Transrectal high‐intensity focused ultrasound (HIFU) for the management of rectosigmoid deep infiltrating endometriosis: results of phase I clinical trial

OBJECTIVES: Deep invasive endometriosis (DIE) of the rectosigmoid is associated with painful symptoms. When medical treatments are ineffective, surgical resection remains the standard despite significant adverse events. High intensity focused ultrasound (HIFU) is a minimally invasive ablative procedure. FocalOne is a transrectal HIFU (TR-HIFU) device used in prostatic cancer treatment. The primary objective of this study was to confirm the feasibility of TR-HIFU in patients presenting posterior DIE with rectosigmoid involvement. We also assessed its safety and clinical efficacy in this indication. METHODS: Phase I, non-controlled, prospective monocentric clinical study. The inclusion criteria were patients older than 25, without any project of pregnancy in the next 6 months, who presented a single lesion of posterior DIE with a rectosigmoid invasion and after failure of hormonal therapy. All lesions were assessed using transvaginal sonography and MRI. Patients filled questionnaires on gynecologic and intestinal symptoms, and on quality of life (MOS-SF36 score, EHP-5) before and at one, three and six months after treatment. RESULTS: Twenty-three patients were included between September 2015 and October 2018. All the lesions were visualized. Twenty lesions were treated ("feasibility rate": 87.0%): thirteen entirely and seven partially. The mean duration of the procedure was 55.6 minutes. We observed a significant improvement in visual analogic scales at six month for dysmenorrhea (-3.6, p=0.004), dyspareunia (-2.4, p=0.006), diarrhea (-3.0, p=0.006), constipation (-3, p=0.002), dyschezia (-3.2, p=0.003), false urges to defecate (-3.3, p=0.007), posterior pelvic pain (-3.8, p=0.002), and asthenia (-4.3, p=0.002).There was also a significant improvement of the MOS-SF36 with an increase of both Physical Composite Score (+9.3%, p=0.002) and Mental Composite Score (+10.9%, p=0.017) at six months. No major complications occurred during and after the procedure. CONCLUSIONS: TR-HIFU therapy for posterior DIE is feasible. It could be an interesting minimally invasive alternative to surgery for the treatment of rectosigmoid endometriosis if its efficacy and safety is confirmed. This article is protected by copyright. All rights reserved.