Luteinizing hormone-releasing hormone agonist triptorelin in combination with cytotoxic chemotherapy in patients with advanced ovarian carcinoma. A prospective double blind randomized trial. Decapeptyl Ovarian Cancer Study Group

Hormone therapy for ovarian cancer: Emphasis on mechanisms and applications (Review)

Ovarian cancer (OC) remains the leading cause of mortality due to gynecological malignancies. Epidemiological studies have demonstrated that steroid hormones released from the hypothalamic-pituitary-ovarian axis can play a role in stimulating or inhibiting OC progression, with gonadotropins, estrogens and androgens promoting OC progression, while gonadotropin-releasing hormone (GnRH) and progesterone may be protective factors in OC. Experimental studies have indicated that hormone receptors are expressed in OC cells and mediate the growth stimulatory or growth inhibitory effects of hormones on these cells. Hormone therapy agents have been evaluated in a number of clinical trials. The majority of these trials were conducted in patients with relapsed or refractory OC with average efficacy and limited side-effects. A better understanding of the mechanisms through which hormones affect cell growth may improve the efficacy of hormone therapy. In the present review article, the role of hormones (GnRH, gonadotropins, androgens, estrogens and progestins) and their receptors in OC tumorigenesis, and hormonal therapy in OC treatment is discussed and summarized.

Long-term effect of repeated deslorelin acetate treatment in bitches for reproduction control

Long-acting gonadotropin-releasing hormone (GnRH) analogs, which are approved for male dogs and ferrets, have been used off-label to suppress estrus in bitches predisposed to the side effects of spaying. Health data from the past 12 years were evaluated from bitches without progestogen pretreatment that received deslorelin acetate (DA) to suppress estrus for the first time before the age of 4.5 years. The study population included 32 client-owned bitches repeatedly treated with either 4.7 mg or 9.4 mg DA implants for a period of 5.3 ± 3.4 years (range 0.5-11.3 years). Follow-up information concerning immediate side effects of DA occurring within five months after the first DA treatment (n = 23) as well as long-term side effects of sustained gonadal suppression occurring after five months up to three years (n = 2), three years up to five years (n = 2) or more than five years (n = 8) were assessed through a questionnaire. Treatment was considered successful if no major side effects requiring medical treatment occurred, which applied to 26 out of 32 (81 %) bitches. In the six remaining bitches, the following major side effects led to treatment discontinuation: persistent urinary incontinence (n = 1), reoccurring induced heat (n = 1), uterine disease (n = 3) and/or ovarian tumor (n = 3). The bitches recovered completely after surgical spaying and/or DA implant removal. Minor side effects that did not require therapy or affect animal welfare included body weight changes (n = 18), subtle behavioral changes (n = 13), induced heat (n = 12), coat changes (n = 11), pseudocyesis (n = 6), transient urinary incontinence (n = 4), and/or temporary thickening of the uterine wall with little anechogenic content (n = 2). To examine a possible causal relationship between adverse side effects and DA treatment, further studies should compare the frequency of pathologies between groups of GnRH-treated, intact and spayed bitches of similar breeds and ages. Nevertheless, DA application before the age of 4.5 years may be a means of postponing surgical spaying for several years in breeds at high risk for developing urinary incontinence. Before DA is used in bitches, owners should be fully informed regarding possible side effects.

Role of Gonadotropin-Releasing Hormone (GnRH) in Ovarian Cancer

The hypothalamus–pituitary–gonadal (HPG) axis is the endocrine regulation system that controls the woman’s cycle. The gonadotropin-releasing hormone (GnRH) plays the central role. In addition to the gonadotrophic cells of the pituitary, GnRH receptors are expressed in other reproductive organs, such as the ovary and in tumors originating from the ovary. In ovarian cancer, GnRH is involved in the regulation of proliferation and metastasis. The effects on ovarian tumors can be indirect or direct. GnRH acts indirectly via the HPG axis and directly via GnRH receptors on the surface of ovarian cancer cells. In this systematic review, we will give an overview of the role of GnRH in ovarian cancer development, progression and therapy.

Treatment of Breast Cancer With Gonadotropin-Releasing Hormone Analogs

Although significant progress has been made in the implementation of new breast cancer treatments over the last three decades, this neoplasm annually continues to show high worldwide rates of morbidity and mortality. In consequence, the search for novel therapies with greater effectiveness and specificity has not come to a stop. Among the alternative therapeutic targets, the human gonadotropin-releasing hormone type I and type II (hGnRH-I and hGnRH–II, respectively) and its receptor, the human gonadotropin-releasing hormone receptor type I (hGnRHR-I), have shown to be powerful therapeutic targets to decrease the adverse effects of this disease. In the present review, we describe how the administration of GnRH analogs is able to reduce circulating concentrations of estrogen in premenopausal women through their action on the hypothalamus–pituitary–ovarian axis, consequently reducing the growth of breast tumors and disease recurrence. Also, it has been mentioned that, regardless of the suppression of synthesis and secretion of ovarian steroids, GnRH agonists exert direct anticancer action, such as the reduction of tumor growth and cell invasion. In addition, we discuss the effects on breast cancer of the hGnRH-I and hGnRH-II agonist and antagonist, non-peptide GnRH antagonists, and cytotoxic analogs of GnRH and their implication as novel adjuvant therapies as antitumor agents for reducing the adverse effects of breast cancer. In conclusion, we suggest that the hGnRH/hGnRHR system is a promising target for pharmaceutical development in the treatment of breast cancer, especially for the treatment of advanced states of this disease.

Gonadotropin-Releasing Hormone Analogs for Gonadal Protection During Gonadotoxic Chemotherapy: A Systematic Review and Meta-Analysis

OBJECTIVE

A systematic review and meta-analysis was conducted to investigate whether gonadotropin-releasing hormone analogs (GnRHa) have a protective role in women treated with alkylating agents.

DATA SOURCES

Major databases (PubMED, EMBASE, Cochrane Central Register of Controlled Trials), systematic snowballing, and trial registries were screened from the inception dates until September 2017.

METHODS AND STUDY SELECTION

Comparative studies involving reproductive-aged women undergoing chemotherapy with or without coadministration of GnRHa were included. Spontaneous menstrual resumption was assessed as a main outcome. Statistical analyses were performed with STATA 14.2 statistical software. Effect estimates were presented as risk ratios (RR) with 95% confidence intervals (CIs).

