Leuprolide acetate treatment and myoma arterial size

To compare the size of arterial vessels in myomas from women treated with GnRH agonist (GnRH-a) or given placebo.

Our study group included 46 women about to undergo myomectomy or hysterectomy; 30 were treated with leuprolide acetate (3.75 or 7.5 mg) in three monthly doses, and 16 were given placebo. Arterial diameters of the intramyomatous vessels were measured using an ocular micrometer on hematoxylin and eosin-stained slides.

Clinically and radiologically, the uterine volume of GnRH-a-treated patients decreased by an average of 30%, and the diameter of the largest myoma decreased by 27%. The average diameter of intramyomatous arteries was 24% smaller in GnRH-a subjects compared with those receiving placebo (136 +/- 42 versus 178 +/- 60 microns, P < .01). In addition, arteriosclerotic changes, including intimal and medial fibrosis, were seen more often in the GnRH-a-treated subjects (48 versus 25%, P < .05).

Intramyomatous arteries were smaller and more often showed arteriosclerotic changes in leiomyomas removed from women treated with GnRH-a compared with those given placebo. The estrogen deprivation induced by GnRH-a may cause a relative vasoconstriction of myomatous vessels. Whether this decreased vessel size is the principal contributor to decreased myoma size will require further study.