Switch to a Sirolimus‐Based Immunosuppression in Long‐Term Renal Transplant Recipients: Reduced Rate of (Pre‐)Malignancies and Nonmelanoma Skin Cancer in a Prospective, Randomized, Assessor‐Blinded, Controlled Clinical Trial

Renal transplant recipients (RTR) have a 50–200‐fold higher risk for nonmelanoma‐skin cancer (NMSC) causing high rates of morbidity and sometimes mortality. Cohort‐studies gave evidence that a sirolimus‐based immunosuppression may inhibit skin tumor growth. This single‐center, prospective, assessor‐blinded, randomized trial investigated if switching to sirolimus treatment inhibits the progression of premalignancies and moreover how many new NMSC occur compared to continuation of the original immunosuppressive therapy. Forty‐four RTR (mean age 59.9 years, mean duration of immunosuppression 229.5 months) with skin lesions were randomized to sirolimus or continuation of their original immunosuppression. Blinded dermatological assessment at month 6 and 12 by the same dermatologist evaluated the clinical change compared to baseline. Biopsy was performed in suspected malignancy. Already the 6‐month‐assessment showed significant superiority of sirolimus‐therapy: a stop of progression, even regression of preexisting premalignancies (p < 0.0005). This effect was increased at month 12 (p < 0.0001). Nine patients developed histologically confirmed NMSC: one in the sirolimus group, eight in the control group, p = 0.0176. Sirolimus‐based immunosuppression in RTR, even when established many years after transplantation, can delay the development of premalignancies, induce regression of preexisting lesions and decelerate the incidence of new NMSC. This single‐center trial found that switching long‐term renal transplant recipients to sirolimus inhibits the progression of premalignancies of the skin and reduces the occurance of new NMSC compared to continuation of the original immunosuppressive therapy. See editorial by Mitchell 1343.