Daniels B, et al. - In this retrospective, whole-of-population cohort study, researchers analyzed the real-world treatment patterns and overall survival (OS) for women surviving five or more years from initiation of trastuzumab for HER2-positive metastatic breast cancer (HER2+MBC). Using dispensing claims, timing of cancer treatments used by long-term survivors (LTS) was determined, along with time on and off HER2-targeted therapies and OS from trastuzumab initiation for HER2+MBC. A total of 1082 (26%) of 4177 women had survival ≥ 5 years. Death of 36% of LTS was reported at a median follow-up of 9.4 years; their conditional probability of surviving an additional 5 years was 55%. The observed median time on trastuzumab and all HER2-targeted therapy was 58.9 months and 69.1 months, respectively. Overall, HER2-targeted therapies were generally received by LTS for periods of time longer than in clinical trials, but most LTS also had breaks in treatment.