More than one-half of melanoma cases diagnosed among White patients in 2014 may represent cases of overdiagnosis, according to study findings published in JAMA Dermatology.
The findings are based on a retrospective observational study that sought to estimate excess melanoma incidence in White patients in the United States. Data from the Surveillance, Epidemiology, and End Results (SEER) program were used to compare melanoma incidence and mortality trends among Black and White patients from 2014 to 1975.
The percentage of cases overdiagnosed in 2014 was calculated as the difference in observed incidence and true cancer occurrence trends from 1975 to 2014 divided by the observed incidence trend.
The melanoma incidence increased about 4-fold in White women (incidence rate ratio [IRR], 4.01 [95% CI, 3.65-4.41]) and 6-fold in White men (IRR, 5.97 [95% CI, 5.47-6.52]) from 1975 to 2014. The change in incidence was small among Black women (IRR, 1.21 [95% CI, 0.97-1.49]) and Black men (IRR, 1.17 [95% CI, 0.77-1.78]) during the same period.
Mortality owing to melanoma was stable among White women (mortality rate ratio [MRR], 1.02 [95% CI, 0.96-1.09]) and increased by nearly 50% in White men (MRR, 1.49 [95% CI, 1.25-1.77]). Melanoma mortality was reduced by about 25% in Black women (MRR, 0.76 [95% CI, 0.63-0.90]) and in Black men (MRR, 0.72 [95% CI, 0.62-0.84]).
Using these mortality trends as a proxy for changes in true cancer occurrence, the investigators found that the percentage of cases overdiagnosed in 2014 was 59% (95% CI, 45%-70%) among White women and 60% (95% CI, 32%-75%) among White men.
Study limitations include a cohort of only Black and White patients in the United States, and so the findings may not be generalizable to other populations, the investigators note. Also, the estimates are based on populations and do not provide information on individual patients, and the analysis did not include more recent trends in overdiagnosis.
“As with clinicians in other subspecialties, dermatologists must grapple with the very real prospect that screening is a major source of the increased incidence of melanoma,” the study authors commented. They also suggested that additional studies may “quantify the reservoir of asymptomatic, indolent disease by performing an ‘epidemiologic necropsy,’ an autopsy study in which individuals not known to have melanoma during life have all moles biopsied to fully understand the contribution of medical care to the melanoma epidemic.”
Adamson AS, Suarez EA, Welch HG. Estimating overdiagnosis of melanoma using trends among black and white patients in the US. JAMA Dermatol. 2022;158(4):426-431. doi:10.1001/jamadermatol.2022.0139