Detecting cancer early could save untold lives, and new research provides a glimpse of what that treatment might look like — something as simple as a blood test.
Because our bodies’ cells, including cancer cells, emit chemical signals into the bloodstream when they die, researchers hope that emerging treatment methods that can locate trace amounts of tumor-cell byproduct, known as circulating tumor DNA (ctDNA), can identify cases of cancer earlier than ever.
Currently, oncologists can configure cancer treatments for specific people based on tumor DNA, but only for those with advanced stages of cancer, when DNA amounts are high. By zeroing in on miniscule amounts of DNA, researchers believe they can catch cancer early and save countless lives.
“It’s fair to say that if you could detect all cancers while they are still localized, you could diminish cancer deaths by 90 percent,” Dr. Bert Vogelstein, a professor of Oncology at Johns Hopkins School of Medicine in Baltimore, told The Guardian.
A group of cancer researchers convening at an oncology conference in Chicago unveiled a new study that may help bring blood-detection treatment to the fore.
Specifically, the team’s findings found that a novel blood assay discovered genetic mutations with “high sensitivity.” The new approach would allow scientists to “detect cancer mutations in the blood without already knowing which mutations are in a patient’s tumor,” report the authors.
“The ability of this assay to detect ctDNA without prior knowledge of tumor sequencing results and with an unprecedented breadth of signals are both important findings that support the possible feasibility of applying this approach to detection of cancer at earlier stages,” Dr. Pedram Razavi, the study’s first author, said. “This new assay demonstrates early promise for the future development of blood tests for early cancer detection.”
The new blood test can detect up to 508 genes, which is about 10 times as many genes as previous tests could identify. The researchers note that because cancer cells can produce distinct mutations, the more of the genome that a test can cover the better.
Also, the specificity of the gene test can help pinpoint tumor DNA, which comprises only about 1 percent or less of the circulating DNA pieces in a person’s blood. The new assay produced compelling results — it detected 73 percent of tumor mutations in the blood and found at least one mutation in 89 percent of patients studied.
One day soon, researchers believe a simple blood-based test will be available to help reduce the impact of many forms of cancer.
“You’d have your cholesterol check, your blood sugar check and DNA check at the same time. That’s what I would envisage happening,” said Dr. Peter Gibbs, associate professor of Medical Oncology at the Royal Melbourne and Western Hospitals in Australia.
Gibbs estimated that, realistically, a blood test for cancer was about three to five years away from being an option for patients. Part of the challenge is that blood tests may result in false positives, or a false reading of cancer, that can lead to harmful interventions.
“Working out how you can develop assays that accurately predict who’s got cancer and who will go on to get cancer is a real challenge,” Dr. Nicholas Turner from the London-based Institute of Cancer Research told The Independent.
“It’s clearly going to be many years until the assays come through but a large number of biotech firms are devoting a substantial amount of money so I think we should be very optimistic that they will come through and the challenge of false positives will be overcome,” said Turner.
Richard Scott is a health care reporter focusing on health policy and public health. Richard keeps tabs on national health trends from his Philadelphia location and is an active member of the Association of Health Care Journalists.