Investigators analyzed blood samples from 50 patients with gastric cancer who participated in the CRITICS trial, a phase III, randomized controlled study of chemotherapy given at about the time of surgery. They performed deep sequencing of both circulating cell-free DNA (cfDNA) and of white blood cells to look for mutations. Subtracting the white blood cells’ information from cfDNA yielded data investigators could use to predict cancer recurrence within nine weeks following preoperative treatment and surgery.

“We performed this study to see if we could predict whether gastric cancers would recur using noninvasive liquid biopsies. Using a deep sequencing approach of cell-free DNA and white blood cells, we found an outstanding prediction of whether the therapy was successful,” says senior study author Victor Velculescu, M.D., Ph.D., professor of oncology, pathology and medicine. Velculescu also is co-director of the Kimmel Cancer Center’s cancer genetics and epigenetics program, and associate director for precision medicine.

Alessandro Leal, M.D., Ph.D., lead author of the paper on the study and former graduate student at the Johns Hopkins University School of Medicine says, “Patients who did not have mutations in the blood after surgery were all cured of cancer, while patients who had mutations in the blood typically recurred. We were able to predict patient outcome about nine months earlier through the blood test than we otherwise could have through clinical evaluation.”

The study was performed by Leal and Velculescu, colleagues from Johns Hopkins and with Nicole van Grieken, Gerrit Meijer and Annemieke Cats and other investigators in the Netherlands. Plans to validate the method in larger clinical trials have begun.

Velculescu and Leal are available for media interviews about the study. For more information or to schedule an interview, contact the Johns Hopkins Kimmel Cancer Center Office of Public Affairs at 410-955-1287, [email protected] or [email protected].