RESULTS

The literature search yielded 25 436 citations and 84 papers were assessed in full text. Eighteen studies (11 randomized controlled trials [RCTs] and 7 cohort studies) published between 1987 and 2015 were included in the analysis, revealing a significant protective effect of GnRHa (n = 1043; RR:1.38; 95% CI: 1.18-1.63) although with high heterogeneity (I² = 83.3%). Subgroup analyses revealed a significant benefit of GnRHa cotreatment both in RCTs and in cohort studies. Statistical significance was found in all subgroups by the underlying disease, that is, hematological malignancies, autoimmune diseases, and breast cancer. Sensitivity analyses in GnRH agonist-treated patients, in patients younger than 40 years old, and in patients without supradiaphragmatic radiotherapy also revealed a significant benefit of GnRHa cotreatment.

CONCLUSION

Our results indicate that concurrent GnRHa administration is an effective method to decrease gonadotoxicity of alkylating agents. The presence of low-quality evidence favoring gonadoprotective effect requires a strong recommendation for offering GnRHa coadministration to young women who are to undergo gonadotoxic chemotherapy.

CAPSULE

The present systematic review and meta-analysis shows a significant gonadoprotective effect of gonadotropin-releasing hormone analogs in women treated with alkylating agents.

Luteinising hormone releasing hormone (LHRH) agonists for the treatment of relapsed epithelial ovarian cancer

BACKGROUND

Ovarian cancer is seventh most common cancer in women worldwide. Approximately 1.3% of women will be diagnosed with ovarian cancer at some point during their life time. The majority of tumours arise from surface of the ovary (epithelial). Two thirds of these women will present with advanced disease, requiring aggressive treatment, which includes debulking surgery (removal of as much disease as possible) and chemotherapy. However, most women (75%) with advanced epithelial ovarian cancer (EOC) will relapse following surgery and chemotherapy. Patients who relapse are treated with either platinum or non-platinum drugs and this is dependent on the platinum-sensitivity and platinum-free interval. These drug regimens are generally well-tolerated although there are potential severe side effects. New treatments that can be used to treat recurrence or prevent disease progression after first-line or subsequent chemotherapy are important, especially those with a low toxicity profile. Hormones such as luteinising hormone releasing hormone (LHRH) agonists have been used in the treatment of relapsed EOC. Some studies have shown objective remissions, while other studies have shown little or no benefit. Most small studies report a better side-effect profile for LHRH agonists when compared to standard chemotherapeutic agents used in EOC.

OBJECTIVES

To compare the effectiveness and safety of luteinising hormone releasing hormone (LHRH) agonists with chemotherapeutic agents or placebo in relapsed epithelial ovarian cancer (EOC).

SEARCH METHODS

We searched the Cochrane Gynaecological Cancer Group trials register, Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and Embase up to January 2016. We also searched registers of clinical trials and abstracts of scientific meetings.

SELECTION CRITERIA

Randomised controlled trials (RCTs) that compared LHRH agonists with chemotherapeutic agents or placebo in relapsed EOC.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed whether relevant studies met the inclusion criteria, retrieved data and assessed risk of bias.

MAIN RESULTS

Two studies, including 97 women, met our inclusion criteria: one assessed LHRH agonist (leuprorelin) use in relapsed (platinum-resistant and platinum-refractory) EOC in comparison with a chemotherapeutic agent (treosulfan) (Du Bois 2002); the other examined LHRH agonist (decapeptyl) versus a placebo (Currie 1994). Since both studies had different control groups, a meta-analysis was not possible.There may be little or no difference between treatment with leuprorelin or treosulfan in overall survival (OS) (hazard ratio (HR) 0.98, 95% confidence interval (CI) 0.58 to 1.67; very low-quality evidence) or progression-free survival (PFS) at six and 12 months (risk ratio (RR) 0.61, 95% CI 0.22 to 1.68, and RR 0.65, 95% CI 0.12 to 3.66; very low-quality evidence), respectively (Du Bois 2002). The duration of follow-up was 2.5 years and quality of life (QoL) was not reported in this study.Alopecia and fatigue were probably more common with treosulfan than leuprorelin (alopecia RR 0.32, 95% CI 0.12 to 0.91 (very low-quality evidence)). There may be little or no difference in other Grade 3/4 side effects: nausea and vomiting (RR 0.65, 95% CI 0.12 to 3.66 (very low-quality evidence)); neurotoxicity (RR 0.32, 95% CI 0.01 to 7.71 (very low-quality evidence)) and neutropenia (RR 0.97, 95% 0.06 to 14.97 (very low-quality evidence)),The Currie 1994 study, which compared decapeptyl treatment with placebo, reported mean PFS of 16 weeks verus 11.2 weeks, respectively. No relative effects measures or P value at a particular time point were reported. Overall survival (OS) and QoL outcomes were not reported. In addition, adverse events were only mentioned for the decapeptyl group.Adverse events were incompletely reported (no adverse events in decapeptyl group, but not reported for the placebo group).

AUTHORS' CONCLUSIONS

Based on this review of two small RCTs, there is not enough evidence to comment on the safety and effectiveness of LHRH agonists in the treatment of platinum-refractory and platinum-resistant (relapsed) EOC. Overall, the quality of evidence for all outcomes (including OS, PFS, QoL and adverse events) is very low.

Effect of gonadotropin-releasing hormone agonist on ES-2 ovarian cancer cells

OBJECTIVE

Gonadotropin-releasing hormone (GnRH) receptor is found in the ovarian tissue, including epithelial ovarian cancer (EOC), suggesting that GnRH agonists may have direct action on EOC.

MATERIALS AND METHODS

Ovarian clear cell cancer (ES-2) cells were treated with low-dose GnRH agonist with/without low-dose paclitaxel (1 μM D-Lys(6) with/without 0.5 μM or 1.0 μM paclitaxel). Growth and behavior of ES-2 cells were evaluated.

RESULTS

Use of either D-Lys(6) or paclitaxel or a combination of the two did not affect the morphology and growth pattern of ES-2 cells. However, ability of migration and invasion of ES-2 cells was significantly decreased in either use of D-Lys(6) or paclitaxel and more apparent with the combination. Type I GnRH receptor expression of ES-2 was not altered significantly by the combination.

CONCLUSION

GnRH agonist might modify the ES-2 ovarian cancer cells, and its role might be independent, additional or synergistic, suggesting the potential role of the use of GnRH agonist in the management of clear cell type of the ovarian cancer. However, the results of this study were derived using ES-2 ovarian cancer cells, and might not be valid in other cell types of ovarian cancers.

