A Multi-center Real-world Efficacy and Safety of Trastuzumab-deruxtecan in Advanced Gastric Cancer

* Institutions will be selected * This study aims to collect real-world data, targeting patients who started treatment with Enhertu from September 2022, for clinical data collection * Among patients treated with Enhertu, those who have passed away or are no longer visiting due to hospice care will have their clinical data collected without consent until August 19, 2024 * For patients who are scheduled to receive Enhertu treatment, are currently undergoing treatment, or have previously undergone treatment but experienced disease progression and are now receiving subsequent chemotherapy (i.e., patients with newly added data after registration) * Efficacy evaluation