Background: MR guided Focused Ultrasound (MRgFUS) has emerged as an effective, low-risk, non-invasive treatment for a wide range of patients with symptomatic fibroids. Using consecutive sonications of high intensity ultrasound within a defined target area, a volume of ablated tissue can be produced. Previous studies have demonstrated that symptomatic improvement at six months following treatment correlates directly with the size of the initial non-perfused volume created.
Gonadotrophin Releasing Hormone Analogues (GNRHa) cause a temporary decrease in volume and vascularity in uterine fibroids. We hypothesize that the use of GNRHa in conjunction with MRgFUS will enable us to produce larger volumes of thermo-coagulation at a similar energy input.
Methods: Women who presented to the Gynaecology clinic with fibroids, who would have otherwise have been offered surgery, were considered. Those with symptomatic fibroids (Symptom Severity Score > 20), which appeared device accessible on MRI scan, and in whom the overall infero-superior diameter of the uterus was 10 cm or greater were invited to participate.
Study subjects were given 3 injections of Goserelin (Zoladex® 3.6 mg AstraZeneca) at 28-day intervals commencing on the first day of their menstrual period. MR guided Focused Ultrasound was carried out 14-21 days after the final injection.
End-point of treatment was considered to be achieved when a maximum volume of tissue had been ablated within the time available. A margin of 5 mm between the treatment zone and fibroid periphery was observed. A maximum of two treatments was offered per patient. T1 weighted images with Gadolinium enhancement, demonstrating non-perfused volume were obtained following MRgFUS.
Results: 30 women met the inclusion criteria and were enrolled. 3 candidates were excluded from the analysis. Of the 27 results analysed 14 patients had a solitary fibroid and 13 had more than one fibroid. Average uterine volume was 1230 cm3 with average fibroid volume being 720 cm3.
Following Zoladex administration the mean decrease in uterine volume was measured as 40.10% and the mean decrease in fibroid volume 34.94%.
The average non-perfused volume immediately post-treatment was 135 ccs or 36% of the target fibroid. This required a mean of 47 sonications and 2430 joules per sonication. The non-perfused volume created, per joule of energy delivered, was increased by 44% when compared to previous studies, without GnRHa pre-treatment.
Conclusion: The use of GNRHa in combination with MRgFUS increases the area of non-perfused volume produced, at similar energy levels and decreases the overall fibroid volume to be treated.
We believe this is a very significant development allowing more effective treatment of moderate size fibroids and extension of this treatment modality to women with larger fibroids, which were previously problematic.