Clinical aspects of LHRH analogues in gynaecology: a review

Will GNRH antagonists be worth the wait?

Gonadotropin-releasing hormone (GnRH) is also known as luteinizing hormone-releasing hormone (LHRH), formerly luteinizing hormone releasing factor (LRF). Since this hormone regulates the secretion of both FSH and LH, we prefer to call it GnRH. GnRH antagonists, as the name implies, are a class of compounds that actively compete with GnRH for the GnRH receptor, thereby neutralizing the effects of GnRH by competitive receptor occupancy. In order to fully appreciate their potential clinical utility, it is first important to comprehend the critical role of GnRH in the regulation of the pituitary-gonadal axis and secondly to familiarize ourselves with the mechanisms of action of GnRH, GnRH agonists and GnRH antagonists.

Gene therapy of uterine leiomyomas: adenovirus-mediated expression of dominant negative estrogen receptor inhibits tumor growth in nude mice

BACKGROUND

Leiomyomas (fibroids) are common estrogen-dependent uterine tumors with no effective medicinal treatment; hysterectomy is the mainstay of management.

STUDY DESIGN

This study was undertaken to investigate a potential therapy for leiomyoma; we used a mutated dominant-negative estrogen receptor gene delivered via an adenoviral vector (Ad-ER-DN).

RESULTS

Ad-ER-DN transduction, in both human and rat leiomyoma cell lines, induced an increase in both caspase-3 levels and BAX/Bcl-2 ratio with evident apoptosis in the TdT-mediated dUTP nick-end labeling assay. In nude mice, rat leiomyoma cells ex vivo transduced with Ad-ER-DN supported significantly smaller tumors compared with Ad-LacZ-treated cells 5 weeks after implantation. In mice treated by direct intratumor injection into preexisting lesions, Ad-ER-DN caused immediate overall arrest of tumor growth. The Ad-ER-DN-treated tumors demonstrated severely inhibited cell proliferation (BrdU index) and a marked increase in the number of apoptotic cells (TdT-mediated dUTP nick-end labeling index).

CONCLUSION

Dominant-negative estrogen receptor gene therapy may provide a nonsurgical treatment option for women with symptomatic uterine fibroids who want to preserve their uteri.

Uterine leiomyoma in the Eker rat: A unique model for important diseases of women

Eker rats carry a defect in the Tsc-2 tumor suppressor gene and female Eker rats develop uterine leiomyoma with a high frequency. The presentation, response to hormones and molecular alterations in these mesenchymal smooth muscle tumors, closely resembles their cognate human disease. Female rats and tumor-derived cell lines from Eker rat leiomyomas (ELT lines) have been developed as an in vivo/in vitro model system for preclinical studies to identify novel therapeutic agents for this disease and for studying disease pathogenesis. In addition to serving as a model for uterine leiomyoma, Eker rats have proven valuable for studying lymphangioleiomyomatosis, a related proliferative smooth muscle disease of women.

Fertility after treatment for Hodgkin's disease

BACKGROUND

The investigational endeavors of ovarian cryopreservation await the clinical experience of auto- or xenotransplantation, in vitro maturation of thawed primordial follicles, their in vitro fertilization and embryo transfer. Although promising, this experience is not yet available. Moreover, the risk of possible reimplantation of malignant stem cells with the thawed cryoperserved ovary has been raised following experimental animal observations. Therefore, until these innovative endeavors prove successful, we have attempted to minimize the gonadotoxic effect of chemotherapy by the co-treatment with a gonadotropin-releasing hormone agonistic analog (GnRH-a) to induce a temporary prepubertal milieu. The immunoreactive inhibin-A and -B in these patients was measured before, during and following the gonadotoxic chemotherapy.

METHODS

A prospective clinical protocol was undertaken in 60 women aged 15-40 years with lymphoma, 10 with leukemia and 10 undergoing chemotherapeutic treatments for non-malignant diseases such as systemic lupus erythematosus or other autoimmune diseases. A monthly injection of depot D-TRP(6)-GnRH-a was administered from before starting the chemotherapy until its conclusion, up to a maximum of 6 months. Hormonal profile [follicle-stimulating hormone (FSH), luteinizing hormone (LH), E2, T, P4, insulin-like growth factor (IGF)-1, IGF-BP3 and prolactin) was taken before starting the GnRH-a/chemotherapy co-treatment, and monthly thereafter until resumtion of spontaneous ovulation. This group was compared with a control group of 60 women who have been treated with similar chemotherapy.

RESULTS

Whereas all but three (40, 36 and 34 year old) of the surviving patients within the GnRH-a/ chemotherapy co-treatment group resumed spontaneous ovulation and menses within 12 months, less than half of the patients in the 'control' group (chemotherapy without GnRH-a co-treatment) resumed ovarian function and regular cyclic activity (P <0.05). The remaining 55% experienced premature ovarian failure (POF). Temporarily increased FSH concentrations were experienced by about one-third of the patients resuming cyclic ovarian function, suggesting reversible ovarian damage in a larger proportion of women than those experiencing POF. Inhibin-A and -B decreased during the GnRH-a/ chemotherapy co-treatment but increased to normal levels in patients who resumed regular ovarian cyclicity, and/or spontaneously conceived, as compared with low levels in those who developed POF.

CONCLUSIONS

If these preliminary data are consisent in a larger group of patients, GnRH-a co-treatment should be considered in every woman of reproductive age receiving chemotherapy, in addition to assisted reproductive technologies and the investigation into ovarian cryopreservation for future in vitro maturation, autotransplantation or xenotransplantation.

Preservation of fertility and ovarian function and minimalization of chemotherapy associated gonadotoxicity and premature ovarian failure: the role of inhibin-A and -B as markers

BACKGROUND

Following the improved long term survival in young women with lymphoma and leukemia undergoing chemotherapy, the preservation of future fertility has been the focus of recent interest. The investigational endeavors of ovarian cryopreservation awaits the clinical experience of in-vitro maturation of thawed primordial follicles, their in-vitro fertilization and ET. Although promising, this experience is not available yet. Moreover, the risk of possible reimplantation of malignant stem cells with the thawed cryopreserved ovary has been raised, following experimental animal observations. Therefore, until these innovative endeavors prove successful, and in parallel to them we attempted to minimize the gonadotoxic effect of chemotherapy by the co-treatment with a GnRH agonistic analogue to induce a temporary prepubertal milieu. Whereas, inhibin-B concentrations in serum may reflect the ovarian granulosa cell compartment, inhibin-A reflects luteal function. The immunoreactive inhibin-A and -B in these patients, before, during, and following the gonadotoxic chemotherapy were measured.

METHODS

A prospective clinical protocol was undertaken in 55 women with lymphoma, aged 15-40 years, ten with leukemia and eight undergoing chemotherapeutic treatments for non malignant diseases such as systemic lupus erythematosus (SLE) or other autoimmune diseases. A monthly injection of depot D-TRP6-GnRH-a was administered from before starting the chemotherapy until its conclusion, up to a maximum of 6 months. Hormonal profile (FSH, LH, E2, T, P4, IGF-1, IGF-BP3, and PRL) was taken before starting the GnRH-a/chemotherapy co-treatment, and monthly thereafter, until resuming spontaneous ovulation. This group was compared with a control group of 55 women who have been treated with similar chemotherapy. Inhibin-A and -B immunoactivity was measured by an ELISA commercial kit (Serotec).

RESULTS

Whereas, all but three (40- and 36-year-old) of the surviving patients with GnRH-a/chemotherapy co-treatment group resumed spontaneous ovulation and menses within 12 months, less than half of the patients in the control group (chemotherapy without GnRH-a co-treatment) resumed ovarian function and regular cyclic activity (P<0.05). The remaining 56% experienced premature ovarian failure (POF). Temporary increased FSH concentrations were experienced by about a third of the patients resuming cyclic ovarian function, suggesting a reversible ovarian damage in a larger proportion of women than those experiencing POF. Inhibin-A and -B decreased during the GnRH-a/chemotherapy co-treatment but increased to normal levels in patients who resumed regular ovarian cyclicity, and/or spontaneously conceived, as compared with low levels in those who developed POF.

CONCLUSIONS

If these preliminary data are consistent in a larger group of patients, inhibin-A or -B concentrations may serve as prognostic factors for predicting the resumption of ovarian function, in addition to the levels of FSH, LH and E2. The GnRH-a co-treatment should be considered in every woman in the reproductive age receiving chemotherapy, in addition to ART, and to the investigational attempts of ovarian cryopreservation for future in-vitro maturation, autotransplantation, or xenotransplantation.

Long-term use of gonadotropin-releasing hormone analogs and hormone replacement therapy in the management of endometriosis: a randomized trial with a 6-year follow-up

OBJECTIVE

To identify the effects of long-term GnRH agonist use (6-24 months), with and without add-back therapy, and spontaneous reversibility of bone mass density (BMD) up to 6 years after treatment.

DESIGN

A prospective, randomized, long-term follow-up study.

SETTING

Obstetrics and gynecology department in a university hospital in the United Kingdom.

PATIENT(S)

Forty-nine symptomatic women with a laparoscopic diagnosis of endometriosis who had been identified for treatment with long-acting GnRH agonist and volunteered to participate in the study.

INTERVENTION(S)

Women were randomly allocated to receive hormone replacement therapy (HRT) as a daily oral dose of estradiol, 2 mg, and norethisterone acetate, 1 mg, or no treatment in addition to monthly subcutaneous implants of goserelin acetate for up to 2 years, until cessation of symptoms. Bone mineral density (BMD) at the lumbar spine (C2-C4) and hip (Ward triangle) was measured every 6 months.

MAIN OUTCOME MEASURE(S)

BMD changes in both groups.

RESULT(S)

45 women were followed up for 6 years, at the end of which the groups did not differ significantly in the reduction in mean BMD at the lumbar spine or hip.

CONCLUSION(S)

BMD reduction occurs during long-term GnRH agonist use and is not fully recovered by up to 6 years after treatment. Use of HRT does not affect this process.

Gonadotrophin hormone-releasing hormone analogue treatment of fibroids

Gonadotrophin hormone-releasing hormone analogue (GnRHa) therapy can induce a reduction in fibroid volume by up to 50% over a period of 3 months treatment. This effect may be beneficial in selected patients, prior to open or endoscopic myomectomy, to aid the surgical procedure by improving vision because of reduced blood loss and reduced uterine artery blood flow. Symptoms of excessive menstrual bleeding, pelvic pain and dysmenorrhoea will also be controlled. Long-term administration of GnRHa requires the use of concomitant add-back therapy, the optimal combination investigated to date being an oestrogen-progestogen continuous combined preparation.

Dysfunctional uterine bleeding

Dysfunctional uterine bleeding (DUB) is a frequent gynecological problem during adolescence and the most frequent cause of urgent admission to the hospital over this period of life. In about 95% of cases it is caused by the late maturation of the hypothalamic-pituitary-ovarian axis (HPO), leading to anovulatory cycles. These adolescents lack the E2 positive feedback on LH. Thus, the continuous production of estrogen with endometrial stimulation is the basic cause of dysfunctional uterine bleeding. The initial step in the evaluation of DUB includes detailed clinical history, followed by complete physical examination. Laboratory tests should include coagulation profile, complete blood count with platelet evaluation, and sometimes a serum pregnancy test. The treatment of DUB is related to the severity of symptomatology with the objective of stopping bleeding and preventing recurrences. Modern hormonal and other medical therapies enable physicians to treat DUB effectively, regardless of the cause. Surgical treatment, such as dilatation and curettage, is rarely indicated in the adolescent patient. The importance of continued follow-up in DUB cases should be underlined, until stabilization of ovulatory menstrual cycles.

An in vitro bioassay for testing the direct effect of luteinizing hormone-releasing hormone agonists on progesterone secretion by rat ovarian cells

It is known that luteinizing hormone-releasing hormone (LHRH) and its agonistic analogs could act directly on various extrapituitary target tissues by activating their specific receptors present in these tissues. In this report, we proposed an in vitro assay method for testing the bioactivities of LHRH agonists based on their inhibitory effect on human chorionic gonadotropin (HCG)-induced progesterone secretion by rat ovarian cells. Ovaries from five to ten pseudopregnant rats (prepared by sequential hormone treatment) were mechanically and enzymatically dispersed to prepare luteal cell-rich suspensions. Addition of [D-Ala6, Pro9-Ethylamide]LHRH to ovarian cell suspensions inhibited different concentrations (1, 10 or 100 mIU/ml) of HCG-induced progesterone secretion in concentration-dependent manners. In the presence of 1 mIU/ml HCG as a stimulant, the percent inhibition of progesterone secretion by the same concentrations of [D-Ala6, Pro9-Ethylamide]LHRH was most pronounced and the results were usually more readily reproducible and with less experimental variations. In this study, LHRH and twelve agonistic analogs (at 10(-9) and 10(-7) M concentrations) were compared for their inhibitory effect on 1 mIU/ml HCG-induced progesterone secretion, and their relative agonistic activities were evaluated based on their inhibition potencies. This in vitro bioassay is simple and time- and cost-efficient, and can be employed as a supplementary method to the commonly utilized bioassays for LHRH agonists. This method may also be useful in screening for LHRH agonists with potent extrapituitary effects.

