Ultrasound-guided percutaneous cryoablation of renal tumors

INTRODUCTION: Surgery remains the gold-standard curative treatment for localized (T1) renal carcinoma. However, recent medical-technological advances have led to the development of new minimally invasive treatment options, one of which is percutaneous cryoablation. AIM: To assess the effectiveness and safety of ultrasound-guided percutaneous cryoablation of renal tumors. MATERIALS AND METHODS: The study comprised 12 patients aged 52 to 76 years who underwent ultrasound-guided percutaneous cryoablation of renal tumors from 2015 to 2017. In 11 patients, the size of the renal mass was 3.0 cm (T1a), in 1 patient 4.5 cm (T1b). A Doppler ultrasound, contrast-enhanced MSCT and computer 3D modeling were performed in all patients pre-operatively and 6 months after surgery to assess the tumors size and extent and the spatial location of the tumor internal surface to the pelvicalyceal system. In all patients, the tumors were located along the posterior or lateral surface of the kidney, in the lower or middle segment and without sinus invasion. We used a 3rd generation Galil Medicals SeedNet Gold Cryotherapy System and IceSeed and IceRod cryoprobes. Intraoperatively, immediately before cryoablation, the tumor was biopsied. In all patients the diagnosis of renal cell carcinoma was confirmed morphologically. RESULTS: Mean duration of cryoablation was 60 minutes. Endotracheal, spinal, local and intravenous anesthesia was used in 1, 6, 5 and 1 patients, respectively. Doppler ultrasound at 6 months after surgery showed that in 11 patients (T1a) the tumor size decreased on average by 8 mm, with no blood flow in the tumors. MSCT with 3D modeling also revealed a decrease in tumor size and total absence of contrast agent accumulation, or accumulation gradient not exceeding 10 HU (initially it was about 200 HU). In the patient with T1b stage renal carcinoma, MSCT showed a decrease in tumor size from 4.5 to 3.7 cm, however, there was a mass up to 1.5 cm with a high gradient of contrast agent accumulation. The patient underwent kidney resection. No intra- and postoperative complications were observed. CONCLUSION: The accumulated experience allows to confirm the effectiveness and safety of ultrasound-guided percutaneous cryoablation and to consider it a method of choice for patients with stage T1a renal carcinoma located along the posterior or lateral surface of the kidney in the lower or middle segment, without sinus invasion.