Dr. Grothey on the Differences Between Available ctDNA Assays in CRC

Axel Grothey, MD, medical oncologist and director of Gastrointestinal Cancer Research at West Cancer Center and Research Institute, discusses the differences between available assays evaluating circulating tumor DNA (ctDNA) in colorectal cancer (CRC).

Tumor-informed ctDNA testing comprises highly sensitive and individualized polymerase chain reaction–based assays, says Grothey. This type of assay is developed from whole-exome sequencing of the tumor to inform the genetic fingerprint of the individual patient’s cancer, Grothey explains.

Conversely, non-tumor informed ctDNA assays are one-size-fit-all, off-the-shelf testing approaches that are likely less specific but test for a range of common mutations, such as APC and RAS, as well as methylation markers, Grothey says. Both testing modalities are available for patients with CRC, concludes Grothey.