Multifocal renal cell tumors: a retrospective analysis of 56 patients treated with radical nephrectomy.

In this retrospective analysis of 56 patients with multifocal renal cell tumors the effect of secondary tumors on the prognosis was examined and the incidence of tumors in the contralateral kidney was evaluated. All of the primary tumors were renal cell carcinomas, the majority of which had a local tumor stage of pT2 (31 cases, 55.3%) and a cytological grading of 1 (23 cases, 41%). The mean size of the secondary tumors was 1.0 cm. An additional tumor was diagnosed in 23 patients (41%), 2 to 5 secondary tumors in 23 (41%) and more than 5 additional tumors in 10 (18%). The overall 5-year survival rates were 69.4%, 72.2% and 40%, respectively (p = 0.313). Histopathological differentiation of the additional lesions revealed 23.2% renal cell carcinomas, 71.4% adenomas and 5.3% renal tumors of "doubtful dignity," with overall 5-year survival rates of 67.2% for adenomas, and 60.6% for carcinomas and renal tumors of "doubtful dignity" (p = 0.546). After a mean followup of 60 months 33 patients (58.9%) were alive without evidence of disease, 1 (1.7%) was alive with tumor progression, 8 (14.2%) died of the disease and 14 (25%) died of other causes; only 1 patient presented with a tumor in the contralateral kidney (incidence 1.7%). Thus, the overall 5-year survival rate for the entire group was 66.0% and the histopathological parameters of the additional tumors had no effect on the prognosis of the patients.