Renal cryoablation approaches yield similar outcomes

October 1, 2009

Cryoablation of small renal masses yields similar survival rates with a laparoscopic or percutaneous approach, but the options involve tradeoffs of disease control versus convenience and cost.

Key Points

Percutaneous procedures led to a significantly shorter hospital say, but a laparoscopic approach produced more complete treatment, according to Sebastien Crouzet, MD, working with Jihad H. Kaouk, MD, and colleagues. Using overall survival as the bottom line, the two approaches were similar, although longer follow-up is required to make a final determination.

"The principal limitations of laparoscopic renal cryoablation are the need for general anesthesia, more invasive procedure, longer hospital stay, and higher cost," Dr. Crouzet said. "For percutaneous renal cryoablation, the limitations are the need for two-dimensional imaging to direct trocar placement, the limited ability to separate vital structures and viscera from the kidney, and difficulty in reaching anterior tumors.

Cryoablation has emerged as a viable treatment option for small renal masses. Conventionally, treatment has been via a laparoscopic approach, but recently percutaneous cryoablation has gained popularity as an alternative minimally invasive option.

The relative safety and efficacy of the two approaches to renal cryoablation had not been determined. Toward that end, Dr. Crouzet and colleagues retrospectively reviewed data on oncologic and functional outcomes for 244 patients treated with laparoscopic renal cryoablation and 63 treated percutaneously. Their data were presented at the AUA annual meeting in Chicago.

The review included perioperative morbidity, oncologic outcomes, and renal function at day 1 and at 6 months. Researchers defined incomplete treatment as the presence of an enhancing lesion within 6 months of cryoablation. Lesions that appeared beyond that interval were considered recurrent.

Tumor and patient characteristics were similar, except for the proportion of patients with a solitary kidney or history of renal surgery, which were significantly greater in percutaneously treated patients (30.2% vs. 11.8%, p=.0012; 55.6% vs. 21.9%, p<.0001, respectively).

Laparoscopy: More complete treatment

Percutaneous procedures required more probes (2.2 vs. 1.4, p<.0001), but operative time was identical (175.5 min) for both approaches. Ice-ball size, intraoperative complications, transfusion rate, and cryoablation time did not differ between groups.

Renal function, as determined by absolute creatinine values and estimated glomerular filtration rate, did not differ between groups before surgery or afterward. Cryo-lesion size averaged approximately 4 cm on day 1 in both groups and approximately 3 cm at the 6-month follow-up.

Incomplete treatment occurred significantly more often with percutaneous renal cryoablation (7.6% vs. 1.6%, p=.018). Recurrences also were more frequent after percutaneous treatment, but the difference did not achieve statistical significance (6.2% vs. 3.0%, p=0.31).

Length of stay averaged 22 hours with percutaneous cryoablation and 59.1 hours with laparoscopic procedures (p<.0001). Mean follow-up was briefer in the percutaneously treated patients (15.5 vs. 51.4 months, p<.0001).

Two-year recurrence-free survival was 94.4% in patients who underwent laparoscopic renal cryoablation and 96.5% in those who had percutaneous treatment. Overall and cancer-specific survival also did not differ between groups.