Journal of Clinical & Experimental Pathology
Open Access

Abstract

Introduction: The significance of complete pathological response (pCR) as a prognostic factor in breast cancer patients undergoing neoadjuvant chemotherapy was established by the NSABP-B27 study. Subsequently, the Residual Cancer Burden (RCB) score was developed to assess the impact of incremental pathological response improvements beyond pCR on patient outcomes. In this study, we present an external validation of the RCB score in a diverse Brazilian population. Objectives: This study aims to investigate the correlation between the Residual Cancer Burden (RCB) index and both overall survival (OS) and disease-free survival (DFS) in women who underwent neoadjuvant chemotherapy at the Cancer Institute of the State of S�£o Paulo. Methods: We conducted a retrospective analysis of medical records from breast cancer patients who received neoadjuvant chemotherapy and breast surgery between 2011 and December 2017. Variables examined included age, clinical and pathological staging, molecular subtype, recurrence/metastasis count, mortality count, as well as the value and classification of the residual cancer burden index. We employed Kaplan-Meier and Log-rank statistical methods to assess the association between RCB and OS/DFS. A regression model was applied to determine the independent relationship between RCB and outcomes, while accounting for confounding factors. Results: The analysis comprised 347 patients, with a mean age of 49.39 years. Initial clinical staging revealed that 57.9% of patients had T3 stage, and 43.8% exhibited N1 axillary status. Survival analysis indicated a statistically significant favorable prognosis in the RCB 0 subgroup (pCR) compared to RCB 1, 2, and 3 subgroups (Log-rank p = 0.01). In a multivariate analysis, the RCB classification emerged as the sole factor significantly correlated with disease-free survival: RCB-1 (HR 6.9, CI 1.9 - 25.4, p = 0.004), RCB-2 (HR 4.2, CI 1.6 â�� 10.8, p = 0.03), and RCB-3 (HR 7.6, CI 2.76 â�� 20.8, p = 0.00). Conclusion: This study establishes a robust and meaningful relationship between the RCB index and the risk of relapse and mortality. The findings reinforce the utility of the RCB score as a valuable predictive tool for assessing patient outcomes following neoadjuvant chemotherapy in breast cancer patients, even within the diverse Brazilian population.

Biography

Breast Specialist Doctor at ICESP/FMUSP, graduated in Medicine from the State University of Campinas (2005) and completed Medical Residency Programs at UNICAMP in the specialties of Gynecology and Obstetrics in 2009 and Mastology in 2011.