Influence of gonadotropin-releasing hormone agonist on the effect of chemotherapy upon ovarian cancer and the prevention of chemotherapy-induced ovarian damage: an experimental study with nu/nu athymic mice

BACKGROUND AND OBJECTIVE

Gonadotropin-releasing hormone (GnRH) plays an important role in the regulation of ovarian function and ovarian cancer cell growth. In this study, we determined whether administration of the GnRH agonist (GnRHa), triporelin, prior to cisplatin treatment affects cisplatin and/or prevents cisplatin-induced ovarian damage.

METHODS

nu/nu mice were injected with ovarian cancer OVCAR-3 cells intraperitoneally. After two weeks, the mice were treated with saline (control), cisplatin, GnRHa, or cisplatin plus GnRHa for four weeks. At the end of the experimental protocol, blood, tumor, ovary, and uterine tissues were resected for hematoxylin and eosin (H&E) staining, immunohistochemical analyses of Ki67, nuclear factor-κB (NF-κB), and caspase-3, transmission electron microscopy of apoptosis, or enzyme-linked immunosorbent assay (ELISA) analyses of anti-Mullerian hormone (AMH).

RESULTS

Cisplatin treatment effectively inhibited tumor growth in mice treated with human ovarian cancer cells; however the treatment also induced considerable toxicity. Immunohistochemical analyses showed that Ki67 expression was reduced in cisplatin-treated mice compared to control (P<0.05), but there was no statistically significant differences between cisplatin-treated mice and cisplatin plus GnRHa-treated mice (P>0.05), while expressions of NF-κB and caspase-3 were reduced and induced, respectively, in cisplatin-treated mice and cisplatin plus GnRHa-treated mice. Apoptosis occurred in the GnRHa, cisplatin, and cisplatin plus GnRHa-treated mice, but not in control mice. Ovaries exposed to GnRHa in both GnRHa mice and cisplatin-treated mice (combination group) had significantly more primordial and growth follicles and serum levels of AMH than those in the control mice and cisplatin-treated mice (P<0.05).

CONCLUSIONS

Administration of GnRHa to mice significantly decreased the extent of ovarian damage induced by cisplatin, but did not affect the anti-tumor activity of cisplatin.

Differential signaling of the GnRH receptor in pituitary gonadotrope cell lines and prostate cancer cell lines

The GnRH receptor (GnRHR) mediates the pituitary functions of GnRH, as well as its anti-proliferative effects in sex hormone-dependent cancer cells. Here we compare the signaling of GnRHR in pituitary gonadotrope cell lines vs. prostate cancer cell lines. We first noticed that the expression level of PKCα, PKCβII and PKCε is much higher in αT3-1 and LβT2 gonadotrope cell lines vs. LNCaP and DU-145 cell lines, while the opposite is seen for PKCδ. Activation of PKCα, PKCβII and PKCε by GnRH is relatively transient in αT3-1 and LβT2 gonadotrope cell lines and more prolonged in LNCaP and DU-145 cell lines. On the otherhand, the activation and re-distribution of the above PKCs by PMA was similar for both gonadotrope cell lines and prostate cancer cell lines. Activation of ERK1/2 by GnRH and PMA was robust in the gonadotrope cell lines, with a smaller effect observed in the prostate cancer cell lines. The Ca(2+) ionophore A23187 stimulated ERK1/2 in gonadotrope cell lines but not in prostate cancer cell lines. GnRH, PMA and A23187 stimulated JNK activity in gonadotrope cell lines, with a more sustained effect in prostate cancer cell lines. Sustained activation of p38 was observed for PMA and A23187 in Du-145 cells, while p38 activation by GnRH, PMA and A23187 in LβT2 cells was transient. Thus, differential expression and re-distribution of PKCs by GnRH and the transient vs. the more sustained nature of the activation of the PKC-MAPK cascade by GnRH in gonadotrope cell lines vs. prostate cancer cell lines respectively, may provide the mechanistic basis for the cell context-dependent differential biological responses observed in GnRH interaction with pituitary gonadotropes vs. prostate cancer cells.

The role of hormonal factors and endocrine therapy in ovarian cancer

The efficacy of the second-line chemotherapy commonly used in both relapsed ovarian cancer patients and those with primary treatment failure remains unsatisfactory. This therapy has a small effect on survival, whereas associated toxicity may diminish the patient's quality of life.

Hormonal factors play a role in ovarian tumorigenesis, and inhibition of the stimulating effects of estrogens may exert a clinical benefit. The role of hormonal therapy as a palliative therapeutic alternative for ovarian cancer remains undetermined. This modality may result in long-term stabilization of disease in individual patients and less frequently in tumor remission.

In this article the role of hormonal factors and recent literature of various forms of hormonal therapy for ovarian cancer are presented.

GnRH receptors in cancer: from cell biology to novel targeted therapeutic strategies

The crucial role of pituitary GnRH receptors (GnRH-R) in the control of reproductive functions is well established. These receptors are the target of GnRH agonists (through receptor desensitization) and antagonists (through receptor blockade) for the treatment of steroid-dependent pathologies, including hormone-dependent tumors. It has also become increasingly clear that GnRH-R are expressed in cancer tissues, either related (i.e. prostate, breast, endometrial, and ovarian cancers) or unrelated (i.e. melanoma, glioblastoma, lung, and pancreatic cancers) to the reproductive system. In hormone-related tumors, GnRH-R appear to be expressed even when the tumor has escaped steroid dependence (such as castration-resistant prostate cancer). These receptors are coupled to a G(αi)-mediated intracellular signaling pathway. Activation of tumor GnRH-R by means of GnRH agonists elicits a strong antiproliferative, antimetastatic, and antiangiogenic (more recently demonstrated) activity. Interestingly, GnRH antagonists have also been shown to elicit a direct antitumor effect; thus, these compounds behave as antagonists of GnRH-R at the pituitary level and as agonists of the same receptors expressed in tumors. According to the ligand-induced selective-signaling theory, GnRH-R might assume various conformations, endowed with different activities for GnRH analogs and with different intracellular signaling pathways, according to the cell context. Based on these consistent experimental observations, tumor GnRH-R are now considered a very interesting candidate for novel molecular, GnRH analog-based, targeted strategies for the treatment of tumors expressing these receptors. These agents include GnRH agonists and antagonists, GnRH analog-based cytotoxic (i.e. doxorubicin) or nutraceutic (i.e. curcumin) hybrids, and GnRH-R-targeted nanoparticles delivering anticancer compounds.

