Comparison of the effects of cabergoline and bromocriptine on prolactin levels in hyperprolactinemic patients

Treatment of sexual dysfunction induced by hyperprolactinemia accompanied by reduced luteinizing hormone levels: A case report

Key Clinical Message

Sexual dysfunction induced by hyperprolactinemia accompanied by reduced luteinizing hormone (LH) is common in anrology clinics. A low dose of bromocriptine is helpful for restoring penile erectile function and libido in patients.

Abstract

Sexual dysfunction is closely related to hormonal disorders, of which prolactin (PRL) and luteinizing hormone (LH) disorders are common. How to treat sexual dysfunction induced by hyperprolactinemia accompanied by reduced LH levels is worth discussing. In this study, we aimed to present the case of a 35-year-old male patient with sexual dysfunction. The treatment process and physical and laboratory examination results were recorded. Before treatment, the PRL and LH levels in this patient were 31.27 ng/mL and 1.62 mIU/mL, respectively. The International Index of Erectile Function-5 (IIEF-5) score was initially 14 points. After regular treatment with low doses of bromocriptine and tadalafil, the hormonal disorder was corrected (PRL: 11.16 ng/mL and LH: 2.28 mIU/mL) and sexual function was recovered (IIEF-5: 23 points). This case report suggested a sufficient exposure to low-dose bromocriptine for such patients. Conversely, the exogenous supplementation of human chorionic gonadotropin may not be appropriate.

Evaluation of Treatment Strategies for Male Prolactin-Secreting Pituitary Neuroendocrine Tumors

Prolactin-secreting pituitary neuroendocrine tumors (PitNETs) are more common in women. Male patients may also have few symptoms and have macroadenomas extending outside the sella turcica. This study aimed to report the results of cabergoline treatment in male patients with prolactin-secreting PitNET. The study included nine male patients aged 26-65 years (median, 46 years) diagnosed with prolactin-secreting PitNETs. The age at onset, prolactin values, tumor size, symptoms, and treatment were assessed. The mean prolactin value at the initial presentation was 2734.6 ng/mL, and the mean maximum tumor diameter was 40.4 mm. Visual field disturbance was the most common symptom (44.4%), followed by headaches (33.3%), asymptomatic symptoms (11.1%), and galactorrhea (11.1%). Eight patients responded to cabergoline treatment with normalization of prolactin levels and tumor shrinkage. One patient did not respond to the cabergoline treatment and required surgical intervention. There were no cases of cerebrospinal fluid leakage. Cabergoline was found to be an effective treatment for male prolactin-secreting PitNETs.

How to manage intolerance to dopamine agonist in patients with prolactinoma

PURPOSE

Dopamine agonists (DA) are the gold-standard for prolactinoma and hyperprolactinemia treatment. Intolerance to DA leading to drug drop out occurs in 3 to 12% of cases. We provide here a review of published data about DA intolerance and present a case report concerning the use of intravaginal cabergoline.

METHODS

We review the literature on the definition, the pathogenesis, frequency and management of DA intolerance. In addition, the review provides strategies to enhance tolerability and avoid precocious clinical treatment withdrawal.

RESULTS

Cabergoline is often cited as the most tolerable DA and its side effects tend to ameliorate within days to weeks. Restarting the same drug at a lower dose or switching to another DA can be used in cases of intolerance. The vaginal route can be tried specifically if there are gastrointestinal side effects in the oral administration. Symptomatic treatment could be attempted, although mainly based on a strategy used in other diseases.

CONCLUSIONS

Due to limited data, no guidelines have been developed for the management of intolerance in DA treatment. The most frequent management is to perform transsphenoidal surgery. Nevertheless, this manuscript provides data derived from published literature and expert opinion, suggesting new approaches to this clinical issue.

Macroprolactinoma with secondary resistance to dopamine agonists: a case report and review of the literature

BACKGROUND

Resistance to dopamine agonists is not uncommonly seen in prolactinomas. However, development of resistance to dopamine agonists after an initial period of robust treatment response is rare, and only 39 cases have been reported in the past four decades. We describe a Chinese man with this rare condition and explored the postulated mechanisms that may explain this phenomenon. We compiled similar cases that were previously reported and compared their etiology, progress, and response to treatment. On the basis of these cases, we derived a list of differential diagnoses to consider in patients with secondary resistance to dopamine agonists.

