An Evaluation of the Effect of Gonadotropin-releasing Hormone Analogs and Medroxyprogesterone Acetate on Uterine Leiomyomata Volume by Magnetic Resonance Imaging: a Prospective, Randomized, Double Blind, Placebo-controlled, Crossover Trial

The purpose of this study was to prospectively compare the effectiveness of administering medroxyprogesterone acetate (MPA; 20 mg/day) in either the first (protocol A) or last (protocol B) 12-week period along with a 6-month course of the GnRH analog (GnRH-a; leuprolide acetate; 1 mg/day, sc) on uterine and leiomyomata volumes and hormone (estradiol, LH, and FSH) and serum lipid (total cholesterol, triglycerides, and high and low density lipoprotein) levels. Sixteen women were randomized into protocol A or B, received either MPA or placebo along with GnRH-a, respectively, and were then crossed over at 12 weeks to placebo or MPA, respectively, for the final 12-week interval of GnRH-a therapy. Total, myoma, and nonmyoma uterine volumes were determined by magnetic resonance imaging, and serum studies were performed at the beginning of the study and at 12 and 24 weeks. In both protocols, LH and estradiol levels declined by 80-90% (P < 0.03) and 55-72% (P < 0.02) of the baseline, respectively, at 12 weeks and remained at this level at 24 weeks. There were no significant changes in the other laboratory tests between protocols or longitudinally over time. Total uterine volume decreased to 73% of the baseline at 12 weeks in protocol B (P < 0.04), but did not change in protocol A. After crossover at 12 weeks, the total uterine volume of women in protocol A decreased to 74% of the baseline (P < 0.02) at 24 weeks. Between-protocol comparisons demonstrated a greater decline in total uterine volume in protocol B than A at 12 weeks, but after cross-over, MPA addition was associated with a significant increase in total uterine volume (protocol B) compared to a decrease in protocol A at 24 weeks (P < 0.005). In contrast, although myoma volume declined in both protocols, no significant changes in myoma volume were detected within or between groups over the treatment period. Nonmyoma volume changes in protocols A and B roughly paralleled total uterine volume changes, with MPA coadministration showing a correlation with a reversal in the GnRH-a-associated decrease in nonmyomatous tissue volume.(ABSTRACT TRUNCATED AT 400 WORDS)