[KRAS mutation does not influence oxaliplatin or irinotecan efficacy, in association with bevacizumab, in first line treatment of metastatic colorectal cancer]

Abstract

Introduction: The identification of RAS status (KRAS and NRAS) has changed the management of metastatic colorectal cancer (mCRC). The impact of the RAS mutation on cytotoxic chemotherapy efficacy has not yet been determined. Nevertheless, several retrospective studies suggest a greater efficacy of oxaliplatin in mCRC with KRAS mutation.

Methods: We analyzed retrospectively the progression free survival (PFS) and overall survival (OS) in 216 patients with mCRC receiving first line treatment between 2008 and 2010 according to KRAS status and chemotherapy regimen used (oxaliplatin- or irinotecan-based, in association with fluoropyrimidine and bevacizumab).

Results: In KRAS mutated tumors, median OS was 23.4 months with oxaliplatin-based regimen, and 23.6 months with irinotecan-based regimen, with no significant difference (HR 1.30; 95 % CI 0.81-2.09; P=0.27). In KRAS wild-type tumors, median OS was 30.3 months with oxaliplatin-based regimen, and 25.4 months with irinotecan-based regimen, with no significant difference (HR 0.81; 95 % CI 0.52-1.24; P=0.33). Similarly, KRAS mutational status had no significant effect on efficacy of oxaliplatin or irinotecan regarding PFS.

Discussion: In this retrospective study, KRAS mutational status does not influence the efficacy of first line cytotoxic chemotherapy in association with bevacizumab.

Keywords: Bevacizumab; Bévacizumab; Cancer colorectal; Colorectal cancer; Irinotecan; Irinotécan; KRAS; Metastasis; Métastases; Oxaliplatine.