Objective: To compare the pathological features of clear cell renal cell carcinoma (ccRCC) with papillary RCC (pRCC) and further differentiate type I and II pRCC as independent prognosticators for survival.
Patients and methods: From September 1994 to February 2007 557 RCCs were treated and reviewed. All patients underwent radical nephrectomy or nephron-sparing surgery. We reviewed patient data and correlated RCC subtypes to tumour size, pathological stage, nuclear grade, and 5-year cancer-specific survival (CSS). pRCC was re-evaluated in to type I and II. The 2002 Tumour-Node-Metastasis and Fuhrman classifications were used.
Results: In all, 391 (70%) patients had ccRCC, 96 (17%) had pRCC, 34 (6%) had chromophobe RCC, seven (1%) had ductus Bellini RCC and 29 (5%) had unclassified RCC. Upon re-evaluation 34 patients had type I pRCC and 62 had type II. The pRCCs were significantly smaller than the ccRCCs, at a mean (sd) of 4.5 (2.5) cm vs 5 (2.9) cm (P = 0.013), and multifocal (25% vs 12%, P = 0.001). Whereas patients with ccRCC had significantly more primary metastases (12% vs 3%, P = 0.014). The mean (sd) follow-up was 42.3 (41.4) months. The 5-year CSS for M0 patients was 84% for ccRCC and 90% for pRCC (P = 0.573). At multivariate analyses predictors for 5-year CSS were only tumour size (hazard ratio, HR 2.6, P < 0.001), pathological stage (HR 3.9, P < 0.001) and nuclear grade (HR 2.7, P < 0.001). The type I and II pRCCs had significantly different lymphovascular invasion (LVI) and 5-year CSS rates (94% vs 74%, P = 0.03).
Conclusions: The ccRCCs were significantly larger at diagnosis than the pRCCs. The histological subtype (pRCC vs ccRCC) had no impact on the 5-year CSS in multivariate analyses. The type I and II pRCCs had similar histopathological features except for a significant difference in LVI. However, the 5-year CSS was significantly different in type I and II pRCC.