Increased risk of melanoma in organ transplant recipients: systematic review and meta-analysis of cohort studies.

Transplant recipients have a raised risk of melanoma but the relative magnitude is uncertain. We undertook a systematic review by searching major databases for relevant publications to June 2014. Cohort studies quantifying the association between transplantation and melanoma were included and data were pooled using the weighted average method. Among 20 eligible studies the pooled relative risk (pRR) of melanoma was 2.71 (95% confidence interval (CI), 2.23-3.30) with significant heterogeneity (p < 0.001). There was no indication of publication bias. Sub-group analyses by study design, follow-up period, adjustment for confounding and quality score did not materially alter results. Among liver and heart transplant patients pRR for melanoma was 5.27 (95% CI 4.50-6.62), higher than the pRR of 2.54 (95% CI 2.18-2.96) among kidney transplant patients. Transplant recipients are at more than double the risk of melanoma overall compared with the general population.