[The efficacy of cetuximab for metastatic colorectal cancer]

Cetuximab (Erbitux) is a targeted therapy that used to treat metastatic colorectal cancer. It is classified as a "monoclonal antibody" and "signal transduction inhibitor" by binding to epidermal growth factor receptors (EGFR). We report 6 patients who responded well to cetuximab out of 8 patients with recurrent/advanced colorectal cancer who have received the drug at our hospital since November 2008. Four patients were men and 2 were women, with their ages ranging from 48 to 77 years. The primary cancers were located in the rectum (n=1), sigmoid colon (n=4), and ascending colon (n=1). Performance status (PS) was 0-1. These patients were treated with cetuximab as second-line (n=1), third-line (n=3), fifth-line (n=1), or seventh-line (n=1) therapy. Three patients received cetuximab monotherapy, while the other 3 were given CPT-11 (150 mg/m2, every 2 weeks) as concomitant therapy. Among the 3 patients receiving combination therapy, 2 patients had already received treatment with FOLFIRI. Even in the cetuximab monotherapy group, a partial response (PR) was observed in 2 patients, demonstrating a strong cytoreductive effect. Tumor markers also showed large decreases, with the percent decrease at 1 month being 31.7% and 60.8% in the monotherapy and combination therapy groups, respectively, while it was respectively 14.1% and 29.5% at 2 months. The mean progression-free survival (PFS) time and the time to treatment failure (TTF) were respectively 3.0 months and 4.5 months in the monotherapy group versus 7.3 months and 9.3 months in the combination therapy group. Acneiform rash and paronychia occurred in all 6 patients.