Relationship between hormone receptor concentration and tumor shrinkage in uterine myoma after treatment with a GnRHa.

BACKGROUND: Uterine myomas are benign tumors of the uterus, occurring in up to 25% of women of reproductive age. We examined the possible causes for different degrees of volume reduction in patients with uterine myomas who received gonadotropin-releasing hormone agonist (GnRHa) treatment by investigating the hormone receptors at the end of GnRHa treatment. METHODS: This trial was designed as a prospective study of five premenopausal women presenting with symptomatic uterine myoma. All patients were treated with a subcutaneous injection of goserelin depot 3.6 mg every four weeks for 16 weeks. Clinical examinations, hormonal evaluation and ultrasound determinations were performed before, during and after treatment. At the end of the treatment period, all patients underwent myomectomy. The concentrations of the unbound progesterone receptors and estrogen receptors were evaluated. RESULTS: The volume of the uterine myoma decreased by 21% to 65%. The percentage of decrease in volume of treated uterine myomas was found to negatively correlate with the concentration of unbound progesterone receptors (r2 = 0.92, p = 0.008). This percentage was not significantly correlated with the concentration of unbound estrogen receptors (r2 = 0.02, p = 0.84). CONCLUSIONS: The limited data available suggested that the volume decrease of uterine myomas in GnRHa-treated patients is partly dependent on the concentrations of unbound sex-hormone receptors in the uterine myomas.