The overall incidence of melanoma appears to be stabilizing in the United States, but the incidence of thick melanomas is rising, according to research published in JAMA Oncology.
For this study, researchers evaluated the incidence of melanoma between 2010 and 2018 using data from the SEER registry. The researchers also looked at melanoma subtypes by thickness.
Tumor thickness categories were defined as: less than or equal to 1 mm (T1), greater than 1 mm to 2 mm (T2), greater than 2 mm to 4 mm (T3), and greater than 4 mm (T4).
The study included 187,487 patients with newly diagnosed cutaneous melanoma — 62.4% with T1 tumors, 12.7% with T2, 7.9% with T3, and 6.4% with T4. The patients’ median age was 62 (range, 52-72) years, and 58.4% of patients were men.
There was no significant increase in overall melanoma incidence during the study period. The annual percentage change (APC) from 2010 through 2018 was 0.39% (95% CI, -.40 to 1.18).
In fact, there was a slight decrease in incidence for T1, T2, and T3 melanomas. The APC was -0.28% for T1 (95% CI, -1.98 to 1.46), -0.70% for T2 (95% CI, -1.67 to 0.29), and -0.66% for T3 (95% CI, -1.69 to 0.38).
However, there was a significant increase in T4 melanomas over time, with an APC of 3.32% (95% CI, 2.06 to 4.60).
“This population-based cohort study is, to our knowledge, the first study to suggest potential stabilization of overall melanoma incidence rates in the US after nearly a century of continuous increase in incidence,” the researchers wrote.
“However, the continued increase in incidence of the thickest melanomas is concerning. The continued increase … is unlikely to be because of overdiagnosis given the stability of thin melanoma incidence rates.”
Chen ML, de Vere Hunt IJ, John EM, Weinstock MA, Swetter SM, Linos E. Differences in thickness-specific incidence and factors associated with cutaneous melanoma in the US from 2010 to 2018. JAMA Oncol. Published online March 24, 2022. doi:10.1001/jamaoncol.2022.0134