Comparative Prognostic Utility of CPS+EG, Neo-Bioscore, and Conventional Staging Systems in Breast Cancer Patients Without Pathological Complete Response to Neoadjuvant Chemotherapy.

BACKGROUND

Breast cancer patients with non-pathologic complete response (non-pCR) after neoadjuvant chemotherapy (NAC) exhibit heterogeneous outcomes. While the CPS+EG and Neo-Bioscore staging systems integrate clinical, pathological, and biologic factors to improve post-NAC prognostication, their utility in the non-pCR cohort warrants further evaluation. This study aimed to compare their prognostic performance with traditional clinical (CS) and pathologic stage (PS).

MATERIALS AND

METHODS

This retrospective single-center study included 784 non-pCR breast cancer patients after NAC. Prognostic discrimination of CS, PS, CPS+EG, and Neo-Bioscore for DFS and OS was assessed by Kaplan-Meier analysis and concordance index (C-index). Subgroup analyses were performed by molecular subtype. An exploratory comparison with Residual Cancer Burden (RCB) was conducted in a subset of 167 patients with available RCB scores.

RESULTS

In the overall cohort, both CPS+EG and Neo-Bioscore provided superior prognostic stratification for DFS and OS compared to CS or PS alone (all C-index comparisons P < .001 vs. CS). Their performance was subtype-dependent. In HR-positive/HER2-negative and HER2-positive subtypes, CPS+EG and Neo-Bioscore showed significantly better prognostic value. However, in triple-negative breast cancer, neither composite score offered significant stratification, where PS emerged as the most robust predictor. In the RCB-available subset, RCB did not significantly stratify DFS or OS, whereas both CPS+EG and Neo-Bioscore showed significant associations with DFS.

CONCLUSIONS

The CPS+EG and Neo-Bioscore systems offer refined prognostic stratification for non-pCR patients, outperforming conventional staging systems in most subtypes. These readily available tools provide a practical framework for risk-adapted adjuvant therapy planning in the postneoadjuvant setting, though further prospective validation is warranted.