Collier V, Patel J, Chiu CY, Fowke JH, Patel TS, Liu-Smith F. Distinctive lower incidence rates of cutaneous melanoma on the hips and lower extremities of men.
Clin Exp Dermatol 2023;
48:1333-1340. [PMID:
37467730 DOI:
10.1093/ced/llad236]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 06/14/2023] [Accepted: 07/05/2023] [Indexed: 07/21/2023]
Abstract
BACKGROUND
Cutaneous melanomas (CMs) are more frequently found on the trunk in men, and on the hip and lower extremities (legs) in women. This discrepancy has been attributed to greater exposure to ultraviolet (UV) radiation of women's legs due to their dressing habits.
OBJECTIVES
To understand the sex difference in the bodily distribution of CMs, especially those on the legs.
METHODS
This was a cancer registry-based cohort study. CM incidences, relative tumour density and tumour mutational burdens (TMBs) were compared among different body sites in different sex and racial groups using the SEER (Surveillance, Epidemiology, and End Results) and TCGA SKCM (The Cancer Genome Atlas skin cutaneous melanoma) databases.
RESULTS
White men had lower rates and lower relative tumour density (RTD) of CMs on their legs compared with the rest of their body sites, or compared with White women. Men classified by SEER into racial groups other than White did not show such a trend. White women had comparable RTDs among different body sites. The ratios between the 'White' and the 'other' groups were used to evaluate the approximate effect of sun exposure at different body sites, which further validated a distinct protective effect of men's legs in melanoma. TMB on leg melanomas was lower than on other sites in both sexes.
CONCLUSIONS
The legs of both sexes in White patients show lower RTDs and lower levels of TMB, suggesting a weaker association with UV exposure. Furthermore, White men are especially protected against CM on their legs, suggesting an unknown intrinsic protective factor as compared with women.
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