CASE PRESENTATION

A 63-year-old Chinese man presented with blurred vision and was subsequently diagnosed with a macroprolactinoma. He had initial response to cabergoline but developed secondary resistance to it after 5 years. The prolactinoma continued to grow, and his serum prolactin remained markedly elevated despite adherence to escalating dosages of cabergoline up to 6 mg/week. The patient finally underwent transsphenoidal surgery and was found to have a sparsely granulated lactotroph tumor with Ki-67 index of 5%. Postoperatively, there was improvement in his serum prolactin level, although he still required treatment with cabergoline at 6 mg/week.

CONCLUSIONS

Surgery can facilitate disease control in patients with prolactinomas that develop secondary resistance to dopamine agonists. Malignant prolactinoma is an important differential diagnosis in this group of patients, especially when serum prolactin remains markedly elevated despite resolution or stability of the primary pituitary lesion, suggesting a metastatic source of prolactin secretion.

Peripartum Cardiomyopathy with the Cardiac Function Restored by Cabergoline

Peripartum cardiomyopathy (PPCM) is a left ventricular systolic dysfunction associated with heart failure (HF) in late-term pregnancy or peripartum. A 29-year-old pregnant woman with no history of cardiac disease noted lower extremity edema around 34 weeks' gestation with significant weight gain. She delivered twins via caesarean section, and the edema regressed postpartum. On postpartum day 4, however, she experienced difficulty breathing at night and was diagnosed with HF owing to PPCM. HF treatment along with cabergoline was initiated. With low prolactin blood levels, her symptoms and cardiac function improved over time. This case demonstrated the usefulness of anti-prolactin therapy with cabergoline in PPCM.

Are dopamine agonists still the first-choice treatment for prolactinoma in the era of endoscopy? A systematic review and meta-analysis

Background

For prolactinoma patients, dopamine agonists (DAs) are indicated as the first-line treatment and surgery is an adjunctive choice. However, with the development of surgical technique and equipment, the effect of surgery has improved. The aim of this study was to assess the efficacy and safety of surgery versus DAs in patients with different types of prolactinomas.

Methods

A systematic search of literature using Web of Science, PubMed, Cochrane Library, and Clinical Trial databases was conducted until July 12, 2019. Prolactinoma patients treated with DAs (bromocriptine or cabergoline) or surgery (microscopic or endoscopic surgery) were included. Outcomes included the biochemical cure rate, recurrence rate, prolactin level, improvement rates of symptoms, and incidence rates of complications. A random-effects model was used to pool the extracted data. Qualitative comparisons were conducted instead of quantitative comparison.

Results

DAs were better than surgery in terms of the biochemical cure rate (0.78 versus 0.66), but surgery had a much lower recurrence rate (0.19 versus 0.57). Full advantages were not demonstrated in improvement rates of symptoms and incidence rates of complications with both treatment options. In microprolactinoma patients, the biochemical cure rate of endoscopic surgery was equal to the average cure rate of DAs (0.86 versus 0.86) and it surpassed the biochemical cure rate of bromocriptine (0.86 versus 0.76). In macroprolactinoma patients, endoscopic surgery was slightly higher than bromocriptine (0.66 versus 0.64) in terms of the biochemical cure rate.

Conclusion

For patients with clear indications or contraindications for surgery, choosing surgery or DAs accordingly is unequivocal. However, for patients with clinical equipoise, such as surgery, especially endoscopic surgery, in microprolactinoma and macroprolactinoma patients, we suggest that neurosurgeons and endocrinologists conduct high-quality clinical trials to address the clinical equipoise quantitatively.

Supplementary Information

The online version contains supplementary material available at 10.1186/s41016-022-00277-1.

Efficacy and safety in the treatment of hyperprolactinemia: A systematic review and network meta-analysis

WHAT IS KNOWN AND OBJECTIVE

Hyperprolactinemia is a neuroendocrine disease that is responsible for a quarter of cases of secondary amenorrhea, which can lead to infertility in women. Dopaminergic agonists (bromocriptine, cabergoline, quinagolide) can be used in the treatment. However, there is a lack of secondary studies that compare their efficacy and safety, especially through a network meta-analysis. Thus, to contribute to the decision-making, a systematic review and network meta-analyses (NMA) were performed to evaluate the efficacy and safety of dopaminergic agonists in the treatment of hyperprolactinemia.

