Erick Marc Remer MD, Presenter: Nothing to Disclose

Charles M. O'Malley MD, Abstract Co-Author: Nothing to Disclose

Monish Aron MD, Abstract Co-Author: Nothing to Disclose

Jihad H Kaouk MD, Abstract Co-Author: Speakers Bureau, Endocare, Inc

Inderbir S. Gill MBBCH, Abstract Co-Author: Consultant, Hansen Medical, Inc Stockholder, Hansen Medical, Inc

To describe long-term imaging follow-up after laparoscopically-guided renal cryoablation.

From 09/1997 - 09/2007, laparoscopic renal cryoablation was performed in 288 patients. Of these, 84 patients have minimum 5-year follow-up. Intraoperative pre-cryoablation needle biopsy showed: RCC in 56 patients (67%), oncocytoma in 9 (11%) and other nonmalignant conditions in 17 (20%). Follow-up involved MRI on postoperative day 1, 3 months, 6 months, 12 months, and then annually. Cryoablation site CT-guided biopsy was performed at 6-months. All data were prospectively accrued. Mean patient age was 67 years. 78 patients had a single renal mass and 6 had multiple masses. Mean tumor size was 2.3 cm (0.9-5.0 cm). 26 patients (32%) had a history of contralateral radical or partial nephrectomy.  MRI examinations included t1 (either 2D or 3D gradient echo) weighted images before and after intravenous gadolinium (0.1 mmol/kg) and t2-weighted images.

At 6 months, 67 patients (80%) had CT-guided core needle biopsy. RCC was found in 1 patient with positive findings on the MRI. 66 patients with negative biopsy had no abnormal MRI findings. By 5 years, the size of the cryoablated tumor had decreased by a mean of 89% and complete disappearance of the cryoablated tumor was seen in 73% of patients. No ablation size was stable or increased in size including patients with local recurrence. In 56 patients with biopsy proven RCC, 3 patients developed local recurrence, 1 had local recurrence with metastases and 4 had distant metastases without local recurrence (4/5 had a history of contralateral radical or partial nephrectomy). Time to local recurrence ranged from 6-58 months.

 Renal tumors show marked shrinkage after cryoablation. MRI detects local progression that may manifest after a long delay, suggesting that prlonged imaging surveillance is necessary. The true primary treatment success in this series is obfuscated by the fact that almost all patients with metastases had contralateral nephrectomy. 5% of patients with biopsy proven RCC had local progression.

Local progression after renal cryoablation was found in 5% of patients and was found after nearly 6 years in one patient, suggesting that prolonged imaging surveillance is needed.

Remer, E, O'Malley, C, Aron, M, Kaouk, J, Gill, I, Long-term Imaging Follow-up after Renal Cryoablation.  Radiological Society of North America 2008 Scientific Assembly and Annual Meeting, February 18 - February 20, 2008 ,Chicago IL. http://archive.rsna.org/2008/6011121.html