Collecting duct (Bellini duct) renal cell carcinoma: A nationwide survey in Japan

Purpose: Collecting duct carcinoma, a rare type of renal cell carcinoma, remains poorly understood. To analyze the nature of collecting duct carcinoma a retrospective survey was performed in Japan. Materials and Methods: This survey was done from August 2001 to April 2003. A total of 281 institutions throughout Japan were requested to document all cases of collecting duct carcinoma. All pertinent clinical information was compiled, including patient age, sex, mode of presentation, evaluation modality, preoperative laboratory data, surgery type, macroscopic and microscopic findings, and survival data. Two urological pathologists reviewed microscopic slides of all tumor specimens to confirm collecting duct carcinoma. Results: Two pathologists confirmed collecting duct carcinoma in 81 of the 120 cases documented as collecting duct carcinoma. Mean patient age was 58.2 years and males comprised 71.6% of all patients. The mode of presentation was classified as symptomatic in 65.4% of cases, incidental in 24.7% and not available in 9.9%. Regional lymph node metastasis was histologically detected in 44.2% of patients who underwent lymph node dissection, while 32.1% of the population had distant metastasis at presentation. Although postoperative adjuvant therapy against metastasis or recurrence was performed in 25 patients, no obvious responses were identified except in 1 with lung metastases, who showed a partial response to combined gemcitabine and carboplatin therapy. At a median followup of 15 months 1, 3, 5 and 10-year disease specific survival was 69.0%, 45.3%, 34.3% and 13.7%, respectively. Conclusions: We report what is to our knowledge the largest known series of collecting duct carcinoma. Since advanced or recurrent collecting duct carcinoma is resistant to standard treatment modalities, new treatment strategies are needed for advanced collecting duct carcinoma.