The purposes of this study were to investigate the effect of a superactive agonistic analog of
gonadotropin-releasing hormone,
nafarelin, on uterine
leiomyomas and to assess the use of magnetic resonance imaging in monitoring uterine and
myoma size. Eleven women with uterine
leiomyomas were treated with 800 micrograms of
nafarelin per day for 6 months. Serum
gonadotropin and
estradiol concentrations were suppressed during treatment. The mean +/- SEM serum
luteinizing hormone level decreased from 11.1 +/- 1.4 to 5.6 +/- 0.42 mlU/ml and
follicle-stimulating hormone from 9.5 +/- 0.66 to 7.5 +/- 0.72 mlU/ml by 3 months of treatment (p less than 0.01). The
estradiol level decreased from a pretreatment follicular phase mean +/- SEM of 43 +/- 8.3 to 19.8 +/- 3.1 (p less than 0.05) and 14.8 +/- 2.2 pg/ml (p less than 0.01) at 3 and 6 months of treatment, respectively. Mean pretreatment
androgen levels (
testosterone,
androstenedione, and
dehydroepiandrosterone sulfate) were low in these women and did not change significantly during treatment. Ten women had magnetic resonance imaging, which provided excellent resolution of individual uterine
myomas. As assessed by magnetic resonance imaging, the largest
myoma decreased in size in nine of 10 women; the mean decrease was 46% +/- 9%. Uterine volume decreased in all 10 patients; the mean decrease was 57% +/- 7%. In several women
myomas reenlarged after discontinuance of
nafarelin treatment. Posttreatment
myomectomy was carried out in four women; there was minimal blood loss and no surgical complications. These data indicate that suppression of ovarian
estrogen production with
nafarelin is associated with a decrease in uterine
myoma size in many women but that
myomas may regrow with reinstitution of ovarian function. Magnetic resonance imaging is an excellent method by which to monitor treatment as changes in the size of the uterus, as well as individual
myomas, can be assessed. The optimal use of
gonadotropin-releasing hormone analogs may be in perimenopausal women or as presurgical treatment to decrease uterine and
myoma size to facilitate
myomectomy.