Chumsri S, Li Z, Serie DJ, et al. - Researchers determined the risk of late relapses in human epidermal growth factor receptor 2-positive (HER2+) breast cancer patients treated with adjuvant trastuzumab-based chemotherapy. From the North Central Cancer Treatment Group N9831 and National Surgical Adjuvant Breast and Bowel Project B-31 trials, they selected 3,177 patients managed with adjuvant chemotherapy alone or with trastuzumab for HER2+ breast cancer. Overall, a significant link of hormone receptor-positive (HR+) breast cancer with improved recurrence-free survival (RFS) during the first 5 years was observed. They noted a lower cumulative hazard for RFS during the first 5 years in patients treated with trastuzumab for HR+ HER2+ breast cancer. However, no significant difference in RFS was seen depending on HR status during years 5 to 10. Findings revealed a long-time persistence of the benefit of adjuvant trastuzumab. Between HR+ and HR− HER2+ disease, despite a distinct pattern of recurrence, a similar degree of benefit from adjuvant trastuzumab was noted. Patients with HR+ HER2+ breast cancer exhibited a low risk of recurrence in years 5 to 10; this was especially seen in those with N0 or N1 disease.