Melanoma Deaths by Thickness: Most Melanoma Deaths Are Not Attributable to Thin Melanomas

Previous population-based studies have reported that the majority of melanoma mortality is related to patients with thin (≤1 mm Breslow thickness) melanomas. The aim of the present study was to evaluate the relative proportion of melanoma-specific deaths across all stages of melanoma at diagnosis over the past 20 y in the United States.

A review of all cutaneous melanoma cases in the US Surveillance, Epidemiology, and End Results registry from 2004 to 2020 was performed. Breslow thickness was categorized as thin (≤1.0 mm), intermediate (>1-4 mm), or thick (>4 mm). All-cause deaths and melanoma-specific deaths were compared across tumor thickness and stage groups at diagnosis. Survival analysis was performed with nonmelanoma deaths considered as a competing risk to estimate the cumulative incidence of melanoma-specific death.

Most melanoma deaths occurred in patients who initially presented with local disease (53%) compared to regional (36%) or distant (11%) disease (P < 0.001). However, most (66%) of the melanoma-specific deaths in patients who presented with localized disease were in those with intermediate or thick (i.e., Breslow thickness >1.0 mm) primary tumors compared to those with thin melanomas (34%). The cumulative incidence of melanoma-specific death at 10 y in patients with localized thin melanomas at the time of diagnosis was 2.6% (95% confidence intervals 2.5%-2.7%).

The public health burden in terms of melanoma-specific mortality is related to patients with tumors >1 mm Breslow thickness, many of whom have regional and distant metastatic disease at the time of diagnosis, not patients with thin melanomas.