Abstract
BACKGROUND: Colorectal choriocarcinoma is a rare condition with a poor prognosis, and no standard chemotherapy regimen has been established. A combination of cetuximab, encorafenib, and binimetinib as adjuvant chemotherapy may be effective for colorectal choriocarcinoma. This treatment approach has not been previously reported for this rare malignancy. CASE DESCRIPTION: We describe the case of a 59-year-old woman who underwent right hemicolectomy for a transverse colon perforation and was diagnosed with primary colorectal adenocarcinoma with choriocarcinoma differentiation. Adjuvant chemotherapy with folinic acid, fluorouracil, and oxaliplatin (FOLFOX) and bevacizumab was administered for colorectal adenocarcinoma, but disease progression was observed. The patient had a BRAF V600E mutation, tested negative for human chorionic gonadotropin (hCG), and was switched to a combination of encorafenib, cetuximab, and binimetinib. The treatment response was monitored through regular imaging studies and tumor marker measurements. The patient has been alive for 34 months with no metastases or recurrence, and with continued reduction in the size of the lymph nodes and peritoneal lesions. CONCLUSIONS: Standard chemotherapy for the treatment of choriocarcinoma and colorectal adenocarcinoma has been applied to colorectal choriocarcinoma. In patients with a BRAF V600E mutation and decreased hCG levels, a combination of encorafenib, cetuximab, and binimetinib may be a useful chemotherapeutic option when treating patients with colorectal choriocarcinoma.