (44.67 ± 10.90) as shown in Table2.Table 2
Analysis of T-scores of various dimensions and subtests of MCCB (n = 172,%).
Cognitive dimensionSubtestScope (scores)Average value (scores, mean ± SD)ResultProcessing speedScore21–7248.83 ± 10.73NormalCategory fluency29–8262.50 ± 14.79ExtraordinaryTrail making test26–8052.72 ± 12.48NormalSymbolic coding test10–6133.31 ± 13.53AbnormalWorking memoryScore11–5936.84 ± 10.25AbnormalNumber sequence test15–6744.85 ± 9.95NormalSpatial span test10–4931.75 ± 12.02AbnormalSpeech learningVerbal memory test12–6544.67 ± 10.90NormalVisual learningVisual memory14–6442.19 ± 9.38AbnormalReasoning and problem solvingMaze test29–7050.06 ± 9.08NormalAttention/alertnessContinuous operation test10–6837.20 ± 12.50AbnormalSocial cognitionEmotion management test20–7239.54 ± 10.17AbnormalMCCB10–6336.99 ± 13.06Abnormal


## 3.1.2. Ratio Analysis of the Current Status of Various Dimensions and Subtest Results of Cognitive Function in Patients with Breast Cancer

Chemotherapy among the 172 breast cancer patients undergoing chemotherapy: the percentages of cognitive impairment in various dimensions, from high to low, were working memory (73.3%), attention/alertness (70.3%), social cognition (65.1%), and visual memory (61.6%), verbal memory (34.3%), processing speed (27.3%), reasoning and problem-solving ability (23.3%), and MCCB cognitive total score (66.3%), as shown in Table3.Table 3
Ratio analysis of the current status of cognitive dimensions and subtests in patients with breast cancer chemotherapy (n = 172,%).
Subtests/dimensionsResultFrequencyPercentage (%)Cumulative percentage (%)MCCBAbnormal11466.2866.28Normal4023.2689.54Extraordinary1810.46100.00In total172100.00Working memoryAbnormal12673.2673.26Normal4425.5898.84Extraordinary21.16100.00In total172100.00Attention/alertnessAbnormal12170.3570.35Normal4325.0095.35Extraordinary84.65100.00In total172100.00Social cognitionAbnormal11265.1265.12Normal5531.9897.10Extraordinary52.90100.00In total172100.00Visual memoryAbnormal10661.6361.63Normal5029.0790.70Extraordinary169.30100.00In total172100.00Verbal memoryAbnormal5934.3034.30Normal9052.3386.63Extraordinary2313.37100.00In total172100.00Processing speedAbnormal4727.3327.33Normal8147.0974.42Extraordinary4425.58100.00In total172100.00Reasoning and problem-solvingAbnormal4023.2623.26Normal8650.0073.26Extraordinary4626.74100.00In total172100.00Trail making testAbnormal4526.1626.16Normal5531.9858.14Extraordinary7241.86100.00In total172100.00Symbolic coding testAbnormal13679.0779.07Normal3017.4496.51Extraordinary63.49100.00In total172100.00Category fluency testAbnormal2313.3713.37Normal4023.2636.63Extraordinary10963.37100.00In total172100.00Number sequence testAbnormal5733.1433.14Normal9354.0787.21Extraordinary2212.79100.00In total172100.00Spatial span testAbnormal13980.8180.81Normal3218.6099.41Extraordinary10.59100.00In total172100.00


## 3.2. Comparison of Cognitive Function of Breast Cancer Patients Undergoing Chemotherapy with Different Demographic Characteristics

The results of the comparison of cognitive function in breast cancer chemotherapy patients with different demographic characteristics showed that differences in place of residence, literacy, monthly income, timing of chemotherapy, chemotherapy regimen, and chemotherapy times may be associated with abnormal cognitive function (p<0.05). See Table 4 for details.Table 4
Comparison of scores of various dimensions of cognitive function in breast cancer patients with different characteristics.
FactorCase (n)Score (mean ± SD)t/FpMarital statusUnmarried2332.09 ± 10.99−1.9460.053Married14937.99 ± 13.89Place of residenceCity9239.85 ± 13.592.7770.006Rural8034.16 ± 13.18Educational levelElementary school and below5225.50 ± 9.3773.322≤0.001Junior high school3329.12 ± 8.95High school6547.09 ± 7.60University and above2247.77 ± 12.10Monthly income (yuan)<10001532.47 ± 8.449.085≤0.0011000–30005430.61 ± 12.273001–50008741.32 ± 13.87>50001641.50 ± 11.34Pathological typeCarcinoma in situ2039.55 ± 16.760.3340.717Invasive carcinoma12636.93 ± 13.52Metastatic cancer and others2636.73 ± 11.99Clinical stageI3440.12 ± 17.611.9790.119II4439.16 ± 13.75III6136.48 ± 11.29IV3332.94 ± 12.26Surgical approachRadical mastectomy5633.84 ± 12.991.7850.152Modified radical mastectomy5638.21 ± 13.87Breast conservation3339.67 ± 12.00No surgery2739.07 ± 15.76Timing of chemotherapyBefore surgery5533.89 ± 13.14−2.2050.029After surgery11738.76 ± 13.68Chemotherapy regimenCEF4939.49 ± 14.012.9450.035CET4938.49 ± 12.81TP2129.48 ± 14.45TCH5336.96 ± 13.04Chemotherapy times1–94448.16 ± 10.5623.659≤0.00110–182941.10 ± 14.1519–366232.23 ± 11.76≥373729.46 ± 10.00


## 3.3. Multiple Linear Regression Analysis of Cognitive Function in Patients with Breast Cancer Chemotherapy

The MCCB score of patients with breast cancer chemotherapy was used as the dependent variable, and the statistically significant variables in the univariate analysis were used as independent variables to perform multiple linear stepwise regression analysis (αin = 0.05, αout = 0.10). The analysis revealed that education level, chemotherapy times, and personal monthly income (see Table 5 for assignments) were risk factors for cognitive function in breast cancer chemotherapy patients (p<0.05), as shown in Table 6.Table 5
Assignment for multivariate analysis of factors.
FactorsAssignmentMonthly income1 = <1000, 2 = 1000–3000, 3 = 3001–5000, 4 = >5000Education level1 = elementary school and below, 2 = junior high school, 3 = high school, 4 = university and aboveChemotherapy times1 = 1–9, 2 = 10–18, 3 = 19–36, 4 = ≥37Table 6
Multiple linear regression analysis of cognitive function in patients with breast cancer chemotherapy (n = 172).
ModelBSEBetatp95.0% CILower limitUpper limitConstant term21.7645.3430.0164.073≤0.00111.21332.315Monthly income3.4860.9850.1983.541≤0.0011.5425.431Education level6.7180.8020.5138.378≤0.0015.1358.301Chemotherapy times−3.8610.708−0.309−5.455≤0.001−5.259−2.464Note:R2 = 0.599, adjust R2 = 0.579, F = 30.455, p<0.001. B is the regression coefficient, SE is the standard error, and 95% CI is the 95% confidence interval.


## 4. Discussion

### 4.1. Analysis of the Status Quo of Cognitive Function in Breast Cancer Patients Undergoing Chemotherapy

Tables2 and 3 of the results of this study show that the total standardized T score of MCCB for cognitive function in breast cancer patients is 10 to 63 points, and the average T score is 36.99 ± 13.06. The result is abnormal, and the cognitive function of breast cancer patients undergoing chemotherapy is impaired. It shows that the cognitive function of breast cancer patients undergoing chemotherapy is generally impaired, which is basically consistent with previous studies. Huang’s [8] study showed that 19% to 78% of breast cancer chemotherapy patients experienced varying degrees of decline in cognitive function. Most studies [9] have shown that the cognitive function of breast cancer patients undergoing chemotherapy is impaired, which has attracted the attention of clinical medical staff. In clinical practice, medical staff should pay attention to the cognitive status of patients, analyze its influencing factors, and conduct cognitive interventions for patients to improve the quality of life of patients.


