Background: This study attempted to search for the possible mechanism of regrowth of uterine myoma after cessation of gonadotropin-releasing hormone agonist (GnRHa) therapy.
Methods: Five premenopausal women presenting with symptomatic uterine myoma were prospectively studied in this trial. All patients were treated with a subcutaneous injection of goserelin depot 3.6 mg every four weeks for 16 weeks. Clinical examinations as well as hormonal and ultrasound determinations were performed before, during and after treatment to monitor the efficacy of therapy. At the end of the treatment period, all patients underwent myomectomy. The ultrastructural change of the myoma was evaluated postoperatively.
Results: The volume of the uterus decreased 21-57% and the volume of the uterine myoma decreased 21-65% after therapy. There was no significant change in resistance index of the uterine vessels or major vessels supplying the uterine myoma between pretreatment and post-treatment values. The morphologic features of the treated myoma showed marked cellular shrinkage and loss of myofibrillar structure.
Conclusions: There is no significant cellular damage to the cellular structure that contributes to regrowth of treated intramural uterine myoma following cessation of treatment.