Papillary renal cell carcinoma: correlation of tumor grade and histologic characteristics with clinical outcome

SummaryHistologic prognostic parameters in papillary renal cell carcinoma (PRCC) are unclear. The aims were to review the clinicopathological features of PRCC, including Fuhrman grade and International Society of Urological Pathology (ISUP) nucleolar grade, and to identify parameters that may be independent prognostic indicators. PRCCs in patients treated by nephrectomy were retrieved from the pathology files from 1984 to 2010. Parameters studied included tumor multifocality, size, PRCC type (1 or 2), Fuhrman grade, ISUP nucleolar grade, presence of necrosis, lymphovascular invasion, and stage at presentation. Cancer-specific survival (CSS) and overall survival (OS) were used as prognostic measures. Of 154 PRCCs, 112 (73%) were type 1, and 42 (27%), type 2. A total of 125 patients were male, and 29, female, with ages from 26 to 86 (mean, 62.7) years. Fuhrman grade was 1 in 8 (5%), 2 in 95 (62%), 3 in 49 (32%), and 4 in 2 (1%) tumors, respectively. ISUP nucleolar grade was 1 in 47 (31%), 2 in 56 (36%), 3 in 49 (32%), and 4 in 2 (1%) tumors, respectively. Mean follow-up interval was 73.9 months (0.13-222 months). ISUP nucleolar grade was a significant predictor of both CSS and OS in univariate (CSS, P = .001; OS, P = .004) and multivariate (CSS, P = .04; OS, P = .008) analyses, whereas Fuhrman grade was only predictive of CSS in univariate (P = .001) and multivariate (P = .04) analyses. Only ISUP nucleolar grade and lymphovascular invasion were independently prognostic for CSS and OS in univariate and multivariate analyses. Therefore, the ISUP nucleolar grade appears to be superior in predicting survival in patients with PRCC.