Differences in mean age at diagnosis of invasive melanoma for men and women by anatomical site, thickness and subtype.

Abstract

Background: Understanding the factors that influence age at melanoma diagnosis by sex and anatomical site is crucial for developing effective prevention and early detection strategies. While previous research has highlighted sex-based differences in melanoma incidence by age and anatomical distribution, the underlying mechanisms remain unclear.

Objectives: To investigate sex-specific patterns in melanoma age at diagnosis across different anatomical sites and thickness categories, considering the potential influence of disease progression and detection rates.

Methods: We conducted a registry-based study to examine mean age at diagnosis of invasive melanoma over two decades for White men and women in the USA and for the population in Queensland, Australia. Mean age at diagnosis was calculated for men and women according to anatomical site (head/neck, trunk, upper limb, lower limb), and by Breslow thickness (≤ 1.00 mm, 1.01-2.00 mm, 2.01-4.00 mm, > 4.00 mm) and histological subtype (superficial spreading, nodular, lentigo maligna, 'other' subtypes and subtype 'not otherwise specified'). Case listings of all invasive melanoma diagnoses between 1 January 1999 and 31 December 2018 were obtained from the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) programme (nine registries) and from the Queensland Cancer Registry. Sensitivity analyses were performed that restricted the data to the most recent 5-year time period (2014-2018). All analyses were conducted between 15 July and 19 August 2024.

Results: On average, women were diagnosed with invasive melanoma 3-8 years earlier than men. The sex difference in mean age at diagnosis was observed at all body sites and across most thickness categories in the US and Queensland populations, but was most marked for thinner melanomas (≤ 1.00 mm) and melanoma of the trunk. Women were significantly younger than men at diagnosis of superficial spreading and nodular melanoma at all body sites in both populations, even within the 0.1-mm thickness strata.

Conclusions: Sex may be a factor that influences melanocytic progression. The consistently younger age at melanoma diagnosis of women vs. men suggests a need for tailored approaches to melanoma control.