Leone JP, et al. - Researchers investigated differences in the overall survival (OS) by tumor subtypes (TS) according to stage vs other factors among women with breast cancer diagnosed between 2010 and 2013 with known estrogen receptor and progesterone receptor (together hormone receptor [HR]) status and human epidermal growth factor receptor 2 (HER2) status in the SEER program. Among 166,054 included patients, the best OS in stage I was noted for HR-positive/HER2-negative (3-year OS, 97.2%). In contrast, the best 3-year OS was observed for HR-positive/HER2-positive in stage II (94.5%), stage III (87.8%), and stage IV (54.8%). In stage IV, a 40.1% difference in OS at 3 years was observed between triple-negative and HR-positive/HER2-positive. These findings suggest significant differences in OS by TS in each of the 4 stages; the multivariate model confirmed these results.