Cryoablation for Small Renal Masses: Selection Criteria, Complications, and Functional and Oncologic Results.

Context: Cryoablation (CA) is a minimally invasive modality with low complication rates, but its use in urology is relatively recent.

Objective: To summarize available evidence for CA for small renal masses (SRMs) and to assess the selection criteria, complications, and functional and oncologic results based on the latest CA literature.

Evidence Acquisition: A systematic literature search of the Medline, Embase, and Scopus databases was performed in August 2014 using Medical Subject Headings and free-text protocol. The following search terms were included: kidney cryosurgery, renal cryosurgery, kidney cryoablation, renal cryoablation, kidney cryotherapy, and renal cryotherapy.

Evidence Synthesis: Due to the relatively recent mainstream utilization of CA and lack of long-term efficacy data from large prospective or randomized studies, most of the data available on CA are limited to treatment of SRMs in patients who are often older or are poor surgical candidates. The rates of major complications across the CA literature remain relatively low. Studies assessing renal function after CA suggest a degree of functional decline following CA because proper application includes freezing of a tumor margin; however, often this is not clinically significant. Specific oncologic outcomes should be evaluated in patients with biopsy-proven renal cell carcinoma; when SRM series include benign or unbiopsied tumors, the results of these outcomes are skewed. Although earlier series were suggestive of a higher recurrence rate after CA, some studies have challenged this view reporting recurrence rates comparable with extirpative nephron-sparing surgery.

Conclusions: CA represents an alternative approach to treatment for patients diagnosed with renal neoplasm. There is no consensus within the literature on the best patient selection criteria. Due to higher rates of treatment failure, it is often not offered to patients with minimal comorbidities and good life expectancy. In terms of functional outcomes, CA signifies a modality with minimum impact on renal function; however, well-designed studies precisely assessing this factor are lacking. CA is a minimally invasive modality with suitably low rates of complications, particularly if delivered via the percutaneous route.

Patient Summary: Cryoablation (CA) represents an alternative approach for treating renal neoplasm. Excellent functional outcomes and low rates of complications make CA an ideal minimally invasive modality. Patient selection criteria and oncologic outcomes require further study.