New screening test for biomarkers are able to determine recurrence of colon cancer at better rates

Researchers from Ludwig Institute for Cancer Research have found a way to use biomarkers in blood to determine the rate of reoccurrence for colon cancer and the efficacy of chemotherapy following surgery.

By analyzing pieces of tumor DNA that was circulating in the blood stream of colon cancer patients, researchers were able to increase the accuracy of detecting reoccurrences. With the recent innovations in technology, researchers were able to examine the DNA that cancer cells had shed within the blood stream. They were then able to identify the mutations of circulating tumor DNA (ctDNA) which represent a very specify cancer biomarker.

"Prior studies, including ones from our group, have shown that this technique is sensitive enough to detect tumor DNA fragments in patients with advanced cancer," Bert Vogelstein, co-director of the Ludwig Center at Johns Hopkins and one of the study leaders. "But this new study gets us one major step closer to the real goal, because it suggests that it can detect residual disease in early stage patients well before conventional clinical or radiologic criteria can."

A study was conducted on 230 patients with stage II colorectal cancer. Blood samples were compared to samples taken four to 10 weeks after surgery to remove tumors. Results showed that 20 patients tested positive for ctDNA. Of these, 80 percent had a relapse of cancer within two years while only 10 percent of the remaining population experienced a relapse.

"A positive ctDNA test is an indicator that cancer cells from the original tumor are hiding somewhere in the body," said Peter Gibbs, a Ludwig investigator at WEHI. "When such a generic test is developed, it could still catch more than 90 percent of colorectal cancers, and it would eliminate the need to retrieve and test individual tumor samples, thus saving time, effort and money.”