How well a cancer treatment works in real-world patient care

This is an observational study of trastuzumab deruxtecan (T-DXd), a targeted cancer medication for patients with HER2-positive solid tumors who have already tried other treatments. Instead of testing the medication in a controlled trial setting, researchers will follow about 100 patients across different types of cancer clinics and medical centers as they receive this treatment as part of their regular care, to understand how well it works and how long its benefits last in everyday practice.

While this medication has shown promise in clinical trials, doctors and patients need to understand how it performs in real-world settings—with diverse patient populations, different types of cancers, and various care settings—rather than just in controlled research environments. This study will help fill that gap by tracking outcomes in everyday medical practice.