Although T-DXd has been approved for the treatment of metastatic HER2-positive breast cancer, as well as metastatic HER2-positive gastric and gastroesophageal junction adenocarcinoma, its effect on HER2 overexpressing UC is still being evaluated (Tong et al., 2021). This evidence concerns the gene ERBB2 and gastroesophageal junction adenocarcinoma.