A New Frontier: Identifying Traces of Colorectal Cancer in the Blood

For patients who have undergone surgery to remove colon cancer, one of the significant stressors is waiting to see if CT scans show that the cancer has recurred.

Now, new technology to detect cancer much earlier may alleviate the agonizing wait and lead to better outcomes. In 2020, Medicare recommended coverage for a new test that detects small amounts of circulating tumor DNA (ctDNA) in the blood of patients who previously received a diagnosis of certain types of cancer.

The Signatera test, developed by Natera, is being used in a clinical trial looking at how well the ctDNA testing works to predict the benefit of chemotherapy treatment after surgery for stage 3 colon cancer.

Recently, CURE® spoke with Dr. Scott Kopetz, a professor in the department of gastrointestinal medical oncology at the University of Texas MD Anderson Cancer Center in Houston, about the test’s potential value for patients.

“In early stage 2 colon cancer, for example, we do not typically recommend chemotherapy, but what if the test came back positive for cancer in the blood?” he said. “Then we might suggest chemotherapy.”

In patients with stage 3 disease, chemotherapy is usually prescribed, but a negative ctDNA test result might indicate that this treatment is not needed, Kopetz explains. The new blood test detects unique mutations in a patient’s tumor and has been shown in clinical studies to identify residual disease up to two years earlier than standard imaging.

“The challenge now is learning what to do with the information we gather from the test, but ultimately I think this technology will dramatically accelerate our ability to cure more patients,” Kopetz says.

To read more on how the identification of rare genomic alterations in patients with colorectal cancer has given oncologists the opportunity to treat patients who otherwise might not have many options, click here to read a feature in CURE®’s recent special gastrointestinal cancers issue.

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