Introduction

Collecting (Bellini) Duct renal cell carcinoma (CDRCC) is a rare type of renal cell cancer (RCC), estimated to represent 0.4-2.0% of all RCCs. This subtype has been predominantly studied in single-institution datasets and little is known about treatment patterns and outcomes. We sought to utilize a large, population-level database to assess survival outcomes for this rare disease.

Methods

The national cancer database (NCDB) was queried for all cases of CDRCC and clear cell RCC (CCRCC) from 2004-13. After patients with other cancer diagnoses were removed, the analytic cohort was composed of 202,263 CCRCC and 577 CDRCC cases. Kaplan-Meier and cox proportional hazards analysis were employed to model survival.

Results

Compared to CCRCC, patients with CDRCC presented with higher grade and stage, node-positive and metastatic disease (70.7% versus 30.0% with metastasis). Overall median survival for CDRCC was 13.2 months (95% CI 11.0-15.5) compared to the 122.5-month (121.0-123.9) for CCRCC. On multivariate analysis of the CDRCC cohort, increasing T stage, high-grade disease and metastasis were predictors of mortality. Of 184 patients with metastatic CDRCC, 113 underwent cytoreductive nephrectomy (CNx) while the rest were treated with multimodal therapy (MMT) alone or observed. Survival outcomes were improved in patients who received both CNx with MMT compared to surgery alone (HR 0.51, 95% CI 0.32-0.79) or MMT alone (HR 0.57, 95% CI 0.37-0.89) on multivariate analysis.

Conclusions

Collecting (Bellini) Duct carcinoma is an aggressive subtype of RCC. Median survival is 13 months after diagnosis, drastically lower than for CCRCC. Over 70% of patients are diagnosed with metastatic disease. Multimodal therapy in addition to cytoreductive nephrectomy is associated with a survival benefit over single mode therapy.

Funding

none