Analysis of clinical characteristics and survival trends of BRAF mutated metastatic colorectal cancer (mCRC) patients receiving metastases surgery.

Abstract

e15552 Background: BRAF mutated mCRC patients have worse prognosis compared with BRAF wildtype mCRC. Within this group, those with resectable disease have a better prognosis compared to those with unresectable disease. However, it is not well known whether there are clinical differences that may help clinicians to identify this subgroup of patients. Methods: We conducted a retrospective analysis of 24 patients with BRAF mutated mCRC, describing their clinical characteristics and the differences between those who have undergone metastatic surgery (n = 18) versus those who have not (n = 6). We applied the exact test of Fisher to identify significant association between categoric variables, while we used Mann-Whitney test to identify significant differences between quantitative variables. PFS and OS were compared using a long-rank test, and the estimate of hazard ratio (HRs) between studied groups was calculated by means of Cox proportional hazards model. Results: Twenty-four patients with BRAF mutated mCRC have been identified. 58% (n = 14) of them were < 65 years old; 54% (n = 13) had BMI > 25, and all of them had a good PS at diagnosis (0 or 1). The most frequent tumor location was the right colon (58%; n = 14) and in 79% (n = 19) of the cases the primary tumor was resected. Most of the patients presented peritoneal (41%, n = 10) or liver (41%, n = 10) disease, and 70% of them (n = 17) had synchronous disease. Within the 18 patients who underwent surgery, the most frequent surgery was liver metastasectomy (50%, n = 9) followed by peritoneal metastasectomy (28%, n = 5). Regarding first-line chemotherapy treatment, only 12% (n = 3) presented disease progression in the first reassessment. No statistically significant differences were found between surgical and non-surgical patients regarding the following variables: age, BMI, ECOG, primary tumor side, location of the metastases, synchronous presentation of the metastatic disease, analytical parameters (CEA, Ca 19.9 and LDH), response to chemotherapy treatment and first line progression-free survival. However, we found significant differences in overall survival with an HR for mortality of 0.22 (95% CI 0.049-0.99; p = 0.031) in patients undergoing metastases surgery, with a median of 38 months in patients who underwent surgery vs 20 months in those who did not. Conclusions: BRAF mutated mCRC who receive surgery for metastases have better prognosis with higher overall survival, compared to those who have not undergone surgery. Still, no other statistically significant differences were found in the rest of the clinical characteristics analyzed to identify a subgroup with better prognosis.