METHODS

Randomized clinical trials (RCT) were retrieved through PubMed, Web of Science and Scopus databases. The efficacy and safety of the drugs were compared, considering the following outcomes: prolactin (PRL) levels, number of patients with galactorrhoea, menstrual irregularities and adverse drug reactions. NMA was built for each outcome. Results were reported as odds ratios (OR) with 95% credibility intervals. Ranking probabilities were calculated by surface under the cumulative ranking analysis (SUCRA) and Stochastic multicriteria acceptability analysis (SMAA).

RESULTS AND DISCUSSION

Seventeen RCTs were included in the systematic review and fifteen in the meta-analyses. The drugs had similar efficacy, considering the PRL levels. The SUCRA analysis showed that quinagolide (0.075 and 0.05 mg/day) was superior for reducing irregular menstruation, whereas bromocriptine was the best (97%) for galactorrhoea. Cabergoline proved to be the safest drug, except for abdominal pain at a dose of 1 mg/week. The SMAA demonstrated similar results to SUCRA.

WHAT IS NEW AND CONCLUSION

This is the first network meta-analysis that evaluated the efficacy and safety of dopaminergic agonists in the treatment of hyperprolactinemia. The results of this review revealed that these drugs have similar efficacy, but cabergoline has a better safety profile.

Long-term follow-up of female prolactinoma patients at child-bearing age after transsphenoidal surgery

CONTEXT

Prolactinoma is the most common subtype of functional pituitary adenoma. Effective therapy is required for women of child-bearing age to achieve remission at serum prolactin level and regain reproductive function.

PURPOSE

To evaluate long-term outcomes, including menstrual recovery, after transsphenoidal surgery on female prolactinoma patients by experienced neurosurgeons.

DESIGN

Observational study.

PATIENTS

Consecutive female prolactinoma patients aged from 16 to 45 years were included. Histological analysis after surgery revealed adenoma with positive staining for prolactin. Plurihormonal cell adenomas were excluded.

MAIN MEASUREMENTS

Clinical manifestations, surgical indications, serum prolactin level before and after surgery, surgical complications, pituitary fuctions, drug maintenance, the status of menstruation, and pregnancy.

RESULTS

Sixty-three consecutive female patients with a mean age of 29.5 ± 1.1 years were included. Based on magnetic resonance imaging findings before surgery, 31 (49.2%) patients had microadenoma, and the remaining 32 (50.8%) had macroadenoma. The median follow-up after transsphenoidal surgery was 53 (33-74) months, and long-term surgical remission was achieved in 50 (79.37%) patients with 28 (90.32%) microadenomas and 22 (68.75%) macroadenomas. No meningitis or persistent cerebrospinal fluid leaks occurred. Only one case suffered from persistent diabetes insipidus at follow-up. No severe pituitary dysfunction was observed in microprolactinoma patients. Of patients with menstrual disorders, 85% regained regular menstrual cycles after surgery. Nineteen patients in this cohort desired pregnancy and 15 of them successfully gave birth after surgery. All 17 microadenoma patients with modern surgical indications achieved normal prolactin levels and regular menstrual cycles with only one patient on drug therapy at follow-up.

CONCLUSION

Long-term follow-up showed a high remission rate in female prolactinoma patients, especially in microadenoma patients, after surgery. Transsphenoidal surgery performed by experienced neurosurgeons may offer a valuable approach to treat female microprolactinoma patients of child-bearing age with modern indications for surgery.

Cabergoline versus bromocriptine for the treatment of giant prolactinomas: A quantitative and systematic review

The aim of this study is to compare the efficacy of bromocriptine (BRC) versus cabergoline (CAB) in patients with giant prolactinomas. We searched MEDLINE, EMBASE, CENTRAL and Clinical Trials.gov for studies dated before March 1st, 2016, that used BRC or CAB for the treatment of patients with giant prolactinomas. Specific eligibility criteria were set to identify articles and cases. The selected articles were reviewed, and the data were extracted for analysis. The compared outcomes included tumor shrinkage, tumor response, normalization of prolactin (PRL) level, and visual field defect (VFD) improvement. Gender differences were also considered. Differences between the groups were assessed using Student's t test and the chi-square test. Two hundred and forty-five records were identified, and 10 articles and 104 cases met the inclusion criteria. Based on our analysis, CAB is significantly better than BRC in normalizing PRL levels in patients, especially males, with giant prolactinomas (69.4% versus 31.7%, p = 0.01). However, there was no significant difference between the two drugs in terms of tumor shrinkage, tumor response and VFD improvement (p > 0.05) in male or female patients. CAB exhibits significantly better efficacy than BRC in the normalization of PRL levels in male patients with giant prolactinomas. Regarding tumor reduction and VFD improvement, both drugs are comparably effective for patients of both genders. This quantitative and systematic review provides preliminary evidence in favor of CAB as a medical therapy for treating giant prolactinomas in male patients, especially those with extremely high PRL levels.

