Pathologic analysis of ex vivo plasma energy tumor destruction in patients with ovarian or peritoneal cancer.

INTRODUCTION Cytoreduction of all visible disease has been associated with improved survival in patients with advanced-stage ovarian or peritoneal cancer. This is best achieved by minimizing injury to normal tissues. We report on the tumor destruction potential, in an ex vivo model, of a novel energy source that uses an electrically neutral beam of pure plasma to vaporize tissue. METHODS Tumors were harvested from patients undergoing primary surgical cytoreduction for ovarian or peritoneal cancer. Specimens were divided into 1-cm sections and treated with pure plasma energy for 2 or 4 seconds using standardized power settings. Bright-field microscopy was used to measure the depth of tissue vaporization and lateral thermal damage (LTD). RESULTS The mean (SD) tissue vaporization depth was 2.7 (1.3) mm (n = 96). Lateral thermal damage was minimal at all tissue interaction settings (0.13 [0.031] mm). Lateral thermal damage was approximately 5% of the depth of tissue vaporization. Tissue interaction time was a more powerful predictor of vaporization than power. When tissue interaction time increased from 2 to 4 seconds, depth of vaporization and LTD increased by 1.7 and 0.03 mm, respectively (P < 0.001 for both). When power was increased from low to high settings, depth of vaporization increased by 0.6 mm (P = 0.02), and LTD did not change. CONCLUSIONS Plasma energy can effectively vaporize ovarian and peritoneal cancer cells. Greater power and tissue interaction time results in more tumor vaporization while maintaining minimal LTD. This is an attractive characteristic of plasma energy that may be useful for eradicating tumor from visceral surfaces.