Association between melanoma thickness, clinical skin examination and socioeconomic status: results of a large population-based study

Survival from melanoma is inversely related to tumour thickness and is less favorable for those in lower socioeconomic (SES) strata. Reasons for this are unclear but may relate to a lower prevalence of skin screening. Our aim was to examine the association between melanoma thickness, individual-level SES and clinical skin examination (CSE) using a population-based case-control study. Cases were Queensland (Australia) residents aged 20-75 years with a histologically confirmed first primary invasive cutaneous melanoma diagnosed between January 2000 and December 2003. Telephone interviews were completed by 3,762 cases (77.7%) and 3,824 (50.4%) controls. Thickness was dichotomized to thin (<= 2 mm) and thick (> 2 mm). Compared with controls, the risk of thick melanoma was significantly increased among men [relative risk ratio (RRR) = 1.56, 95% CI = 1.22-2.00], older participants (RRR = 1.76, 95% CI = 1.10-2.82), those educated to primary level (RRR = 1.70, 95% CI = 1.08-2.66), not married/living as married (RRR = 1.47, 95% CI = 1.15-1.88), retired (RRR = 1.39, 95% CI = 1.01-1.94) and not having a CSE in past 3 years (RRR = 1.45, 95% CI = 1.12-1.86). There was a significant trend to increasing prevalence of CSE with higher education (p < 0.01) and the benefit of CSE in reducing the risk of thick melanoma was most pronounced among that subgroup. There were no significant associations between cases with thin melanoma and controls. Melanoma thickness at presentation is significantly associated with educational level, other measures of SES and absence of CSE. Public health education efforts should focus on identifying new avenues that specifically target those subgroups of the population who are at increased risk of being diagnosed with thick melanoma.