With the rapid rise in incidental small renal mass detection, some of which have malignant potential, comes the need to either survey or treat these masses safely and with minimal morbidity. This large series of 147 patients with 171 masses, requiring 153 procedures in total, covers a five-year period from May 2007. Each patient was imaged prior to a prone oblique procedure under general anaesthetic with a minimum of two core biopsies taken where possible before cryoablation under computed tomography (CT) guidance was performed. Hydro-dissection to displace adjacent structures was employed in 49%, with 4% having ureteric warming to protect the pelviureteric junction (PUJ) / pelvis. Three subsets were analysed: 62 patients with a solitary kidney and biopsy proven renal cell carcinoma (RCC) and no metastases with at least six months’ follow-up, 42 patients with multiple tumours, and 43 patients with less than six months’ follow-up. Ninety-one out of 171 masses were proven RCC, 23 oncocytomas, 15 indeterminate and 36 had no biopsy (due to size, location, multiplicity). Four required repeat procedures and eight had multiple tumours treated at the same sitting. Incomplete treatment was suspected in 12 and confirmed in 11 on subsequent CT. There were 16 complications, seven (4.6%) being Clavien 2 or above (haemorrhage requiring embolisation, transfusion, stent insertion, pneumothoraces). The mean hospital stay was one day, with 76% of solitary kidneys requiring only a single night’s stay. Single treatment resulted in a 92.4% success, rising to 97.6% with repeat procedures, but there were four failures, two requiring salvage nephrectomy and two showing disease progression, although both had bilateral disease and were high-risk. A procedural learning curve was evident but despite reports to the contrary, anterior and larger tumours were no more likely to recur than other sites. Follow-up is too short to be able to comment on reliability, especially as metastatic progression is around 6% in similar sized masses, but as a definitive and low-risk procedure, it seems that cryotherapy is the least morbid but most efficacious modality currently available when surveillance is not indicated.
Cryotherapy for small renal masses: better than surveillance?
Reviewed by Mark Harris
Percutaneous cryoablation of renal tumours: outcomes from 171 tumours in 147 patients.
