Risk of skin cancer in kidney, liver and heart recipients: A nationwide population-based study in Taiwan

Background: Previous population-based studies in western countries had revealed increased skin cancer risk among transplant recipients compared to the general population. However, population-based studies in Asia on skin cancer among recipients of different transplanted organs were lacking in the literature. Aims: This study aims to estimate skin cancer risk among recipients in Taiwan, examine the association between each specific type of skin cancer and each type of transplanted organ, and compare skin cancer risk between different immunosuppressive regimens. Methods: This population-based retrospective cohort study identified 7550 patients with heart, lung, kidney or liver transplantation and 30,200 controls matched for gender, age and comorbidity index from the National Health Insurance Research Database in Taiwan between 2000 and 2015. Using multivariable Cox proportional hazard models, we estimated the hazard ratios and 95% confidence intervals for the correlation of skin cancer with organ transplantation as well as immunosuppressive regimen. Results: Organ transplant recipients in Taiwan had an increased risk of skin cancer with adjusted hazard ratios of 4.327 (95% confidence intervals 2.740–6.837, P < 0.001), with the greatest risk, observed among heart recipients (adjusted hazard ratios 6.348, 95% confidence intervals 3.080–13.088, P < 0.001). The risk of non-melanoma skin cancer and melanoma was 4.473 (95% confidence intervals 2.568–7.783, P < 0.001) and 3.324 (95% confidence intervals 1.300–8.172, P < 0.001), respectively. When comparing immunosuppressants, those with calcineurin inhibitors carried the highest risk of skin cancer (adjusted hazard ratios 4.789, 95% confidence intervals 3.033–7.569, P < 0.001), followed by those with antimetabolites (adjusted hazard ratios 4.771, 95% confidence intervals 3.025–7.541, P < 0.001). Limitations: We could not evaluate confounding behavioural risk factors of skin cancers that were not documented in the database, nor could we recognize patients’ compliance with immunosuppressants. Conclusion: Organ recipients have a greater risk of skin cancer. Clinicians should inform recipients of the importance of photoprotection and regular dermatologic follow-up