Initial experience with retroperitoneoscopic microwave ablation of clinical T(1a) renal tumors

To evaluate the feasibility, safety, and efficacy of retroperitoneoscopic microwave ablation (MWA) for clinical stage T(1a) (cT(1a)) renal tumors.

Consecutive renal cell carcinomas (RCCs) managed since April 2006 with a minimal follow-up of 12 months were included. A total of 23 tumors in 22 patients were managed with laparoscopic MWA. A cooled shaft needle antenna was inserted into the tumor under direct visual guidance. Microwaves were emitted at 50 W for 8 minutes and prolonged as necessary to ensure complete tumor kill. Short-term efficacy was assessed by contrast-enhanced CT at 1, 3, and 6 months, and every 6 months thereafter.

Pathologic analysis revealed low-grade clear-cell RCC in all patients. Mean tumor size was 2.8 cm (range 0.9-4.0 cm). Excluding 5 lost patients, the initial ablation was successful in 17 (94.4%) of 18 tumors. One patient with an incomplete ablation lesion under strict surveillance had no evidence of disease progression at 31 months of follow-up. No recurrence was observed at a median follow-up of 20 months (range 12-45 mos). All 17 remaining patients had no clinical or radiographic evidence of disease at last follow-up. In addition, complications were mild and tolerable (18.2%), and there was no significant deterioration of renal function.

Retroperitoneoscopic MWA appears to be a safe and effective technique for cT(1a) RCC in selected patients. Additional follow-up is needed to assess long-term effectiveness.