### 4.2. Influencing Factors of Cognitive Function Changes in Breast Cancer Patients Undergoing Chemotherapy

#### 4.2.1. Cognitive Function Analysis of Breast Cancer Chemotherapy Patients with Different Education Levels

In this study, patients with different educational levels (F = 73.322, p<0.001), elementary school, junior high school, high school, and university degrees had standardized T scores of 25.50 ± 9.37, 29.12 ± 8.95, 47.09 ± 7.60, and 47.77 ± 12.10, respectively, indicating that the higher the educational level, the better the cognitive function. This is consistent with the results of other scholars on the cognitive function and education level of breast cancer chemotherapy patients [10]. The results of this study show that there are significant differences in cognitive function among patients with different education levels. Patients with higher education levels have better cognitive functions. The possible reason is that patients with higher educational levels can better communicate with medical staff, strive for more social support, and reduce their negative emotions. Patients with a low level of education have more conservative thinking, less communication with others, and greater psychological pressure. This requires medical staff in clinical practice to give corresponding cognitive psychological interventions according to the education level of the patients and to provide the patients with the best quality care.


#### 4.2.2. Analysis of the Relationship between Different Monthly Income and Cognitive Function

Personal monthly income (F = 9.085, p<0.001): the average standardized T-scores of cognitive function of patients from low to high personal monthly income groups were (32.47 ± 8.44), (30.61 ± 12.27), (41.32 ± 13.87), and (41.50 ± 11.34), indicating that the higher the monthly income, the better the cognitive function. At the same time, the level of education and personal monthly income are synergistically related. Generally, the higher the level of education means the higher the monthly income. Patients living in cities have better cognitive functions than those living in rural areas. The possible reason is that patients living in cities have more convenient access to disease information, can participate in more social activities, relieve their negative emotions, and further improve their cognitive function.


#### 4.2.3. Analysis of the Relationship between Chemotherapy (Timing of Chemotherapy, Chemotherapy Regimen, Chemotherapy Times) and Cognitive Function of Breast Cancer Patients

The results of this study showed that the average cognitive standardized T scores of patients undergoing preoperative and postoperative chemotherapy were 33.89 ± 13.14 and 38.76 ± 13.68, respectively, indicating that the cognitive function of patients undergoing preoperative chemotherapy was worse than that of patients undergoing postoperative chemotherapy (t = −2.205, p=0.029); patients with TP (paclitaxel, cisplatin) chemotherapy regimens have the lowest average cognitive standardized T score, and the average value is 29.48 ± 14.45, which is worse than patients with other chemotherapy regimens (t = 2.945, p=0.035). The more the chemotherapy times, the worse the cognitive function (t = 23.659, p<0.001). One scholar [11] studied the effect of three different chemotherapy regimens on the cognitive function of breast cancer patients, and the results showed that the EC-T regimen (epirubicin+cyclophosphamide sequential docetaxel) is more likely to cause cognitive impairment in patients than the FEC regimen (epirubicin, fluorouracil, cyclophosphamide) and the TC regimen (docetaxel, cyclophosphamide). Chemotherapy is the most important risk factor for cognitive dysfunction in breast cancer patients. Chemotherapy for breast cancer patients, including timing of chemotherapy, chemotherapy regimen, and chemotherapy times, will have an important impact on the cognitive function of breast cancer patients undergoing chemotherapy [12]. However, some studies [13] have shown during the 0–3 chemotherapy cycles, the patient’s cognitive ability gradually declines but some improve in cognitive ability during cycles 4–7 and above. The possible reason for the difference in results is related to the different measurement tools and sample size in this study, and future studies should be conducted with larger samples to further check the research hypothesis.


