Carcinosarcoma is a malignant neoplasm that is composed of both epithelial and mesenchymal
elements and aggressive tumor that are staged as high-grade cancer in NCCN guideline. They
are regarded as rare aggressive malignancies with a high potential to develop distant
metastases and are associated with an overall poor survival. The aggressive nature of this
malignancy coupled with a high relapse rate defines a poor clinical course for most patients.
First line treatment of patients with advanced uterine carcinosarcoma with paclitaxel plus
carboplatin achieved an objective response rate of 54% of patients. For this orphan tumor,
carcinosarcoma, as these drugs would hypothetically act only on tissues with overexpression
of PD-L1, they theoretically provide a more precise therapeutic effect on tumor cells with
considerably less side effects. Therefore, the investigators suggest phase II trial of
nivolumab for metastatic/recurred carcinosarcoma who have progressed after prior
chemotherapy.