Standard chemotherapy with cetuximab for treatment of colorectal cancer.

Aim: To review and assess the evidence related to cetuximab treatment in metastatic colorectal cancer (mCRC) with regard to KRAS status.

Methods: PubMed, EMBASE, Cochrane database and American Society of Clinical Oncology meeting abstracts were searched for randomized controlled trials (RCTs) reporting the effect of KRAS status on efficacy of chemotherapy regimen with or without cetuximab in mCRC. Baseline information such as sex and age was summarized from the included studies. Hazard ratios of progression-free survival (PFS) and overall survival (OS) as well as objective response based on KRAS status were extracted for analysis.

Results: A total of 8 RCTs with 6780 patients were included. The combined analysis showed that cetuximab failed to improve the OS and PFS in patients with mCRC. However, in subgroup analysis, the pooled data showed that addition of cetuximab to irinotecan containing chemotherapy regimen was sufficient to improve OS and PFS in wild-type KRAS mCRC patients, but not in patients with mutant-type KRAS. The addition of cetuximab increased the incidence of adverse events such as diarrhea, rash, skin toxicity/rash, and nausea and vomiting. There was no significant publication bias existing in the included studies.

Conclusion: The clinical benefit of cetuximab was only confirmed in patients with wild-type KRAS. KRAS status could be considered a biomarker of efficacy of cetuximab.