The Problem of Overdiagnosis
Some medical conditions are being diagnosed too often and therefore could be dangerously over-treated, according to five influential Australian health care organizations that recently released a joint statement calling for action to tackle the problem.
Overdiagnosis occurs when someone is diagnosed with a disease that wouldn’t harm them, or when treatment does more harm than good. It happens because healthy people are often tested or screened to find the early signs of disease and because diagnostic technology can see ever-smaller abnormalities.
The problem is that early detection of disease is a double-edged sword. While it can be life-saving, for some people the “abnormalities” that are diagnosed and treated would never have caused harm if left alone.
The number of people diagnosed with thyroid cancer has tripled in recent decades—many of them with very small tumors, according to research published in The New England Journal of Medicine (NEJM) last year.
The problem, say researchers, is that many of those small tumors are in fact benign. And many of the people being diagnosed and then treated with potentially risky operations and drugs, are overdiagnosed.
The NEJM piece estimated that over 500,000 people may have been overdiagnosed in the past two decades, across 12 countries.
There are ongoing debates about whether too many children are being diagnosed with and medicated for attention deficit hyperactivity disorder (ADHD).
A study of almost 1 million Canadian children found those born in December were much more likely than those born in January to receive an ADHD diagnosis and medication, which could mean that immaturity is being pathologized.
“These findings raise concerns about the potential harms of overdiagnosis and overprescribing,” researchers concluded.
Concerns about overdiagnosing prostate cancer date back at least 30 years. Many men will die with prostate cancer, rather than from it. Despite evidence of unnecessary diagnoses and overtreatment, the push to test healthy men, with no symptoms, for prostate cancer continues.
While it’s hard to know exactly how many men are overdiagnosed with prostate cancer, recently reported estimates from the United States suggest between 20 to 50 percent of prostate cancers diagnosed during screening may be overdiagnosed. In other words, they would not have caused harm if left undetected.
Polycystic Ovary Syndrome
Polycystic ovary syndrome (PCOS) is an example of a condition for which changes in the definition have greatly increased the number of people labeled. In a piece published this month in the British Medical Journal (BMJ), researchers from the University of Sydney show how the proportion of women of reproductive age who could potentially be labeled has jumped dramatically from around 5 percent using the 1990 definition, to up to 21 percent when using the 2003 definition.
As the authors suggest, there are concerns many healthy women may be labeled unnecessarily, causing anxiety about their fertility or long-term health. The authors, therefore, recommended a cautious approach to diagnosing the condition.
Reflecting uncertainty around exactly how to measure overdiagnosis, there are sometimes wide variations in estimates of the size of the problem. A major independent review of the global evidence suggested 19 percent of the breast cancers diagnosed during active mammography screening may be overdiagnosed. This means they would not have caused harm to the women because they were most likely benign.
Previous estimates in Australia suggest the rate could be around 30 percent.
What Can We Do About Overdiagnosis?
We recently published a comprehensive analysis in the BMJ of possible drivers of overdiagnosis and potential solutions. Causes range from cultural beliefs that “more is better” in medicine, to financial incentives driving unnecessary tests and treatments.
The good news is that doctors’ groups across the globe are now publicly acknowledging the problem of overdiagnosis.
As our BMJ analysis highlights, there are many potential solutions. There’s an urgent need for public information and awareness campaigns. New educational curricula for health professionals are a priority. And screening programs need to be reformed to make sure we’re only targeting those at high risk.
in Gold Coast, Australia. This article was originally publishedenior research fellow at Bond University
on The Conversation.