Associations Between Genetic Polymorphisms of Epidermal Growth Factor Receptor (EGFR) and Survival of Colorectal Cancer (CRC) Patients Treated with 5-Fluorouracil-Based Chemotherapy

Abstract

This retrospective cohort study investigated the association between epidermal growth factor receptor (EGFR) polymorphisms and clinical outcomes in colorectal cancer (CRC) patients treated with 5-fluorouracil (5-FU)-based chemotherapy. We genotyped 3 EGFR polymorphisms including R497K, G-216T, and the (CA)n repeat, among 499 histologically confirmed CRC patients who had received 5-FU-based chemotherapy after surgery between 1995 and 2001. Survival analyses of EGFR polymorphisms were performed by the log rank test and Kaplan-Meier curves. We used the Cox proportional hazard model to evaluate the association between EGFR genotypes and clinical outcomes. Stratification analysis by gender, tumor stage, and subsite were also carried out. CRC patients with the EGFR (CA)n L/L genotype compared to those with the S/S+S/L genotype had a significantly better overall survival (L, ≥ 20 repeats; S, <20 repeats) (hazard ratio (HR) 0.74; 95 % confidence interval (CI) 0.57-0.95), particularly for patients who were male (HR 0.63; 95 % CI 0.44-0.90), who had stage IV disease (HR 0.70; 95 % CI 0.49-0.99), and who had rectal cancer (HR 0.62; 95 % CI 0.42-0.92). Better survival was prominent among patients with the combined genotypes of EGFR (CA)n L/L, G-216T G/G, and R497K K/K (HR 0.51; 95 % CI 0.30-0.87), compared to those with the most common genotypes of the EGFR (CA)n S allele, G-216T G/G, and R497K R allele. EGFR polymorphisms can serve as prognostic predictors for CRC patients receiving 5-FU-based chemotherapy.