In this study, survival analysis was performed in 2,372 patients with single primary melanoma (SPM) and 1,206 with MPM, with a median follow-up of 7.6 (0.4-10.6) years.
The Genes, Environment, and Melanoma Study enrolled incident cases of melanoma from population-based cancer registries in Australia, Canada, Italy and the US. Results showed that melanoma thickness was the main determinant of fatality (HR for >4mm, 7.68, 95% CI 4.46-13.23); other independent predictors were ulceration, mitoses and scalp location.
After adjustment for these other predictors, there was little difference in fatality between MPM and SPM (HR for MPM relative to SPM, 1.24, 95% CI 0.91-1.69; p = 0.18). However, a greater increase in risk of death with thick SPMs (HR for >4mm, 13.56, 95% CI 6.47-28.40) than thick MPMs (2.93, 1.17-7.30) was seen, indicating a possible difference between outcomes in these groups. Kricker A, Armstrong B, Goumas C et al. JAMA Dermatol 2013; 149: 921-92