Are gonadotrophins tumorigenic--a critical review of clinical and experimental data

The growth of many gonadal and extragonadal tumors is stimulated by gonadal sex hormones. Because gonadal hormone production is regulated by pituitary gonadotrophins, the latter hormones can be considered as indirect tumor promoters. In addition, there is a growing body of evidence that both gonadal (e.g. ovarian cancer) and extragonadal (e.g. breast, uterus, prostate and adrenal) tumors express gonadotrophin receptors, indicating the possibility of a direct tumorigenic role for FSH and LH. The purpose of this brief review is to present a critical evaluation of the current information, both clinical and experimental, about the direct involvement of gonadotrophins in the induction and growth of gonadal and extragonadal tumors.

Prognostic value of hormonal receptors, p53, ki67 and HER2/neu expression in epithelial ovarian carcinoma

OBJECTIVE

The role of molecular and biological factors in ovarian cancer is controversial. We investigated the levels of the estrogen (ER) and progesterone (PR) receptors, HER2/neu, p-53 and Ki 67 in patients with advanced ovarian cancer and correlated the results with the clinical course in order to define their predictive or prognostic significance.

METHODS

Paraffin-embedded tumor tissues from 72 patients with ovarian cancer treated from 1999 to 2003 were analyzed. Overexpression of C-erb-B2 was defined as herceptest ++/+++ and positive fluorescence in situ hybridization (FISH) or herceptest +++/+++. Positivity for ER and PR was determined by > or =10% of the cellular membranes immunostained. Statistical analysis was performed to evaluate the prognostic impact of the molecular markers.

RESULTS

49 of the 72 patients were ER + (68%) and 36 PR + (50%). In 45 patients (62.5%) expression of p53 was > or =10%. Overexpression of C-erb-2 was found in 4 tumor samples (5%). A Ki67 labelled nuclear area >30% was found to be associated with a higher rate of complete response (chi(2); p=0.05). None of the biological markers were significantly associated with progression free survival (PFS). By multivariate analysis residual tumor after debulking surgery and ER status were associated with OS (p< or =0.05).

CONCLUSIONS

Ki67 nuclear expression >30% is predictive of complete response in advanced ovarian cancer. HER2/neu overexpression is scarce in our study. Positive ER is an independent prognostic factor for OS. Further research with larger studies and hormonal treatment is guaranteed.

Gonadotropins and ovarian cancer

Ovarian epithelial cancer (OEC) accounts for 90% of all ovarian cancers and is the leading cause of death from gynecological cancers in North America and Europe. Despite its clinical significance, the factors that regulate the development and progression of ovarian cancer are among the least understood of all major human malignancies. The two gonadotropins, FSH and LH, are key regulators of ovarian cell functions, and the potential role of gonadotropins in the pathogenesis of ovarian cancer is suggested. Ovarian carcinomas have been found to express specific receptors for gonadotropins. The presence of gonadotropins in ovarian tumor fluid suggests the importance of these factors in the transformation and progression of ovarian cancers as well as being prognostic indicators. Functionally, there is evidence showing a direct action of gonadotropins on ovarian tumor cell growth. This review summarizes the key findings and recent advances in our understanding of these peptide hormones in ovarian cancer development and progression and their role in potential future cancer therapy. We will first discuss the supporting evidence and controversies in the "gonadotropin theory" and the use of animal models for exploring the involvement of gonadotropins in the etiology of ovarian cancer. The role of gonadotropins in regulating the proliferation, survival, and metastasis of OEC is next summarized. Relevant data from ovarian surface epithelium, which is widely believed to be the precursor of OEC, are also described. Finally, we will discuss the clinical applications of gonadotropins in ovarian cancer and the recent progress in drug development.

Hormonal therapy in ovarian cancer

Ovarian carcinoma continues to be the leading cause of death due to gynecological malignancy. Epidemiologic studies indicate that steroid hormones play roles in ovarian carcinogenesis. Gonadotropins, estrogen, and androgen may be causative factors, while gonadotropin-releasing hormone and progesterone may be protective factors in ovarian cancer pathogenesis. Experimental studies have shown that hormonal receptors are expressed in ovarian cancer cells and mediate the growth-stimulatory or growth-inhibitory effects of the hormones on these cells. Hormonal therapeutic agents have been evaluated in several clinical trials. Most of these trials were conducted in patients with recurrent or refractory ovarian cancer, with modest efficacy and few side effects. Better understanding of the mechanisms through which hormones affect cell growth may improve the efficacy of hormonal therapy. Molecular markers that can reliably predict major clinical outcomes should be investigated further in well-designed trials.

Drug Insight: clinical use of agonists and antagonists of luteinizing-hormone-releasing hormone

This article reviews the clinical uses of agonists and antagonists of luteinizing-hormone-releasing hormone (LHRH), also known as gonadotropin-releasing hormone. In particular, the state of the art treatment of breast, ovarian and prostate cancer, reproductive disorders, uterine leiomyoma, endometriosis and benign prostatic hypertrophy is reported. Clinical applications of LHRH agonists are based on gradual downregulation of pituitary receptors for LHRH, which leads to inhibition of the secretion of gonadotropins and sex steroids. LHRH antagonists immediately block pituitary LHRH receptors and, therefore, achieve rapid therapeutic effects. LHRH agonists and antagonists can be used to treat uterine leiomyoma and endometriosis; furthermore, both types of LHRH analogs are used to block the secretion of endogenous gonadotropins in ovarian-stimulation programs for assisted reproduction. The preferred primary treatment of patients with advanced, androgen-dependent prostate cancer is based on the periodic administration of depot preparations of LHRH agonists; these agonists can be likewise used to treat estrogen-sensitive breast cancer in premenopausal women. LHRH antagonists have been successfully used to treat prostate cancer and benign prostatic hypertrophy. Since receptors for LHRH are present on a variety of human tumors, (notably breast, prostate, ovarian, endometrial and renal cancers), cytotoxic therapy that targets these tumors with hybrid molecules of LHRH might be possible in the near future. Analogs of LHRH are now a well-established means of treating sex-steroid-dependent, benign and malignant disorders.

