Implications of KRAS status in first line chemotherapy with bevacizumab in advanced colorectal cancer: A phase IV study of Hellenic Oncology Research Group (HORG).

e15521Background: Bevacizumab (BEV) is an active antiangiogenic agent for the treatment of all patients (pts) with advanced colorectal cancer (CRC). We investigated the toxicity, compliance and survival of pts with locally advanced/inoperable or metastatic CRC treated with BEV-based treatment according to KRAS status. Methods: This phase IV study recorded prospectively (July 2009-June 2016) the clinicopathologic characteristics, safety and survival of pts receiving BEV with 1st line chemotherapy according to oncologist’s preference. Results: Of 682 pts providing consent for BEV-based therapy, 382pts completed treatment; 144pts had disease progression and 156pts discontinued treatment (adverse events: 58pts; toxic deaths: 2pts; consent withdrawn: 34pts; lost to follow up: 5pts; other reasons: 33pts whereas 24pts underwent curative metastasectomy/surgery). On treatment initiation KRAS status was recorded as mutant (mtKRAS) in 229pts (33.65%), wild type (wtKRAS) in 177pts (26%) and unknown (uKRAS) in 276pts ...