title: Radiofrequency ablation of renal tumours with clinical, radiographical and pathological results.
abstract: WHAT'S KNOWN ON THE SUBJECT? AND WHAT DOES THE STUDY ADD?: Radiological imaging is heavily relied on for follow up after renal ablative therapy. We show that while this is largely reliable, there are quantifiable false negative and false positive findings. A non-involuting zone of ablation should be considered for multisite-directed core biopsies even in the absence of detectable enhancement.
  
  
  OBJECTIVE
  To evaluate our experience with radiofrequency ablation (RFA) for renal masses and to report on clinical, radiological and post-RFA biopsy results.
  
  
  METHODS
  The study collected clinical, radiological and pathological data from 150 consecutive patients who were treated with RFA of a renal mass between 2002 and 2008 at a tertiary referral centre. Post-ablation biopsies were performed in patients with non-involuting lesions or suspicion of recurrence on imaging. Comparisons were performed using the Mann-Whitney U-test. Survival was estimated using the Kaplan-Meier method.
  
  
  RESULTS
  Renal malignancy was found in 72.1% of patients based on the initial diagnostic biopsy. Median tumour size was 2.6 cm, 22.7% of patients had a solitary kidney, and most were central tumours. The mean follow-up period was 40.1 month. There was no recurrence in 96.7% of the entire cohort. Cancer-specific survival for 106 patients with sporadic, localized, biopsy proven renal malignancy was 100% at 38.5 months. Biopsies were obtained in 43 patients for a median of 21 months after RFA. Among 38 patients who had biopsy for non-involuting, non-enhancing zones of ablation, three (7.9%) were positive.
  
  
  CONCLUSIONS
  Short-term cancer-specific survival after RFA remains excellent and most cases are successful based on a combination of imaging and post-ablation biopsies performed almost 2 years after treatment. There were four out of 150 (2.7%) patients who had recurrences with tissue confirmation; one of these patients was detected on imaging and three (2%) were radiologically occult. The absence of enhancement in the setting of non-involuting lesions is not always a guarantee of a successful ablation.
authors.affiliation: Department of Urology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
authors.forename: Jose A
authors.initials: JA
authors.lastname: Karam
authors.forename: Kamran
authors.initials: K
authors.lastname: Ahrar
authors.forename: Raghunandan
authors.initials: R
authors.lastname: Vikram
authors.forename: Claudio A
authors.initials: CA
authors.lastname: Romero
authors.forename: Eric
authors.initials: E
authors.lastname: Jonasch
authors.forename: Nizar M
authors.initials: NM
authors.lastname: Tannir
authors.forename: Priya
authors.initials: P
authors.lastname: Rao
authors.forename: Christopher G
authors.initials: CG
authors.lastname: Wood
authors.forename: Surena F
authors.initials: SF
authors.lastname: Matin
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002292:Carcinoma, Renal Cell / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D017115:Catheter Ablation; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D053208:Kaplan-Meier Estimate; D007680:Kidney Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome