Validation of new AJCC staging system for breast cancer

Abstract

Purpose: The aim of this study is to verify the feasibility of the 5th, 6th, and 7th editions of AJCC staging system by analyzing the 10-year overall survival (OS) and disease-free survival (DFS) of breast cancer patients according to the each editions of American Joint Committee on Cancer (AJCC) staging system that staged by 5th and 6th editions of AJCC staging system. Methods: A total of 419 breast cancer patients were analyzed who had received initial treatment between 1998 and 2003 at Pusan National University Hospital. Patients were restaged using 5th, 6th, and 7th editions of AJCC staging system with retrospective data and 10-year OS and DFS analysis were performed. Results: The mean age of patients was 51 years old and the mean follow-up period was 138 months. Ten-year OS was 89.9% and DFS was 88.3%. Ten-year DFS was affected significantly by the tumor size, lymph node metastasis, differentiation of tumor, lymphovascular invasion, HER2 gene and triple negative breast cancer. The stage of breast cancer according to the 5th, 6th, and 7th edition of AJCC staging system and the each T and N stage of breast cancer was statistically significant in 10-year OS and DFS. Although the significance was confirmed between 10-year DFS in each edition, higher significance were found in more recent edition. Conclusion: Restaging and predict prognosis based on 7th edition of AJCC staging system would be helpful to patients who had been previously staged based on 5th or 6th system. Keywords: Breast neoplasm, Stage, Survival rate