Cancer tumours release tiny traces of mutated DNA and proteins into a person’s bloodstream. Potentially, people could have an annual blood test and if the result is positive, they would then undergo more stringent tests to determine what form of cancer it is and what is the best treatment.
Paul Pharoah, professor of cancer epidemiology at the University of Cambridge, said the test needed more work in detecting early stage symptomatic cancer. These included 93 patients with stage I to I-III pancreatic cancer who were enrolled in the study and compared with 812 healthy control individuals with no known history of cancer, high-grade dysplasia, autoimmune disease, or chronic kidney disease. The team, he said, developed a “robust panel” of tests that could detect at least one mutation in the DNA that could predict the cancer.
Some independent experts saw great promise. Neither of these attempts has been able to give reliable results.
“I’m enormously excited”, he said. Papadopoulos explained that these cancers were chosen on the basis of their prevalence among the populations and because many of these do not have a screening test at present.
‘While screening tests for some cancers have already been developed, and are associated with earlier diagnosis and better outcomes, for many major tumour types there are no effective screening tests, ‘ he said. That can happen if they set off too many false alarms or if doctors end up treating slow-growing cancers that are not likely to do much harm. The researchers estimate that the cost of this single blood test for eight cancer types may be less than US$500, which is comparable to or lower than screening tests such as colonoscopy.
Scientists have named the experimental blood test as CancerSEEK that focuses on eight main types of cancers- lung, breast, pancreas, liver, colon, stomach, ovary and esophagus. “A test does not have to be flawless to be useful”, Papadopoulos says.
The next steps for the Johns Hopkins research team include ensuring that the test works in patients who are not symptomatic. It can reveal early-stage cancers in about 70percent of cases, and up to 98percent for some types of cancer. In collaboration with Johns Hopkins, the Geisinger Health System in Pennsylvania has already begun to use CancerSEEK on blood samples from female volunteers between ages 65 and 75 who have never had cancer.
Some cancers do not have screening programmes available for early detection.
But Professor Gibbs said they expected the cost to come down over time as the technology progressed and the number of people being tested rose.
Cell biopsy studied under a microscope – the current way of detecting cancer. The new blood detected signs of cancer in nearly 70 percent of the cancer patients. Researchers plan to follow those participants for five years.
“So hopefully, eventually this will be a few hundred dollars, which puts it in the ballpark of many other tests that we routinely do”, he said.