Prognosis and Impact of EGFR Expression and anti-EGFR Treatment in Metastatic Left Colon and Rectal Cancer, a Retrospective Study

Background: Over the past decade, targeted therapies have revolutionized treatment for advanced colorectal cancer. EGFR, linked to poor prognosis and aggressive disease, is also a key target for therapy in colon cancer, so we aimed to evaluate EGFR expression in metastatic colorectal cancer and the outcome of treatment with anti-EGFR therapy between left colon and rectal cancer.Methods: This retrospective study was conducted on patients diagnosed with histopathological adenocarcinoma of left colon or rectum, metastatic stage, Kirsten rat sarcoma viral oncogene wild type and who were eligible to receive chemotherapy (renal and liver chemistry, and normal CBC) were included in this study.Results: No significant difference was observed in disease response when anti EGFR treatment was received as 1st or 2nd line CTH (P=0.135). In rectal cancer, no significant difference was observed in disease response when anti EGFR treatment was received as 1st or 2nd line with CTH (P=0.529). During five years of follow-up, tumor grade and tumor size were shown to affect overall survival among the participants studied. Tumor grade: at five years of follow-up, the OS rate was 33.3% in patients with tumor grade 1, 29.4% in patients with tumor grade 2 and 0.0% in patients with tumor grade 3 (P<0.001). Tumor size: at five years of follow-up, the OS rate was 68.6% in patients with tumor stage T1/T2, and 0.0% in patients with tumor stage T3/T4 (P=0.031).Conclusions: Anti-EGFR treatment, as a 1st line treatment, is less effective in metastatic rectal cancer than left-sided colon cancer.