Introduction: Thermal ablation is increasingly utilized as a management strategy for small renal masses (<4 cm). Partial nephrectomy is recognized as the gold standard; thermal ablation has been reserved for older patients with comorbidities due to concern for local tumor recurrence. As long-term data regarding the safety and efficacy of ablative techniques accumulate with encouraging results, clinicians are widening the utility in select patient populations. This review summarizes the currently available technologies in terms of procedural differences, oncologic outcomes, renal function, and complication rates.
Evidence acquisition: A structured literature review was conducted using PubMed and Web of Science, using the keywords: "renal cell carcinoma," "ablation techniques," "cryosurgery," "radiofrequency ablation," "microwave ablation," "outcomes assessment," "post-operative complication," and "hospital costs." Articles were reviewed to summarize oncologic outcomes, complications, and impact on renal function of cryoablation, radiofrequency ablation, and microwave ablation.
Evidence synthesis: Thermal ablation is a safe and effective management option for small renal masses in select patients, particularly in those with multiple tumors and/or those unable or unwilling to undergo more invasive surgery. Slightly higher rates of local recurrence rates (~1-10%) with thermal ablation are offset by lower complication rates and reduced morbidity, and equivalent or better renal function outcomes compared to surgery.
Conclusions: The established modalities of cryo-, radiofrequency, and microwave ablation offer equivalent outcomes with similar complication rates; technique choice is primarily based on tumor characteristics and operator preference. Better quality evidence comparing thermal ablation with surgical nephron-sparing intervention is needed to make informed conclusions on efficacy.