#### 4.2.4. Analysis of the Relationship between Cancer Factors (Pathological Type, Cancer Stage) and Cognitive Function

The results of this study showed that the average standardized T-score of cognitive function of patients with carcinoma in situ (39.55 ± 16.76) was higher than that of patients with invasive cancer (36.93 ± 13.52) and metastatic cancer (36.73 ± 11.99), indicating that the cognition function of patients with mild pathological types is better. According to different clinical stages, the average cognitive function T scores from high to low are stage I (40.12 ± 17.61), stage II (39.16 ± 13.75), stage III (36.48 ± 11.29), and stage IV (32.94 ± 12.26), indicating the condition of the disease was lighter, the function was better. At present, most research is carried out after patients undergoing chemotherapy or surgery. A few scholars pay attention to the cognitive function of patients before treatment. Studies abroad [14] found that patients have symptoms of cognitive decline before surgery. And the incidence rate is as high as 40%. Chemotherapy-related cognitive dysfunction has different manifestations in different patients, pathological types, and cancer stages and can appear at different stages of cancer treatment. Studies by scholars have also shown that the percentages of cognitive impairment in breast cancer patients before, during, and after chemotherapy are 40%, 75%, and 60%, respectively. Therefore, breast cancer itself can also affect the cognitive status of breast cancer patients. Clinical medical staff can take different cognitive correction nursing measures according to the patient’s different pathological types, different clinical stages, and whether they have metastasis and should take more targeted prevention and treatment of cognitive dysfunction in breast cancer patients undergoing chemotherapy.


#### 4.2.5. Analysis of the Relationship between the Treatment of Breast Cancer Patients (whether Surgery, Operation Method) and Cognitive Function

The results of this study showed that the average T-scores of breast cancer patients who underwent surgery and those who did not undergo surgery were (36.86 ± 13.27) and (39.07 ± 15.76), respectively, indicating that the cognitive function of patients who underwent surgery was worse than that of patients who did not undergo surgery. From the point of view of the standardized T-score of cognitive function, the cognitive function of patients with breast-conserving surgery (39.67 ± 12.00) or without surgery (39.07 ± 15.76) is better than that of radical mastectomy (33.84 ± 12.99) or patients with modified radical mastectomy (38.21 ± 13.87) . Reference [15] showed that the visuospatial function, visual memory, and verbal learning of patients with breast cancer chemotherapy were significantly lower than those of patients with surgery alone. At the same time, studies have shown that radiotherapy and other treatments have a superimposing effect, further aggravating the decline of cognitive function. A study by Huehnchen et al. [16] found that radiotherapy can also cause cognitive impairment in patients, and simultaneous radiotherapy and chemotherapy can cause more severe cognitive impairment. One study [17] assessed cognitive function assessment on 60 patients with early breast cancer before surgery, after surgery, before chemotherapy, and after chemotherapy and found that patients at each stage had cognitive dysfunction, indicating that surgery and chemotherapy may both cause cognitive dysfunction. The abovementioned shows that surgery can add to the psychological and physical trauma of breast cancer patients and that different surgical procedures and postoperative radiotherapy can have an impact on cognitive function. In clinical practice, medical staff must pay special attention to patients undergoing radical mastectomy and radiotherapy and, through effective communication and information support, instruct patients to face their illness correctly and avoid the psychological pressure of negative thoughts on patients, improve patients’ cognitive function and the quality of life.


## 4.1. Analysis of the Status Quo of Cognitive Function in Breast Cancer Patients Undergoing Chemotherapy

Tables2 and 3 of the results of this study show that the total standardized T score of MCCB for cognitive function in breast cancer patients is 10 to 63 points, and the average T score is 36.99 ± 13.06. The result is abnormal, and the cognitive function of breast cancer patients undergoing chemotherapy is impaired. It shows that the cognitive function of breast cancer patients undergoing chemotherapy is generally impaired, which is basically consistent with previous studies. Huang’s [8] study showed that 19% to 78% of breast cancer chemotherapy patients experienced varying degrees of decline in cognitive function. Most studies [9] have shown that the cognitive function of breast cancer patients undergoing chemotherapy is impaired, which has attracted the attention of clinical medical staff. In clinical practice, medical staff should pay attention to the cognitive status of patients, analyze its influencing factors, and conduct cognitive interventions for patients to improve the quality of life of patients.


