title: Intermediate oncological outcomes of percutaneous radiofrequency ablation for small renal tumors: initial experience.
abstract: BACKGROUND
  For T1 stage incidental renal cell carcinoma (RCC), partial nephrectomy with or without laparoscopy is widely used on the basis of its nephron- sparing and minimally invasive nature. However, high-risk patients of advanced age, or with cardiovascular events are not often suitable candidates for surgery under general anesthesia. Percutaneous radiofrequency ablation (RFA) for mainly the treatment of these patients reportedly achieves satisfactory outcomes. We evaluated the clinical usefulness of this procedure in our initial cases.
  
  
  METHODS
  In total, 24 renal tumors in 22 patients who had been diagnosed with T1 stage RCC were treated by percutaneous RFA. A LeVeen Needle (Radiotherapeutics) was used with an RF3000 generator. The overlapping ablation method was applied to these tumors, which were larger than 3 cm or located close to the renal hilus. Dynamic contrast-enhanced computed tomography or magnetic resonance imaging was routinely carried out to evaluate the post-treatment state.
  
  
  RESULTS
  Maximum tumor diameters ranged from 1.0 to 4.5 cm (mean=2.4 cm). The follow-up period was 1-61 months (mean=18 months) after RFA treatment. Contrast enhancement completely disappeared immediately after this procedure in 23 tumors, the one exception being a 4.5-cm tumor. The tumor recurrence-free and overall survival rates were 85% and 79%, respectively, at two years after RFA.
  
  
  CONCLUSIONS
  Percutaneous RFA is a feasible option for the treatment of RCCs, particularly for those less than 3 cm in diameter.
authors.affiliation: Department of Urology, Osaka City University Graduate School of Medicine, 1-4-3 Asahimachi, Abenoku, Osaka 545-8585, Japan.
authors.forename: Yujiro
authors.initials: Y
authors.lastname: Nitta
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Tanaka
authors.forename: Kazuya
authors.initials: K
authors.lastname: Morimoto
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Makino
authors.forename: Noriaki
authors.initials: N
authors.lastname: Nishikawa
authors.forename: Kouichiro
authors.initials: K
authors.lastname: Tashiro
authors.forename: Toshihide
authors.initials: T
authors.lastname: Naganuma
authors.forename: Taro
authors.initials: T
authors.lastname: Iguchi
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Matsuoka
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Nakatani
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002292:Carcinoma, Renal Cell / Q000473:pathology / Q000601:surgery*; D017115:Catheter Ablation / Q000379:methods*; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000473:pathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D015996:Survival Rate; D016896:Treatment Outcome