Comparison of the performance of four staging systems in determining the prognosis of breast cancer among women undergoing neoadjuvant chemotherapy.

Objective: Different tumor-related factors have been proposed to assess the risk of disease progression and death in women undergoing neoadjuvant breast cancer chemotherapy. Recently, besides the classical pre-treatment clinical stage (CS) and post-treatment pathologic stage (PS), estrogen receptor status and histologic grade (CPS + EG score) and HER2 results (Neo-Bioscore) have also been added to this suite of staging systems, generating new scores. The present study aims to compare the performance of these four staging systems, namely CS, PS, CPS + EG and Neo-Bioscore, in the prognosis of breast cancer in women undergoing neoadjuvant chemotherapy.

Methods: This study comprises a retrospective cohort study of female breast cancer patients diagnosed at the Brazilian National Cancer Institute, Brazil from January 2013 to December 2015. A descriptive analysis of patient characteristics was conducted, and Kaplan-Meier curves, a Cox proportional hazard analysis and Receiver Operating Characteristic (ROC) curves were developed according to the assessed staging system scores.

Results: A total of 803 patients were eligible for this study. Most were under 65 years old (88.0%), presented advanced tumors (clinical stage ≥ IIB 77.1%), with positive estrogen receptor (71.2%) and negative HER2 (75.7%) results. During the follow-up, 172 patients (21.4%) evolved to death. A statistical difference (p < 0.001) was observed between 5 year disease-free survival and 5 year overall survival rates according to the PS, CPS + EG and Neo-Bioscore staging systems.

Conclusions: The PS, CPS + EG and Neo-Bioscore staging systems were proven to be equivalent to predict the prognosis of patients undergoing neoadjuvant chemotherapy.