Body composition and melanoma incidence risk: insights from a longitudinal lung cancer screening cohort

ObjectiveThis study explored the association between low-dose computed tomography (LDCT)-derived body composition and melanoma incidence risk. MethodsLDCT scans from the Pittsburgh Lung Screening Study (n=3,422, 22 follow-up years) were analyzed. Body composition features were segmented and quantified from baseline scans using in-house artificial intelligence algorithms. Features were selected before modeling. Fine-Gray subdistribution hazard models assessed the association between body composition and melanoma incidence. Model performance was evaluated using time-dependent area under the curve (AUC). Restricted mean survival time (RMST) compared melanoma-free survival across BMI and body composition groups at 5, 10, and 15 years. Participants were stratified into risk groups, with risk estimated at each time point. Sex-specific analyses were conducted separately. Statistical significance was defined as p<0.05. ResultsAmong 3,422 participants, 80 developed melanoma (43 males, 37 females). In the overall model, visceral adipose tissue (VAT) volume (hazard ratio [HR]=1.27), skeletal muscle (SM) density (HR=0.81), and bone density (HR=1.33) were included, achieving a 21-year AUC of 0.68 (95% CI: 0.65-0.70). The male-specific model included only SM density (HR=0.74; AUC=0.67, 95% CI: 0.65-0.68). The female-specific model (AUC=0.68, 95% CI: 0.65-0.71) included VAT volume (HR=1.47), intramuscular adipose tissue (IMAT) ratio (HR=0.67), and bone density (HR=1.75). Higher VAT, IMAT volume, and lower SM density showed shorter melanoma-free survival and stratified risk better than BMI. Males exhibited higher estimated risk than females. ConclusionLDCT-derived body composition metrics may provide incidental insights into melanoma risk during lung cancer screening, though their predictive utility remains limited and warrants further investigation. Key PointsO_ST_ABSQuestionC_ST_ABSTo investigate the association between CT-derived three-dimensional (3D) body composition and the risk of developing melanoma. FindingsCT-derived body composition was associated with melanoma incidence. Males demonstrated higher estimated risk than females over both short- and long-term follow-up periods. Clinical RelevanceGiven melanomas high mortality and the limited effectiveness of current screening programs, these findings highlight the potential of leveraging routinely acquired lung cancer screening CT scans to enhance melanoma risk assessment.