COSA 2015* Thermal ablation of small renal tumours (#86)
Percutaneous thermal ablation is increasingly being used to treat small renal tumours in patients who are not candidates for surgery. The main indications are renal insufficiency, a single kidney, multiple tumours and hereditary conditions associated with renal neoplasms.
The goal of thermal ablation is to coagulate the target tumour as well as a 5-10 mm circumferential cuff of normal renal parenchyma.
Additional manoeuvres are needed in certain situations: when tumours are in contact with bowel loop, ‘hydrodissection’ is used to protect the bowel from thermal injury. This involves the injection of 5% dextrose in the retroperitoneum to displace the bowel away from the kidney. In patients with tumours close to the ureter, it is possible to use a retrograde ureteric catheter to perfuse the ureter with ice-cold saline during the procedure.
The procedure is usually performed under CT guidance, sedation, intravenous analgesia and local anaesthesia. It is tolerated well in most patients. Serious complications are rare and consist mainly perinephric haematoma, urinoma and (very rarely) thermal injury to the ureter.
The follow-up of patients usually involves contrast enhanced-CT, which can demonstrate remaining viable tumour requiring treatment.
Effective ablation is achieved in approximately 90% of patients in a single session of therapy. However, tumours larger than 3 cm in diameter are more difficult to eradicate at the first attempt, usually requiring a second session of treatment.
Ablation is particularly helpful in patients with solitary kidneys and impairment of renal function. In such patients, partial nephrectomy can lead to renal failure. Ablation enables most patients to be treated with minimal loss of function and avoids the need for dialysis in the vast majority.
Percutaneous ablation is likely to replace partial nephrectomy in many patients with small neoplasms.
