Treatment and Outcomes of Patients with Metastatic Colorectal Cancer (mcrc) with Epidermal Growth Factor Receptor (egfr) Therapy in the Third-Line Setting

579 Background: Monoclonal antibodies targeting the EGFR improve outcomes of patients with mCRC in the first-, second-, and third-line settings. The optimal treatment setting for use of these agents is not yet defined. In British Columbia, cetuximab and panitumumab are limited to patients with KRAS wild type (wt) mCRC previously treated with 5-fluorouracil (5-FU), oxaliplatin (Ox), and irinotecan (Iri). The objective of this study was to describe the treatment and outcomes of patients with mCRC after the introduction of EGFR targeted therapy in the third-line setting. Methods: All patients with newly diagnosed mCRC and referred to 1 of 5 BC Cancer Agency clinics in 2009 were included. Prognostic and treatment information was prospectively collected while KRAS testing information was determined by chart review. Results: 443 patients with a median age of 66 were included of which 59% were men, 73% received any systemic therapy for metastatic disease of which 13% underwent hepatic resection of metastatic disease. Of 117 patients who received 5-FU, Ox and Iri, 10% were not tested for KRAS. Among those tested, 38% were KRAS mutant. In patients who were KRAS wt, 23% did not receive EGFR therapy. On chart review, poor performance status was the dominant reason for not receiving KRAS testing and anti-EGFR therapy in 67% and 50% of cases, respectively. Median survival of 321 patients who received any systemic therapy for metastatic disease was 22.3 months. Conclusions: In this study, when EGFR therapy is limited to patients with KRAS wt mCRC previously treated with 5-FU, Ox and Iri, only 15% received such therapy and poor performance status was the dominant reason for non-treatment. Earlier initiation of EGFR therapy may increase the proportion of patients treated with all active systemic agents. [Table: see text]