Cabergoline or bromocriptine for prolactinoma?

Cabergoline and bromocriptine are among the most commonly used drugs to treat prolactinoma. Cabergoline is a long-acting dopamine receptor agonist which might offer advantages over bromocriptine. However, it is not clear if this translates into clinical benefits. Searching in Epistemonikos database, which is maintained by screening 30 databases, we identified two systematic reviews including 12 studies addressing the question of this article, including five randomized controlled trials. We combined the evidence using meta-analysis and generated a summary of findings following the GRADE approach. We concluded cabergoline is more effective than bromocriptine in resolution of amenorrhea/oligomenorrhea and galactorrhea, it probably increases pregnancy rate, and it is associated to less adverse effects. It is not clear whether cabergoline is also more effective with respect to tumor growth because the certainty of the evidence is very low.

Cost-Effectiveness Analysis of Microscopic and Endoscopic Transsphenoidal Surgery Versus Medical Therapy in the Management of Microprolactinoma in the United States

BACKGROUND

Although prolactinomas are treated effectively with dopamine agonists, some have proposed curative surgical resection for select cases of microprolactinomas to avoid life-long medical therapy. We performed a cost-effectiveness analysis comparing transsphenoidal surgery (either microsurgical or endoscopic) and medical therapy (either bromocriptine or cabergoline) with decision analysis modeling.

METHODS

A 2-armed decision tree was created with TreeAge Pro Suite 2012 to compare upfront transsphenoidal surgery versus medical therapy. The economic perspective was that of the health care third-party payer. On the basis of a literature review, we assigned plausible distributions for costs and utilities to each potential outcome, taking into account medical and surgical costs and complications. Base-case analysis, sensitivity analysis, and Monte Carlo simulations were performed to determine the cost-effectiveness of each strategy at 5-year and 10-year time horizons.

RESULTS

In the base-case scenario, microscopic transsphenoidal surgery was the most cost-effective option at 5 years from the time of diagnosis; however, by the 10-year time horizon, endoscopic transsphenoidal surgery became the most cost-effective option. At both time horizons, medical therapy (both bromocriptine and cabergoline) were found to be more costly and less effective than transsphenoidal surgery (i.e., the medical arm was dominated by the surgical arm in this model). Two-way sensitivity analysis demonstrated that endoscopic resection would be the most cost-effective strategy if the cure rate from endoscopic surgery was greater than 90% and the complication rate was less than 1%. Monte Carlo simulation was performed for endoscopic surgery versus microscopic surgery at both time horizons. This analysis produced an incremental cost-effectiveness ratio of $80,235 per quality-adjusted life years at 5 years and $40,737 per quality-adjusted life years at 10 years, implying that with increasing time intervals, endoscopic transsphenoidal surgery is the more cost-effective treatment strategy.

CONCLUSIONS

On the basis of the results of our model, transsphenoidal surgical resection of microprolactinomas, either microsurgical or endoscopic, appears to be more cost-effective than life-long medical therapy in young patients with life expectancy greater than 10 years. We caution that surgical resection for microprolactinomas be performed only in select cases by experienced pituitary surgeons at high-volume centers with high biochemical cure rates and low complication rates.

Retrospective comparison of cabergoline and bromocriptine effects in hyperprolactinemia: a single center experience

INTRODUCTION

Patients with hyperprolactinemia who require medical therapy are typically treated with dopamine agonists (DAs). In most cases, DAs normalize prolactin levels, control symptoms, and substantially decrease tumor size. Here, we aimed to compare the efficacy of cabergoline (CAB) and bromocriptine (BRC) in patients with hyperprolactinemia at a single center.

