title: Long-term oncologic outcomes after radiofrequency ablation for T1 renal cell carcinoma.
abstract: BACKGROUND
  Radiofrequency ablation (RFA) of renal cell carcinoma (RCC) is used to obtain local control of small renal masses. However, available long-term oncologic outcomes for RFA of RCC are limited by small numbers, short follow-up, and lack of pathologic diagnoses.
  
  
  OBJECTIVE
  To assess the oncologic effectiveness of RFA for the treatment of biopsy-proven RCC.
  
  
  METHODS
  Exclusion criteria included prior RCC or metastatic RCC, familial syndromes, or T2 RCC. We retrospectively reviewed long-term oncologic outcomes for 185 patients with sporadic T1 RCC. Median follow-up was 6.43 yr (interquartile range [IQR]: 5.3-7.7).
  
  
  METHODS
  The chi-square test and Wilcoxon rank-sum tests were used to compare proportions and medians, respectively. Disease-specific survival and overall survival (OS) were calculated using Kaplan-Meier analysis, then stratified by tumor stage, and comparisons were made using log-rank analysis. The 5-yr disease-free survival (DFS) and OS rates are reported. A p value <0.05 was considered statistically significant.
  
  
  CONCLUSIONS
  Median tumor size was 3 cm (IQR: 2.1-3.9 cm). Tumor stage was T1a: 143 (77.3%) or T1b: 42 (22.7%). Twenty-four patients (13%) were retreated for residual disease. There were 12 local recurrences (6.5%), 6 recurrences in T1a disease (4.2%) and 6 in T1b disease (14.3%) (p=0.0196). Median time to recurrence was 2.5 yr. Local salvage RFA was performed in six patients, of whom five remain disease free at 3.8-yr median follow-up. Tumor stage was the only significant predictor of DFS on multivariate analysis. At last follow-up, 164 patients (88.6%) were disease free (T1a: n=132 [92.3%]; T1b: n=32 [76.2%]; p=0.0038). OS was similar regardless of stage (p=0.06). Five patients developed metachronous renal tumors (2.7%). Four patients developed extrarenal metastases (2.2%), three of whom died of metastatic RCC (1.6%).
  
  
  CONCLUSIONS
  In poor surgical candidates, RFA results in durable local control and low risk of recurrence in T1a RCC. Higher stage correlates with a decreased disease-free survival. Long-term surveillance is necessary following RFA. Patient selection based on tumor characteristics, comorbid disease, and life expectancy is of paramount importance.
authors.affiliation: Department of Urology, Massachusetts General Hospital, Boston, MA 02114, USA.
authors.forename: Sarah P
authors.initials: SP
authors.lastname: Psutka
authors.forename: Adam S
authors.initials: AS
authors.lastname: Feldman
authors.forename: W Scott
authors.initials: WS
authors.lastname: McDougal
authors.forename: Francis J
authors.initials: FJ
authors.lastname: McGovern
authors.forename: Peter
authors.initials: P
authors.lastname: Mueller
authors.forename: Debra A
authors.initials: DA
authors.lastname: Gervais
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002292:Carcinoma, Renal Cell / Q000401:mortality* / Q000473:pathology / Q000601:surgery*; D017115:Catheter Ablation / Q000379:methods*; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007680:Kidney Neoplasms / Q000401:mortality* / Q000473:pathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009364:Neoplasm Recurrence, Local / Q000401:mortality / Q000601:surgery; D009367:Neoplasm Staging; D018579:Patient Selection; D011237:Predictive Value of Tests; D012086:Reoperation / Q000706:statistics & numerical data; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome