Use of an agonistic analog of gonadotropin-releasing hormone (nafarelin) to treat leiomyomas: assessment by magnetic resonance imaging.

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.