Hormonal therapy for epithelial ovarian cancer

Despite the fact that hormonal therapy has been employed in the management of ovarian cancer for more than 40 years, there is limited information available in the peer-reviewed medical literature to document the beneficial impact of the strategy, either on improvement in cancer-related symptoms or prolongation of survival. Existing data suggest that approximately 5-10% of ovarian cancer patients treated with a hormone-based strategy in the second-line setting will achieve evidence of substantial tumor shrinkage, with a larger proportion of individuals likely to demonstrate stabilization of the disease process for a highly variable time interval. The major advantage with the use of hormonal treatments is the well-recognized and highly favorable toxicity profile associated with this class of antineoplastic agents.

Endocrine signaling in ovarian surface epithelium and cancer

Ovarian cancer is the sixth most common cancer and the fifth leading cause of cancer-related death among women in developed countries. Greater than 85% of human ovarian cancer arises within the ovarian surface epithelium (OSE), with the remainder derived from granulosa cells or, rarely, stroma or germ cells. The pathophysiology of ovarian cancer is the least understood among all major human malignancies because of a poor understanding of the aetiological factors and mechanisms of ovarian cancer progression. There is increasing evidence suggesting that several key reproductive hormones, such as GnRH, gonadotrophins and sex steroids, regulate the growth of normal OSE and ovarian cancer cells. The objective of this review was to highlight the effects of these endocrine factors on ovarian cancer cell growth and to summarize the signalling mechanisms involved in normal human OSE and its neoplastic counterparts.

Does hormone replacement therapy prevent epithelial ovarian cancer?

Two much-debated hypotheses regarding the aetiology of epithelial ovarian cancer (EOC) are incessant ovulation and gonadotrophin stimulation. A significant inverse correlation is found between the risk of EOC and number of pregnancies, duration of oral contraceptive use (about 10% risk reduction per year) and duration of breastfeeding. Whereas ovulation in the 20-29 year age group was associated with a 20% increase in risk for each year of ovulation, maximum protective effect was noticed in late childbirth (>35 years). Although both in-vitro and in-vivo studies showed that gonadotrophins may initiate and stimulate the growth of EOC, it is not known whether gonadotrophins promote EOC. FSH and LH receptors have been detected by ligand-binding assay and by reverse transcriptase polymerase chain reaction in ovarian surface epithelium (OSE) and in malignant epithelial ovarian tissue. Key aetiological events for this cancer may occur in the premenopausal period. Although hormone replacement therapy (HRT) can lower FSH and LH concentrations substantially, it cannot reduce EOC. The ideal time of ovulation and/or gonadotrophin suppression for prevention of EOC, and why oral contraceptives (OC) can but HRT cannot reduce EOC effectively, are unknown. Various growth-related genes, factors, adhesion molecules and angiogenic factors are present in OSE. Pituitary ovarian axis hormones seem to maintain a delicate balance towards growth control whilst the resultant chain of abnormal growth-promoting events occur at cellular level. Reports regarding the relation of exogenous and endogenous hormones, especially oestrogen, and post-menopausal EOC are reviewed.

Profiling follicle stimulating hormone-induced gene expression changes in normal and malignant human ovarian surface epithelial cells

Epidemiological data have implicated the pituitary gonadotropin follicle stimulating hormone (FSH) as both a risk factor for and a protective agent against epithelial ovarian cancer. Yet, little is known about how this hormone could play such opposing roles in ovarian carcinogenesis. Complementary DNA microarrays containing 2400 named genes were used to examine FSH-induced gene expression changes in ovarian cancer (OC) and immortalized normal human ovarian surface epithelial (HOSE) cell lines. Two-way t-statistics analyses of array data identified two distinct sets of FSH-regulated genes in HOSE and in established OC cell lines established from patients (OVCA cell lines). Among the HOSE cell lines, FSH increased expression of 57% of the 312 genes and downregulated 43%. In contrast, FSH diminished expression of 92% of the 177 genes in the OVCA cell lines. All but 18 of the genes affected by FSH in HOSE cell lines were different from those altered in OVCA cell lines. Among the 18 overlapping genes, nine genes exhibited the same direction of change following FSH challenge, while the other nine showed discordance in response between HOSE and OVCA cell lines. The FSH-induced differential expression of seven out of nine genes was confirmed by real-time RT-PCR. Gene-specific antisense oligonuleotides (ODNs) were used to inhibit the expression of genes encoding GTPase activating protein (rap1GAP), neogenin, and restin in HOSE and OVCA cells. Antisense ODNs to neogenin and restin, but not an antisense ODN to rap1GAP, were effective in inhibiting OVCA cell growth, diminishing proliferating cell nuclear antigen expression, and increasing caspase 3 activities. Furthermore, the ODN to rap1GAP was further shown to be ineffective in altering migration properties of OVCA cell lines. HOSE cell proliferation was not affected by treatment with any of the antisense ODNs. In summary, gene profiling data reveal for the first time that FSH may exert different biological actions on OVCA cells than on HOSE cells, by differential regulation of a set of putative oncogenes/tumor suppressors. Specifically, neogenin and restin were found to exhibit proproliferation/survival action on OC cells.

GnRH analogues as an adjuvant therapy for ovarian cancer patients

OBJECTIVES

Lowering gonadotropin levels with gonadotropin-releasing hormone (GnRH) analogues in patients with ovarian cancer remains open to debate. The aim of this study was to assess the results of treatment in stage III and stage IV ovarian cancer patients who had surgery supplemented with chemotherapy, radiotherapy, and GnRH analogues. Gonadotropin levels were monitored during treatment.

METHODS

The study group comprised 69 patients aged 27-70 years, stratified according to the type of treatment. The overall disease-free, 5-year survival rates and the frequency of remissions were analyzed. Hormonal tests [follicle-stimulating hormone (FSH) and luteinizing hormone (LH)] were performed in 58 patients. Associations were checked between gonadotropin levels, clinical findings, and survival. The results were statistically compared.

RESULTS

Statistically significant differences were noted when chemotherapy was supplemented with GnRH analogues and/or radiotherapy. Administration of GnRH analogues resulted in significantly lower levels of LH than of FSH. Levels of FSH were significantly lower in patients surviving at least 5 years or in complete remission at the time of this study.

CONCLUSIONS

Combined therapy can produce favorable results in late-stage ovarian cancer, and GnRH analogues have an important role in treatment strategy.

Effects of a lytic peptide conjugated to beta HCG on ovarian cancer: studies in vitro and in vivo

OBJECTIVE

The aim of this study was to determine the in vitro and in vivo effects of the lytic peptide, hecate, alone and conjugated to a 15-amino-acid fragment of the beta-chain of hCG (hecate-beta hCG) on the ovarian carcinoma cell line NIH: OVCAR-3 and determine the expression of luteinizing hormone (LH)/human chorionic gonadotropin (hCG) receptors in cell cultures and tumor tissues.

