Effect of collecting duct histology on renal cell cancer outcome.

purposeCollecting duct renal cell carcinoma is a rare entity. Recent surgical series of the condition showed conflicting results. We used an American population based data set to compare the survival experience of patients with collecting duct vs clear cell renal cell carcinoma. MATERIALS AND

methodsCases of collecting duct and clear cell renal cell carcinoma were identified in the Surveillance, Epidemiology and End Results program (2001 to 2005). Demographic and pathological characteristics at diagnosis were compared. Differences in disease specific survival were compared with univariate and multivariate Cox regression analysis.

resultsA total of 160 collecting duct renal cell carcinoma cases were present in the database from 2001 to 2005. In that time 33,252 clear cell renal cell carcinoma cases were diagnosed. Collecting duct renal cell carcinoma was more common in black than in white patients (23% vs 9%, p <0.001). Collecting duct renal cell carcinoma was more commonly T3+ than T2/T1 (33% vs 18%, p <0.001) and metastatic than regional/local (28% vs 17%, p = 0.001). Nephrectomy rates were similar (84% and 78%, p = 0.06). The 3-year disease specific survival rate was 58% and 79% for collecting duct and clear cell renal cell carcinoma, respectively. On multivariate analysis there was an increased mortality risk in patients with collecting duct vs clear cell renal cell carcinoma (HR 2.42, 95% CI 1.72-3.39, p = 0.001).

conclusionsCompared to patients with clear cell renal cell carcinoma those with collecting duct renal cell carcinoma have higher stage and are more often black. Even after adjusting for demographic, surgical and pathological factors disease specific survival is significantly worse in patients with collecting duct rather than clear cell renal cell carcinoma. Further research into the biology of this rare tumor is required to explain these results.