Factors Affecting Survival Prognosis of Patients with Rectal Cancer After Neoadjuvant Chemoradiotherapy
Authors: Li Baokun , Han Jiachao , Wang Feifei , Yu Bin , Wang Guiying , Yang Fei 
Published: October 2023

Objective: To identify potential factors influencing the survival prognosis of locally advanced rectal cancer patients receiving neoadjuvant chemoradiotherapy.
Methods: A retrospective study was conducted to collect data from January 2009 to December 2020 on 270 patients with locally advanced rectal cancer who were admitted to the Fourth Hospital of Hebei Medical University. The study included patients who met the inclusion and exclusion criteria. The clinical data of patients before and after neoadjuvant chemoradiotherapy and postoperative treatment were compiled. This included information such as gender, age, comorbidities, family history, smoking and alcohol history, tumor distance from the anal verge, tumor size, tumor invasion of the bowel wall, cT stage, cN stage, pre-treatment white blood cell count, neutrophil count, lymphocyte count, platelet count, albumin level, NLR, SII, PLR, PNI, CEA, CA19-9, CA72-4, tumor regression grade, KRAS gene mutation status, BRAF gene mutation status, and mismatch repair protein expression. The endpoints of the study were disease-free survival and overall survival of the patients. Statistical analysis methods were used to identify factors that influence the patients' survival prognosis.
Results:
1 Different patients showed diverse survival prognoses. Among the patients, 172 (63.7%) were male, 203 (75.2%) were below 65 years of age, 111 (41.1%) had underlying diseases, 105 (38.9%) were smokers, 89 (33.0%) were drinkers, 18 (6.7%) had a family history of cancer, 184 (68.1%) had CEA > 5ng/mL, 126 (46.7%) had CA19-9 > 30U/mL, and 122 (45.2%) had CA72-4 >7U/mL. The average white blood cell count was 6.12 (×109/L), and 165 (61.1%) had a count greater than 6.12. The average neutrophil count was 4.11 (×109/L), and 166 (61.5%) had a count greater than 4.11. The average lymphocyte count was 1.50 (×109/L), and 164 (60.7%) had a count greater than 1.50. The platelet count was normal in 142 patients (52.6%), and albumin level was normal in 199 patients (73.7%). The median NLR value was 2.64, the median PLR was 61.46, the median SII was 683.16, and the median PNI was 49.23. Patients were divided into two groups based on the median values. A total of 210 patients (77.8%) had a tumor distance from the anal margin greater than 5cm, 157 patients (58.1%) had a tumor length greater than 5cm, and 218 patients (80.7%) had tumor invasion of the bowel wall greater than 50%. The cT stage was T1-T2 in 16 cases (5.9%), T3 in 170 cases (63.0%), and T4 in 84 cases (31.1%). The cN stage was N0 in 15 cases (5.6%) and N+ in 255 cases (94.4%). The tumor regression grade was 0 in 34 cases (12.6%), 1-2 in 151 cases (55.9%), and 3 in 85 cases (31.5%). Nineteen cases (7%) had KRAS gene mutations, 5 cases (1.9%) had BRAF gene mutations, and 20 cases (7.4%) had mismatch repair protein deficiency.
2 Results of the univariate analysis showed that factors associated with good prognosis in neoadjuvant chemotherapy patients included age <65 years, CEA value ≤5ng/mL, lymphocyte count >1.5×109/L, normal albumin level, NLR ≤2.64, SII ≤683.16, PNI >49.23, tumor distance from the anal margin >5cm, tumor length ≤5cm, tumor invasion of the bowel wall ratio ≤50%, lower T stage and N stage, good tumor regression response, absence of KRAS gene mutation, and mismatch repair protein deficiency. Patient gender, presence of underlying diseases, smoking and alcohol history, family history of cancer, white blood cell count, neutrophil count, platelet count, CA19-9, CA72-4, PLR, and BRAF status showed no significant correlation with prognosis.
3 Results of the multivariate analysis showed that age (HR=0.385, P=0.007), NLR (HR=0.294, P=0.011), cT stage (HR=0.287, P<0.001), and tumor regression grade (HR=0.273, P<0.001) were significant factors influencing DFS in patients receiving neoadjuvant chemoradiotherapy. For OS, age (HR=0.497, P=0.035), cT stage (HR=0.387, P=0.001), and tumor regression grade (HR=0.307, P<0.001) were significant factors influencing OS in patients receiving neoadjuvant chemoradiotherapy.
Conclusion: Age, cT stage, NLR, and tumor regression grade are significant factors influencing DFS and OS in patients with locally advanced rectal cancer. Younger age, lower cT stage, lower NLR value, and lower tumor regression grade are associated with better survival prognosis.