A retrospective prognostic evaluation analysis using the 8th edition of the American Joint Committee on Cancer staging system for breast cancer

PURPOSE: Breast cancer is a group of diseases with different intrinsic molecular subtypes. However, anatomic staging alone is insufficient to determine prognosis. The present study analyzed the prognostic value of the American Joint Committee for Cancer (AJCC) 8th edition cancer staging system. METHODS: This retrospective, single-center study included breast cancer cases diagnosed from January 1999 to December 2008. We restaged patients based on the 8th edition AJCC cancer staging system and analyzed the prognostic value of the anatomic and prognostic staged groups. Follow-up data including disease-free survival (DFS), overall survival (OS), and clinic-pathological data were collected to analyze the differences between the two staging subgroups. RESULTS: The study enrolled 7458 breast cancer patients with a 98.7-month median follow-up. Both the 5-year DFS and OS were significantly different between the anatomic and prognostic staged groups. The 5-year OS according to disease subtype was as follows: hormone receptor-positive/human epidermal growth factor receptor 2-negative [HR(+)/HER2(−)], 90.9%; HR(+)/HER2(+), 84.7%; HR(−)/HER2(+), 81.1%; and HR(−)/HER2(−), 80.9%. According to the anatomic stage, the 5-year OS of patients with stage III HR(+)/HER2(−) disease was superior to that of patients with stage II HR(−)/HER2(−) disease (88.3 vs. 86.5%). Per the prognostic stage, both the 5-year DFS and OS rates of patients with stage II HR(−)/HER2(−) disease were higher than those of patients with stage III HR(+)/HER2(−) disease (90.1 and 94.3% vs. 79.1 and 88.9%). CONCLUSIONS: The prognostic staging system is a refined version of the anatomic staging system and encourages a more personalized approach to breast cancer treatment.