Analysis of clinicopathologic predictors of oncologic outcome provides insight into the natural history of surgically managed papillary renal cell carcinoma

BACKGROUND. To gain further insight into the natural history of papillary renal cell carcinoma (pRCC), the authors evaluated oncologic impact of important clinical and pathologic prognostic factors and performed survival analyses in a large group of contemporary patients surgically treated for pRCC. METHODS. The institutional nephrectomy database was searched for patients who were managed with radical or partial nephrectomy for pRCC or clear cell RCC (cRCC) from 1994 to 2006. RESULTS. A total of 2157 patients with pRCC (n = 245) or cRCC (n = 1912) met protocol inclusion criteria. Kaplan-Meier analyses revealed equivalent 5-year cancer-specific survival (CSS) in the nonmetastatic pRCC patient group and revealed significantly decreased CSS in pRCC patients with distant metastases compared with matched cRCC patient cohorts. Presence of venous tumor thrombus was associated with a significant decrease in CSS and was an independent prognostic feature in pRCC patient cohort but not in patients with cRCC (5-year CSS pRCC = 35%; cRCC = 66%; P = .012). Patients with pRCC were at a significantly increased risk of harboring metastatic lymph nodes compared with patients with cRCC (13% and 8.6%, respectively; P = .019); however, presence of lymph node metastases in patients with pRCC was associated with a relatively indolent disease course (5-year CSS pRCC = 65%; cRCC = 19%; P = .029). CONCLUSIONS. The authors demonstrated significant differences in presentation, prognostic features, and patient outcomes among papillary and clear cell histologic subtypes of RCC. The authors' findings may potentially link unique molecular genetics that have been reported in pRCCs to its distinct clinical behavior.