Percutaneous vs surgical cryoablation of the small renal mass: is efficacy compromised?

OBJECTIVE To review and analyse the cumulative literature to compare surgical and percutaneous cryoablation of small renal masses (SRMs). METHODS A MEDLINE search was performed (1966 to February 2010) of the published literature in which cryoablation was used as therapy for localized renal masses. Residual disease was defined as persistent enhancement on the first post-ablation imaging study, while recurrent disease was defined as enhancement after an initially negative postoperative imaging study, consistent with the consensus definition by the Working Group on Image-Guided Tumor Ablation. Data were collated and analysed using the two-sample Mann-Whitney test and random-effects Poisson regression, where appropriate. RESULTS In all, 42 studies, representing 1447 lesions treated by surgical (n = 28) or percutaneous (n = 14) cryoablation were pooled and analysed. No significant differences were detected between approaches regarding patient age (median 67 vs 66 years, P = 0.55), tumour size (median 2.6 vs 2.7 cm, P = 0.24), or duration of follow-up (median 14.9 vs 13.3 months, P = 0.40). Differences in rates of unknown pathology also failed to reach statistical significance (14 vs 21%, P = 0.76). The difference in the rate of residual tumour was not statistically different (0.033 vs 0.046, P = 0.25), nor was the rate of recurrent tumour (0.008 vs 0.009, P = 0.44). The reported rate of metastases was negligible in both groups, precluding statistical analysis. CONCLUSIONS Cryoablation has shown acceptable short-term oncological results as a viable strategy for SRMs. Analysis of the cumulative literature to date shows that surgical and percutaneous cryoablation have similar oncological outcomes.