Pathological Predictors of Residual Cancer Burden Following Neoadjuvant Chemotherapy in Breast Cancer

Background: Neoadjuvant chemotherapy (NAC) has become standard treatment for locally advanced breast cancer.The residual cancer burden (RCB) system provides standardized quantification of residual disease with established prognostic value.However, relationships between pre-treatment characteristics and post-treatment RCB outcomes remain incompletely characterized.Objective: To comprehensively evaluate associations between pre-treatment pathological characteristics (pre-treatment stage, Nottingham grade) and post-treatment outcomes (RCB class and score, post-therapy grade) and to assess prognostic significance of additional pathological features including tumor necrosis, lymphovascular invasion (LVI), perineural invasion (PNI), and in situ carcinoma and neoplasm focality.Methods: This retrospective cohort study included 180 breast cancer patients who received NAC followed by definitive surgery.Pre-treatment assessment included pathological T (pT) stage and Nottingham histological grade from core biopsies.Post-treatment evaluation included RCB classification (RCB-0 through RCB-III), RCB continuous score, post-therapy grade and assessment of necrosis, LVI, PNI, tumoral necrosis and uni/multifocal disease.Results: Pre-treatment tumor characteristics and post-treatment pathological features provide complementary prognostic information.RCB classification effectively stratifies patients, with additional refinement through LVI, PNI, necrosis and focality assessment.Conclusions: Integration of multiple pathological parameters enhances risk stratification and may guide personalized adjuvant treatment decisions.