Increased risk of melanoma in patients with chronic lymphocytic leukaemia: systematic review and meta-analysis of cohort studies

An increased risk of melanoma has been variously reported in patients with chronic lymphocytic leukaemia (CLL), analogous with other immunosuppressed populations. To fully assess this association, we performed a systematic review and meta-analysis of available evidence from observational cohort studies. All such longitudinal studies of patients diagnosed with CLL that enabled quantitative assessment of the risk of melanoma compared with the general population were eligible. We identified seven studies from a search of all published literature to July 2014 in Medline, Embase and ISI science citation index databases. Data were pooled using a random-effects model. There was an almost four-fold increase in the risk of melanoma in patients with CLL compared with the general population (pooled standardized incidence ratio 3.88 [95% confidence interval (CI) 2.08-7.22]), although significant heterogeneity was evident among studies (I=96.0%,