The Effect of Conversion from a Calcineurin Inhibitor to Sirolimus on Skin Cancer Reduction in Post-renal Transplantation Patients

In kidney transplant patients, skin cancer is the most commonly involved neoplasm. More than 90% of post-transplantation skin cancers are nonmelanoma skin cancers (NMSCs). The majority of them are squamous cell carcinomas and basal cell carcinomas. Calcineurin inhibitors (CNIs) such as cyclosporine and tacrolimus are immunosuppressive agents given after solid organ transplantation, but they can also promote tumor growth. Sirolimus is a novel class of immunosuppressants and has been proven to have antineoplastic properties. We review clinical trials and meta-analyses studying if conversion from CNI to sirolimus in post-renal transplantation patients decreases the development of NMSCs. A critical appraisal of the literature demonstrated that, while smaller scale studies tended to yield no clinically significant data, larger clinical trials and meta-analyses supported the conclusion that converting to sirolimus in post-renal transplant patients leads to reductions in skin cancer development. As a result, we conclude that conversion to sirolimus likely reduces NMSC in post-renal transplantation patients. Larger scale clinical trials with more rigorous stratification and less patient dropout rate are needed for more definitive conclusions.