Effects of GnRH antagonist on lymphocyte subpopulations in primary and secondary lymphoid tissues of female mice

PROBLEM

GnRH analogs are playing an increasing role in the treatment of many clinical disorders. Recent studies have indicated that GnRH agonists suppress immune function in mice in vivo. The present study investigated the effects of GnRH antagonist of functional lymphocyte subsets of mice in vivo.

METHOD

Three- and 10-wk old female mice received 10 micrograms of Nal-Glu daily for 15 and 30 days; changes in the immunophenotypic expression of lymphocytes from thymus, bone marrow, spleen and blood were analyzed by flow cytometry.

RESULTS

The administration of GnRH antagonist to pre- and postpubertal female mice induced slight increases in lymphocyte subpopulations in primary and secondary lymphoid tissues. These effects are opposite those obtained with GnRH agonist in our earlier studies in mice.

CONCLUSIONS

Assuming similar effects in humans and rodents, the gonadal steroid suppression achieved by GnRH antagonist treatment has no apparent suppressive effects on the immune system.

Alterations in thymic and bone marrow lymphocyte subpopulations in GnRH agonist treated prepubertal female mice

Complex endocrine relationships exist among the hypothalamus, pituitary, ovaries and thymus. There is also considerable evidence showing gonadotropin releasing hormone (GnRH) involvement in modulating immune system functions. The present study investigated the sequential changes in functional lymphocyte subsets in primary lymphoid tissues of prepubertal female mice in vivo following GnRH agonist treatment in slow release microcapsule formulation. A direct two color immunofluorescence staining followed by flow cytometry was employed. Single i.m injection of agonist significantly decreased both absolute and relative thymic weights and absolute thymocyte counts. No differences, however, were observed in the percentage of thymocytes expressing Thy 1.2, CD4 and CD8. Absolute levels of thymic T cells, CD8 positive cells, immature cells expressing both CD4 and CD8, and immature subsets differentiating toward CD4 were significantly reduced two weeks after agonist treatment. The percentage of bone marrow B cells was also significantly decreased at the second and third weeks following agonist administration. Functional studies to determine in vivo cell-mediated immune function also indicated a significant suppression following agonist administration. These data, together with our earlier observations on secondary lymphoid tissues, suggest a general suppression of lymphocyte maturation at an early stem cell stage of development in prepubertal female mice in vivo.

Pemphigoid gestationis--response to chemical oophorectomy with goserelin

A 46-year-old caucasian female presented in January 1991 with a 17-year history of severe pemphigoid gestationis. She had been on systemic steroids for 10 years since her last pregnancy in 1981 and required doses of 20-80 mg prednisolone daily to control her disease. A chemical oophorectomy was induced using a new luteinizing hormone releasing hormone (LHRH) analogue known as goserelin. A complete remission occurred within 6 months of initiating this treatment and the systemic steroids were discontinued.

Evolving role of Gonadotropin-Releasing Hormone antagonists

GnRH antagonists, unlike GnRH agonists, do not act via "downregulation." Instead, GnRH antagonists monopolize the GnRH receptors to such an extent that endogenous GnRH is unable to bind to sufficient numbers of GnRH receptors to provoke release of LH/FSH. This fundamental difference in the mechanism of action of GnRH antagonists versus GnRH agonists is anticipated to result in clinical benefits for certain applications.

