[Malignant tumors following renal transplantation].

Patient survival time following renal and other solid organ transplantation has been increasing recently, in part due to modern immunosuppressive regimens. However, the probability of malignant tumor formation is also increasing proportionally to survival time, as a side effect of long-term immunosuppression. The primary factor of increased tumor risk is the deficient antitumoral and antiviral function of the immune system. The frequency of posttransplantation tumors is 2 to 4-fold compared to the non-transplanted population, and the distribution of tumor types is also different. The most frequent tumor types--skin cancer, lymphoma, Kaposi's sarcoma, oral cancer, anogenital tumors, etc.--are often associated with oncogenic viruses. Treatment options and the prognosis of posttransplant tumors are worse than in the normal population. The increasing frequency of posttransplantation tumors is an important factor determining the long-term fate of transplant patients. The reduction of carcinogenic agents, the early diagnosis and treatment of tumors and precancerous conditions, low dose immunosuppression and the usage of immunosuppressive agents with an oncologically favorable, anti-proliferative effect will help reduce the risk of posttransplant tumor formation.