Clinicopathological Features and Prognosis of Unresectable Colorectal Cancer With the BRAF V600E Mutation.

Background/aim: Patients with unresectable advanced and recurrent colorectal cancer (CRC) and the BRAF V600E mutation have poor prognosis, and conventional chemotherapy is often ineffective. This study aimed to retrospectively evaluate the clinicopathological features and prognosis of this patient population.

Patients and methods: We examined clinicopathological characteristics and treatment outcomes of 26 patients with BRAF V600E-mutated unresectable advanced and recurrent CRC treated between June 2015 and October 2022.

Results: The mean age was 63.1±14.0 years; out of 26 patients, nine (34.6%) were female, 12 (46.2%) had right-sided CRC, and eight (30.8%) had poorly differentiated or mucinous adenocarcinoma. One patient (3.8%) had a RAS mutation, and three (11.5%) had high microsatellite instability. The median overall survival (OS) was 12.0 months. The median OS for patients treated with the BEACON regimen (encorafenib plus cetuximab, with or without binimetinib) was 13.3 months, which was significantly better than that of patients treated without it (7.2 months; hazard ratio=4.180, 95% confidence interval=1.036-18.631, p=0.029). The median progression-free survival for patients treated with BEACON regimen was 6.6 months.

Conclusion: The BRAF V600E mutation was associated with poor prognosis. The BEACON regimen resulted in improved OS compared with other CRC treatment regimens.