title: Sonographically guided radio frequency thermal ablation for unresectable recurrent tumors in the retroperitoneum and the pelvis.
abstract: OBJECTIVE
  To evaluate the feasibility of sonographically guided radio frequency thermal ablation as a minimally invasive method for treatment of unresectable recurrent or metastatic tumors in the retroperitoneum and the pelvis, which often pose difficult surgical problems.
  
  
  METHODS
  Radio frequency thermal ablation was performed on 7 patients with unresectable recurrent retroperitoneal or pelvic tumors from colorectal (n = 4), renal (n = 2), and prostate (n = 1) cancers. Under sonographic guidance, a total of 11 radio frequency thermal ablation operations were performed by a percutaneous or transanal approach.
  
  
  RESULTS
  Three patients were asymptomatic, whereas 4 patients were symptomatic. The sizes of the tumors ranged from 29 to 100 mm (mean, 50.5 mm). Radio frequency thermal ablation was technically completed in all operations without intraoperative complications. The ablation time ranged from 25 to 238 minutes depending on the tumor size. There was no mortality. There were postoperative complications in 3 operations (27.3%): an enterovesical fistula, a skin burn, and fecal incontinence. The hospital stay was generally 0 to 1 day. Tumor marker levels decreased after radio frequency thermal ablation in all operations. Symptoms of 4 patients were controlled by radio frequency thermal ablation. One patient with recurrent renal cancer and uncontrollable hypercalcemia became asymptomatic immediately after radio frequency thermal ablation. Local recurrence at the radio frequency thermal ablation site occurred in 2 patients (28.6%), but these local recurrent tumors were treated effectively by additional sonographically guided radio frequency thermal ablation.
  
  
  CONCLUSIONS
  Minimally invasive sonographically guided radio frequency thermal ablation is technically feasible for local treatment of unresectable recurrent retroperitoneal and pelvic tumors from different origins. Care should be taken to avoid thermal injury to surrounding organs. Further study is needed to evaluate its safety and efficacy.
authors.affiliation: Department of Surgery, University of Hawaii at Manoa, USA.
authors.forename: Junji
authors.initials: J
authors.lastname: Machi
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Oishi
authors.forename: Nancy L
authors.initials: NL
authors.lastname: Furumoto
authors.forename: Robert H
authors.initials: RH
authors.lastname: Oishi
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D017115:Catheter Ablation / Q000379:methods*; D015179:Colorectal Neoplasms / Q000473:pathology*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000601:surgery*; D010166:Palliative Care; D010386:Pelvic Neoplasms / Q000000981:diagnostic imaging / Q000556:secondary / Q000601:surgery*; D011471:Prostatic Neoplasms / Q000473:pathology*; D012186:Retroperitoneal Neoplasms / Q000000981:diagnostic imaging / Q000556:secondary / Q000601:surgery*; D018084:Ultrasonography, Interventional