Prognostic Value of the CPS-EG Score in Locally Advanced Triple-Negative Breast Cancer: A Multicenter Retrospective Cohort Study

Abstract Triple-negative breast cancer (TNBC) is an aggressive subtype with limited treatment options and poor prognosis. Effective prognostic tools are essential to guide risk-adapted strategies following neoadjuvant chemotherapy (NACT). In this multicenter retrospective study, we evaluated 690 patients with locally advanced TNBC treated between 2010 and 2023 across 25 oncology centers. Patients were stratified into CPS-EG risk groups: low (0–1), intermediate (2–3), and high (≥4). The CPS-EG score was strongly associated with pathological complete response (pCR), recurrence, disease-free survival (DFS), and overall survival (OS). Five-year DFS rates were 80.6%, 53.2%, and 31.5% in the low-, intermediate-, and high-risk groups, respectively, while OS rates were 76.7%, 53.2%, and 48.8% (p<0.001). Multivariate analysis confirmed CPS-EG as an independent predictor of both DFS and OS after adjusting for clinicopathological factors. These findings highlight the CPS-EG score as a simple, cost-effective, and widely applicable prognostic tool that may improve post-NACT risk stratification and support treatment decisions, especially in resource-limited oncology settings.