Conversion Surgery After Encorafenib Plus Cetuximab for Chemorefractory BRAF V600E-mutated Colorectal Cancer With Para-aortic Lymph Node Metastases

Background/Aim: Mutant BRAF V600E colorectal cancer accounts for 5% of metastatic colorectal cancers, and it has a poor response to systemic chemotherapy and a poor prognosis. However, combination treatment involving MAPK pathway blockade is effective for this cancer. Herein, we report a case of a patient who underwent conversion surgery after encorafenib plus cetuximab for chemorefractory BRAF V600E-mutated colorectal cancer with para-aortic lymph node metastases. Case Report: A 68-year-old woman was diagnosed with ascending colon cancer and multiple para-aortic lymph node metastases. After primary tumor resection, molecular genetic testing of the primary tumor revealed a BRAF V600E mutation. She was treated with FOLFOXIRI plus bevacizumab as first-line chemotherapy. After disease progression, the regimen was changed to encorafenib plus cetuximab, and the metastatic lesions shrank. She underwent para-aortic lymph node dissection as conversion surgery, and pathology revealed complete response of the lymph nodes. She achieved long-term survival. Conclusion: The development of new treatments for BRAF V600E-mutated metastatic colorectal cancer will increase opportunities for conversion therapy.