Surgical Resection Provides Excellent Outcomes for Patients With Cystic Clear Cell Renal Cell Carcinoma

Abstract

Previous observations suggest that cystic clear cell renal cell carcinoma (RCC) is cured with surgical resection. However, long-term outcome data are lacking. We reviewed our experience with RCC and report on pathologic features and patient outcome associated with the cystic variant. We identified 2431 patients treated with nephrectomy for unilateral, sporadic clear cell RCC between 1970 and 2002. A single urologic pathologist (J.C.C.) reviewed all of the microscopic slides without knowledge of patient outcome. Cystic clear cell RCC was characterized by numerous confluent cysts lined by clear cells, and containing nests of clear cells within the cyst walls. There were 85 (3.5%) patients with cystic RCC. Among these patients, 22 died during follow-up, although no patient died of RCC. The median follow-up for the remaining 63 patients was 5 years. The estimated cancer-specific survival rate at 5 years after surgery for patients with noncystic clear cell RCC was 70.6% compared with 100% for patients with the cystic variant (P <0.001). This difference persisted even when comparing patients with cystic RCC to the subset with noncystic RCC who had pT1, pNx/pN0, and no clinical evidence of metastases (cM0). No patient with cystic clear cell RCC had extrarenal disease at time of nephrectomy with the exception of 1 patient who had perinephric fat invasion. Cystic RCC is a distinct pathologic entity and should be assessed routinely during pathologic evaluation. Furthermore, we present data supporting that cystic RCC patients should expect to be cured after surgical extirpation.