Oncologic Results of Laparoscopic Renal Cryoablation for Clinical T1a Tumors: 8 Years of Experience in a Single Institution

Abstract

To review the oncologic outcomes of laparoscopic renal cryoablation (LRC) for small renal masses (SRMs) <4 cm. The present study was an observational, retrospective analysis of LRC in 123 patients. The indications for LRC were solid SRMs of the kidney <4 cm in diameter diagnosed on preoperative computed tomography or magnetic resonance imaging as an enhancing mass. Follow-up was determined using magnetic resonance imaging. Local recurrence after LRC was defined as an enlarging or persistently enhancing treatment site on follow-up imaging. A total of 131 SRMs in 123 patients (91 men and 32 women) were treated from September 2000 to June 2008. The mean tumor size was 2.14 ± 0.86 cm (range 0.5-4). Biopsy cores from the 123 patients revealed clear cell renal cell carcinoma (RCC) in 69 patients (56.1%), papillary RCC in 8 (6.53%), chromophobe RCC in 3 (2.4%), mucinous, tubular, and spindle RCC in 1 (0.8%), oncocytoma in 27 (21.9%), angiomyolipoma in 5 (4.1%), and xanthogranulomatous pyelonephritis in 1 patient (0.8%). The biopsy findings were nondiagnostic (fibrotic/necrotic tissue) in 9 cases (7.3%). The mean follow-up was 46.04 ± 25.75 months (median 41, range 12-96). In 44 patients with RCC and a mean follow-up of 61.3 ± 13.76 months, the cancer-specific survival rate was 100% and the overall survival rate was 93.2%. None of the 53 patients (RCC plus those with nonmalignant lesions) who had follow-up >5 years developed radiographic recurrence. Our findings have confirmed that LRC can be considered a safe and intermediate-term effective method to treat SRMs.