Survival Outcomes of Resected BRAF V600E Mutant Colorectal Liver Metastases: A Multicenter Retrospective Cohort Study in Japan.

Abstract

Although the prognosis for patients with resected BRAF mutant colorectal liver metastases (CRLM) is poor, the survival impact of the BRAF V600E mutation in such cases remains unclear. A multicenter retrospective cohort study was performed to investigate the survival outcomes of patients who underwent initial hepatectomy for histologically confirmed BRAF V600E mutant CRLM between January 2005 and December 2017. Thirty-three patients from 6 institutions were included in this study. During the median duration of the post-hepatectomy follow-up period of 49.2months, 31 patients (93.9%) developed recurrence after a median period of 5.3months and the 1-year recurrence-free survival (RFS) rate was 24.2%. Only two patients underwent repeated surgery for recurrence. The other 29 patients had unresectable recurrent lesions, and 27 of them received systemic chemotherapy. The median overall survival (OS) period was 31.1months and the 5-year OS rate was 18.2%. The factors for a poor RFS prognosis were an elevated serum CA19-9 level (≥ 37IU/ml) at hepatectomy (HR: 2.139, 95% CI: 1.009-4.534, P = 0.047) and R1 resection (HR: 5.827, 95% CI: 1.585-21.42, P = 0.008), and that for OS was R1 resection only (HR: 4.129, 95% CI: 1.104-15.45, P = 0.035). Since the early onset unresectable recurrence rate was very high, systemic chemotherapy should be considered for resectable BRAF V600E mutant CRLM. A novel perioperative treatment strategy is needed to improve the survival of such patients.