title: CT-Guided Percutaneous Cryoablation in Renal Cell Carcinoma: Factors Affecting Local Tumor Control.
abstract: OBJECTIVE
  To retrospectively evaluate factors affecting local tumor control in cryoablation of renal cell carcinomas (RCCs).
  
  
  METHODS
  This study examined 61 patients (43 men, 18 women) with a mean age of 69.1 years ± 10.8 (range 38-87 y) who underwent computed tomography (CT)-guided percutaneous cryoablation for a single RCC and were followed for 6 months or longer. Maximum tumor diameter was 0.8-4.8 cm (mean ± standard deviation, 2.4 ± 0.9 cm). Factors affecting local tumor control were evaluated. Deep tumor location was defined as the center side of the body perpendicular to the kidney midline.
  
  
  RESULTS
  Median follow-up was 12.7 months. Residual unablated tumors and local tumor progression were observed after initial cryoablation in 4 patients each (13%, 8 of 61). All uncontrolled tumors were located in the deep side of the kidney (100%, 8 of 8), and were covered by an ice-ball margin of 5 mm or less. Deep tumor location (P = .005) and ice-ball margin (P = .002) were detected as significant factors affecting local tumor control on univariate analysis, and ice-ball margin remained significant in a stepwise logistic regression model (P = .006; odds ratio, 0.57; 95% confidence interval, 0.38-0.83). Complete tumor control rates were 42.9% (3 of 7), 92.6% (50 of 54), and 100% (20 of 20) with ice-ball margins of less than 3 mm, 3 mm or larger, and 6 mm or larger, respectively.
  
  
  CONCLUSIONS
  Deep tumor location and ice-ball margins less than 6 mm were associated with incomplete local control following CT-guided percutaneous cryoablation for RCC.
authors.affiliation: Department of Radiology, Mie University School of Medicine, Tsu, Japan. Electronic address: t-yama@clin.medic.mie-u.ac.jp.
authors.forename: Takashi
authors.initials: T
authors.lastname: Yamanaka
authors.affiliation: Department of Radiology, Mie University School of Medicine, Tsu, Japan.
authors.forename: Koichiro
authors.initials: K
authors.lastname: Yamakado
authors.affiliation: Department of Clinical Epidemiology and Biostatistics, Graduate School of Medicine, Osaka University, Suita, Japan.
authors.forename: Tomomi
authors.initials: T
authors.lastname: Yamada
authors.affiliation: Department of Radiology, Mie University School of Medicine, Tsu, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Fujimori
authors.affiliation: Department of Radiology, Mie University School of Medicine, Tsu, Japan.
authors.forename: Haruyuki
authors.initials: H
authors.lastname: Takaki
authors.affiliation: Department of Radiology, Mie University School of Medicine, Tsu, Japan.
authors.forename: Atsuhiro
authors.initials: A
authors.lastname: Nakatsuka
authors.affiliation: Department of Radiology, Mie University School of Medicine, Tsu, Japan.
authors.forename: Hajime
authors.initials: H
authors.lastname: Sakuma
authors.affiliation: Department of Nephro-Urologic Surgery, Mie University School of Medicine, Tsu, Japan.
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Sugimura
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002292:Carcinoma, Renal Cell / Q000000981:diagnostic imaging / Q000401:mortality* / Q000601:surgery*; D018572:Disease-Free Survival; D006801:Humans; D015994:Incidence; D007564:Japan / Q000453:epidemiology; D007680:Kidney Neoplasms / Q000000981:diagnostic imaging / Q000401:mortality* / Q000601:surgery*; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000401:mortality / Q000517:prevention & control*; D012189:Retrospective Studies; D012307:Risk Factors; D025321:Surgery, Computer-Assisted / Q000401:mortality*; D015996:Survival Rate; D014057:Tomography, X-Ray Computed / Q000706:statistics & numerical data; D016896:Treatment Outcome