First Prize (tie): Laparoscopic renal cryoablation: efficacy and complications for larger renal masses

In expanding our indications for cryoablation of renal cortical neoplasms, there was an increased morbidity with laparoscopic cryoablation. As such, we evaluated our single institution experience with laparoscopic renal cryoablation for complications and oncologic effectiveness as a function of tumor size.

We retrospectively evaluated our prospectively established urologic oncology database and identified 44 laparoscopic cryoablation procedures performed for the management of 51 renal masses. Measured parameters included patient age, tumor size and location, estimated blood loss, complications, and recurrences. Patients were stratified into two groups. In group 1, the patients presented with a maximum tumor diameter less than 3.0 cm. Group 2 patients had a maximum tumor diameter of 3.0 cm or larger.

Group 1 included 30 tumors in 23 patients, and group 2 had 21 tumors in 21 patients. The mean tumor size for groups 1 and 2 were 1.8 cm (range 0.7 to 2.8 cm) and 4.0 cm (range 3.0 to 7.5 cm), respectively (P < 0.0001). The average patient age for group 1 was 70.2 and group 2 was 77.6 years (P = 0.04). The mean American Society of Anesthesiologists score was 1.8 and 2.1 for groups 1 and 2, respectively (P = 0.06). There were no complications in group 1. Group 2 had 13 (62%) complications, including two mortalities. The most common complication was blood transfusions at 38%. With a mean follow-up of 9 months, there were no recurrences in group 1. With a mean follow-up of 11 months, there was a single (4.8%) recurrence in group 2. Biopsy histopathology revealed renal cell carcinoma variants in 46.7% in group 1 and 66.7% in group 2, respectively (P = 0.079).

Renal cryoablation of renal cortical neoplasms smaller than 3.0 cm is effective and safe. Our initial experience, however, demonstrates that cryoablation of larger renal masses may be associated with increased morbidity.