Skin cancer screenings associated with greater incidence of thin melanoma lesions

Results from a quality-improvement study showed that primary care-based melanoma screening correlated with an increased detection of thin melanoma, according to data published in JAMA Dermatology.

“Melanoma can be detected with a simple naked-eye examination, and stage at diagnosis is the best predictor of prognosis, so systematic skin cancer screening may reduce melanoma mortality,” Martha Matsumoto, MD, a dermatologist in Pittsburgh who is affiliated with United Hospital, and colleagues wrote. “However, to our knowledge, no randomized clinical trials of melanoma screening have been performed.”

To compare thickness-specific incidence of melanoma among screened and unscreened patients, Matsumoto and colleagues conducted an observational study that comprised 595,799 individuals. Of those, 144,851 received at least one screening.

Screened patients were slightly older (median age, 59 vs. 55 years), more likely to be female (56.8% vs. 55.6%; P < .001) and more likely to have a self-identified race and ethnicity of non-Hispanic white (86.1% vs. 83.4%; P < .001) compared with unscreened patients. Additionally, 32.9% of screened patients and 28.4% of unscreened patients were aged at least 65 years.

A total of 994 patients, including 356 screened patients, received a diagnosis of melanoma with a determined thickness. After 60 days from the first screen date, 110 patients in the screened group and 73 patients in the unscreened group has a melanoma diagnosis. The remaining melanoma diagnoses occurred during the observation period of the study and considered interval melanomas.

After adjusting for age, sex and white race, the researchers found that melanomas among the screened patients were more likely than those in unscreened patients to be in situ (HR = 2.6; 95% CI, 2.1-3.1) or thin invasive melanoma of 1 mm or smaller (HR = 1.8; 95% CI, 1.5-2.2).

Matsumoto and colleagues also found that screened patients were more likely than unscreened patients to be diagnosed with interval melanomas that were in situ (HR = 2.1; 95% CI, 1.7-2.6) or thin invasive lesions of 1 mm or smaller (HR = 1.3; 95% CI, 1-1.7).

“Our findings and study design are important because we will be able to quantify the association of screening with melanoma overdiagnosis (a potential harm of screening), and with more follow-up time, with the incidence of thick melanomas (a benefit of screening that would be anticipated to influence survival, morbidity and treatment costs),” Matsumoto and colleagues wrote.

The researchers concluded that screening older patients for melanoma, particularly men, may be cost-effective.

“Real-world data can add to this to help to determine which patients, if any, can benefit from screening and the optimal screening strategies that maximize benefit and minimize cost and harms,” Matsumoto and colleagues wrote. “Longer follow-up is needed to fully determine the association of screening with outcomes such as the incidence of thick melanoma, treatment cost and morbidity, distant metastasis and death.”