Percutaneous CT-Guided Renal Cryoablation: Technical Aspects, Safety, and Long-Term Oncological Outcomes in a Single Center

Abstract

Background and objectives: Cryoablation is emerging as a safe and effective therapeutic option for treating renal cell carcinoma. This study analyzed the safety and long-term oncological outcomes of cryoablation in our center. Materials and methods: Patients who underwent computed tomography (CT)-guided percutaneous cryoablation between February 2011 and June 2020 for one or more clinically localized renal tumors were identified. Technical success and treatment efficacy were assessed. Post-procedural complications were classified according to the Clavien-Dindo system. Recurrence-free survival was determined for biopsy-proven malignant renal tumors. Results: A total of 174 renal tumors, 78 of which were biopsy-proven malignant carcinomas, were treated in 138 patients (97 males and 41 females, mean age: 73 years, range: 43-89 years). Mean tumor size was 2.25 cm and 54.6% of the lesions required a complex approach. Technical success was achieved in 171 out of 174 tumors (98.3%). Primary treatment efficacy was 95.3% and increased to 98.2% when retreats were taken into account. The overall complication rate was 29.8%. No complications of Clavien-Dindo grade III or more were encountered. Median follow-up was 21.92 months (range: 0.02-99.87). Recurrence-free survival was 100% at 1 year, 95.3% (95% CI: 82.1%-98.8%) at 3 years, and 88.6% (95% CI: 71.8%-95.7%) at 5 years. Conclusions: Cryoablation is a safe and effective technique for the treatment of small renal lesions, with no major complications when performed by expert interventional radiologists. The multidisciplinary discussion is essential, especially considering the high number of histologically undetermined lesions. Our long-term oncological outcomes are encouraging and in line with the literature.

Keywords: interventional radiology; outcomes; percutaneous; renal cryoablation; renal mass; technical aspects.

Figure 1

Male, 73 years old. (a) Preparation of the treatment of a lesion located at the upper pole of the left kidney (*). The initial scan shows the interposition of the costophrenic sinus (white arrow). (b) The patient was positioned in an oblique decubitus, on the same side of the costophrenic sinus, to free the path for the two cryoprobes and the lesion was adequately treated without pneumothorax.

Figure 2

Male, 75 years old. Hydrodissection technique. (a) At the initial scan, the distance between the lesion (*) and an intestinal loop was 3.76 mm, significantly inferior to the safety margin of 1 cm required. (b) A 16G needle cannula (green arrow) was inserted for the injection of sterile water to increase the distance between the structures. The lesion was adequately treated with three cryoprobes (orange arrow). (c,d): Coronal plane and 3D reconstruction images, respectively.

Figure 3

Male, 78 years old. (a) The initial scan shows a lesion (*) located at the upper pole of the right kidney covered by the costophrenic sinus posteriorly (white arrow) and the hepatic parenchyma laterally. (b,c) The lesion was adequately treated with two cryoprobes inserted through the hepatic parenchyma in order to avoid pneumothorax. No complications occurred.

Figure 4

Kaplan Meier curve of recurrence-free survival for biopsy-proven malignant lesions treated with percutaneous cryoablation.

Figure 5

Kaplan Meier curve of overall survival for patients with biopsy-proven malignant lesions treated with percutaneous cryoablation.