Ablation of metastatic ovarian carcinoma with the argon beam coagulator: Pathologic analysis of tumor destruction

Objective. The aim of this study was to characterize the histopathologic ef fects of electrosurgical tumor destruction of metastatic ovarian carcinoma using the argon beam coagulator (ABC) and evaluate the depth of tissue dama ge produced by a range of power settings and tissue interaction times. Methods. Epithelial ovarian carcinoma tumor specimens (1 cm(3)) were harves ted intraoperatively. Following surgical excision, electrosurgical destruct ion of tumor was effected using the ABC at three power settings (60, 80, an d 100 W) and three tissue interaction time intervals (1, 3, and 5 s), yield ing nine experimental groups of 16 samples each (n=144). Samples were forma lin-fixed, cross-sectioned, stained with hematoxylin and eosin, and examine d microscopically for histologic characteristics and depth of tissue destru ction. Results. Microscopic evaluation revealed that the total depth of destructio n (TDD) produced by the ABC was composed of three distinct zones of tissue injury: vaporization, carbonized eschar (ESC), and coagulative necrosis (NE C). For each power setting, the mean TDD increased in a linear fashion as t he 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, b oth 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 t hat for each resulting ESC, an equivalent or greater degree of underlying N EC 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. I ncreasing depth of destruction is due predominantly to a deeper level of ti ssue vaporization. The NEC/ESC ratio provides a reliable means of estimatin g the true depth of tumor destruction produced by the ABC and may contribut e to increased safety and efficacy of electrosurgical cytoreduction of usin g this technique. (C) 2001 Academic Press.