Abstract P3-10-17: Predictors of overall survival and disease-free survival for women diagnosed with invasive breast cancer: A large single-center study
Authors: Singh M , Konduri SD , Bobustuc GC , Rovin RA 
Published: February 2018

Background/Objective: Biomarkers such as estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor 2 (HER2neu) are associated with the survival and recurrence of invasive breast cancer (IBC). Presence of these markers often helps to dictate treatment plans. The purpose of this study is to identify the predictors of overall survival (OS) and disease-free survival (DFS) for women diagnosed with IBC. In this study, we compared OS and DSF in the following five categories based on biomarker expression: triple-negative (TN), triple-positive (TP), HER2neu-positive, Luminal A (LA) and Luminal B (LB).

Method: We retrospectively examined 6,231 records of women diagnosed with IBC from 2006 through 2015 within the Aurora Health Care system. The majority of the women were white (90.8%) and non-Hispanic (97.4%). The women in this study were categorized in the age groups: 20-39 (4.9%), 40-59 (42.8%), 50-69 (40.7%) and 70+ years (11.6%). We used descriptive statistics for all category and numeric variables. Kaplan-Meier curve was used to compare OS and DFS in the five categories. Cox proportional hazards regression was used to identify the significant predictors of OS and DFS. We used alpha of 0.05 for all statistical tests and all statistical analysis was done using SAS 9.4.

Results: OS was 86.39% and the DFS rate was 84.43%. In multivariate analysis significant predictors of OS included age (HR=1.94 for 60-69 vs 20-39 p=0.001 and HR=5.3 for 70+ vs 20-39 p&lt; 0.001), race (HR=0.57, p=0.043 for white vs other), ethnicity (HR=0.34, p=0.032), HER2neu expression (HR=0.58, p &lt;0.001), size of the tumor (HR=1.001 p=0.011), grade differentiation (HR=0.62 p &lt; 0.001) and cancer stages (HR of 1.17, 4.8, 15.2 for II, III and IV vs I, p &lt;0.001). Furthermore treatments such as surgery (HR=0.64, p&lt; 0.001), radiation (HR=0.64, p &lt;0.001), chemotherapy (HR=0.63, p &lt;0.001) and hormonal therapy (HR=0.48, p &lt;0.001) showed significantly improved OS in the patients. Similarly significant predictors of DFS included, age (HR=1.8, p &lt;0.001 for 70+ vs 20-39); PR (HR=0.70, p=0.003), HER2neu (HR=0.60, p &lt;0.001) tumor size (HR=1.001, p=0.002), cancer stage (HR=2.7, 9.2, 25.5 for II, III, IV vs I, p&lt;0.001); differentiation of the tumor (HR=0.75, p=0.002, moderate differentiation; well differentiated, HR=0.50, p &lt;0.001). Moreover, the treatments such as surgery (HR=0.42, p &lt;001) radiation, chemotherapy and hormonal therapy (HR=0.58, 0.62, 0.51 p &lt;0.001) significantly increased DFS. Furthermore OS was better for women diagnosed with TP, LA, HER2, LB types compared to women with TN (p&lt;0.001). Similarly the probability for DFS was higher for TP also was higher compared to the probabilities all the other categories (LA, LB, HER2 and TN p &lt;0.05). LA had better DFS then LB, HER2 and TN. LB and HER2 had better DFS than TN (p&lt;0.05).

Conclusion: This large study suggests that treatment based on biomarker expression (ER, PR and HER2/Neu) has improved OS and DFS for women with IBC. Increase in tumor size, cancer stage and poor differentiation of the tumor had adverse effect on both OS and DFS. Treatment modalities such as surgery, radiation, chemotherapy and hormonal therapies significantly improved both OS and DFS.

Citation Format: Singh M, Konduri SD, Bobustuc GC, Rovin RA. Predictors of overall survival and disease-free survival for women diagnosed with invasive breast cancer: A large single-center study [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P3-10-17.