Long-term survival of patients with unilateral sporadic multifocal renal cell carcinoma according to histologic subtype compared with patients with solitary tumors after radical nephrectomy

To determine the pathologic features, including histologic subtype and tumor size, associated with multifocal renal cell carcinoma (RCC) and the impact of multifocality on survival after radical nephrectomy, about which controversy exists. We studied 2373 patients who underwent radical nephrectomy for RCC from 1970 to 2000. Histologic subtype, stage (2003 TNM), nuclear grade, tumor size, and multifocality, defined as the presence of more than one ipsilateral RCC tumor of the same histologic subtype, were evaluated. Associations of multifocality with ipsilateral and contralateral recurrence and death from RCC were evaluated using Cox proportional hazards models. The incidence of sporadic histologically concordant multifocality was greater in papillary RCC (29 of 266; 10.9%) compared with clear cell RCC (40 of 1934; 2.0%; P