Clinical predictors of response to cetuximab-chemotherapy in metastatic colorectal cancer.

Objective: To identify clinical markers to predict which patients with advanced colorectal cancers are likely to benefit from cetuximab-chemotherapy.

Design: Retrospective review.

Setting: Oncology unit in a university teaching hospital in Hong Kong.

Patients: A total of 102 patients with metastatic colorectal cancer treated with cetuximab-chemotherapy.

Main Outcome Measures: Correlation of multiple potential clinical predictive factors with tumour response to cetuximab-chemotherapy.

Results: The objective response rates to cetuximab plus chemotherapy were 53% in patients receiving first-line treatment and 17% in previously treated patients. The univariate analysis indicated that fewer prior lines of chemotherapy (odds ratio=0.36; 95% confidence interval, 0.21-0.63; P<0.01) and development of cetuximab-related grade 3 rash (5.52; 1.62-18.76; P<0.01) were associated with significantly higher response rates. Multivariate analysis confirmed the independent predictive value of the number of prior chemotherapy regimens (odds ratio=0.37; 95% confidence interval, 0.20-0.69; P<0.01) and grade 3 rash (4.65; 1.21-19.29; P=0.03).

Conclusions: In this cohort of Chinese patients with advanced colorectal cancer, the presence of grade 3 rash and the number of prior chemotherapy regimens were independent predictors of response to cetuximab-chemotherapy. The utility of these clinical markers in clinical practice should be further evaluated together with established biomarkers.