Cetuximab plus chemotherapy as first-line treatment for metastatic colorectal cancer: effect of KRAS mutation on treatment efficacy in Taiwanese patients.

Cetuximab, either alone or in combination with chemotherapy, is approved for treatment of patients with metastatic colorectal cancer (mCRC). We reviewed retrospectively records of 50 patients with mCRC from a single center in Taiwan. All patients had ECOG performance status grade 2, histological diagnosis of advanced CRC based on RECIST criteria, and were given at least three cycles of chemotherapy plus cetuximab. We compared the effectiveness of therapy in patients with wild-type and mutant KRAS genes, assessed the overall response (OR) rate of patients with locally advanced or metastatic non-resectable CRC, and assessed the progression-free survival (PFS) time. The ten patients with KRAS mutations had poorer response rates than the 40 patients with the wild-type KRAS gene. Patients with the wild-type and mutant genes had similar progression free survival (PFS) status and median time to PFS. The median overall survival time was significantly greater in patients with the wild-type gene than in those with the mutant gene (28.77 ± 6.43 months vs. 15.13 ± 0.50 months, p=0.014). Taiwanese patients with mCRC respond better to a cetuximab plus chemotherapy regime if their tumors have the wild-type KRAS gene.