## 4.2. Influencing Factors of Cognitive Function Changes in Breast Cancer Patients Undergoing Chemotherapy

### 4.2.1. Cognitive Function Analysis of Breast Cancer Chemotherapy Patients with Different Education Levels

In this study, patients with different educational levels (F = 73.322, p<0.001), elementary school, junior high school, high school, and university degrees had standardized T scores of 25.50 ± 9.37, 29.12 ± 8.95, 47.09 ± 7.60, and 47.77 ± 12.10, respectively, indicating that the higher the educational level, the better the cognitive function. This is consistent with the results of other scholars on the cognitive function and education level of breast cancer chemotherapy patients [10]. The results of this study show that there are significant differences in cognitive function among patients with different education levels. Patients with higher education levels have better cognitive functions. The possible reason is that patients with higher educational levels can better communicate with medical staff, strive for more social support, and reduce their negative emotions. Patients with a low level of education have more conservative thinking, less communication with others, and greater psychological pressure. This requires medical staff in clinical practice to give corresponding cognitive psychological interventions according to the education level of the patients and to provide the patients with the best quality care.


### 4.2.2. Analysis of the Relationship between Different Monthly Income and Cognitive Function

Personal monthly income (F = 9.085, p<0.001): the average standardized T-scores of cognitive function of patients from low to high personal monthly income groups were (32.47 ± 8.44), (30.61 ± 12.27), (41.32 ± 13.87), and (41.50 ± 11.34), indicating that the higher the monthly income, the better the cognitive function. At the same time, the level of education and personal monthly income are synergistically related. Generally, the higher the level of education means the higher the monthly income. Patients living in cities have better cognitive functions than those living in rural areas. The possible reason is that patients living in cities have more convenient access to disease information, can participate in more social activities, relieve their negative emotions, and further improve their cognitive function.


### 4.2.3. Analysis of the Relationship between Chemotherapy (Timing of Chemotherapy, Chemotherapy Regimen, Chemotherapy Times) and Cognitive Function of Breast Cancer Patients

The results of this study showed that the average cognitive standardized T scores of patients undergoing preoperative and postoperative chemotherapy were 33.89 ± 13.14 and 38.76 ± 13.68, respectively, indicating that the cognitive function of patients undergoing preoperative chemotherapy was worse than that of patients undergoing postoperative chemotherapy (t = −2.205, p=0.029); patients with TP (paclitaxel, cisplatin) chemotherapy regimens have the lowest average cognitive standardized T score, and the average value is 29.48 ± 14.45, which is worse than patients with other chemotherapy regimens (t = 2.945, p=0.035). The more the chemotherapy times, the worse the cognitive function (t = 23.659, p<0.001). One scholar [11] studied the effect of three different chemotherapy regimens on the cognitive function of breast cancer patients, and the results showed that the EC-T regimen (epirubicin+cyclophosphamide sequential docetaxel) is more likely to cause cognitive impairment in patients than the FEC regimen (epirubicin, fluorouracil, cyclophosphamide) and the TC regimen (docetaxel, cyclophosphamide). Chemotherapy is the most important risk factor for cognitive dysfunction in breast cancer patients. Chemotherapy for breast cancer patients, including timing of chemotherapy, chemotherapy regimen, and chemotherapy times, will have an important impact on the cognitive function of breast cancer patients undergoing chemotherapy [12]. However, some studies [13] have shown during the 0–3 chemotherapy cycles, the patient’s cognitive ability gradually declines but some improve in cognitive ability during cycles 4–7 and above. The possible reason for the difference in results is related to the different measurement tools and sample size in this study, and future studies should be conducted with larger samples to further check the research hypothesis.


