Guideline-recommended incorporation of biomarker testing results in metastatic colorectal cancer therapy.

Aim: To describe pharmacogenomic tumor testing among patients with metastatic colorectal cancer. Methods: This was a retrospective study of patients with metastatic colorectal cancer diagnosed between 1 January 2014 and 30 June 2018. Patients were assessed for pharmacogenomic testing and appropriateness of chemotherapy use. Results: Overall, 112/167 (67.1%) patients had at least one of the three recommended pharmacogenomic tests and 41/167 (24.6%) had all tests. Twenty-four patients were treated with cetuximab with 8/167 (4.7%) identified as being treated with a RAS variant (n = 3) or incomplete testing (n = 5); thus, not in accordance with guidelines. Conclusion: Uptake of testing was variable but increased over time; however, a small proportion of patients received cetuximab with a variant or not all recommended tests being performed.