Objectives: Collecting duct renal cell carcinoma (CDRCC) is a rare but reportedly aggressive histologic subtype. We assessed the stage and histologic features of patients with CDRCC and compared cancer-specific mortality in CDRCC and matched patients with clear-cell renal cell carcinoma (CRCC).
Methods: Forty-one (0.6%) patients with CDRCC and 5246 CRCC patients were identified within a cohort of 6608 patients treated with either radical or partial nephrectomy for renal cancer. Within the 5246 CRCC cases, 105 were matched with CDRCC cases for grade, tumour size, and T, N, and M stages. Kaplan-Meier and life table analyses addressed RCC-specific survival.
Results: Of all CDRCC patients, 76% had pT3 disease at nephrectomy versus 37% for those with CRCC. The predominant Fuhrman grades were III (56%) and IV (22%) in CDRCC versus II (42%) and III (28%) for CRCC. Moreover, 49% of CDRCC patients were pN1-2 versus 8% for CRCC. Of CDRCC patients 19% had distant metastases at nephrectomy versus 14% for CRCC. Finally, 73% of CDRCC patients had either local or systemic symptoms versus 56% for CRCC. After matching, the RCC-specific mortality of CDRCC patients was no different from that for CRCC patients (RR=1.1; p=0.8). One- and 5-yr CDRCC-specific survival rates were 86% and 48%, respectively, versus 86% and 57% for matched CRCC controls.
Conclusions: CDRCC patients present with more advanced stage and with more aggressive disease compared with CRCC patients. After nephrectomy, when CDRCC cases were matched with CRCC, the same cause-specific survival was seen.