Radiofrequency ablation and cryoablation of renal tumours

With widespread utilization of noninvasive cross-sectional abdominal imaging, small solid renal masses are being found with increasing frequency 1. These small tumours are often discovered incidentally by abdominal ultrasound or computer tomography (CT). These incidentally discovered renal tumours are generally slower growing, are detected at an earlier stage, and are localized to the kidney 2,3. The triad of pain, hematuria, and palpable mass is now more the exception than the rule. Many patients now treated for renal cell carcinoma (RCC) are asymptomatic at presentation. The radical nephrectomy has been the “gold standard” for the treatment of clinically localized RCCs, but a shift has occurred toward treating small, incidentally found renal neoplasms in a nephron-sparing manner. Nephron-sparing techniques have been shown to offer oncologic and functional outcomes that are equivalent to those with radical nephrectomy for patients with renal tumours 4 cm or smaller in size 4–6. Since the mid 1990s, the movement toward minimally invasive alternatives has meant the replacement of open surgery (radical or partial nephrectomy) with laparoscopic techniques and now with in situ ablative technologies 7,8. Ablative techniques offer advantages over extirpative techniques by reducing perioperative morbidity, shortening the hospital stay, promoting faster recovery, and importantly, potentially treating patients who are poor surgical candidates while preserving renal parenchyma 9,10. Several ablative technologies have been investigated, among them, cryoablation (CA), radiofrequency ablation (RFA), microwave 11, high-intensity focused ultrasound 12,13, laser interstitial thermotherapy 14, microwave thermotherapy, and radiosurgery. The current outcomes with RFA and CA are promising, but long-term studies are ongoing to validate their oncologic efficacy and durability. This overview briefly outlines advances in energy-ablative techniques for RCC and provides a synopsis of recent clinical studies of RFA and CA.