Incidence and types of malignant tumors in renal transplant recipients: a single center experience.

We reviewed the incidence and types of de novo malignancies which developed in 792 renal transplant recipients who received their grafts between 1979 and 1996 and followed up for an average period of 5.6 years. There were 56 malignant tumors detected in 54 patients, representing an overall incidence of 6.8%. These tumors occurred in a relatively young group of patients whose average age was 33.4 years at the time of transplantation and 40 years at the time of diagnosis of malignancy. The average latency period between transplantation and malignant disease was 7.4 years for solid tumors and 16 months for Kaposi's sarcoma. Tumors included 39 Kaposi's sarcomas, four malignant lymphomas, three hepatomas, two bladder cancers, one renal cell carcinoma of the allograft, two colorectal cancers, two thyroid cancers, one adenocarcinoma of unknown primary, one nasopharyngeal carcinoma and one leiomyosarcoma of the uterus. Kaposi's sarcoma was the most common malignancy and comprised 70% of all tumors in this study. It is imperative for renal transplant recipients to have diligent follow-up at regular intervals for early detection of cancer.