Retrospective cohort study on the safety and efficacy of bevacizumab for metastatic colorectal cancer patients: The HGCSG0801 study—Efficacy of KRAS mutational status.

Abstract

680 Background: Mutations of the KRAS gene were identified as a prognostic marker in metastatic colorectal cancer(mCRC). Previously reported data suggests that the longer overall survival (OS) observed with bevacizumab(BV) treatment in mCRC is independent of alterations in the KRAS mutation status. So we analyzed efficacy of bevacizumab combined chemotherapy in mCRC relative to KRAS mutation status. Methods: In the retrospective analysis(n=212) of patients treated with BV(HGCSG0801), additional statistical analyses were done with data from KRAS mutation analyses. The Response Evaluation in Solid Tumors (RECIST) criteria version 1.0 was used to assess tumor response. The Kaplan–Meier method was used to determine Progression-free survival(PFS) and OS. Log-rank test was used to compare with mutant or wild-type KRAS in terms of PFS and OS. All statistical tests were performed using SPSS. Results: KRAS status was assessed in 88 patients (41.5%). Response rate was 58.9% with wild-type and 62.5% with mutant KRAS, that was not significant(p=0.823). The median Progression-free survival was 11.5 months with wild-type and 11.5 months with mutant KRAS, that was not significant(p=0.222). And median OS was 31.8 months with wild-type and 27.5 months with mutant KRAS, that was not significant(p=0.760) as well. Similar results were seen among patients with first-line therapy. Conclusions: Bevacizumab provides clinical benefit in patients with mCRC expressing either mutant or wild-type KRAS.