Individualization of immunosuppressive therapy. III. Sirolimus associated with a reduced incidence of malignancy

OBJECTIVE: We examined the occurrence of neoplasms among 1008 renal transplant recipients treated with a sirolimus-cyclosporine (CsA) +/- prednisone (Pred) regimen. METHODS: A comprehensive database of demographic, laboratory, clinical, and histopathologic features of these patients all followed in our transplant center was analyzed using Student t test and Mann-Whitney U test for continuous and chi-square test for categorical variables. Comparisons were performed with information in the Israel Penn International Transplant Tumor Registry (IPITTR). RESULTS: During the mean patient follow-up of 62.3 +/- 26.1 months (range 27.1 to 131), 36 tumors occurred in 35 patients (3.6%) at 32.5 +/- 29.8 months. The most common neoplasms were skin tumors (2.4%), a value that was significantly lower than the 6% rate observed with CsA-azathioprine-Pred treatment. Also, the 0.4% incidence of posttransplant lymphoproliferative disorders and 0.2% incidence of renal cell carcinomas were less than half of those previously reported with a combination of tacrolimus and mycophenolate mofetil. The distribution of tumor types was similar to that reported to the IPITTR. The mean trough drug concentrations in affected recipients at the time of diagnosis were within the putative target ranges. CONCLUSION: Renal transplant recipients treated with the sirolimus-CsA +/- Pred combination showed a low incidence of tumors of similar types as those encountered with other regimens.