Dr. Kasi on the Prognostic Value of ctDNA in CRC

Pashtoon M. Kasi, MD, MBBS, MS, assistant professor of oncology, senior associate consultant, Division of Hematology/Oncology, Mayo Clinic, discusses the prognostic value of circulating tumor DNA (ctDNA) in colorectal cancer (CRC).

Investigators have shown that the presence of ctDNA after curative-intent surgery or multimodality treatment in patients with CRC may be an indicator for relapse, says Kasi.

ctDNA is typically tested 2 to 4 weeks following surgical resection. Patients who are ctDNA-positive following surgery have a high likelihood of disease recurrence within 2 years, says Kasi.

Unlike carcinoembryonic antigen testing and carbohydrate antigen 19-9 testing, false positives are not common with ctDNA assays. In patients who are ctDNA-negative and recur, Kasi reasons that the results may reflect low tumor volume, tumor location, or a less sensitive assay.