Based on current research findings that an additional 15% of patients with colorectal cancer (CRC) with now-identifiable RAS-mutated tumors will derive no benefit from an EGFR inhibitor, the old test, which involves testing KRAS exon 2 codon 12 and 13, is no longer adequate. Standard of care is now the extended RAS test, which also includes the KRAS exons 3 and 4 and NRAS exons 2, 3, and 4.

NCCN guidelines now recommend expanded RAS testing, and it is listed in the package insert for EGFR-targeted therapies. RAS testing is completely necessary to make the decision about whether or not to administer an anti-EGFR antibody for patients with CRC. Whether the treatment choice is an anti-EGFR therapy upfront or in a later line of treatment determines how quickly the test needs to be completed.

To speed up the utilization of expanded testing, issues surrounding long turnaround times and lack of coverage are being resolved. However, there is still an educational gap. There are compliance issues on the oncologist’s end, but there are also problems around billing from the pathology end, explains Herbert Hurwitz, MD. The oncology community needs to organize and get beyond these hurdles in order to improve patient care. RAS test is state-of-the-art and there is the potential for harm if it is not conducted, emphasizes Axel Grothey, MD.

Next on the horizon is BRAF testing, which should currently be conducted as well, says Daniel Haller, MD. BRAF-positive tumors are aggressive and might benefit from more aggressive therapy such as FOLFIRINOX with bevacizumab, if the patient can tolerate it, or a clinical trial.