Changes in thromboxane A2 generation and plasma lipid pattern in pseudomenopause induced by gonadotropin releasing hormone (GnRH) analogue buserelin

An increased risk of cardiovascular disease has been found in postmenopausal women in comparison to premenopausal women. The aim of this study was to investigate platelet function, blood clotting and plasma lipid levels in 12 women with a condition of hypoestrogenism, similar to the postmenopausal status induced by treatment with the GnRH analogue buserelin for uterine leiomyoma. Platelet aggregation in whole blood and platelet-rich plasma (PRP), serum thromboxane (TX) B2 production, fibrinopeptide A (FPA) plasma levels and plasma lipid pattern were measured before and after 13 weeks of buserelin treatment. No changes of platelet aggregability were found either in whole blood or PRP. Serum TXB2 generation increased significantly after 13 weeks of therapy (p less than 0.001). No signs of increased thrombin generation were found, as indicated by unchanged FPA plasma levels. Total cholesterol plasma levels were found increased after 13 weeks, LDL cholesterol levels showed a tendency to increase although not significantly. HDL cholesterol and triglyceride concentrations were unaffected. The changes of arachidonic acid metabolism and lipid pattern suggest that buserelin treatment may induce a condition of increased thrombotic risk even if the lack of enhanced thrombin generation and increased platelet aggregability indicates that no blood clotting activation occurs.

Treatment of a patient with severe menstrual migraine using the depot LHRH analogue Zoladex

Migraine occurring at menstruation is frequently difficult to treat. A 38-year-old woman with exceptionally severe menstrual migraine was treated by temporary ovarian suppression using Zoladex, a long acting luteinizing hormone-releasing hormone agonist. There was prompt relief of headache, and after several months of treatment the patient elected to undergo surgical oophorectomy with subsequent resolution of her migraine. A trial of reversible hypogonadism using an LHRH agonist may thus be helpful in predicting the result of surgical castration in this situation.

A comparative treatment trial of endometriosis using the gonadotrophin-releasing hormone agonist, nafarelin, and the synthetic steroid, danazol

A randomized and double-blind trial was carried out comparing intranasal nafarelin acetate (400 micrograms daily) and oral danazol (600 mg daily), given over 6 months, in the treatment of 49 patients with laparoscopically proven endometriosis. Both drugs produced a highly significant and similar reduction (of 60 to 70%) in objective American Fertility Society scoring, even in severe disease. No effect was seen on adhesions. Both drugs suppressed oestradiol levels to a similar extent, although nafarelin caused a substantial rise in the first 2 weeks after the initiation of therapy. Nafarelin suppressed LH substantially and FSH, testosterone and prolactin to a small degree, whereas FSH and LH increased slightly during danazol. Pregnancies occurred in 12 of 22 infertile women in the 12 months following nafarelin, and in 6 of 14 in the danazol group. Side-effects were reported at a similar rate with both drugs, but the pattern was different. Hot flushes were the predominant side effect with nafarelin, although oestradiol levels were not suppressed to the extent expected. Small amounts of spotting or light bleeding were experienced with both drugs, but these tended to decrease with time with nafarelin and increase with danazol.

Luteinizing hormone determinations obtained with either a monoclonal and a polyclonal antibody radioimmunoassay and their correlations with clinical findings

Detection of circulating levels of gonadotropin is fundamental in reproductive physiology and related disorders. The advent of monoclonal antibodies might supply the clinician with faster and more accurate estimates of these hormones. We have evaluated the hormonal determinations provided by a monoclonal assay and those generated from our previous assay, produced by the same manufacturer, based on polyclonal antibodies. Comparison was performed on blood samples collected from volunteers with regular menstruation (n = 51) or patients attending our Clinic. The correlation between data provided by the two assays fluctuated from the almost complete overlap of the physiological menstrual cycle to the striking dissociation of the patients (n = 13) receiving a Gonadotropin Hormone-Releasing Hormone analog for gonadotropin suppression. Intermediate coefficients of correlations were recorded in normal subjects undergoing a Gonadotropin Hormone-Releasing Hormone stimulation test (n = 12) and in patients with functional hypothalamic amenorrhea (n = 19) or polycystic ovarian disease (n = 37). Values obtained with the monoclonal assay tended to be lower than those recorded with the previous system. A closer correlation with the clinical findings was observed in the hormonal values originated with the monoclonal assay.

Chemotherapy-induced premature ovarian failure: mechanisms and prevention

Significant advances have been made in the previously unexplored areas of the mechanisms involved in cyclophosphamide (CTX)-induced ovarian toxicity and the protective effects of luteinizing hormone-releasing hormone (LHRH agonists. The structure and function of granulosa cells and oocytes are affected by the chemotherapeutic agent, CTX. Results of experiments in female rats indicate that LHRH agonists may protect the ovaries from the toxic effects of chemotherapy. The protective effect may be related to the inhibition of ovarian mitotic activity during LHRH agonist administration. This inhibition is much more pronounced in female compared to male rats. This may be related to the observed better gonadal protective effects in females compared to males. Further experiments are underway to determine whether similar protective effects occur in female primates.

