Deep and Repeated Response to Trastuzumab Deruxtecan in a Patient With Human Epidermal Growth Factor Receptor 2–Amplified Large-Cell Neuroendocrine Carcinoma With Brain Metastases: A Case Report
Metastatic CUP is complex, especially NCUP. Precision oncology is crucial for rare, aggressive cancers. A 54-year-old had HER2+ neuroendocrine carcinoma of unknown origin. T-DXd treatment, response, re-challenge show importance of genomics and caution.