Time-Dependent Effects of Cryoablation for Renal Tumor on Overall and Split Renal Function.

Purpose: To evaluate the influence of percutaneous cryoablation for renal cell carcinoma on function of the affected kidney.

Materials And Methods: Between June 2016 and September 2017 at our institution, 12 inoperable patients underwent 15 cryoablation sessions for 17 small renal tumors. Of these, 9 patients who underwent 11 sessions of cryoablation were the focus of this study. For those patients, time-dependent changes in postoperative renal function were investigated by a retrospective review of clinical records. Evaluated were the estimated glomerular filtration rate (eGFR) and scintigraphy using 99m technetium-mercaptoacetyltriglycine (99mTc-MAG3) before and 1 week, 1-2 months, and more than 6 months after cryoablation.

Results: Mean baseline eGFR was 76.88 ± 29.82 mL/min/1.73 m (mean ± standard deviation; range, 23.4-112.5). Mean eGFR 1 week, 1-2 months, and more than 6 months after cryoablation were 74.56 ± 26.68 mL/min/1.73 m (21.0-101.1), 69.5 ± 25.28 mL/min/1.73 m (24.1-105.6), and 75.08 ± 26.25 mL/min/1.73 m (29.0-107.3), respectively. Changes were statistically insignificant (P = .6044, P = .6699, and P = .9038, respectively). Regarding split renal function, the mean baseline contribution of the affected kidney determined by 99mTc-MAG3 was 47.27% ± 6.14 (38.8%-57.0%). Mean contributions of the affected kidney 1 week after, 1-2 months after, and more than 6 months after cryoablation were 44.40% ± 5.37 (38.3%-53.6%), 44.57% ± 6.52 (34.35%-55.0%), and 45.41% ± 7.77 (34.4%-56.5%), respectively. Differences from baseline were significant for the earliest 2 periods (P = .0473 and P = .0334, respectively) but not the later period (P = .2532).

Conclusions: Results suggested that total renal function does not worsen after cryoablation; however, function of the affected kidney worsened after cryoablation but later partially recovered.