Incidence of skin cancer in 5356 patients following organ transplantation

Background Skin cancer following solid organ transplantation is an importan t cause of morbidity in long-term survivors. This risk is well known but im precisely quantified. Objectives We aimed to determine: (i) the skin cancer risks in transplant p atients more precisely; (ii) whether the risk of malignant melanoma is alte red: and (iii) whether the risk of epithelial cancers occurring at non-expo sed sites is comparable with that seen in sun-exposed sites. Methods We linked a population-based cohort of 5356 patients who had receiv ed organ transplants in Sweden between 1970 and 1994 with the compulsory Sw edish Cancer Registry, to identify all cancer cases except basal cell carci nomas, which are not registered. Results After a mean follow-up of 5 . 6 years post-transplantation, 172 of 5356 patients developed 325 non-melanoma skin cancers (excluding basal cell carcinomas) and six malignant melanomas. The relative risk of non-melanoma skin cancer was 108 . 6 [95% confidence interval (CI) 94 . 6-123 . 1] for men and 92 . 8 (95% CI 73 . 2-116 . 0) for women. The highest risks were no ted for upper limbs, and the risk increased with time. No significant incre ase in malignant melanomas was noted: the relative risk was 1 . 6 (95% CI 0 . 5-3 . 7) for men and 0 . 5 (95% CI 0 . 0-2 . 6) for women, Except for th e lip, which is also sun-exposed, other epithelial sites did not show compa rable increases in cancer risk. Conclusions We conclude that organ transplant recipients are at a highly in creased risk for nonmelanoma skin cancer and must be closely followed throu ghout their lives. Cancer risk associated with transplantation is higher fo r sun-exposed than for non-sun-exposed epithelial tissues, even among popul ations living in regions with low solar insolation.