In-Depth Evaluation of the AJCC 2010 Staging System for Luminal-like Breast Cancer-An Analysis from a Free-Standing Cancer Hospital
摘要
Purpose: Hormonal receptor (HR) positive breast cancer biologically differs from human epidermal growth factor receptor-2 (HER2) positive disease. The purpose of this study was to re-visit the current AJCC staging system in luminal-like (HR positive and HER2 negative) breast cancer.Materials and Methods: A total of 2051 breast cancer patients treated between 1990 and 2008 were included in this study who met the following criteria: 1) surgery as first treatment; 2) pathology stage I-III; 3) HR positive; and 4) HER2 negative. The T- and N-stage were each re-visited to examine their correlation with 5-year breast cancer-related survival (BCRS).Results: According to the AJCC 2010 staging system, the stage I patients showed a 5-year BCRS of 98.9%; stage IIA: 95.8%; stage IIB: 94.0%; stage IIIA: 90.4%, and stage IIIC: 75.8% (p＜0.001). Re-visiting the T-classification, the 5-year BCRS in T ≤ 0.5 cm N0 patients was same as that of T 1.1-1.5 cm N0 patients (98.4% versus 99.2%); the 5-year BCRS in T1.6-2 cm N1 and N2 patients were no better than those of T ＞2 cm N1 and N2 patients (91.2% and 86.5% versus 94.1% and 88.8%). For the nodal stage, the 5-year BCRS were 91-98.0% for node-negative to 5-node positive patients; the 5-year BCRS were around 80-90% for nodal positivity of 6 to 12, and then dropped below 80% for patients with more than 12 involved nodes.Conclusions: The AJCC 2010 staging system overestimated the risk of breast cancer-related death in early stage luminal-like breast cancer in our hospital. Tumor size 1.5 cm is a crucial point to determine extensive nodal involvement and long-term survivals. Patients with 1-5 positive lymph nodes still had a 5-year BCRS rate exceeding 90%. Given our results, a modification for the current staging system is warranted if other hospitals, especially in Taiwan and Asia, have observed similar outcomes.