An Unconventional Regimen of Carboplatin and Paclitaxel in Metastatic Colorectal Carcinosarcoma: A Case Report and Review of Literature.

Colorectal carcinosarcoma is an exceedingly rare subtype of colorectal cancer that displays the histological and molecular features of both mesenchymal and epithelial tumors. Due to its rarity, there are no guidelines regarding the systemic treatment of this disease. This report describes a case of a 76-year-old woman with colorectal carcinosarcoma with extensive metastatic burden treated with carboplatin and paclitaxel. After four cycles of chemotherapy, the patient had an excellent clinical and radiographical response to treatment. To the best of our knowledge, this is the first report addressing the use of carboplatin and paclitaxel in this disease. We reviewed seven published case reports of metastatic colorectal carcinosarcoma where various systemic treatments were offered. Remarkably, there are no previously published reports where even a partial response was noted, which underscores the aggressiveness of this disease. While further studies are required to validate our experience and assess long-term outcomes, this case suggests an alternative treatment regimen for metastatic colorectal carcinosarcoma.