### 4.2.4. Analysis of the Relationship between Cancer Factors (Pathological Type, Cancer Stage) and Cognitive Function

The results of this study showed that the average standardized T-score of cognitive function of patients with carcinoma in situ (39.55 ± 16.76) was higher than that of patients with invasive cancer (36.93 ± 13.52) and metastatic cancer (36.73 ± 11.99), indicating that the cognition function of patients with mild pathological types is better. According to different clinical stages, the average cognitive function T scores from high to low are stage I (40.12 ± 17.61), stage II (39.16 ± 13.75), stage III (36.48 ± 11.29), and stage IV (32.94 ± 12.26), indicating the condition of the disease was lighter, the function was better. At present, most research is carried out after patients undergoing chemotherapy or surgery. A few scholars pay attention to the cognitive function of patients before treatment. Studies abroad [14] found that patients have symptoms of cognitive decline before surgery. And the incidence rate is as high as 40%. Chemotherapy-related cognitive dysfunction has different manifestations in different patients, pathological types, and cancer stages and can appear at different stages of cancer treatment. Studies by scholars have also shown that the percentages of cognitive impairment in breast cancer patients before, during, and after chemotherapy are 40%, 75%, and 60%, respectively. Therefore, breast cancer itself can also affect the cognitive status of breast cancer patients. Clinical medical staff can take different cognitive correction nursing measures according to the patient’s different pathological types, different clinical stages, and whether they have metastasis and should take more targeted prevention and treatment of cognitive dysfunction in breast cancer patients undergoing chemotherapy.


### 4.2.5. Analysis of the Relationship between the Treatment of Breast Cancer Patients (whether Surgery, Operation Method) and Cognitive Function

The results of this study showed that the average T-scores of breast cancer patients who underwent surgery and those who did not undergo surgery were (36.86 ± 13.27) and (39.07 ± 15.76), respectively, indicating that the cognitive function of patients who underwent surgery was worse than that of patients who did not undergo surgery. From the point of view of the standardized T-score of cognitive function, the cognitive function of patients with breast-conserving surgery (39.67 ± 12.00) or without surgery (39.07 ± 15.76) is better than that of radical mastectomy (33.84 ± 12.99) or patients with modified radical mastectomy (38.21 ± 13.87) . Reference [15] showed that the visuospatial function, visual memory, and verbal learning of patients with breast cancer chemotherapy were significantly lower than those of patients with surgery alone. At the same time, studies have shown that radiotherapy and other treatments have a superimposing effect, further aggravating the decline of cognitive function. A study by Huehnchen et al. [16] found that radiotherapy can also cause cognitive impairment in patients, and simultaneous radiotherapy and chemotherapy can cause more severe cognitive impairment. One study [17] assessed cognitive function assessment on 60 patients with early breast cancer before surgery, after surgery, before chemotherapy, and after chemotherapy and found that patients at each stage had cognitive dysfunction, indicating that surgery and chemotherapy may both cause cognitive dysfunction. The abovementioned shows that surgery can add to the psychological and physical trauma of breast cancer patients and that different surgical procedures and postoperative radiotherapy can have an impact on cognitive function. In clinical practice, medical staff must pay special attention to patients undergoing radical mastectomy and radiotherapy and, through effective communication and information support, instruct patients to face their illness correctly and avoid the psychological pressure of negative thoughts on patients, improve patients’ cognitive function and the quality of life.


## 4.2.1. Cognitive Function Analysis of Breast Cancer Chemotherapy Patients with Different Education Levels

In this study, patients with different educational levels (F = 73.322, p<0.001), elementary school, junior high school, high school, and university degrees had standardized T scores of 25.50 ± 9.37, 29.12 ± 8.95, 47.09 ± 7.60, and 47.77 ± 12.10, respectively, indicating that the higher the educational level, the better the cognitive function. This is consistent with the results of other scholars on the cognitive function and education level of breast cancer chemotherapy patients [10]. The results of this study show that there are significant differences in cognitive function among patients with different education levels. Patients with higher education levels have better cognitive functions. The possible reason is that patients with higher educational levels can better communicate with medical staff, strive for more social support, and reduce their negative emotions. Patients with a low level of education have more conservative thinking, less communication with others, and greater psychological pressure. This requires medical staff in clinical practice to give corresponding cognitive psychological interventions according to the education level of the patients and to provide the patients with the best quality care.