Serum CA-125 levels in women with endometriosis

Forty-two women with laparoscopically-confirmed pelvic endometriosis (assessed according to the American Fertility Society modified classification) had serum levels of the cell-surface antigen CA-125 measured before, during and after medical therapy with nafarelin acetate or danazol combined with follow-up laparoscopic surgery or laparotomy. Serum levels before treatment (39.3 [SE 6.6] U/ml) were elevated above accepted normal levels in many subjects, and these were highly significantly suppressed during medical therapy with both nafarlin and danazol (13.1 [SE 1.5] U/ml at 5 months); t = 3.198; p = 0.002). Levels tended to rise following therapy but a clear correlation between a rise in serum CA-125 and recurrence of disease was not demonstrated. In 3 individuals treated with nafarelin a dramatic rise in serum CA-125 levels was seen after 2 weeks of therapy. This did not correlate with any exacerbation of symptoms or with any rise in serum oestradiol or with pretreatment AFS scoring. Serum CA-125 levels provide a potential approach to the monitoring of treatment and recurrence in a substantial proportion of women with endometriosis, although preliminary evidence suggests that there will be individual exceptions to any broad correlations.

Effects of gonadotrophin-releasing hormone agonist on uterine fibroids and bone density

Bone density (BD) was evaluated by single photon absorptiometry (SPA) in 18 women treated with Buserelin a gonadotrophin-releasing hormone (LHRH) analogue, for uterine fibroids. Buserelin was administered for a period of 6 mth. Amenorrhoea and oestradiol levels in the follicular-phase range were recorded in all patients during treatment. Fibroid volume was evaluated by means of ultrasound. SPA was performed at the 1/3 proximal radius and at the 1/10 distal radius sites before starting therapy and every 2 mth subsequently for 12 mth. BD was also measured in a control group of 18 normally-menstruating premenopausal women, matched for age and body mass index. No significant changes in BD at the proximal or distal radius sites were observed in either the cases or the controls during the study. Moreover, comparison of the data on the cases and the controls revealed no differences in BD at 0, 6 or 12 mth. Thus, although LHRH analogue treatment proved effective in reducing fibroids, it did not cause any significant changes in BD.

The duration of pituitary suppression by means of intranasal gonadotropin hormone-releasing hormone analogue administration does not influence the ovarian response to gonadotropin stimulation and success rate in a gamete intrafallopian transfer (GIFT) program

The aim of the study was to compare the ability to prevent endogenous luteinizing hormone interferences, ovarian response, and success rate between two groups of patients undergoing GIFT procedures and treated with the same stimulatory protocol but with a different timing in the administration of the gonadotropin hormone-releasing hormone analogue (GnRH-a). The former underwent a concomitant administration of gonadotropin and analogue; the latter started stimulation only after the achievement of complete hypogonadotropinism. The analogue was always given intranasally and stimulation was identical in the two groups. Our results showed that (1) prevention of premature luteinization is obtained with both approaches and (2) no significant difference in terms of length of stimulation, gonadotropin doses, ovarian response, and success rate was recorded between the two groups.

Long-term follow-up of patients with uterine fibroids after treatment with the LHRH agonist buserelin

Ten patients with uterine fibroids palpable abdominally were treated with the luteinizing hormone-releasing hormone (LHRH) agonist buserelin, administered intransally, 300 micrograms three times daily, for 6 months, and were then followed for a further 12 months. Oestrogen levels were markedly reduced in all patients during treatment. At the end of treatment the mean volume reductions were 44.4% (SEM 3.5) for total uterine volume and 57.3% (SEM 7.4) for volume of discrete fibroids as assessed ultrasonically. There was also marked improvement in associated symptoms. After buserelin therapy was stopped, the total uterine and discrete fibroid volumes returned to, or slightly exceeded, pretreatment volumes within 6 months in five patients, and by 12 months in two patients. Three other patients who underwent surgery for their fibroids during the first 4 months after treatment showed regrowth of fibroids to pretreatment size. Four comparable asymptomatic untreated patients showed no significant change in the total uterine or fibroid volume during six monthly ultrasonic assessments. Buserelin therapy may facilitate rather than replace surgery in the management of uterine fibroids.