Editorial Comment for Chen et al.

T he authors are first and foremost to be congratulated for completing a randomized surgical trial. These are rare in the urologic surgical literature. This study proposed that contrast-enhanced Ultrasonography (CEUS) during radiofrequency ablation (RFA) may improve the short-term local tumor control rate. As it stands, the results were not statistically significant, leaving the authors to, at most, suggest that CEUS may improve laparoscopic RFA effectiveness. A power analysis to justify the size of the study arms is not provided in the article, raising the issue of whether additional patient enrollment may identify a statistically significant advantage for CEUS utilization to improve local tumor control rate. Perhaps the authors can provide this analysis in their response.

Nevertheless, the shortcoming of laparoscopic RFA is an inability to image the ablation zone in real time or at least immediately after treatment as occurs with CT-guided percutaneous procedures where intravenous contrast is administered to delineate the ablation zone. Thus, the use of CEUS during the laparoscopic approach would logically provide the surgeon with a comparable “perfusion-deficit” surrogate for treatment success. Currently, temperature monitoring and needle position confirmation by ultrasonography are the only laparoscopic methods. It must be emphasized that immediate ablation success, defined as lack of enhancement immediately (or on the initial post-treatment CT), does not translate perfectly to long-term treatment success. Recurrences as late as 5 years after RFA and cryoablation have been reported, despite initial success. Whether the lack of perfusion on CEUS at the time of ablation improves the long-term oncologic outcome of the procedure is not known. Unfortunately, this study's follow-up was insufficient (median 16 months) to assess whether the oncologic efficacy was improved with CEUS. This would be the ultimate test and cost justification for using CEUS routinely during laparoscopic RFA.