Cryoablation of renal tumours in patients with solitary kidneys

To investigate the use of cryoablation for small renal tumours (less than or equal to 5 cm) in patients with solitary kidneys, as the advantage of this technique might be to preserve nephrons for maintaining renal function with minimal morbidity. Patients with a radiographically documented solid renal mass in a solitary kidney were evaluated for treatment with percutaneous cryoablation. Under general anaesthesia the patients were placed in an interventional magnetic resonance imaging (MRI) unit. A gradient imaging technique was used to locate the tumour and one to four 3-mm cryoprobes placed percutaneously into the tumour. An argon-based cryoablation system was used to treat the tumour with three freeze-thaw cycles, at a probe tip temperature of -120degreesC. Patients were admitted for 23 h observation and assessed for follow-up at 1 week, 1, 3 and 6 months, and then every 6 months. Radiological imaging studies (computed tomography or MRI) were used at 1, 3 and 6 months and every 6 months afterward, to assess for recurrent or new tumour appearance. To date, 14 patients with renal masses in a solitary kidney have been treated; two were lost to follow-up and excluded from the analysis, leaving 10 men and two women (mean age 62.5 years, range 29-76). In all, 15 tumours (mean diameter 3.1 cm) were treated; the mean (range) treatment time was 96.7 (30-143) min. There were no complications during treatment. Two patients had gross haematuria afterward that resolved within 24 h. The mean follow-up was 17 (2-30) months, with three patients requiring re-treatment for incomplete tumour ablation. There is no radiographic evidence of local tumour recurrence to date. In two patients the tumour was not completely ablated. There was no significant change in serum creatinine from preoperative values. Percutaneous cryoablation of tumours in solitary kidneys caused minimal morbidity and little change in serum creatinine levels. Although the follow-up is brief there was no local recurrence. Cryoablation may be a treatment option for patients with tumour in solitary kidneys but a long-term follow-up is needed to confirm these results.