Clinical outcomes of magnetic resonance-guided focused ultrasound surgery for uterine myomas: 24-month follow-up.

OBJECTIVES

To assess the volume reduction ratio, symptom improvement and reintervention rate following magnetic resonance-guided focused ultrasound surgery (MRgFUS) for uterine myomas.

METHODS

A total of 91 Japanese women with symptomatic myomas underwent MRgFUS between June 2004 and June 2008 using the ExAblate 2000 system. The volume change ratio was calculated at 6, 12 and 24 months following MRgFUS based on T2-weighted magnetic resonance images. The symptom severity score (SSS) was examined before and after the treatment (at 3, 6, 12 and 24 months). Additional post-MRgFUS treatments, such as hysterectomy, myomectomy, uterine artery embolization or repeat MRgFUS, were recorded and the reinterventional treatment rates were compared according to the signal intensity of pretreatment T2-weighted magnetic resonance images of the myomas.

RESULTS

The mean volume change ratios of low- and intermediate-intensity (Type 1/2) myomas were -36.5% 6 months post-procedure and -39.5% 24 months post-procedure. The mean +/- SD SSS value for patients with Type 1/2 myomas before MRgFUS was 35.1 +/- 21.0, and the values diminished significantly during the 24-month follow-up period to a mean value of around 15.0. High-intensity (Type 3) myomas were not observed to have decreased in size 6 months after MRgFUS. Of the 45 Type 1/2 myoma patients with complete follow-up, seven required reinterventional treatment within 24 months. The reintervention rates were 14.0% for Type 1/2 patients and 21.6% for Type 3 patients at 24 months post-treatment.

CONCLUSIONS

Moderate volume reductions of Type 1/2 myomas were noted following MRgFUS, and the reduction in SSS values and the relatively low reintervention rates observed are encouraging. We found MRgFUS to be an appropriate treatment method for Type 1/2 uterine myomas.