Cancers after renal transplantation: multicenter experience.

Renal transplant recipients are at higher risk of certain tumors such as lymphomas and skin cancers and than the general and dialysis populations. We retrospectively studied the prevalence of tumors in adult renal transplant recipients in four Tunisian centers of transplantation in Tunis, Monsatir and Sfax from January 1986 to January 2005. The study included 36 patients; 19 men and 17 women with a mean age of 34.6 years (range from 18-54 years). The mean time since dialysis to transplantation was 43 months (6-131months). Maintenance therapy was based on calcineurin inhibitors (CNI) in 86 % of cases, on antimetabolites and corticosteroids in 100 % of cases. Anti-thymoglobulin was administered in a mean course of 12.4 days in 78 % of the patients. Acute rejection occurred in 25 cases and was treated with polyclonal or monoclonal antibodies on 40 % of cases. Incidence of cancer among our population was 7 % and occurred after a mean period of 54 months of transplantation (range from 4-160 months). Eighty three percent of the tumors were solid, and the rest were in the skin. Kaposi sarcoma formed 41.6 % and non-Hodgkin or Hodgkin lymphoma 27.7 % of the solid tumors, while spinocellular carcinoma formed 83% and basocellular carcinoma 17% of the skin tumors. Switching CNI to sirolimus in 8.3% cases was associated with a favorable outcome. Mortality was the outcome in 33.3% of the patients with cancer, while partial or complete regression of cancers was observed in 55.5% cases after decreasing the doses of the immunosuppressive medications. We conclude that post renal transplant cancer is mainly characterized by the predominance of Kaposi sarcoma favored by solar exposure and rigorously induced and maintained immunosuppression. Careful follow-up may results in early intervention and decrease mortality.