Characteristics and outcomes of tumors arising from the distal nephron.

OBJECTIVE: To compare the characteristics and predictors of cancer-specific survival (CSS) of 2 rare distal nephron tumors--medullary renal cell carcinoma (MRCC) and collecting duct carcinoma (CDC). METHODS: All cases of histologically verified MRCC and CDC reported to The Surveillance, Epidemiology and End Results (SEER) database between 1995 and 2007 were considered. A number of characteristics were compared by tumor histology. Subset analyses were performed for metastatic patients and those managed surgically. CSS was analyzed using Cox proportional hazard models. RESULTS: Overall, 21 cases of MRCC and 227 cases of CDC met the criteria for analysis. Patients with MRCC were younger (median 24 vs 63 years, P < .001), more often black (71.4% vs 22.7%, P < .001), metastatic at presentation (71.4% vs 27.8%, P < .001), and less likely to undergo surgery (61.9% vs 85.6%, P = .015) compared with patients with CDC. Tumor size was similar between MRCC and CDC (median 6 vs 5 cm, P = .70). Median survival was 5 months for MRCC and 30 months for CDC (P < .001). In metastatic MRCC and CDC patients, surgery predicted CSS (HR 4.61 and 2.24, both P ≤.05) despite having larger primary tumors than those managed nonsurgically (median 7.5 vs 5.0 cm, P < .01). CONCLUSION: Patients with MRCC present younger, at a later stage, and are more often black than patients with CDC. The stage migration toward localized kidney cancer is not apparent for these tumors. Although both cancers have a poor prognosis, the clinical and survival characteristics are distinct. Patients selected for cytoreductive surgery have improved survival.

Duke Scholars

Author Michael R Abern Urology

Author Thomas James Polascik Urology