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Is Melanoma Overdiagnosed?

Is melanoma overdiagnosed? I recently wrote about an article on cancer screening where melanoma was discussed as a cancer that was "overdiagnosed". And now an article, with supporting research, from Health News Review  (an excellent site that does "critical thinking about health care") about the issue of overdiagnosis of melanoma during skin screening tests. What? This is definitely news to many.

The following article was written because of a new skin cancer screening test developed using artificial intelligence (AI) that could distinguish between melanomas and benign moles. It turns out that a lot of people have concerns over melanoma being overdiagnosed (and therefore overtreated), including the U.S. Preventive Services Task Force.

But how do we know melanoma is being overdiagnosed? Because even though more and more melanomas are being found (through screening tests) and treated, the death rate from melanoma has stayed the same over the past 40 years (see the graph below).  Just note that what is described here are moles diagnosed as melanoma during screening tests, meaning that small moles just sitting there on the body are examined. It is not talking about moles that are changing in some worrisome way - those should absolutely be checked out. Excerpts from Kevin Lomangino's post at  Health News Review:

Yes, melanoma can be overdiagnosed, but news stories like these don’t discuss it

Many stories, like this U.S. News & World Report piece, suggested that AI “may serve physicians involved in skin cancer screening as an aid in their decision whether to biopsy a lesion or not.” But none of the stories I looked at paused to ask, Is finding more melanoma definitely a good thing? 

Overdiagnosis: An ‘under-discussed problem’ - That was the question that immediately came to mind for Ade Adamson, MD, an assistant professor in the Department of Dermatology at the University of North Carolina at Chapel Hill. He points out that the number of melanoma diagnoses among white Americans has increased some four to six times over the past 40 years, and yet deaths from melanoma have stayed constant during that period.

This suggests that many of the melanomas being detected today might be better off not being found. These cancers are so slow-growing that they would never cause a problem, he said.

The U.S. Preventive Services Task Force cites overdiagnosis as one of the reasons it doesn’t endorse routine skin cancer screening. The task force concludes that “the current evidence is insufficient and that the balance of benefit and harms of visual skin examination by a clinician to screen for skin cancer in asymptomatic adults cannot be determined.”

And yet doctors are certainly finding and treating more of these cancers every year and creating an ever-growing number of melanoma patients. Adamson believes AI-based evaluations could make the problem worse by increasing the availability of screening outside of doctors’ offices. “Overdiagnosis in melanoma is one of the most under-discussed problems in dermatology,” he said.  “Actually, some call it the ‘third rail’ of dermatology, so many don’t even mention it. It was never discussed when I was training.”

David Elpern, MD, a dermatologist in private practice in Williamstown, MA, agrees that overdiagnosis is a big problem in dermatology and sees technology as contributing to it. He spoke to the Lown Institute conference recently about changes in dermatology practice that promote unnecessary and wasteful care.

Elpern sent me this graph from the National Cancer Institute which documents the disconnect between melanoma incidence (the rising green line which indicates the number of people diagnosed with melanoma each year) and melanoma deaths (the flat dark line at the bottom of the graph indicating no change in the mortality rate).

He says there are many factors driving the increase in melanoma diagnoses. “Pathologists are calling things melanoma that they never called melanoma 30 years ago,” Elpern said. Elpern also points to tools like the dermatoscope, which is used to evaluate suspicious moles. He says they can pick up potentially cancerous changes before they might be detected with the naked eye, which is not always a good thing.

“The dermatoscope and mole scans can pick up very early things, and then the patient is labeled as having a melanoma and they get shunted into the system,” he said. He believes screening “creates a lot of health anxiety on the part of patients” despite the lack of proof that it’s improving outcomes.

 A melanoma of approx. 2.5 cm by 1.5 cm. Credit: Wikipedia

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