Epidermal growth factor receptor in CRC patients in the era of the RAS.

The aim of this study was to investigate EGFR expression patterns and the effect of EGFR expression on stage, prognosis and response to conventional chemotherapy agents other than monoclonal antibodies in CRC patients. This study included 59 metastatic CRC patients. The expression of EGFR was quantified by immunochemistry in biopsy specimens that were obtained before treatment was initiated. The cases were considered to be positive for EGFR if >1% of the tumor cells had complete circumferential membranous staining. The median age of the patients was 54.6 years, and 59% of the patients were male. Twenty-six patients presented with stage IV disease, and the remaining patients developed distant metastasis during follow-up. Fifty-one patients were treated with regimens containing irinotecan. The numbers of patients with EGFR expression in the primary tumors, the metastatic lymph nodes and the normal colonic tissue were 34 (65.4%), 10 (76.9%) and 34 (65.4%) respectively. The initial disease stage and lymph node stage were correlated with EGFR expression (p<0.05). Additionally, EGFR positivity was correlated with a statistically significant reduction in the response rate to chemotherapy, the overall survival (21 vs. 28 months) and the progression-free survival (15 vs. 22 months) in metastatic patiens treated with chemotherapy other than targeted therapies. In conclusion, EGFR expression in correlated with stage in all CRC patients and response to chemotherapy and survival in metastatic CRC patients.