1. ¹Department of Surgery, University of Munich, Klinikum Grohadern, Munich, Germany
2. ²Institute for Medical Information Technology, Biometry and Epidemiology, University of Munich, Munich, Germany

Correspondence: M Guba, Department of Surgery, University Clinic Grosshadern, Ludwig-Maximilians-University, Munich, Marchioninistr. 15, 81377 Munich, Germany. E-mail: markus.guba@med.uni-muenchen.de

³These authors contributed equally to this work

Received 24 May 2006; Revised 11 December 2006; Accepted 27 December 2006; Published online 28 February 2007.

Abstract

After decades of successful organ transplantation clinicians continue to be troubled by the increasing incidence of cancers under maintenance immunosuppression. In this study, we examined rates of malignancies in 2419 renal transplant recipients transplanted in our institution between 1978 and 2005. In renal transplant recipients the cumulative incidence of cancer after 25 years was 49.3% for all tumors and 39.7% excluding non-melanoma skin cancers, compared with 21% for a normal sex- and age-matched population. The most frequent tumors observed were non-melanoma skin cancers (20.5%), kidney cancers (12.0%), and cancers of the pharynx, larynx, or oral cavity (8.2%). The general increase of cancer risk was 4.3-fold. Independent risk factors for the development of a tumor were male gender, older recipient age, the presence of preformed antibodies before transplantation, and the time on immunosuppression. Interestingly, the use of IL-2-receptor antagonists significantly reduced the tumor risk of transplant recipients. The tumor risk between immunosuppressive drugs typically used for maintenance immunosuppression was not significantly different. However, mammalian target of rapamycin (mTOR) inhibitor-based immunosuppressive protocols showed a clear tendency for lower malignancy rates. De novo malignancies following renal transplantation represent a serious problem endangering the prognosis of otherwise successfully transplanted patients. Future studies will have to address whether optimized immunosuppressive regimens including mTOR-inhibitors are capable of reducing the incidence or preventing the development of posttransplant malignancies.