title: Ablation of metastatic ovarian carcinoma with the argon beam coagulator: pathologic analysis of tumor destruction.
abstract: OBJECTIVE
  The aim of this study was to characterize the histopathologic effects of electrosurgical tumor destruction of metastatic ovarian carcinoma using the argon beam coagulator (ABC) and evaluate the depth of tissue damage produced by a range of power settings and tissue interaction times.
  
  
  METHODS
  Epithelial ovarian carcinoma tumor specimens (1 cm(3)) were harvested intraoperatively. Following surgical excision, electrosurgical destruction of tumor was effected using the ABC at three power settings (60, 80, and 100 W) and three tissue interaction time intervals (1, 3, and 5 s), yielding nine experimental groups of 16 samples each (n = 144). Samples were formalin-fixed, cross-sectioned, stained with hematoxylin and eosin, and examined microscopically for histologic characteristics and depth of tissue destruction.
  
  
  RESULTS
  Microscopic evaluation revealed that the total depth of destruction (TDD) produced by the ABC was composed of three distinct zones of tissue injury: vaporization, carbonized eschar (ESC), and coagulative necrosis (NEC). For each power setting, the mean TDD increased in a linear fashion as the interaction time interval increased from 1 to 5 s (60 W, 1.71 to 2.43 mm; 80 W, 2.24 to 3.69 mm; 100 W, 3.21 to 5.58 mm). By regression analysis, both power setting and tissue interaction time were independently associated with increasing TDD, with power having the strongest effect. At all power settings and interaction time intervals, the incremental change in TDD was primarily a function of the degree of tissue vaporization, which increased from 0.59 mm at 60 W (1 s) to 3.22 mm at 100 W (5 s). For all experimental groups, the ratio of NEC/ESC was highly consistent, ranging from 1.03 to 1.33 (P > 0.05, Bonferroni multiple comparisons procedure), and demonstrated that for each resulting ESC, an equivalent or greater degree of underlying NEC was also present.
  
  
  CONCLUSIONS
  The destruction of ovarian carcinoma tumor tissue produced by the ABC is dependent upon both power setting and tissue interaction time. Increasing depth of destruction is due predominantly to a deeper level of tissue vaporization. The NEC/ESC ratio provides a reliable means of estimating the true depth of tumor destruction produced by the ABC and may contribute to increased safety and efficacy of electrosurgical cytoreduction of using this technique.
authors.affiliation: The Kelly Gynecologic Oncology Service, Department of Gynecology and Obstetrics, The Johns Hopkins Medical Institutions, Baltimore, Maryland 21287, USA. rbristo@jhmi.edu
authors.forename: R E
authors.initials: RE
authors.lastname: Bristow
authors.forename: A E
authors.initials: AE
authors.lastname: Smith Sehdev
authors.forename: H S
authors.initials: HS
authors.lastname: Kaufman
authors.forename: F J
authors.initials: FJ
authors.lastname: Montz
mesh_terms: D004847:Epithelial Cells / Q000473:pathology; D005260:Female; D006801:Humans; D017075:Laser Coagulation / Q000379:methods*; D009362:Neoplasm Metastasis; D010051:Ovarian Neoplasms / Q000473:pathology* / Q000601:surgery*