MARCO ISLAND, Florida (GenomeWeb) – Geisinger Health and Johns Hopkins University have teamed up to study whether a liquid biopsy test that combines targeted circulating tumor DNA analysis with a number of protein markers can detect cancer early in healthy individuals.
At the Advances in Genome Biology and Technology meeting here last night, Joshua Cohen, a researcher at Johns Hopkins University who was involved in developing the test, called CancerSEEK, said that the study aims to recruit 50,000 healthy individuals. Cohen pointed out that for many types of cancer, early detection is associated with a better chance of survival, and for some, such as pancreatic or ovarian cancer, no good screening tests exist.
According to Geisinger's website, the Detecting Cancers Earlier Through Elective Mutation-Based Blood Collection and Testing (DETECT) study is currently recruiting 10,000 women between the ages of 65 and 75 with no personal history of cancer for the study by March of this year and had enrolled 7,600 as of January.
The blood test used in the study, which was described about a year ago in a study in Science, looks for mutations in 16 genes in cell-free DNA and will assess the levels of 11 protein markers.
The Science study, which was retrospective and tested samples from patients with eight different types of cancer at various stages, as well as from healthy controls, had shown that the assay was only 40 percent sensitive for stage I cancer. Also, sensitivity differed between cancer types, with the test performing best for ovarian and liver cancer and worst for breast cancer. Specificity was high, with only seven false positives in the 812 healthy controls.
In his presentation last night, Cohen said that the Hopkins team has also developed an algorithm that can help predict the tissue of origin of the cancer in those testing positive. Again, performance differs by cancer type, with the top prediction being 80 percent correct for colorectal cancer, for example, and less accurate for other cancers.
He said that in the DETECT study, patients with a positive result in the initial blood test and a confirmatory second sample will undergo additional testing based on the localization prediction, for example, a colonoscopy if the assay predicts colorectal cancer. If the origin of the cancer cannot be predicted, they will undergo a PET-CT scan.
According to the Geisinger website, patients with two positive blood tests will talk to a genetic counselor and receive a recommendation for a PET-CT scan that will be paid for by the study.
In an interview with ABC last month, Andrew Faucett, co-chair of the Genetic Counseling Professional Council at Geisinger, said that while the current phase of the study, which has been ongoing for about a year, is recruiting only women, who are often more willing to see a doctor and more engaged, the study will expand to include men if successful. All participants will be followed for two years to see if they develop cancer.
He said the test has already detected cancer, including colon and ovarian cancer, in nine study participants.