Ze Li, Xuewei Liu, Longwei Cheng, Zhaocheng Chi,Baosheng Sun, Ying Cheng

Department of Gastrointestinal Surgery, CancerHospital of Jilin Province

Objective:Epidermal growth factor receptor tyrosinekinase (EGFR-TK) inhibitors are useful in treating different advanced humancancers; however, their clinical efficacy varies. This study detected K-rasmutations to predict the efficacy of EGFR-TK inhibitor Cetuximab treatment onChinese patients with metastatic colorectal cancer (mCRC). Method: Atotal of 87 patients with metastatic colorectal cancer were treated withCetuximab for 2-16 months in combination with chemotherapy between August 2008and July 2012 and tissue samples were used to detect for K-ras mutations. Result:A total of 87 patients with metastatic colorectal cancer were treated withCetuximab for 2-16 months in combination with chemotherapy between August 2008and July 2012 and tissue samples were used to detect for K-ras mutations. Thedata showed that K-ras mutation occurred in 27/87 (31%). The objective responserates and disease control rate in K-ras wild type and mutant patients were 42%(25/60) versus 11% (3/27) (P<0.05) and 60% (36/60) versus 26% (7/27)(P<0.05), respectively. Patients with the wild-type K-ras hadsignificantly higher median survival times than patients with mutated K-ras (21months versus 17 months, P=0.017). Conclusion: These findingssuggest that a high frequency of K-ras mutations occurs in Chinese mCRC patientsand that K-ras mutation is required to select patients for eligibility toCetuximab therapy. Further prospective study using a large sample size isneeded to confirm these preliminary findings.

Key Words: K-ras gene mutation  colorectal cancer  prognosis