One moderate quality randomized controlled trial (two publications) regarding the clinical effectiveness of trastuzumab combined with carboplatin and paclitaxel compared with carboplatin and paclitaxel alone in patients with HER2 positive uterine serous carcinoma was identified. The trial showed that trastuzumab combined with carboplatin and paclitaxel significantly improved progression-free survival and improved overall survival in patients with advanced and recurrent HER2 positive uterine serous carcinoma compared with carboplatin and paclitaxel alone. High-grade adverse events during and following treatment were not significantly different between the treatment groups. Objective response rate did not differ between groups. No clinical evidence regarding trastuzumab monotherapy or other types of trastuzumab combination therapies (e.g., trastuzumab in combination with cisplatin and paclitaxel or docetaxel), patients with non-serous uterine cancer, other comparators (e.g., docetaxel), or data on quality of life were identified. No studies were identified regarding the cost-effectiveness of trastuzumab.