KRAS mutations on response to antiEGFR in mCRC: meta-epidemiology

Article type
Authors
Chan AL1, Leung HW2, Lo D3, Leung MS4, Leung J5
1Department of Pharmacy, Min-Sheng General Hospital. Taoyuan, Taiwan
2Department of Radiation Oncology, Wang Fang Hospital, Taipei Medical University, Taipei, Taiwan
3School of Medicine, Taipei Medical University, Taipei, Taiwan
4School of Medicine, Jinan University, Guangzhou, China
5School of Pharmacy, St. John’s University, U.S.A
Abstract
Background: Anti-epidermal growth factor receptor monoclonal antibodies are approved and effective only in KRAS wild-type patients with advanced colorectal cancer.

Objectives: This meta-epidemiology aimed to compare the reported effect of KRAS mutation status on response to anti-EGFR treatment in metastatic CRC in dataset from randomized controlled trials and the quality of meta-analysis.

Methods: This is a meta-epidemiological study. Meta-analyses of KRAS mutation status that included datasets from at least one observational study and at least one randomized controlled trial were identified through Medline (last update, April 2012). Study-specific hazard ratios or risk ratios were extracted from all identified metaanalyses and synthesized with random effects for (a) all studies, and (b) separately for patients with KRAS wild-type patients and KRAS mutated patients for comparison. RevMan 5.0.24 (Cochrane IMS) has been used for statistical analysis. Prisma checklist for meta-analysis has been used for quality assessment.

Results: Seven eligible meta-analyses were identified. The pooled ratio of risk ratio of patients with wild vs. mutated K-ras showed progression free survival advantage in the addition of anti-EGFR to standard chemotherapy (RRR 0.85 [95% CI, 0.52–1.40]). The overall effect is not significant. There was a great discrepancy with meta-analysis studies. The asymmetric funnel plot suggests that inconsistence is likely existed between meta-analysis of RCT. Most of the meta-analysis studies matched with most items in the Prisma checklist, except the item of assessment on risk of bias.

Conclusions: Evidence from this overview indicates that a great discrepancy on average in the risk estimate of KRAS mutations in advanced colorectal cancer treated with anti-epidermal growth factor receptors.