[De novo urological neoplasms in kidney transplant patients: experience in 1,751 patients].

INTRODUCTION: Immunosuppressive treatment promotes development of neoplasms in kidney transplant patients. Cancer prevalence in these patients is 4 to 5 times higher as compared to the general population. Tumors are also known to behave more aggressively in transplant patients.

OBJECTIVE: To perform a descriptive analysis of de novo urological tumors in kidney transplant patients and to analyze patient survival.

MATERIALS AND METHODS: A retrospective study was conducted in 1751 transplant patients from January 1980 to December 2006. Patients in whom the tumor occurred in the first year after transplantation were excluded. The primary variables considered included sex, age at transplant, age at cancer diagnosis, site, clinical stage, treatment, and outcome. A Chi-square test was used for univariate statistical analysis. Survival was assessed using the Kaplan-Meier method.

RESULTS: Twenty-nine de novo tumors (1.6%) were diagnosed in the 1751 transplanted patients, with a median follow-up of 35.28 months (2-121) from tumor diagnosis. Tumors were found in 24 males (82%) and 5 females (18%). Median age at transplantation was 50.8 (17-70) years, and median age at tumor diagnosis was 56.4 (19-79) years. Eleven patients (38%) were diagnosed with prostate cancer, seven (24%) with bladder tumors, 4 (60%) with non-muscle invasive tumors, and 3 (40%) with muscle invasive tumors. A renal adenocarcinoma in the primitive kidney was diagnosed in 6 patients (20%). Five patients (18%) were detected a tumor in the transplanted kidney. Median survival was 75 months for patients with bladder tumors, 82 months for prostate cancer, 59 months for tumors in the native kidney, and 86 months for graft tumors.

CONCLUSIONS: In our series, de novo urological tumors in kidney transplant recipients were more common in males. Prostate cancer is the most common tumor and renal cell carcinoma of the native kidney has the worst survival rate.