Survival analysis of 130 patients with papillary renal cell carcinoma: prognostic utility of type 1 and type 2 subclassification

Abstract

Objectives: To evaluate the prognostic significance of subtyping papillary renal cell carcinoma (PRCC) into type 1 and type 2 tumors.

Methods: From 1995 to 2004, 1358 patients underwent surgery for renal cell carcinoma, of whom 130 had PRCC alone on the specimen. The tumor characteristics, including their subtype, were analyzed; small basophilic cells and large eosinophilic cells were defined type 1 and type 2 tumors, respectively. Survival analyses were performed retrospectively.

Results: Of the 130 patients (110 men and 20 women, mean age 60.6 +/- 15.3 years) with PRCC, 102 underwent radical nephrectomy (78.4%) and 28 underwent partial nephrectomy (21.6%). The median tumor size was 4.5 cm (range 0.5 to 21). The comparison of the 68 (52.3%) type 1 PRCCs and 62 (47.7%) type 2 PRCCs revealed that type 2 tumors were associated with a greater stage and grade and microvascular invasion significantly (P <0.001) more often. The median follow-up was 48 months (range 2 to 111). Of the 130 patients, 22 died of cancer-specific causes, 5 (7%) with type 1 and 17 (27%) with type 2 tumors (P = 0.002). The overall and disease-free survival rate was 89% and 92% in type 1 tumors and 55% and 44% in type 2 tumors, respectively. Univariate analysis identified tumor type, stage (P <0.001), grade (P <0.001), microvascular invasion (P <0.001), an absence of foam cells (P <0.001), the presence of sarcomatoid cells (P = 0.001), and tumor necrosis (P = 0.007) as prognostic factors. Multivariate analysis retained tumor type (P = 0.034) and TNM stage (P <0.001).

Conclusions: The results of our study have shown that histologic subtyping of PRCC allows for the identification of an independent prognostic factor.