CT-Guided Percutaneous Cryoablation in Renal Cell Carcinoma: Factors Affecting Local Tumor Control.

PURPOSE

To retrospectively evaluate factors affecting local tumor control in cryoablation of renal cell carcinomas (RCCs).

MATERIALS AND METHODS

This study examined 61 patients (43 men, 18 women) with a mean age of 69.1 years ± 10.8 (range 38-87 y) who underwent computed tomography (CT)-guided percutaneous cryoablation for a single RCC and were followed for 6 months or longer. Maximum tumor diameter was 0.8-4.8 cm (mean ± standard deviation, 2.4 ± 0.9 cm). Factors affecting local tumor control were evaluated. Deep tumor location was defined as the center side of the body perpendicular to the kidney midline.

RESULTS

Median follow-up was 12.7 months. Residual unablated tumors and local tumor progression were observed after initial cryoablation in 4 patients each (13%, 8 of 61). All uncontrolled tumors were located in the deep side of the kidney (100%, 8 of 8), and were covered by an ice-ball margin of 5 mm or less. Deep tumor location (P = .005) and ice-ball margin (P = .002) were detected as significant factors affecting local tumor control on univariate analysis, and ice-ball margin remained significant in a stepwise logistic regression model (P = .006; odds ratio, 0.57; 95% confidence interval, 0.38-0.83). Complete tumor control rates were 42.9% (3 of 7), 92.6% (50 of 54), and 100% (20 of 20) with ice-ball margins of less than 3 mm, 3 mm or larger, and 6 mm or larger, respectively.

CONCLUSIONS

Deep tumor location and ice-ball margins less than 6 mm were associated with incomplete local control following CT-guided percutaneous cryoablation for RCC.