Blood Test May Lead to Earlier Identification of Common Cancers

A novel blood test may be able to screen for 8 common cancer types simultaneously, while also identifying the location of the disease, according to a study published by Science.

The authors said that 5 out of the 8 cancer types the test examines currently have no screening test, which marks a significant advancement in the oncology landscape.

"The use of a combination of selected biomarkers for early detection has the potential to change the way we screen for cancer, and it is based on the same rationale for using combinations of drugs to treat cancers," said senior author Nickolas Papadopoulos, PhD.

The CancerSEEK test analyzes levels of 8 cancer proteins and gene mutations from circulating DNA in the blood, according to the study.

"Circulating tumor DNA mutations can be highly specific markers for cancer. To capitalize on this inherent specificity, we sought to develop a small yet robust panel that could detect at least one mutation in the vast majority of cancers," said first author Joshua Cohen. "In fact, keeping the mutation panel small is essential to minimize false-positive results and keep such screening tests affordable."

The investigators identified promising segments of 16 genes and 8 proteins. The authors said that this particular test was aimed at screening for cancer and varies from other tests that rely on analyzing a large number of genes to identify a treatment target.

The new screening test was analyzed in 812 healthy controls and resulted in only 7 false-positive results, which is a specificity level greater than 99%, according to the study.

"Very high specificity was essential because false-positive results can subject patients to unnecessary invasive follow-up tests and procedures to confirm the presence of cancer," said researcher Kenneth Kinzler, PhD.

The test was also administered to 1005 patients with non-metastatic, stage 1 to 3 ovarian, liver, stomach, pancreatic, esophageal, colorectal, lung, or breast cancers.

The authors found that the median overall sensitivity was 70%, ranging from 98% for ovarian cancer to 33% for breast cancer, according to the study.

The sensitivity for 5 cancers that currently lack screening tests, which include ovarian, liver, stomach, pancreatic, and esophageal cancers, ranged from 69% to 98%, according to the study.

"A novelty of our classification method is that it combines the probability of observing various DNA mutations together with the levels of several proteins in order to make the final call," said researcher Cristian Tomasetti, PhD. "Another new aspect of our approach is that it uses machine learning to enable the test to accurately determine the location of a tumor down to a small number of anatomic sites in 83% of patients."

To further validate the test, the researchers also analyzed data from more than 30 years of cancer genetics research.

While the test does not screen for all types of cancers, the authors said it does identify diseases that otherwise would likely go undetected.

"This test represents the next step in changing the focus of cancer research from late-stage disease to early disease, which I believe will be critical to reducing cancer deaths in the long term," said Bert Vogelstein, MD.

The authors said that this test could be performed at the time of routine blood work and may cost less than $500. Larger trials of the test are ongoing, according to the study.

"This has the potential to substantially impact patients. Earlier detection provides many ways to improve outcomes for patients. Optimally, cancers would be detected early enough that they could be cured by surgery alone, but even cancers that are not curable by surgery alone will respond better to systemic therapies when there is less advanced disease," said Anne Marie Lennon, MD, PhD, associate professor of medicine, surgery and radiology, clinical director of gastroenterology and director of the Multidisciplinary Pancreatic Cyst Program.