The Prognostic And Predictive Value Of The 8th American Joint Committee On Cancer (Ajcc) Staging System Among Early Breast Cancer Patients Aged <50 Years

Background:This study respectively analyzed the prognostic value and the role in treatment decision-making [breast-conserving surgery (BCS) + radiotherapy (RT) or mastectomy (MAST)] of the 8th American Joint Committee on Cancer (AJCC) pathological prognostic staging system compared with the 7th AJCC anatomical staging system among early breast cancer patients aged <50 years.Methods: Patients with T1-2N0M0 breast cancer aged <50 years were extracted from the Surveillance, Epidemiology, and End Results database between 2010 and 2014. Breast cancer-specific survival (BCSS) was used as the primary endpoint. Chi-squared test, receiver operating characteristics analysis, Kaplan-Meier method, and multivariate Cox proportional models were used to conduct statistical analysis.Results: A total of 22,640 female patients were identified, and 24.4% of them reallocated to new stage groups from the 7th to the 8th AJCC staging. Among them, 46.2% (n=10,450) and 53.8% (n=12,190) of patients received BCS + RT and MAST, respectively. The 8th AJCC staging system was an independent prognostic factor for BCSS. Patients treated with BCS + RT had better BCSS compared to those treated with MAST (P<0.001). According to the 8th AJCC staging, BCS + RT could improve 5-year BCSS compared with MAST in patients with stage IA (P=0.006) and stage IB (P=0.001) diseases, while comparable BCSS was found between the two treatment arms in patients' stage IIA disease (P=0.366). Multivariate analyses replicated similar findings after stratification by the 8th AJCC stages.Conclusions: In patients with T1-2N0 breast cancer and aged <50 years, the 8th AJCC pathological staging system provides accurate prognostic information than the 7th anatomical staging. BCS + RT is the optimal local management for stage IA and IB diseases, while it is the optional management in stage IIA disease according to the 8th AJCC staging.