Clinical Significance of Subclassification of Papillary Renal Cell Carcinoma: Comparison of Clinicopathologic Parameters and Oncologic Outcomes Between Papillary Histologic Subtypes 1 and 2 Using the Korean Renal Cell Carcinoma Database

The aim of the present study was to investigate the clinical significance of the subclassification of papillary renal cell carcinoma (pRCC) in a multi-institutional study of 274 Korean patients with pRCC. Type 2 pRCC displayed more aggressive clinicopathologic characteristics; however, no significant differences in prognosis were found between types 1 and 2 pRCC. Among patients with pRCC, the pathologic T stage was the only prognosticator. Introduction The aims of the present study were to compare the clinicopathologic characteristics between type 1 and type 2 papillary renal cell carcinoma (pRCC) and to evaluate the effect of the subclassification of pRCC on the oncologic outcomes after surgery. Materials and Methods The records of 274 patients with pRCC in the Korean renal cell carcinoma (KORCC) database were included for evaluation. Of the 274 patients, 118 had type 1 pRCC and 156 had type 2 pRCC. The patient characteristics, including clinicopathologic parameters, were investigated, and the oncologic outcomes were evaluated. Results The mean patient age was significantly older in the type 2 pRCC group. Compared with type 1 pRCC tumors, type 2 pRCC tumors were more often localized to the renal hilum (P = .030). Patients with type 2 pRCC had a greater incidence of Fuhrman grade 3 and 4 tumors than those with type 1 pRCC (78.8% vs. 22.8; P < .001). Tumor necrosis and capsular invasion were more frequently found in type 2 pRCC (P = .008 and P = .007, respectively). At a mean follow-up period of 38.0 months (interquartile range, 11.8-57.3 months), the subclassification of pRCC did not influence the prognosis of patients with pRCC. Conclusion From the information available in the KORCC database, we identified significant differences in clinicopathologic variables, including age, Fuhrman grade, tumor location, tumor necrosis, and capsular invasion between type 1 and 2 pRCC. Although type 2 pRCC had more aggressive clinicopathologic characteristics, subclassification of pRCC did not affect the oncologic outcomes.