METHODS

For in vitro studies, hecate or hecate-beta hCG was added to cultures of ovarian cancer cells in the presence or absence of estradiol or follicle stimulating hormone. The cytotoxicity of lytic peptides was measured by trypan blue exclusion and lactate dehydrogenase release. For in vivo studies, OVCAR-3 xenografts were established in female athymic nude mice which were then treated once per week for 3 weeks with hecate or hecate-beta hCG via the lateral tail vein. An immunohistochemical method was used to analyze the expression of LH/hCG receptor in tumor and culture cells.

RESULTS

In in vitro studies, both hecate-beta hCG and hecate destroyed ovarian cancer cells (NIH: OVCAR-3) in a dose-dependent manner. Removal of steroids from the culture medium reduced the sensitivity of the OVCAR-3 cell line to the hecate-beta hCG in a reversible manner. In in vivo studies, the average tumor volume and tumor burden in lytic peptide treated animals were reduced. In the groups of animals treated by hecate, hecate-beta hCG, and estradiol + hecate-beta hCG, tumor volumes after treatment expressed as a percentage of increase (197.4 +/- 21.72, 199.0 +/- 18.57, and 193.8 +/- 22.94%, respectively) were reduced, compared to control (263.0 +/- 21.72%) animals (P < 0.05). Immunocytochemical studies revealed the expression of LH/hCG receptor protein in the OVCAR-3 cells and tumor tissues.

CONCLUSION

Hecate-beta hCG is a putative candidate for treating ovarian cancer.

Tamoxifen therapy for ovarian cancer in the adjuvant and advanced settings: systematic review of the literature and implications for future research

BACKGROUND

Ovarian neoplasms frequently express hormonal receptors and are sensitive to hormonal manipulations, as shown by preclinical and clinical studies. However, despite the outstanding relevance of hormonal adjuvant therapy in breast cancer and the importance of receptor status as a predictive factor, few trials have addressed these issues in ovarian cancer.

METHODS

Computerized and manual searches were performed to identify preclinical and clinical studies evaluating single-agent tamoxifen activity in ovarian cancer or any kind of hormonal therapy employed as adjuvant therapy for ovarian cancer.

RESULTS

In advanced tumors, none of the trials was performed exclusively in chemonaive patients, but those including less heavily pretreated patients showed greater response rates. Some studies found a correlation between receptor status and activity (although differences were not significant), whereas other trials did not. Nevertheless, none were specifically designed to answer this question. Few randomized trials comparing hormonal treatment and chemotherapy versus chemotherapy alone were identified. Although their results were negative, all were small, and none was designed with the rigor that allowed adjuvant hormonal therapy to become successfully established in breast cancer.

CONCLUSION

The activity of tamoxifen in advanced ovarian cancer has not been adequately evaluated and its role may have been underestimated. Furthermore, the relevance of adjuvant hormonal therapy in ovarian cancer and the predictive value of hormonal receptors have never been studied in well-designed trials. Additional studies to clarify the role of tamoxifen for this indication are warranted.

Hypothalamic hormones and cancer

The use of peptide analogs for the therapy of various cancers is reviewed. Inhibition of the pituitary-gonadal axis forms the basis for oncological applications of luteinizing hormone-releasing hormone (LH-RH) agonists and antagonists, but direct effects on tumors may also play a role. Analogs of somatostatin are likewise used for treatment of various tumors. Radiolabeled somatostatin analogs have been successfully applied for the localization of tumors expressing somatostatin receptors. Studies on the role of tumoral LH-RH, growth hormone-releasing hormone (GH-RH), and bombesin/GRP and their receptors in the proliferation of various tumors are summarized, but the complete elucidation of all the mechanisms involved will require much additional work. Human tumors producing hypothalamic hormones are also discussed. Treatment of many cancers remains a major challenge, but new therapeutic modalities are being developed based on antagonists of GH-RH and bombesin, which inhibit growth factors or their receptors. Other approaches consist of the use of cytotoxic analogs of LH-RH, bombesin, and somatostatin, which can be targeted to receptors for these peptides in various cancers and their metastases. These new classes of peptide analogs should lead to a more effective treatment for various cancers.

Gonadotropin-releasing hormone antagonist: how good is the new hope?

Gonadotropin-releasing hormone agonists have been widely used to prevent luteinizing hormone surges during controlled ovarian stimulation in assisted reproductive technologies. Treatment with gonadotropin-releasing hormone agonists of uterine myoma, endometriosis and some hormone-dependent cancers, such as breast, ovarian, endometrial and prostate cancer, also seems to have a beneficial effect. Gonadotropin-releasing hormone agonists have the disadvantage of inducing an initial stimulatory effect on gonadotropin secretion, necessitating 2-3 weeks before pituitary desensitization is achieved. Gonadotropin-releasing hormone antagonists, on the contrary, cause an immediate inhibition of gonadotropin secretion by competitive blocking of pituitary gonadotropin-releasing hormone receptors. Some advantages of their clinical use in controlled ovarian stimulation have already been demonstrated. Randomized comparative studies are needed to investigate their benefit over gonadotropin-releasing hormone antagonists for myoma and hormone-related disorders.

Fertility options for female cancer patients: facts and fiction

OBJECTIVE

To review the latest progress in the prevention of ovarian failure induced by chemo/radiotherapy, as well as the latest advances in culture technology and transplantation of frozen-thawed ovarian tissue.

DESIGN

The English-language literature was searched with PubMed and related references.

CONCLUSION(S)

The development of combination chemotherapy and radiotherapy has improved the long-term survival of young cancer patients who are then frequently faced with iatrogenic ovarian failure and its consequences. The use of prior and concomitant GnRH analogs with chemotherapy offers encouraging results in animal studies with regard to prevention of ovarian failure. Adequately controlled research projects are needed to define the utility of GnRHa cotreatment in women cancer patients exposed to prolonged chemotherapy. Ovarian tissue cryopreservation is the optimal procedure for follicle banking. Theoretic options include returning the banked tissue back to the original pedicle so that pregnancy could be achieved naturally. Alternatively, the tissue can be grafted to a heterotopic site, either as an autograft (i.e., rectus abdominis muscle sheath) or as a xenograft (i.e., immunodeficient mice). Follicles could also be grown in vitro. Until reliable ovarian culture technology becomes available, autologous transplantation offers the best prospect of using frozen-thawed ovarian tissue. A primary concern, however, is the issue of microscopic metastatic disease to the ovary and the possibility of tumor reimplantation. Areas of research should focus on optimizing the freeze/thaw procedure for ovarian tissue, minimizing the ischemia-reperfusion injury after transplantation, and detecting minimal residual disease in ovarian tissue grafts.

