A Prospective Randomized Study Comparing Endocrinological and Clinical Effects of Two Types of GnRH Agonists in Cases of Uterine Leiomyomas or Endometriosis

Abstract Objective: In order to assess the endocrinological changes associated with 2 types of low‐dose GnRH agonists depot as well as their clinical efficacy, we performed a randomized prospective comparison study of patients having uterine leiomyomas or endometriosis. Methods: A prospective randomized study involving 67 patients with uterine leiomyomas or endometriosis was carried out. These patients were randomly administered either buserelin MP 1.8 mg (Group B, n = 34) or leuprolide 1.88 mg (Group L, n = 33). In each group we evaluated the symptoms of genital bleeding and hot flashes during GnRHa treatment, as well as the levels of serum LH, FSH, and estradiol 8 weeks after the start of treatment. In addition, the endometrial thickness was measured by transvaginal ultrasonography, and changes in the volume of the uterine leiomyoma or endometrial cyst at the end of treatment. The GnRHa depot was administered from 3 to 8 times, 28 days apart, in both groups. Results: The incidence of menstruation‐like genital bleeding 8 weeks after treatment was significantly (p < 0.01) higher in Group B. However this difference disappeared by 12 weeks after treatment. The climacteric symptom of hot flashes was found to be significantly (p < 0.01) more severe in Group L, and this tendency continued until 20 weeks after treatment. The 2 groups did not differ significantly with regard to the levels of the serum LH, FSH, and estradiol at 8 weeks after treatment or in the endometrial thickness at the end of the GnRHa treatment. In both groups, the volumes of the uterine leiomyomas were significantly (p < 0.01) lower after the treatment. In contrast, the volumes of the endometrial cysts did not decrease after administration of GnRHa in both groups. Conclusion: Leuprolide 1.88 induced pituitary down regulation more rapidly than buserelin MP. However the hypoestrogenic symptoms such as hot flashes were more severe in cases treated with leuprolide 1.88 than in those treated with buserelin MP. Our data confirm that the therapeutic efficacy of buserelin MP and leuprolide 1.88 are similar, with both being sufficient to treat uterine leiomyomas and endometriosis.