Association between melanoma thickness and clinical and demographic characteristics.

The large-scale implementation of primary and secondary skin cancer prevention strategies in recent decades has led to an increase in the diagnosis of thin melanomas and a decrease in the mean thickness of tumours diagnosed. The number of newly diagnosed thick melanomas, however, has remained stable. To investigate associations between melanoma thickness, clinical presentation and demographic and phenotypic characteristics. The study is based on a cross-sectional study of 1,459 patients with melanoma from a dermatology department at a tertiary hospital in Spain between 2000 and 2017. We analysed associations between median Breslow thickness and demographic, phenotypic, and clinical characteristics, including the method of melanoma detection. Age ≥ 70 years (regression coefficient [RC] =  1.2, 95% CI: 1.1-1.3; p  <  0.001), male sex (RC  =  0.9, 95% CI: 0.8-0.9; p  <  0.001), symptom-based detection (RC  =  1.3, 95% CI: 1.1-1.4; p  <  0.001), and a history of sunburn at the melanoma site (RC  =  0.9, 95% CI: 0.8-0.9; p  =  0.04) were all associated with thicker tumours. Melanomas on the lower extremities, by contrast, were significantly thinner (RC  =  0.9, 95% CI: 0.8-0.9; p = 0.04). Thick melanomas occur preferentially in older men and show changes such as bleeding or an increase in volume or colour. This information should be incorporated into health training and education programs to design better prevention strategies and minimize diagnostic delays.