Clinical considerations of bleomycin based electrochemotherapy with variable electrode geometry electrodes for inoperable, deep-seated soft tissue sarcomas

Abstract

The aim of the current prospective pilot study exclusively for deep-seated soft tissue sarcomas (STS) was to evaluate efficacy and safety of bleomycin-based ECT using VEG (variable electrode geometry) electrodes. During a 2-year period, seven surgically inoperable STSs were treated at the University of Szeged, Department of Surgery in Hungary. Electrode placement was determined by software planning using preoperative imaging (CT/MRI) and intraoperative ultrasound. Intravenous bleomycin (15.000 IU/m²) was administered 8 min before first pulse generation which lasted up to 40 min. Tumour response was evaluated through CT/MRI 2 months after treatment as per RECIST v.1.1. Five male- and 2 female patients were treated with fibromyxoid sarcoma (n = 2), epitheloid sarcoma (n = 3), liposarcoma (n = 1) and myofibroblastic sarcoma (n = 1) with median age of 54 years (49-88). Median tumour diameter, tumour volume and tumour depth was 5.9 cm (3.7-22.5), 131.13 cm³ (35.6-2456.22) and 6.18 cm (3.74-18.18), respectively. Median operative time was 75 min (35-180), median hospital stay 2 days (2-20). Two month follow-up confirmed partial response in 5 patients, while stable disease in 1 patient, and progressive disease in 1 case as per RECIST v.1.1. Grade 2 ulceration was experienced in four cases, and a transient left musculus quadriceps femoris plegia occured in one patient. Local control of deep-seated STSs with BLM-based VEG ECT holds a promising perspective and our results may serve as a practical guide for further investigation and treatment planning.

Keywords: Deep-seated; Electrochemotherapy; Soft tissue sarcoma; Variable electrode geometry.