Validation of the CPS+EG and Neo-Bioscore staging systems after preoperative systemic therapy for breast cancer in a single center in China.

BACKGROUND: Prognostic assessment after preoperative systemic therapy (PST) plays a vital role in determining treatment in breast cancer patients. Many researchers have sought to develop a system to quantitate residual tumor and its correlation with prognosis after PST. This retrospective study validated the CPS + EG staging system and Neo-Bioscore in a single center in China.

METHODS: Data from patients with non-metastatic primary breast cancer who were treated with PST and surgery from Jan. 2008 to Dec. 2014 at the Breast Disease Center of Peking University First Hospital, China, were reviewed. DFS, DSS and OS were calculated using the K-M curve and AUC. Multivariate analysis was used for a Cox proportional hazards model. All calculations were performed with SAS 9.4.

RESULTS: A total of 403 patients were enrolled in this study. The median follow-up period was 45 (range 11-107) months. The five-year DFS, DSS and OS rates were 86.4%, 91.2% and 90.5%, respectively. The CS, PS, CPS + EG staging system and Neo-Bioscore stratified patients according to DFS, DSS, and OS after PST, with all P values < 0.0001. The CPS + EG staging system and Neo-Bioscore stratified prognosis after PST better than CS. HER2-positive patients without trastuzumab treatment had obviously worse DFS and OS than other subgroups with different HER2 statuses that scored a 3 in the Neo-Bioscore system.

CONCLUSIONS: The CPS + EG staging system and Neo-Bioscore can improve prognostic prediction in non-pCR breast cancer patients after PST and, provided unfavorable prognostic factors such as insufficient treatment are incorporated, will have broader clinical applicability.