## 4.2.2. Analysis of the Relationship between Different Monthly Income and Cognitive Function

Personal monthly income (F = 9.085, p<0.001): the average standardized T-scores of cognitive function of patients from low to high personal monthly income groups were (32.47 ± 8.44), (30.61 ± 12.27), (41.32 ± 13.87), and (41.50 ± 11.34), indicating that the higher the monthly income, the better the cognitive function. At the same time, the level of education and personal monthly income are synergistically related. Generally, the higher the level of education means the higher the monthly income. Patients living in cities have better cognitive functions than those living in rural areas. The possible reason is that patients living in cities have more convenient access to disease information, can participate in more social activities, relieve their negative emotions, and further improve their cognitive function.


## 4.2.3. Analysis of the Relationship between Chemotherapy (Timing of Chemotherapy, Chemotherapy Regimen, Chemotherapy Times) and Cognitive Function of Breast Cancer Patients

The results of this study showed that the average cognitive standardized T scores of patients undergoing preoperative and postoperative chemotherapy were 33.89 ± 13.14 and 38.76 ± 13.68, respectively, indicating that the cognitive function of patients undergoing preoperative chemotherapy was worse than that of patients undergoing postoperative chemotherapy (t = −2.205, p=0.029); patients with TP (paclitaxel, cisplatin) chemotherapy regimens have the lowest average cognitive standardized T score, and the average value is 29.48 ± 14.45, which is worse than patients with other chemotherapy regimens (t = 2.945, p=0.035). The more the chemotherapy times, the worse the cognitive function (t = 23.659, p<0.001). One scholar [11] studied the effect of three different chemotherapy regimens on the cognitive function of breast cancer patients, and the results showed that the EC-T regimen (epirubicin+cyclophosphamide sequential docetaxel) is more likely to cause cognitive impairment in patients than the FEC regimen (epirubicin, fluorouracil, cyclophosphamide) and the TC regimen (docetaxel, cyclophosphamide). Chemotherapy is the most important risk factor for cognitive dysfunction in breast cancer patients. Chemotherapy for breast cancer patients, including timing of chemotherapy, chemotherapy regimen, and chemotherapy times, will have an important impact on the cognitive function of breast cancer patients undergoing chemotherapy [12]. However, some studies [13] have shown during the 0–3 chemotherapy cycles, the patient’s cognitive ability gradually declines but some improve in cognitive ability during cycles 4–7 and above. The possible reason for the difference in results is related to the different measurement tools and sample size in this study, and future studies should be conducted with larger samples to further check the research hypothesis.


## 4.2.4. Analysis of the Relationship between Cancer Factors (Pathological Type, Cancer Stage) and Cognitive Function

The results of this study showed that the average standardized T-score of cognitive function of patients with carcinoma in situ (39.55 ± 16.76) was higher than that of patients with invasive cancer (36.93 ± 13.52) and metastatic cancer (36.73 ± 11.99), indicating that the cognition function of patients with mild pathological types is better. According to different clinical stages, the average cognitive function T scores from high to low are stage I (40.12 ± 17.61), stage II (39.16 ± 13.75), stage III (36.48 ± 11.29), and stage IV (32.94 ± 12.26), indicating the condition of the disease was lighter, the function was better. At present, most research is carried out after patients undergoing chemotherapy or surgery. A few scholars pay attention to the cognitive function of patients before treatment. Studies abroad [14] found that patients have symptoms of cognitive decline before surgery. And the incidence rate is as high as 40%. Chemotherapy-related cognitive dysfunction has different manifestations in different patients, pathological types, and cancer stages and can appear at different stages of cancer treatment. Studies by scholars have also shown that the percentages of cognitive impairment in breast cancer patients before, during, and after chemotherapy are 40%, 75%, and 60%, respectively. Therefore, breast cancer itself can also affect the cognitive status of breast cancer patients. Clinical medical staff can take different cognitive correction nursing measures according to the patient’s different pathological types, different clinical stages, and whether they have metastasis and should take more targeted prevention and treatment of cognitive dysfunction in breast cancer patients undergoing chemotherapy.


