1. Pathologic Analysis of Tumour Destruction with Neutral Plasma in Epithelial Ovarian Carcinoma Madhuri TK 1, Butler-Manuel SA 1, Tailor A 1 & Haagsma B 2 1 Department of Gynaecological Oncology, 2 Department of Histopathology Royal Surrey County Hospital NHS Foundation Trust, Guildford, UK BACKGROUND Ovarian cancer (OC) accounted for 225,000 cases worldwide in 2008 with 140,000 deaths recorded the same year. 1 Deaths from OC are more than all the other gynaecological cancers combined. 1 Advanced EOC typically presents with widespread metastases. However, surgical cytoreduction plays a key role in improving overall survival (OS). Various studies including the EORTC study by Vergote et al recommends that complete resection of all macroscopic disease during debulking is the single most important prognostic factor in advanced EOC. 2 Until recently, surgery was considered optimal if residual tumour </= 1cm remained. Today, optimal cytoreduction is defined as removal of all visible macroscopic disease. Bulky disease may be resected with radical surgery. However, removal of miliary peritoneal and serosal metastases is problematic and hence surface tumour ablation with innovative surgical devices is an attractive proposition. Various electrosurgical devices have been developed over the years including the argon beam coagulator (ABC). All these devices have specific applications with several disadvantages including passing electric current through tissue to generate heat, setup time, trained assistance, speed, intra-operative lateral thermal spread (LTS) and variable collateral tissue destruction (TD). Aim The aim of this study is to report the histopathological effects of TD following PlasmaJet (PJ) use focussing on the power settings used and tissue interaction time and its co-relation with the depth of destruction and LTS. Materials & Methods. Following consent from women undergoing debulking for EOC, fresh tissue was harvested intra-operatively. Following tissue excision, 1cm 3 sections of tissue was exposed to PJ at varied power settings and increasing time duration. These were formalin- fixed and stained. Histological examination of tissue destruction included assessment of cavity depth and extent of burn at the base of cavity. RESULTS 48 specimens from the omentum were analysed Depth of Tissue Destruction DTD was defined by the depth of the cavity left by the ablated tissue. Lateral Thermal Spread LTS was defined by the depth of histologically visible tissue damage. This was measured from the surface of the eschar to the level of normal tissue morphology. DTD varied from 0.2 -3.5mm (mean 1.29) LTS was minimal at all the settings mentioned. (mean: 0.22 range 0.1-0.4) Tissue damage at the base of the cavity ranged from 0.07 to 0.4 mm (mean 0.15) Exposure Time (Seconds) Depth (mm) Superficial Margin (mm) Cavity Base (mm) Depth (mm) Superficial Margin (mm) Cavity Base (mm) Depth (mm) Superficial Margin (mm) Cavity Base (mm) Depth (mm) Superficial Margin (mm) Cavity Base (mm) Depth (mm) Superficial Margin (mm) Cavity Base (mm) 10.450.10.40.20.10.0810.350.150.60.180.310.120.1 20.60.150.10.60.150.071.20.30.1110.250.151.250.180.12 330.20.130.40.20.171.50.230.123.50.250.22.250.250.2 40.4 0.120.210.173.50.40.082.750.320.153.50.250.15 Power Setting 10%20%40%60%80% The results of examination of the tumour tissue (serous carcinoma from omental cake) are presented in the Table DISCUSSION We previously explored the role of the PJ for various applications in benign and malignant gynaecological procedures. 3 In ovarian cancer debulking where optimal cytoreduction is desired, the PJ appears to effectively ablate cancer cells effectively. Minimal LTS and DTD is necessary especially when ablating tumour deposits around viscera and bowel surfaces. Increasing power and tissue interaction time resulted in effective tumour ablation while still maintaining minimal LTD. The extent of tissue ablation produced by PJ is dependent upon both power settings and duration of exposure. However, increasing these parameters did not seem to impact on lateral thermal spread making the PJ an attractive electrosurgical device.CONCLUSION PJ appears to be an inherently safe device that may be used for optimal cytoreduction on various tissue surfaces. References 1.Office for National Statistics, 2011. Cancer Statistics registrations: registrations of Cancers diagnosed in 2008, England. 2.Vergote I, Trope CG, Amant F, Kristensen GB et al. Neoadjuvant Chemotherapy or Primary Surgery in Stage IIIC or IV Ovarian Cancer. European Organization for Research and Treatment of Cancer- Gynaecological Cancer Group; NCIC Clinical Trials Group. N Engl J Med 2010; 363:943-53. 3.Madhuri TK, Papatheodorou D, Tailor A, Sutton CJG, Butler-Manuel SA. First clinical experience of argon neutral plasma energy in gynaecological surgery in the UK. Gynecol Surg. 2010:7(4):423-425 As expected the extent of tissue damage around the cavity on the surface of the specimen increased with increasing exposure time and increasing power settings. The extent of this damage was small and did not increase in direct proportion to the increased exposure and power. PlasmaJet® is a trademark of Plasma Surgical, Ltd Corresponding Author:docmadhuri231@doctors.org.uk Figure 1 showing cavity at 40% setting (1sec) Figure 2 showing eschar at 40% setting (1sec) Figure 3 showing cavity at 40% setting (5sec) Figure 4 showing eschar at 40% setting (5 sec)