Prognostic role of histologic subtype in renal cell carcinoma: Results of the SATURN project

Introduction & Objectives: To evaluate the prognostic role of histologic in a large multi-institutional series of patients undergoing radical or partial nephrectomy for renal cell carcinoma (RCC). Materials & Methods: We collected retrospectively the data of 5378 patients who were surgically treated for RCC in 16 academic centers involved in the Surveillance And Treatment Update Renal Neoplasms (SATURN) project. Results: 4371 (81%) patients had clear cell RCC (ccRCC), 579 (11%) papillary RCC (pRCC), 291 (6%) chromophobe RCC (chRCC), 47 (1%) collecting duct RCC (cdRCC) , and 90 (2%) unclassified RCC (uRCC). At a median follow-up of 42 months (IQR 24–75), 1055 patients (20%) had developed disease recurrence and 786 (15%) were dead of RCC. 5-year cancer-specific survival (CSS) estimates were 78.1% in ccRCC, 85.6% in pRCC, 89.3% in chRCC, 55.6% in uRCC, and 31.9% in cdRCC, respectively (pooled p value <0.0001). All the survival differences among the different subtypes were statistically significant (pairwise p values <0.02). On multivariable Cox regression analyses, histological subtype was an independent predictor of CSS (p <0.0001), once adjusted for the effect of all the other covariates. Specifically, both pRCC (H.R. 0.7; p=0.022), and chRCC (H.R. 0.6; p=0.047) had higher CSS compared with ccRCC. Conversely, both cdRCC (H.R. 2.4; p=0.001) and uRCC (H.R. 1.7; p=0.007) had significantly worse outcome in comparisons with clear cell RCC. Conclusions: Histological subtypes was an independent predictors of CSS. For the first time, time significant survival differences were demonstrated among all the major subtypes of RCC.