METHODS

Retrospective analysis of the clinical records of 498 patients with hyperprolactinemia [mean age 33.3 ± 10.8 years (range 16-66), 450 women, and 48 men] who had received either CAB (n = 450) or BRC (n = 48) was performed.

RESULTS

The mean age, gender distribution, and treatment duration were similar between the CAB and BRC groups (33.2 ± 11 vs. 34.1 ± 9.6 years, male/female 44/406 vs. 4/44, 18.7 ± 12.1 vs. 17.8 ± 6.0 months, respectively; p > 0.05 for all). Mean dosage was 1.5 ± 1.6 mg/week for CAB and 3.8 ± 2.7 mg/day for BRC. Baseline prolactin levels, frequency of galactorrhea, amenorrhea, oligomenorrhea, erectile dysfunction, infertility, and visual impairment were similar between the two groups, whereas the baseline tumor volume was higher in the CAB group. The prolactin normalization rate (87.4 vs. 41.4 %, p = 0.029) and tumor volume shrinkage (79.8 ± 39.1 vs. 54.1 ± 55.3 %, p = 0.015) were significantly higher in the CAB-treated patients than in the BRC-treated patients, while the tumor cure rates were similar. Symptom relief was higher in the CAB group than in the BRC group. More side effects were recorded in patients who took BRC (29.1 vs. 5.3 %, p < 0.001).

CONCLUSION

Our data revealed that CAB was more effective than BRC in controlling symptoms associated with hormone excess, normalizing serum prolactin levels, and shrinking prolactinomas.

Successful management of a giant pituitary lactosomatotroph adenoma only with cabergoline

Although advances in endocrinologic and neuroradiologic research allow easier recognition of pituitary adenomas, giant pituitary tumours are relatively rare. In the literature, the term “giant” is generally used when a pituitary tumour becomes larger than 4 cm in diameter. Cabergoline is a potent and long-acting inhibitor of prolactin secretion, which exhibits high specificity and affinity for dopamine D2 receptor. Herein, we report a 46-year-old woman with a giant lactosomatotroph pituitary adenoma, sized 6 × 5 × 5.5 cm, who is treated successfully only with cabergoline. The patient showed dramatic response to cabergoline treatment by means of clinical, biochemical and radiological imaging findings. Cabergoline seems to be safe and effective in the treatment of prolactin and growth hormone cosecreting pituitary adenomas as well as prolactinomas. However, surgical or more aggressive approach must be considered where indicated.

Extralabel use of cabergoline in the treatment of a pituitary adenoma in a rat

CASE DESCRIPTION

A 0.65-kg (1.43-lb) 24-month-old sexually intact male albino pet rat was examined because of a 3-week history of hypodipsia, apparent blindness, and sudden change in behavior.

CLINICAL FINDINGS

The rat was able to move around its cage but appeared unaware of its surroundings, was visually unresponsive, and seemed unusually aggressive. The rat's hind limbs appeared mildly paretic, and it had sporadic difficulty placing its hind limbs on a flat surface. Given the rat's age, history, and physical examination findings, the primary differential diagnosis was a pituitary tumor. Magnetic resonance imaging (MRI) of the rat's brain was performed and revealed a large pituitary mass, which was indicative of a tumor.

TREATMENT AND OUTCOME

Cabergoline (0.6 mg/kg [0.27 mg/lb], PO, q 72 h) was administered. On follow-up MRI 2 months later, the pituitary mass had substantially decreased in size. For 6 months following the second MRI study, the rat continued to receive the same dosage of cabergoline and had no clinical signs of disease or unusual behavior. However, at 8.5 months after the start of the treatment, the rat was in poor condition and had clinical signs similar to those initially. A third MRI study was performed and revealed substantial regrowth of the mass. The rat was euthanized and a necropsy was performed; a histopathologic diagnosis of pituitary adenoma was made.

CLINICAL RELEVANCE

Pituitary adenomas have long been recognized as a common finding in geriatric rats (> 18 months old). Affected rats may respond favorably to oral administration of cabergoline.

