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

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.

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.

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.

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.

Integration of multiple pathological parameters enhances risk stratification and may guide personalized adjuvant treatment decisions.