new research shows.
Without a corresponding decrease in melanoma mortality, an increase in the detection of those thin melanomas “raises the concern that early detection efforts, such as visual skin screening, may result in overdiagnosis,” the study authors wrote. “The value of a cancer screening program should most rigorously be measured not by the number of new, early cancers detected, but by its impact on the development of late-stage disease and its associated morbidity, cost, and mortality.”
The research, published in JAMA Dermatology, has reignited the controversy over the benefits and harms of primary care skin cancer screening, garnering two editorials that reflect different sides of the debate.
In one, Robert A. Swerlick, MD, pointed out that, “despite public messaging to the contrary, to my knowledge there is no evidence that routine skin examinations have any effect on melanoma mortality.
“The stage shift to smaller tumors should not be viewed as success and is very strong evidence of overdiagnosis,” wrote Dr. Swerlick, of the department of dermatology, Emory University, Atlanta.
The other editorial, however, argued that routine screening saves lives. “Most melanoma deaths are because of stage I disease, with an estimated 3%-15% of thin melanomas (≤ 1 mm) being lethal,” wrote a trio of editorialists from Oregon Health & Science University, Portland.
When considering the high mutation rate associated with melanoma and the current limits of treatment options, early diagnosis becomes “particularly important and counterbalances the risk of overdiagnosis,” the editorialists asserted.
Primary care screening study
The new findings come from an observational study of a quality improvement initiative conducted at the University of Pittsburgh Medical Center system between 2014 and 2018, in which primary care clinicians were offered training in melanoma identification through skin examination and were encouraged to offer annual skin cancer screening to patients aged 35 years and older.
Of 595,799 eligible patients, 144,851 (24.3%) were screened at least once during the study period. Those who received screening were more likely than unscreened patients to be older (median age, 59 vs. 55 years), women, and non-Hispanic White persons.
During a follow-up of 5 years, the researchers found that patients who received screening were significantly more likely than unscreened patients to be diagnosed with in situ melanoma (incidence, 30.4 vs. 14.4; hazard ratio, 2.6; P < .001) or thin invasive melanoma (incidence, 24.5 vs. 16.1; HR, 1.8; P < .001), after adjusting for factors that included age, sex, and race.
The screened patients were also more likely than unscreened patients to be diagnosed with in situ interval melanomas, defined as melanomas occurring at least 60 days after initial screening (incidence, 26.7 vs. 12.9; HR, 2.1; P < .001), as well as thin invasive interval melanomas (incidence, 18.5 vs. 14.4; HR, 1.3; P = .03).
The 60-day interval was included to account for the possible time to referral to a specialist for definitive diagnosis, the authors explained.
The incidence of the detection of melanomas thicker than 4 mm was lower in screened versus unscreened patients, but the difference was not statistically significant for all melanomas (2.7 vs. 3.3; HR, 0.8; P = .38) or interval melanomas (1.5 vs. 2.7; HR, 0.6; P = .15).