title: Cancer-free survival and local tumor control after impendence-based radiofrequency ablation of biopsy-proven renal cell carcinomas with a minimum of 1-year follow-up.
abstract: OBJECTIVE
  There are numerous reports describing the use of radiofrequency ablation (RFA) to treat renal cell carcinoma. Many series, however, describe heterogeneous populations, lack histologic descriptions, use various RFA systems, and indicate tumor destruction by different ablation end points. This study examined the outcomes of computed tomography-guided, impedance-based RFA of biopsy-proven renal cell carcinoma clinically staged as T1a with a minimum of 1 year of postablation follow-up.
  
  
  METHODS
  This retrospective study identified all consecutive patients who had undergone renal RFA since May 2005 at our institution. Patients without biopsy-proven renal cell carcinoma (RCCa) were excluded. Of the patients who met these criteria, evaluation was limited to patients with a minimum of 12 months of follow-up. Data collected from the patients' electronic medical and radiologic records included demographic data, tumor-related data, procedural details, and clinical follow-up visits.
  
  
  RESULTS
  A total of 39 patients (46 lesions) met the inclusion criteria. The mean tumor diameter was 2.6 cm (range: 1.2-4.0 cm). The most common histologies were clear cell (n = 27) and papillary (n = 16) renal cancer. The lesion location was equally divided between upper pole (n = 16), middle pole (n = 16), and lower pole (n = 14). Overall, 83% of the tumors were exophytic. No residual or recurrent enhancing mass was identified in the ablation bed on post-RFA imaging during the mean follow-up period of 35.3 months (range: 12-83). All patients were treated in a single encounter and no lesion required a second ablation; technical success (absence of residual tumor) on the initial post-RFA imaging study was 46 of 46 (100%). Clinical success was achieved in 45 of 46 lesions (98%); residual, viable tumor was found in a pretransplant nephrectomy specimen on postprocedure day 127. The mean cancer-free survival was 36.2 months. Comparison of preablation and postablation renal function found no statistically significant change.
  
  
  CONCLUSIONS
  The consistent outcomes in our post-RFA imaging and clinical surveillance allow us to offer image-guided ablation to patients with T1a RCCa as a valid treatment option offering long-term cancer-free survival. Impedance-based RFA in a carefully selected patient population with T1a RCCa is a reliable treatment option, with disease-free survival rates that are comparable to partial nephrectomy.
authors.affiliation: Division of Interventional Radiology, Dartmouth-Hitchcock Medical Center, Lebanon, NH. Electronic address: Andrew.R.Forauer@Hitchcock.org.
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Forauer
authors.affiliation: Geisel School of Medicine at Dartmouth College, Dartmouth-Hitchcock Medical Center, Lebanon, NH.
authors.forename: Benjamin J
authors.initials: BJ
authors.lastname: Dewey
authors.affiliation: Division of Urology, Dartmouth-Hitchcock Medical Center, Lebanon, NH.
authors.forename: John D
authors.initials: JD
authors.lastname: Seigne
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D002292:Carcinoma, Renal Cell / Q000473:pathology / Q000601:surgery*; D017115:Catheter Ablation / Q000379:methods*; D018572:Disease-Free Survival; D017097:Electric Impedance; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007668:Kidney / Q000473:pathology / Q000601:surgery*; D007680:Kidney Neoplasms / Q000473:pathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D015203:Reproducibility of Results; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
keywords: Cancer-free survival; Radiofrequency ablation (RFA); Renal cell carcinoma