Clinicopathologic features, patterns of recurrence, and survival among women with triple‐negative breast cancer in the National Comprehensive Cancer Network

Abstract

The objective of this study was to describe clinicopathologic features, patterns of recurrence, and survival according to breast cancer subtype with a focus on triple-negative tumors. In total, 15,204 women were evaluated who presented to National Comprehensive Cancer Network centers with stage I through III breast cancer between January 2000 and December 2006. Tumors were classified as positive for estrogen receptor (ER) and/or progesterone receptor (PR) (hormone receptor [HR]-positive) and negative for human epidermal growth factor receptor 2 (HER2); positive for HER2 and any ER or PR status (HER2-positive); or negative for ER, PR, and HER2 (triple-negative). Subtype distribution was triple-negative in 17% of women (n = 2569), HER2-positive in 17% of women (n = 2602), and HR-positive/HER2-negative in 66% of women (n = 10,033). The triple-negative subtype was more frequent in African Americans compared with Caucasians (adjusted odds ratio, 1.98; P < .0001). Premenopausal women, but not postmenopausal women, with high body mass index had an increased likelihood of having the triple-negative subtype (P = .02). Women with triple-negative cancers were less likely to present on the basis of an abnormal screening mammogram (29% vs 48%; P < .0001) and were more likely to present with higher tumor classification, but they were less likely to have lymph node involvement. Relative to HR-positive/HER2-negative tumors, triple-negative tumors were associated with a greater risk of brain or lung metastases; and women with triple-negative tumors had worse breast cancer-specific and overall survival, even after adjusting for age, disease stage, race, tumor grade, and receipt of adjuvant chemotherapy (overall survival: adjusted hazard ratio, 2.72; 95% confidence interval, 2.39-3.10; P < .0001). The difference in the risk of death by subtype was most dramatic within the first 2 years after diagnosis (overall survival for 0-2 years: OR, 6.10; 95% confidence interval, 4.81-7.74). Triple-negative tumors were associated with unique risk factors and worse outcomes compared with HR-positive/HER2-negative tumors.