Clinicopathologic features and treatment efficacy of patients with BRAF V600E-mutated metastatic colorectal cancer: a multi-center real-world propensity score matching study.

Abstract

Background: Patients with BRAF 600E mutated mCRC are associated with specific clinicopathological features and poor prognosis. The relative efficacy of first-line FOLFOXIRI triplet chemotherapy or doublet chemotherapy combined with bevacizumab in patients with BRAF 600E mutated mCRC remains controversial.

Methods: BRAF V600E-mutated mCRC patients from 3 institutions were included. The clinicopathological characteristics of the enrolled patients were analyzed. Overall survival (OS) of patients was divided into 4 fractions, including 0-25%, 25-50%, 50-75%,75-100% by quartile method. Patients with OS ranging from 0 to 25% were defined as the poor prognosis group, and patients with OS ranging from 75 to 100% were defined as the good prognosis group. A propensity score matching (PSM) analysis was performed to balance the baseline characteristics of patients treated with doublet chemotherapy and triplet chemotherapy combined with bevacizumab. Survival and tumor response of the two regimens were evaluated.

Results: A total of 125 patients with BRAF V600E-mutated mCRC were enrolled. The median OS of BRAF V600E-mutated mCRC was 14.9 months and the median PFS of first-line therapy was 6.1 months. According to the multivariate analysis and the difference in baseline characteristics between the poor prognosis group and the good prognosis group, poor differentiation and liver metastasis were negative independent prognostic factors for OS in patientsx with BRAF V600E-mutated mCRC. Patients treated with first-line triplets had a longer OS than those treated with doublets both before PSM (17.4 months vs. 13.4 months, p = 0.022) and after PSM (17.4 months vs. 10.4 months, p = 0.004). There was no significant benefit between triplet-drug group and doublet-drug group for PFS, ORR and DCR. Subgroup analysis showed that patients in the triplet-drug group had a better prognosis with the following favorable factors: age ≤ 60 years old, PS score of 0-1, liver metastases and multiple organ metastases.

Conclusion: The overall prognosis of BRAF V600E mutant mCRC patients is poor. Poor differentiation and liver metastases were negative independent prognostic factors for OS. First-line triplet-drug therapy was associated with better OS, especially in patients with good physical condition and high tumor burden.