Dr. Messersmith on the Rise of Molecular Testing in mCRC

Wells A. Messersmith, MD, co-leader of the Developmental Therapeutics Program, and director, GI Cancer Program, at the University of Colorado School of Medicine, discusses the rise of molecular testing in metastatic colorectal cancer (mCRC).

There has been a shift in which molecular analysis is being done for most cases, says Messersmith. However, not all tests that need to be done are done today.

When Messersmith did second opinions a couple years ago, there was nothing to reference, as tests were rarely sent for. If they were, the testing was very outdated. For example, KRAS would be tested for but not NRAS. Now, both alterations should be tested for unless patients have a known KRAS mutation, as they’re probably not going to present together. Back then, only codon 12 and 13 were tested for. Now it is known that codon 61 and 146 should be tested for as well. BRAF or microsatellite status were also commonly ignored, adds Messersmith.

If a patient was tested a few years ago as the test may be outdated. Targets, codons, and mutations have to be tested for in order to interpret the results appropriately. Sometimes further testing is necessary to devise an appropriate treatment strategy, concludes Messersmith.