Primary and salvage therapy with LH-RH analogues in ovarian cancer

The efficacy of modern surgical and chemotherapeutic options for the treatment of ovarian cancer is still unsatisfactory. In spite of the availability of new cytotoxic agents, the majority of ovarian cancer patients will finally die of chemoresistant disease. LH-RH agonists in conventional doses have been shown to induce objective responses in approximately 9% of patients with refractory ovarian cancer and disease stabilization in 26% of these women. As toxicity of LH-RH agonists is low or absent, and since their efficacy is not strikingly inferior to that of experimental chemotherapy, they have a vital indication in the salvage situation. A trial is presently being performed among platinum/taxol-refractory patients, comparing the impact of the LH-RH agonist leuprorelin and that of the cytotoxic agent treosulfane on survival and quality of life. The addition of LH-RH agonists in conventional doses to standard first-line surgical and chemotherapy does not improve relapse-free and overall survival. For many years it has been suggested that LH-RH agonists inhibit proliferation of ovarian cancer by suppressing endogenous gonadotropins, which were considered to be mitogenic in this malignancy. Recent experimental and clinical data have made this hypothesis questionable. In contrast, a large body of experimental evidence has emerged during the past few years indicating that LH-RH agonists and antagonists directly inhibit proliferation of ovarian cancer through LH-RH receptors expressed by 80% of these tumors. To exploit these direct antiproliferative effects of LH-RH analogues, higher tissue concentrations are necessary than those achieved with the conventional doses used today. Alternative routes of administration or higher systemic doses of potent LH-RH antagonists, such as Cetrorelix, might improve the efficacy of this approach. Clinical trials addressing this issue are under way. Finally, the LH-RH receptors expressed by ovarian cancers could be employed for targeted chemotherapy using cytotoxic LH-RH analogues. This approach has been shown to be effective in experimental models and might be tested in clinical trials in the near future.

Targeted cytotoxic analog of luteinizing hormone-releasing hormone AN-207 inhibits growth of OV-1063 human epithelial ovarian cancers in nude mice

OBJECTIVE

The aim of the study was to investigate the effects of the cytotoxic analog of luteinizing hormone-releasing hormone AN-207 on the growth of the OV-1063 human epithelial ovarian cancers, which express luteinizing hormone-releasing hormone receptor. AN-207 consists of doxorubicin derivative 2-pyrrolinodoxorubicin (AN-201) linked with the carrier [D-lysine6 ]luteinizing hormone-releasing hormone.

STUDY DESIGN

Female nude mice bearing xenografts of OV-1063 ovarian cancers were treated with analog AN-207, cytotoxic radical AN-201, or agonist [D-lysine6 ]luteinizing hormone-releasing hormone. The levels and expression of messenger ribonucleic acid of receptors for luteinizing hormone-releasing hormone and epidermal growth factor were evaluated.

RESULTS

The growth of OV-1063 tumor was significantly inhibited by 3 to 5 nmol AN- 207 but not by [D-lysine6 ]luteinizing hormone-releasing hormone. Cytotoxic radical AN-201 was toxic at these doses. After treatment with AN-207 receptors for luteinizing hormone-releasing hormone were not detectable, epidermal growth factor receptor levels declined, and expressions of their respective messenger ribonucleic acids were decreased.

CONCLUSIONS

Targeted cytotoxic luteinizing hormone-releasing hormone analog AN-207 is less toxic than equimolar doses of its radical 2-pyrrolinodoxorubicin and effectively inhibits ovarian tumor growth. Targeted chemotherapy may improve management of ovarian cancer.

Hormonal interactions in ovarian cancer

According to the epidemiologic literature and the laboratory characterization of receptor content and molecular interactions, there is a relationship between the microenvironment of ovarian cancer and steroid hormones. Advances in our knowledge of the molecular-hormonal nature of ovarian cancer will help in designing a rationale for clinical trials in appropriate subsets of patients. However, currently, development of successful therapies and prevention strategies for women at risk remains a true challenge.

Luteinizing hormone-releasing hormone analogs: their impact on the control of tumorigenesis

The development of the luteinizing hormone-releasing hormone (LH-RH) agonists and antagonists and the principles of their clinical use were reviewed. In the 28 years that have elapsed since the elucidation of the structure of LH-RH, various applications in gynecology, reproductive medicine, and oncology have been established for LH-RH agonists and antagonists. These clinical applications are based on inhibition of the pituitary and the gonads. The advantage of the LH-RH antagonists is due to the fact that they inhibit the secretion of gonadotropins and sex steroids immediately after the first injection and thus achieve rapid therapeutic effects in contrast to the agonists, which require repeated administration. LH-RH antagonists should find applications in the treatment of benign gynecologic disorders and benign prostatic hypertrophy and in assisted reproduction programs. The primary treatment of advanced androgen-dependent prostate cancer is presently based on the use of depot preparations of LH-RH agonists, but antagonists like Cetrorelix already have been tried successfully. Antagonists of LH-RH might be more efficacious than agonists in treatment of patients with breast cancer as well as ovarian and endometrial cancer. Recently, practical cytotoxic analogs of LH-RH that can be targeted to LH-RH receptors on tumors have been synthesized and successfully tested in experimental cancer models. Targeted cytotoxic LH-RH analogs show a great promise for therapy of prostate, breast, and ovarian cancers.

In vitro effects of gonadotropin-releasing hormone (GnRH) analogue on cancer cell sensitivity to cis-platinum

Six endometrial cancer cell lines (Ishikawa, EIIL, HEC1A, 6, 50 and 59), one breast cancer cell line (MCF-7) and two ovarian cancer cell lines (OVHS-1, HRA) were treated for 24 or 168 h with a gonadotropin-releasing hormone (GnRH) analogue, Buserelin acetate, and the cellular growth profile was studied. All these cell lines except for the HRA line had positive GnRH receptor mRNA expression detected by reverse transcriptase polymerase chain reaction. GnRHa suppressed cell growth after 168 h of exposure, but not after 24 h. Suppression of cell growth by the exposure to cis-platinum (CDDP, 10 nM for 24 h) was significantly increased in the presence of GnRHa for 168 h. The mechanism of this growth inhibition was tested by examining both RNA components of human telomerase (hTR) expression and telomerase activity. The results showed that GnRHa inhibits telomerase activity without altering the RNA component of telomerase expression. The present data suggest that GnRH analogue may modulate endometrial, breast and ovarian cancer cell growth through modifying the telomerase activity. Since GnRHa increased the cytotoxic effects of CDDP and GnRHa is a compound of high patient compliance, the value of GnRHa as a tumor sensitizer to CDDP should be further tested in clinical trials.

