A-REPEAT (Anti-Epidermal Growth Factor Receptor -EGFR- rechallenge and plasma genotyping of patients with advanced colorectal tumors) is a Greek, investigator-initiated, single arm open-label phase II study of anti-EGFR therapy rechallenge in combination with chemotherapy in patients with advanced colorectal cancer. Patients with a metastatic, histologically proven colorectal carcinoma RAS wild type will be treated with a combination of panitumumab and third-line irinotecan-based or oxaliplatin-based chemotherapy (FOLFOX,FOLFIRI or irinotecan monotherapy).