## 4.2.5. Analysis of the Relationship between the Treatment of Breast Cancer Patients (whether Surgery, Operation Method) and Cognitive Function

The results of this study showed that the average T-scores of breast cancer patients who underwent surgery and those who did not undergo surgery were (36.86 ± 13.27) and (39.07 ± 15.76), respectively, indicating that the cognitive function of patients who underwent surgery was worse than that of patients who did not undergo surgery. From the point of view of the standardized T-score of cognitive function, the cognitive function of patients with breast-conserving surgery (39.67 ± 12.00) or without surgery (39.07 ± 15.76) is better than that of radical mastectomy (33.84 ± 12.99) or patients with modified radical mastectomy (38.21 ± 13.87) . Reference [15] showed that the visuospatial function, visual memory, and verbal learning of patients with breast cancer chemotherapy were significantly lower than those of patients with surgery alone. At the same time, studies have shown that radiotherapy and other treatments have a superimposing effect, further aggravating the decline of cognitive function. A study by Huehnchen et al. [16] found that radiotherapy can also cause cognitive impairment in patients, and simultaneous radiotherapy and chemotherapy can cause more severe cognitive impairment. One study [17] assessed cognitive function assessment on 60 patients with early breast cancer before surgery, after surgery, before chemotherapy, and after chemotherapy and found that patients at each stage had cognitive dysfunction, indicating that surgery and chemotherapy may both cause cognitive dysfunction. The abovementioned shows that surgery can add to the psychological and physical trauma of breast cancer patients and that different surgical procedures and postoperative radiotherapy can have an impact on cognitive function. In clinical practice, medical staff must pay special attention to patients undergoing radical mastectomy and radiotherapy and, through effective communication and information support, instruct patients to face their illness correctly and avoid the psychological pressure of negative thoughts on patients, improve patients’ cognitive function and the quality of life.


## 5. Summary

So far, no drugs are clear and effective for the recovery of cognitive function after chemotherapy. And because of the side effects of neurostimulant drugs, the current research focuses more on cognitive behavioral psychotherapy and other new therapies such as traditional Chinese medicine. Cognitive behavior therapy uses cognitive and behavioral methods to change patients’ inappropriate cognition and correct patients’ unhealthy behaviors [18]. Chen Xiaomin [19] showed that computer virtual rehabilitation training can improve CRCI, by simulating real game scenes with high interaction with patients, providing personalized treatment plans for different patients to help them improve their cognitive functions. This is consistent with the view of Chai Lijun [20]. Studies have shown that traditional Chinese medicine intervention, reconciliation of qi and blood, and nourishing heart and acupuncture can effectively alleviate and improve the cognitive dysfunction of breast cancer patients after chemotherapy [21, 22]. The research of Tong Taishan [23] also supported this view and further pointed out that acupuncture therapy is mainly manifested in the recovery of patients’ subjective cognition, memory, and visual space ability. In addition, high- and low-frequency conversion music therapy and physical exercise can effectively improve the cognitive function of patients with breast cancer chemotherapy and improve the quality of life of patients [24, 25]. In breast cancer chemotherapy patients, with the increase in the number of chemotherapy and the prolongation of the chemotherapy cycle, the cognitive function of the patients is impaired in varying degrees. Clinical medical staff should communicate with patients more, so that patients have a comprehensive understanding of disease-related knowledge, reduce patients’ psychological pressure, increase confidence in overcoming the disease, and ultimately promote patients’ physical and mental health and improve their quality of life. In the process of CRCI treatment for breast cancer patients, more attention is paid to nondrug treatment, cognitive behavioral psychotherapy, and psychological care and rehabilitation training of patients are paid attention to. Pay attention to the integration of Chinese and Western medicine, give full play to the unique advantages of our country’s traditional Chinese medicine industry in the health industry, and strengthen international cooperation in multi-center national and global cooperative researches.



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*Source: 7278853-2021-10-28.xml*