Treatment of Uterine Fibroids With Magnetic Resonance Guided High Intensity Focused Ultrasound

Treatment of Uterine Fibroids With Magnetic Resonance Guided High Intensity Focused Ultrasound

The purpose of this study is to demonstrate the effectiveness of MR-HIFU for the treatment of uterine fibroids in Northwestern Ontario, which is a rural and remote setting.

Uterine fibroids are benign smooth muscle tumours of the muscular wall of the uterus that affect 40 per cent of women. While the majority of fibroids are asymptomatic, fibroids may cause menorrhagia, bulk symptoms (i.e. ureteric obstruction, urinary frequency and urgency, bowel dysfunction), pain and in certain instances infertility.

Magnetic resonance image-guided high-intensity focused ultrasound (MR-HIFU) treatment of fibroids is an established method for symptom alleviation with over 3000 women receiving treatment worldwide. MR-HIFU is a non-invasive, non-surgical procedure that uses ultrasound energy to thermally ablate the fibroid leading to a reduction in bleeding and in the size of uterine fibroids over time. MR-HIFU it is not currently being used for the treatment of symptomatic fibroids in Canada.

The Thunder Bay Regional Research Institute has one of the first clinically available MR-HIFU equipment in Canada. In order to bring this technology into clinical practice, a knowledge translation study is needed to demonstrate that MR-HIFU can treat symptomatic uterine fibroids as successfully in Northwestern Ontario compared to urban centres where all of the clinical trials have been conducted. The ability to screen and follow up women treated with MR-HIFU with ultrasound rather than MRI would allow participants to receive follow up in regional centres in Northwestern Ontario and it would be more cost effective from a health system perspective. In addition, more research is needed to broaden the scope of treatment to include fibroids greater than 8 cm such that more women could benefit from this non-surgical fibroid management option.

Inclusion Criteria:

• Women aged 18 to 50 years
• Weight <140kg
• Pre or perimenopausal
• Uterine size <24 weeks
• Cervical screen by Pap test: Normal, Low Grade Squamous Intraepithelial Lesion, or Atypical Squamous Cells of Undetermined Significance as per Cancer Care Ontario guidelines
• Transformed symptom severity score ≥40
• Willing to attend all study visits
• Willing to complete evaluation forms
• Willing and able to use reliable contraception;

MR-HIFU Criteria Trial Arm 1:

• Minimum of 50% of fibroid volume accessible for treatment
• Dominant fibroid ≤8 cm
• Uterine volume <900 cc
• Total fibroid treatment volume <250 cc
• No more than 5 fibroids planned for ablation
• Completely non-enhancing fibroids should not be treated

MR-HIFU Criteria Trial Arm 2:

• Minimum of 50% of fibroid volume accessible for treatment
• Dominant fibroid >8 cm or uterine volume >900 cc
• Total fibroid treatment volume <250 cc
• No more than 5 fibroids planned for ablation
• Completely non-enhancing fibroids should not be treated

Exclusion Criteria:

• Other pelvic disease (endometriosis, ovarian tumor, acute pelvic disease, other mass)
• Significant systemic disease even if well controlled
• Positive pregnancy test
• Abnormal uterine bleeding (participant can be included if an endometrial biopsy confirms no hyperplasia or malignancy in the past 6 months)
• Extensive scarring along anterior abdominal wall (>50% of area)
• Surgical clips or scar tissue in the path of the MR-HIFU beam
• MRI contraindicated according to standard operating procedure
• MRI contrast contraindicated (including renal insufficiency)
• Calcifications around or throughout uterine tissues
• Fibroids not quantifiable on MRI
• Highly perfused or brighter than myometrium in T2-weighted MRI fibroids (Type 3 fibroids).