Human chorionic gonadotropin (hCG) inhibits cisplatin-induced apoptosis in ovarian cancer cells: possible role of up-regulation of insulin-like growth factor-1 by hCG

Gonadotropins have been suggested to play a role in the development or progression of ovarian cancer, and we have previously reported the expression of luteinizing hormone/ human chorionic gonadotropin (LH/hCG) receptor in 40% of epithelial ovarian carcinomas. To examine the biological effect of LH/hCG on ovarian cancer cells, apoptosis induced by cisplatin with or without hCG treatment was investigated in 2 ovarian cancer cell lines, OVCAR-3 and SK-OV-3. Stimulation of cell proliferation by hCG was also studied. In addition, to analyze further the mechanism of hCG signaling involved in apoptosis-inhibition, we examined the expression of LH/hCG receptors and the regulation by hCG for apoptosis-inhibitory pathways, such as the bcl-2/bax system and the insulin-like growth factor-1 (IGF-1)/IGF-1 receptor (IGFR) system. hCG did not increase cell proliferation in either cell line. However, hCG treatment suppressed cisplatin-induced apoptosis by 58% in the OVCAR-3 cells, as shown by immunofluorescent staining and quantitation of DNA fragmentation. LH/hCG receptor mRNA was expressed only in OVCAR-3, and no apoptosis-inhibitory effect of hCG was observed in the SK-OV-3 cells that did not express the receptor. In the OVCAR-3 cells, hCG significantly increased mRNA expression of IGF-1, but did not change mRNA levels of bcl-2/bax. Our findings suggest that LH/hCG influences the chemosensitivity of ovarian cancer cells through an apoptosis-inhibitory signal possibly via up-regulation of IGF-1 expression.

Growth inhibition of human ovarian cancers by cytotoxic analogues of luteinizing hormone-releasing hormone

BACKGROUND

Receptors for luteinizing hormone-releasing hormone (LH-RH) are found in nearly 80% of human ovarian cancers. The chemotherapeutic agent doxorubicin can be linked to [D-lysine6]LH-RH to form a cytotoxic analogue (AN-152) that may have greater specificity for tumor cells. This study was conducted to investigate the effects of AN-152 on the growth of LH-RH receptor-positive OV-1063 human epithelial ovarian cancers.

METHODS

Nude mice bearing human ovarian tumors, OV-1063 or UCI-107 (LH-RH receptor negative), were injected intraperitoneally with saline (control) or with equimolar doses of AN-152 or doxorubicin; experiments involving mice with OV-1063 tumors also included groups that were administered [D-lysine6]LH-RH either alone or in combination with doxorubicin. Tumor volume, weight, doubling time, and burden (i.e., tumor weight/body weight) as well as tumor apoptotic and mitotic indices were determined. The levels of receptors for LH-RH and epidermal growth factor (EGF) and their messenger RNAs were measured by use of radioreceptor and reverse transcription-polymerase chain reaction assays, respectively.

RESULTS

The growth of OV-1063 ovarian tumors in nude mice, as based on reduction in tumor volume, was inhibited significantly (all P<.05, two-sided) 4 weeks after treatment with AN-152, even at the lowest dose tested (413 nmol/20 g weight); the toxic effects of an equivalent dose of doxorubicin caused substantial mortality. High-affinity receptors for LH-RH and EGF were found on cell membranes of OV-1063 cancers; however, after in vivo treatment with AN-152, LH-RH receptor-binding sites were not detectable and EGF receptors were reduced in number. The growth of UCI-107 ovarian cancers was not inhibited by AN-152.

CONCLUSIONS

In nude mice bearing LH-RH receptor positive OV-1063 epithelial ovarian cancers, systemic administration of AN-152 is less toxic and inhibits tumor growth better than equimolar doses of doxorubicin.

Rational use of agonists and antagonists of luteinizing hormone-releasing hormone (LH-RH) in the treatment of hormone-sensitive neoplasms and gynaecologic conditions

Analogues of luteinizing hormone-releasing hormone (LH-RH) have made possible new approaches to the treatment of some hormone-dependent cancers and diseases and conditions which result from inappropriate sex hormone levels. In the fields of both gynaecology and oncology, the development of sustained delivery depot systems has played a key role in the clinical use of LH-RH agonists and will be also essential for the LH-RH antagonists. Clinical results show that therapy with agonists of LH-RH is the preferred method of treatment for men with advanced prostate cancer. For prostate cancer and other indications, the new LH-RH antagonists such as Cetrorelix may offer an advantage based on the fact that they inhibit LH, FSH and sex-steroid secretion from the start of the administration and thus reduce the time of the onset of therapeutic effects. The use of antagonists would avoid the temporary clinical "flare-up" of the disease which can occur with the agonists in men with prostate cancer. The rapid shrinkage of the prostate and improvement in urinary symptoms obtained with Cetrorelix in men with benign prostatic hyperplasia (BHP) suggests that LH-RH antagonists offer a therapeutic alternative in patients who are considered poor surgical risks. Various experimental and clinical studies suggest that analogues of LH-RH might be useful for treatment of premenopausal women with oestrogen-dependent breast cancer. LH-RH antagonists such as Cetrorelix could be also considered for hormonal therapy of epithelial ovarian cancer which responds only marginally to the agonists, and for treatment of endometrial cancer. Many investigators have reported beneficial effects of LH-RH agonists in the treatment of patients with leiomyomas. LH-RH antagonists also appear to be promising for therapy of uterine leiomyomas, and in addition might be useful for treatment of endometriosis and polycystic ovarian disease (PCOD). LH-RH agonists have been employed in in vitro fertilization and embryo transfer (IVF-ET) programs to prevent a premature rise in LH and various results suggest that the use of antagonist Cetrorelix in assisted reproduction procedures, could be even more advantageous. For most of these indications, the use of sustained release depot preparations will be required.