Cabergoline versus bromocriptine in the treatment of hyperprolactinemia: a systematic review of randomized controlled trials and meta-analysis

Cabergoline and bromocriptine are the most used drugs in the treatment of hyperprolactinemia, they are able to normalize the prolactin levels, restore gonadal function and promote tumor reduction in the majority of patients. We undertake a systematic review and meta-analysis of randomized controlled trials to compare cabergoline versus bromocriptine in the treatment of patients with idiopathic hyperprolactinemia and prolactinomas. The data sources were: Embase, Pubmed, Lilacs and Cochrane Central. The outcome measures were: normalization of prolactin secretion, restoration of gonadal function, reduction of tumoral volume, quality of life and adverse drug effects. Were identified 418 references and after screening by title and abstract, we obtained complete copies of 34 articles potentially eligible for inclusion in the review. From this total, 19 were selected to be included, but fifteen of them were excluded due to the following reasons: one randomized study compared cabergoline versus placebo and other randomized study compared different doses of cabergoline; five references were cases series; four were only controlled studies; three were retrospectives series and; one was a cohort study. Therefore, four publications were included in the review and in the final analysis. The meta-analysis of normalization of serum prolactin levels and menstruation with return of ovulatory cycle showed a significant difference in favor of cabergoline group (RR 0.67 [CI 95% 0.57, 0.80]) e (RR 0.74 [CI 95% 0.67, 0.83]), respectively. The number of adverse effects was significantly higher in the bromocriptine number than in cabergoline group (RR 1.43 [CI 95% 1.03, 1.98]). The meta-analysis showed new evidence favoring the use of cabergoline in comparison with bromocriptine for the treatment of prolactinomas and idiopathic hyperprolactinemia.

Medical treatment of prolactinomas

Prolactinomas, the most prevalent type of neuroendocrine disease, account for approximately 40% of all pituitary adenomas. The most important clinical problems associated with prolactinomas are hypogonadism, infertility and hyposexuality. In patients with macroprolactinomas, mass effects, including visual field defects, headaches and neurological disturbances, can also occur. The objectives of therapy are normalization of prolactin levels, to restore eugonadism, and reduction of tumor mass, both of which can be achieved in the majority of patients by treatment with dopamine agonists. Given their association with minimal morbidity, these drugs currently represent the mainstay of treatment for prolactinomas. Novel data indicate that these agents can be successfully withdrawn in a subset of patients after normalization of prolactin levels and tumor disappearance, which suggests the possibility that medical therapy may not be required throughout life. Nevertheless, multimodal therapy that involves surgery, radiotherapy or both may be necessary in some cases, such as patients who are resistant to the effects of dopamine agonists or for those with atypical prolactinomas. This Review reports on efficacy and safety of pharmacotherapy in patients with prolactinomas.

Long-term control of macroprolactinomas

Hyperprolactinemia is the most prevalent hypothalamic-pituitary dysfunction, with prolactinomas being its main cause. Microprolactinomas (diameter < 10 mm) represent approximately 60% of the prolactin-secreting adenomas, and are far more common in women than in men, whereas macroadenomas have roughly the same prevalence in both genders. The treatment of patients harboring macroprolactinomas is highly gratifying, with more than 80% of them adequately controlled by dopamine-agonist (DA) drugs: cabergoline being the most efficacious to date. Emerging evidence points to remission of the disease after long-term DA therapy in a significant number of patients. The remaining cases, mainly those with enclosed tumors, may be treated successfully by pituitary surgery. Radiotherapy is reserved for cases with dopaminergic drug resistance not surgically cured. The development of new therapeutic approaches may turn the control of the subset of macroprolactinomas refractory to both DA and surgery into reality.

Remarkable effects of cabergoline in a patient with huge prolactinoma resistant to high-dose bromocriptine: case report

BACKGROUND

Cabergoline (CAB) has been proposed as the first-line treatment in the management of prolactin (PRL)-secreting tumors (prolactinoma [PRLoma]), including those resistant to standard dopamine agonist (DAA) therapy. The authors report remarkable effects of CAB in a case of huge PRLoma that had been resistant to a long-term, high-dose treatment with bromocriptine (BRC).

CASE DESCRIPTION

A 28-year-old man was originally presented with oculomotor paresis when he was 9 years old. After 2 partial resections, he was treated with a maximum 60-mg/d dose of BRC for 18 years. Nonetheless, the tumor grew up to more than 8 cm in diameter, serum PRL increased over 60000 ng/mL, and his visual acuity deteriorated. Cabergoline normalized serum PRL level, shrank the tumor mass remarkably, and caused marked improvement of visual acuity.

