Medical tests often offered through smartphones and watches and designed to detect the early signs of disease are being promoted by media without mention of their potential harms, an Australian study published in the leading US medical journal JAMA Internal Medicine has found.
Researchers from the University of Sydney and Bond University in Queensland analysed 1,173 news stories from between 2016 and 2019 from newspapers, blogs, magazines, broadcast and podcast transcripts, and wire news services.
Specifically, researchers examined stories about five new early detection tests, including liquid blood biopsies to detect cancers; using the Apple Watch to detect atrial fibrillation; blood tests for dementia; artificial intelligence tests for dementia; and 3D mammography for breast cancer.
While almost all the stories reported on the potential benefits of these tests, over 60% failed to mention any potential harms or limitations of the tests.
One story claimed: “A simple blood test can now detect dementia decades before any symptoms appear” and advocated using the test during routine health checks. It failed to mention the tests were yet to be proven to be definitive, and there was concern about them returning false-positive results.
Another story described liquid biopsy for cancer diagnosis as a “holy grail” that could “find very early-stage cancer in those with no symptoms”.
The premise of the tests is that because cancer cells can shed DNA into the bloodstream, sequencing this DNA can reveal mutations. But mutations can be found from all kinds of DNA, including from white blood cells, viruses and bacteria, and the difficulty with liquid biopsy cancer tests is that they may in fact be finding some of these benign mutations, and not ones related to cancer.
A senior author of the study, Dr Ray Moynihan, who is an assistant professor at Bond University, said media reports were one of the primary ways people learned about new tests and treatments.
“We know from strong evidence that media information can change healthcare behaviour,” he said. “As a result it’s vitally important that media reporting on new tests and treatments is balanced and complete.”
“No one had really previously studied how media is covering these new screening tests that pop up all the time, that are often targeted towards the healthy as a means of detecting disease before symptoms develop.”
Screening healthy people can have downsides, including over-diagnosis and over-treatment. Australian medical authorities were so concerned about healthy people receiving unnecessary tests and treatments that in 2017 they issued a joint statement calling for a plan to stop patients being harmed by the over-diagnosis and over-treatment of diseases.
The study also found widespread failure of media outlets to cover important conflicts of interest, such as commentators receiving payments from the companies marketing the new tests. For example, 19 of 22 authors of a key trial examining the ability of the Apple Watch to detect atrial fibrillation disclosed taking grants or personal fees from Apple, yet this information was rarely reported in news stories.
Moynihan said half the stories researchers examined quoted someone who had a financially relevant conflict of interest, but only 12% of stories disclosed that.
“These are very worrying findings that suggest that the public is being given an over-optimistic picture about these tests,” he said.
“Some of these tests will be lifesaving and will be incredibly valuable, but we’ve got to stop overhyping them. It is important to remember the test-makers make a shitload of money if they can maximise markets for their tests, but the companies selling the treatments also make a motza.”
Over-diagnosis occurs when people receive a diagnosis of a disease or condition that will never develop to cause any symptoms or early death. It is an unnecessary diagnosis that does more harm than good.
Evidence published last year in the Medical Journal of Australia shows that for common cancers, around one in five cancers may be over-diagnosed.
Medical technology is now so advanced that early abnormal cell changes and lesions, sometimes described as “pre-cancers”, can be detected at much smaller sizes.
However, for some types of cancers, these early changes or lesions will never go on to cause harm in the patient’s lifetime. But identifying these changes can cause distress and prompt patients to undergo treatment to get rid of them, with the treatments sometimes carrying risks.
The JAMA paper concluded that strategies to improve media reporting so that professionals, patients and the public can receive more balanced information about early detection tests were “urgently needed”.