Validation of CPS+EG Staging System in a Cohort of Eastern Indian Breast Cancer Patients

Neoadjuvant chemotherapy (NACT) has become standard for locally advanced breast cancer (LABC), offering opportunities for tailored treatment and improved survival. However, current staging systems fail to incorporate treatment response into prognosis. The CPS+EG staging system presents a novel approach, integrating clinical and pathological stages with ER status and nuclear grade. While validated in Western cohorts, its applicability in Indian patients remains unexplored. This study aimed to validate CPS+EG in an Eastern Indian cohort (n=208) treated with NACT. A retrospective analysis of data from 2016 to 2023 was done. The CPS+EG scores for all the eligible patients were calculated. Clinicopathologic characteristics and patient outcomes were assessed. The discrimination of CPS+EG and CS was assessed using the area under the curve (AUC) for survival data, calculated using Receiver operating time (ROC) curves. CPS+EG effectively stratified patients, with higher scores correlating with poorer outcomes. Median follow-up was 24 months, with 22.1% recurrence and 16.3% mortality. Five-year overall survival (OS) was 67%, and disease-free survival (DFS) 39.3%. The 5-year DFS for CPS+EG scores 1-5 was 50%, 75%, 58.3%, 44.3%, and 37.9%, respectively. None of the patients with a score of 6 survived for 5 years. CPS+EG outperformed CS alone, with AUCs of 0.75 (OS) and 0.73 (DFS) versus 0.57 and 0.58, respectively. This study fills a literature gap by validating CPS+EG in Eastern Indian patients, highlighting its utility in the prognostication of post-NACT patients. CPS+EG offers a simple yet effective, promising tool for personalized prognosis, warranting further investigation and clinical integration.