CONCLUSION

Prolactin normalization and significant tumor shrinkage could be achieved with CAB even in extremely BRC-resistant PRLomas. Surgical resection should be reserved only for patients who are resistant to cabergoline or who require urgent decompression in such emergency as massive intratumoral hemorrhage.

[Male infertility: management strategies]

Although the objective of the urologist is to correct the factors of male infertility and to favour natural procreation, the strategy must consider also the couple and the female aspects of infertility. Some types of male infertility require specific treatment. In severe cases, recent advances in medical assistance to procreation have changed the prognosis of male infertility. Pregnancy can be obtained by the means of gamet manipulation and spermatozoid selection. Nevertheless, such techniques expose to genetic disorders transmission. Subsequently, genetic assessment is required during male infertility management, especially for difficult cases.

Management of resistant prolactinomas

Resistance to dopamine agonists occurs in a subset of patients with prolactin-secreting pituitary tumors. The resistance is mediated by loss of pituitary D2 receptors and occurs in both microadenomas and macroadenomas. Cabergoline is the most effective dopamine agonist and tumors that do not respond to bromocriptine or quinagolide frequently respond to cabergoline. Treatment options include maximizing the dose of the dopamine agonist, changing agonists, trans-sphenoidal surgery and radiation therapy. The goal of therapy is to restore and maintain gonadal and neurologic function, and this might occur in the absence of a normal prolactin level or a significant change in tumor size. Trans-sphenoidal pituitary surgery should be reserved for patients who are intolerant of medical therapy, or in whom this has failed. Radiation therapy has a limited role in treatment of resistant prolactinomas and should be reserved for patients in whom medical and surgical therapy has failed.

Low-dose dopamine agonist administration blocks vascular endothelial growth factor (VEGF)-mediated vascular hyperpermeability without altering VEGF receptor 2-dependent luteal angiogenesis in a rat ovarian hyperstimulation model

No specific treatment is available for ovarian hyperstimulation syndrome (OHSS), the most important complication in infertile women treated with gonadotropins. OHSS is caused by increased vascular permeability (VP) through ovarian hypersecretion of vascular endothelial growth factor (VEGF)-activating VEGF receptor 2 (VEGFR-2). We previously demonstrated in an OHSS rodent model that increased VP was prevented by inactivating VEGFR-2 with a receptor antagonist (SU5416). However, due to its toxicity (thromboembolism) and disruption of VEGFR-2-dependent angiogenic processes critical for pregnancy, this kind of compound cannot be used clinically to prevent OHSS. Dopamine receptor 2 (Dp-r2) agonists, used in the treatment of human hyperprolactinemia including pregnancy, inhibit VEGFR-2-dependent VP and angiogenesis when administered at high doses in animal cancer models. To test whether VEGFR-2-dependent VP and angiogenesis could be segregated in a dose-dependent fashion with the Dp-r2 agonist cabergoline, a well-established OHSS rat model supplemented with prolactin was used. A 100 microg/kg low-dose Dp-r2 agonist cabergoline reversed VEGFR-2-dependent VP without affecting luteal angiogenesis through partial inhibition of ovarian VEGFR-2 phosphorylation levels. No luteolytic effects (serum progesterone levels and luteal apoptosis unaffected) were observed. Cabergoline administration also did not affect VEGF/VEGFR-2 ovarian mRNA levels. Results in the animal model and the safe clinical profile of Dp-r2 agonists encouraged us to administer cabergoline to oocyte donors at high risk for developing the syndrome. Prophylactic administration of cabergoline (5-10 microg/kg x d) decreased the occurrence of OHSS from 65% (controls) to 25% (treatment). Therefore, a specific, safe treatment for OHSS is now available.

Long-term remission following withdrawal of dopamine agonist therapy in subjects with microprolactinomas

OBJECTIVE

Reports suggest that up to 70% of patients with microprolactinomas treated with dopamine agonist therapy may achieve long-term normoprolactinaemic remission following drug withdrawal. Yet, there is no consensus on the duration of therapy nor is therapeutic interruption universally practised. We have assessed remission rates in a large cohort of treatment-naive subjects with microprolactinomas. Subjects received dopamine agonist (DA) therapy with either cabergoline or bromocriptine for a period of 2 to 3 years in the majority of cases, followed by a trial of treatment withdrawal.

