From the Journals

Does screening for skin cancer result in melanoma overdiagnosis?


 

When the COVID-19 pandemic first hit, cancer screening in the United States came to an abrupt halt. That experience, coupled with the financial fallout of the pandemic, has led some doctors to reassess business as usual.

In particular, a trio has taken aim at skin cancer screening – arguing that it should stop – in a ‘sounding board’ commentary published online Jan. 7 in the New England Journal of Medicine.

“The COVID-19 pandemic has functionally stopped skin cancer screening; what is important is not to restart it,” wrote the authors, led by H. Gilbert Welch, MD, MPH, at Brigham and Women’s Hospital, Boston, Massachusetts. Dr. Welch has often raised questions about cancer screening and highlighted the issue of overdiagnosis.

In this latest essay, Dr. Welch teamed up with pathologist Benjamin Mazer, MD, Yale University, New Haven, Conn., who writes commentaries for this news organization, and dermatologist Adewole S. Adamson, MD, University of Texas, Austin, to argue that screening for skin cancer has led to an overdiagnosis of melanoma.

However, two melanoma experts pointed out flaws in some of their arguments, and said the issue is more nuanced than they present.

Arguing that melanoma is overdiagnosed

The incidence of melanoma is six times as high as it was 40 years ago, making it the third most common cancer in the United States, the investigators pointed out. However, while case rates have skyrocketed, death rates from melanoma have remained about the same, which points to overdiagnosis.

They described a cycle of increased diagnostic scrutiny that is driving overdiagnosis of melanoma. This includes heightened awareness (perhaps overly) among patients, widespread skin screenings, lower clinical thresholds for biopsy, and lower thresholds among pathologists for diagnosis of melanoma. Fear of missing cancer, legal concerns, and financial incentives may all contribute.

“We view the rise in the incidence of melanoma as a sentinel event, a warning that an epidemic of inspection, surveillance, and biopsy of pigmented skin lesions is permeating through the general population,” they wrote.

Furthermore, overdiagnosis could contribute to unnecessary intervention.

Between 2004 and 2017, rates of biopsy among fee-for-service Medicare recipients almost doubled (from 5% to 8%), according to coding trends data cited in the article. Overdiagnosis and unnecessary intervention could cause psychological, financial, and physical harm to the patient, and the authors argued for interrupting the cycle.

“The most important step to break the cycle of melanoma overdiagnosis is to stop population-wide screening for skin cancer,” they wrote.

The U.S. Preventive Services Task Force currently states that there is insufficient evidence to weigh the balances versus the harms of skin cancer screening, leaving it open to interpretation.

“[T]he increase in melanoma diagnoses by a factor of 6, with at least an order of magnitude more persons undergoing a biopsy and no apparent effect on mortality, is more than enough to recommend against population-wide screening,” Dr. Welch and colleagues concluded.

But the issue may be more nuanced, argued a melanoma expert.

“Everyone agrees that screening high-risk groups has the greatest chance of reducing cancer mortality. In melanoma, the strongest risk factor is the number of moles and presence of clinically atypical moles,” David Polsky, MD, PhD, commented in an interview. Dr. Polsky is a professor of dermatologic oncology at the Perlmutter Cancer Center at New York University Langone Health.

However, population-based studies have shown that at least half of melanoma patients are not considered high risk based on the appearance of the mole, he explained.

“Studies to identify genetic risk factors for melanoma have not yet progressed to the point where these can be tested in the clinic. We clearly have a knowledge gap that needs to be addressed,” he said.

Moreover, it’s not easy to predict which early melanomas will metastasize, said dermatologist Jennifer Stein, MD, PhD, who specializes in treating patients at high risk for melanoma at NYU Langone.

“This paper suggests that it may not be important to detect and treat melanoma in situ, and that the increase in diagnosis of melanoma in situ has led to more harms than good,” she said. “There is evidence that most melanomas do originate as in situ lesions. Unfortunately, we cannot predict which ones will become more aggressive. For this reason, we treat melanoma in situ.”

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