Metastasectomy in colorectal carcinoma (CRC) patients (pts) with mBRAF: Prospective database analysis.

Abstract

e15549 Background: Role of metastasectomy in pts with mBRAF metastatic CRC is still controversial. We performed analysis of prospective multicentric database of pts with mBRAF mCRC to evaluate the efficacy of metastasectomy in such group of pts in the real clinical practice. Methods: We analyzed a database of pts with mCRC in 7 cancer clinics in Russia and chose pts with metastasectomy with different mutational status. The primary endpoints were disease free survival (DFS) and overall survival (OS), which were calculated from the time of metastasectomy. Analysis was performed with the SPSS v.20 software package. Results: The study included 126 pts: 26 pts with mBRAF, 57 pts with mRAS and 43 pts with wtRAS/BRAF. Pts with mBRAF more often had synchronous metastases (50%/19,3/11,6%, p<0,01), N2 status (38,5%/11%/19,6%, p=0,04). In mBRAF cohort all but 1 pt had V600 mutations; peritonectomy performed in 19,2%, liver resection – in 34,6%, lung resection, ovariectomy, metastasectomy in brain and retroperitoneal lymph nodes dissection with removal of the local relapse – over 11,5%; R0 resection was achieved in 88,5%. Median DFS was 7 months in mBRAF pts, 14 months in mRAS and not achieved in wtRAS/BRAF group treated (HR 2,1, 95%CI 1,5-3.1, p<0.01). Median OS was 26 months in mBRAF, 38 months in mRAS and not achieved in wtRAS/BRAF group (HR 1,5, 95%CI 1,0-2,4, p=0.06). Perioperative chemotherapy didn’t improve DFS in pts with mBRAF (HR 1,9, 95%CI 0,67-5,7, p=0,2). The best median DFS were in pts after ovariectomy – 10 months, the worst - after retroperitoneal lymph nodes dissection with removal of the local relapse – 2 months. Conclusions: Prognosis of pts with mBRAF after metastasectomy is worse than with other mutational phenotypes. However in selected cases metastasectomy might be considered in such aggressive mCRC.