DESIGN

Retrospective analysis of clinic records of 89 patients (mean age 32.7 +/- 8.4 years, 84 women and 5 men) who had received either cabergoline (n = 67) (0.5-3 mg weekly) or bromocriptine (n = 22) (2.5-10 mg daily) for a mean duration of 3.1 years.

RESULTS

Following withdrawal of therapy, 57 subjects developed recurrence (64%) and the mean time to recurrence was 9.6 months (range 1-44 months), while 32 subjects (36%) remained in remission beyond 1 year (mean 3.6 years, range 1-7 years). There was no difference in remission rates between subjects treated with cabergoline (n = 21) and bromocriptine (n = 11), but a direct relationship between pretreatment prolactin concentration and risk of recurrent symptomatic hyperprolactinaemia was observed. No subjects developed clinical features to suggest tumour expansion following therapeutic discontinuation.

CONCLUSIONS

This study confirms that abrupt withdrawal of chronic dopamine agonist therapy, following 2 to 3 years of treatment is safe and associated with long-term remission in 30-40% of subjects with microprolactinomas. This therapeutic strategy is convenient and applicable in clinical practice.

Pharmacologic resistance in prolactinoma patients

Pharmacologic resistance to dopamine agonists is defined here as failure to normalize PRL levels and failure to decrease macroprolactinoma size by >or=50%. Failure to normalize PRL levels is found in about one-quarter of patients treated with bromocriptine and 10-15% of those treated with pergolide or cabergoline. Failure to achieve at least a 50% reduction in tumor size occurs in about one-third of those treated with bromocriptine and 10-15% of those treated with pergolide or cabergoline. The cause of dopamine resistance is primarily a decrease in D(2) receptors but the receptors have normal affinity for dopamine. Treatment approaches for patients resistant to dopamine agonists include changing to another dopamine agonist and increasing the dose of the drug as long as there is continued response to the dose increases and no adverse effects with higher doses. Transsphenoidal surgery is also an option. Clomiphene, gonadotropins, and GnRH can be used if fertility is desired. For those not desiring fertility, estrogen replacement may be used unless there is a macroadenoma, in which case control of tumor growth is also an issue and dopamine agonists are generally necessary. In many patients modest or even no reduction in tumor size may be acceptable as long as there is not tumor growth. Hormone replacement (estrogen or testosterone) may cause a decrease in efficacy of the dopamine agonist so that it must be carried out cautiously. Reduction of endogenous estrogen, use of selective estrogen receptor modulators, and aromatase inhibitors are potential experimental approaches.

Endocrine causes of male infertility

Although endocrinopathies are not often seen in infertile men, these disorders are clinically significant; they often have potentially serious medical significance, regardless of fertility issues. Correction of these disorders represents a possible way to restore normal fertility for the male partner. Male fertility is critically dependent upon a normal hormonal milieu. The hypothalamic-pituitary-gonadal axis is quite sensitive to disruption by endocrine disorders and other generalized medical disorders. Thus, male infertility is occasionally the presenting sign for significant underlying medical disease; it is important to properly evaluate these patients.

Dopamine resistance of prolactinomas

Resistance to dopamine agonists can be defined with respect to failure to normalize PRL levels and failure to decrease tumor size by > or = 50%. Using these definitions, failure to normalize PRL levels is seen in 24% of those treated with bromocriptine, 13% of those treated with pergolide and 11% of those treated with cabergoline. Failure to achieve at least a 50% reduction in tumor size occurs in about one-third of those treated with bromocriptine and 10-15% of those treated with pergolide or cabergoline. Studies of in vitro cell preparations show that the D2 receptors of resistant tumors are decreased in number but have normal affinity. Treatment approaches for resistant patients include switching to another dopamine agonist and raising the dose of the drug as long as there is continued response to the dose increases and no adverse effects. Transsphenoidal surgery can also be done. If fertility is desired, clomiphene, gonadotropins, and GnRH are also options. If fertility is not desired, estrogen replacement may be used unless there is a macroadenoma, in which case control of tumor growth is also an issue and dopamine agonists are generally necessary. However, in many cases modest or even no reduction may be acceptable long-term as long as there is not tumor growth. Hormone replacement (estrogen or testosterone) may cause a decrease in efficacy of the dopamine agonist so that it must be carried out cautiously. Reduction of endogenous estrogen, use of selective estrogen receptor modulators, and aromatase inhibitors are potential experimental approaches.