title: Radiofrequency Ablation of Lung Tumors Using a Multitined Expandable Electrode: Impact of the Electrode Array Diameter on Local Tumor Progression.
abstract: OBJECTIVE
  To retrospectively investigate the impact of the electrode array diameter on local tumor progression after lung radiofrequency ablation.
  
  
  METHODS
  This study included 651 lung tumors treated using multitined expandable electrodes and followed for ≥ 6 months. The mean long-axis tumor diameter was 12 mm ± 7 (range, 2-42 mm). The difference between electrode array diameter and tumor diameter (DAT) was used to investigate the impact of the electrode array diameter. All tumors were classified into 2 groups according to various variables including DAT (≥ 10 mm or < 10 mm). The primary technique efficacy rates were calculated using Kaplan-Meier analysis and compared between the 2 groups of each variable using the log-rank test. In addition, crude and multivariate multilevel survival analyses were performed by sequentially including DAT and the other variables in 5 models.
  
  
  RESULTS
  The median DAT for 651 tumors was 12 mm (range, -15 to 24 mm). The technique efficacy rate was significantly lower in the < 10 mm DAT group than in the ≥ 10 mm group (P < .001). In the crude and multivariate multilevel survival analyses, < 10 mm DAT was a significant risk factor for local progression in all models except model 5 (P = .067). In the ≥ 10 mm group, the technique efficacy rates were not significantly different between the 2 ≥ 10 mm DAT subgroups (10 to <15 mm DAT vs ≥ 15 mm DAT).
  
  
  CONCLUSIONS
  DAT is an important risk factor for local progression. We recommend an electrode that is ≥ 10 mm larger than the tumor diameter.
authors: Department of Radiology, Okayama University Medical School, 2-5-1 Shikata-cho kita-ku, Okayama 700-8558, Japan. Electronic address: ihara.hiroki.0206@gmail.com.
authors: Hiroki
authors: H
authors: Ihara
authors: Department of Radiology, Okayama University Medical School, 2-5-1 Shikata-cho kita-ku, Okayama 700-8558, Japan.
authors: Hideo
authors: H
authors: Gobara
authors: Department of Radiology, Okayama University Medical School, 2-5-1 Shikata-cho kita-ku, Okayama 700-8558, Japan.
authors: Takao
authors: T
authors: Hiraki
authors: Center for Innovative Clinical Medicine, Okayama University Hospital, Okayama, Japan.
authors: Toshiharu
authors: T
authors: Mitsuhashi
authors: Department of Radiology, Okayama University Medical School, 2-5-1 Shikata-cho kita-ku, Okayama 700-8558, Japan.
authors: Toshihiro
authors: T
authors: Iguchi
authors: Department of Radiology, Okayama University Medical School, 2-5-1 Shikata-cho kita-ku, Okayama 700-8558, Japan.
authors: Hiroyasu
authors: H
authors: Fujiwara
authors: Department of Radiology, Okayama University Medical School, 2-5-1 Shikata-cho kita-ku, Okayama 700-8558, Japan.
authors: Yusuke
authors: Y
authors: Matsui
authors: Department of General Thoracic Surgery (J.S., S.T.), Okayama University Hospital, Okayama, Japan.
authors: Junichi
authors: J
authors: Soh
authors: Department of General Thoracic Surgery (J.S., S.T.), Okayama University Hospital, Okayama, Japan.
authors: Shinichi
authors: S
authors: Toyooka
authors: Department of Radiology, Okayama University Medical School, 2-5-1 Shikata-cho kita-ku, Okayama 700-8558, Japan.
authors: Susumu
authors: S
authors: Kanazawa
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017115:Catheter Ablation / Q000295:instrumentation*; D018450:Disease Progression; D004566:Electrodes; D004867:Equipment Design; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008168:Lung / Q000601:surgery; D008175:Lung Neoplasms / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D055815:Young Adult