The natural history of untreated hyperprolactinemia: a prospective analysis

Factors determining the remission of microprolactinomas after dopamine agonist withdrawal

BACKGROUND

Withdrawal of dopamine agonist (DA) therapy in the management of microprolactinoma is common practice, but it is unclear which patients are likely to attain long-term remission.

OBJECTIVE

To identify predictive factors for long-term remission.

DESIGN

Prospective cohort study.

PATIENTS

Forty subjects (39 female, aged 24-60 years) with microprolactinoma; all had been normoprolactinaemic on DA therapy for at least 2 years [mean duration of therapy 9 years (range 2-27)].

MEASUREMENTS

A pituitary magnetic resonance imaging (MRI) was performed on 36 (90%) subjects before DA withdrawal. Relapse was defined as prolactin greater than 480 mIU/l (22.8 microg/l) on two occasions.

RESULTS

Nine out of 40 (22.5%) subjects were normoprolactinaemic 12 months after DA withdrawal. Amongst the relapse group, 24 of 31 subjects (79.4%) had already relapsed at 3 months. Normalization of MRI prior to DA withdrawal (P = 0.0006) and longer duration of DA treatment (P = 0.032) were significant predictors of remission. Age, pre-treatment prolactin, nadir prolactin, previous failure of DA withdrawal, pregnancy, dose and type of DA were not significant predictors of remission. The nine patients who were in remission at 12 months were then followed up for 58.0 +/- 5.8 months; all remained in remission.

CONCLUSIONS

As many as 22.5% of subjects with microprolactinoma remained normoprolactinaemic 12 months after DA withdrawal and these subjects stayed in remission for up to 5 years. Significant predictive factors were normalization of MRI prior to discontinuation, and duration of DA treatment. Our findings support intermittent DA withdrawal after a period of normoprolactinaemia, particularly where MRI appearances have normalized.

Pituitary tumours: the prolactinoma

This review focus on the epidemiology, diagnosis and treatment of prolactinomas. In particular, attention was given to recent data showing a high prevalence of these tumours in the general population, 3-5 times higher than previously reported. The diagnosis of hyperprolactinaemia has been simplified in recent years, and only prolactin (PRL) assay and magnetic resonance imaging of the sella are required. Nonetheless, macroprolactinaemia should be assessed in patients with hyperprolactinaemia in the absence of clinical symptoms of elevated PRL levels. The recent evidence that medical therapy with dopamine agonists should be continued lifelong has been confirmed by several studied. The patients achieving disappearance of the tumours and suppression of PRL levels during treatment are those showing the highest likelihood to have persistent remission of hyperprolactinaemia after treatment withdrawal.

Characterization of resistance to the prolactin-lowering effects of cabergoline in macroprolactinomas: a study in 122 patients

CONTEXT

Macroprolactinomas poorly responsive to dopamine-agonists are often more aggressive and are usually termed 'resistant' but this clinical concept has always been defined empirically.

OBJECTIVE

To define resistance to cabergoline (CAB) on the basis of a dose-response relationship established in a large series of macroprolactinoma patients and to assess the influence of gender and tumor invasiveness on the response to treatment.

DESIGN

Retrospective study.

METHODS

One hundred and twenty-two patients (72 women and 50 men) primarily treated with CAB for at least 1 year were included. Main outcome measures were serum prolactin (PRL) and tumor size.

RESULTS

Normalization of PRL was obtained in 115 out of the 122 patients (94%). The majority of patients (96/115, 83%) were controlled with a CAB dose < or =1.5 mg/week. Most of the other patients (19/26) had only a partial resistance, responding to a further increase of the CAB dose. Beyond the dose of 3.5 mg/week, there was no clear advantage in further increasing the dose instead of continuing the treatment at the same dose. Most tumors (98/119 assessable cases, 82%) showed a significant shrinkage during CAB treatment. It was more likely to occur in cases of PRL normalization. Both cavernous sinus invasion and male gender were significantly and independently associated with partial or complete resistance to treatment.

CONCLUSIONS

Most macroprolactinomas primarily treated with CAB are adequately controlled with doses < or =1.5 mg/week. About 20% of patients, mainly men and/or those with invasive tumors will require a higher dose of CAB. We suggest defining such patients as resistant to CAB.

Current evaluation of amenorrhea

Amenorrhea is absence or abnormal cessation of the menses. Primary and secondary amenorrhea describe the occurrence of amenorrhea before and after menarche, respectively.

Hyperprolactinaemia

Hyperprolactinaemia is a frequent cause of reproductive problems encountered in clinical practice. A variety of pathophysiological conditions can lead to hyperprolactinaemia; therefore, pregnancy, drug effects, hypothyroidism and polycystic ovary syndrome should be excluded before investigating for prolactin-secreting pituitary tumours. Prolactinomas are mainly diagnosed in women aged 20-40 years. They present with clinical features of hyperprolactinaemia (galactorrhoea, gonadal dysfunction), and more rarely with large tumours, headache and visual field loss due to optic chiasm compression. Medical therapy with dopamine agonists is the treatment of choice for both micro- and macroprolactinomas. Tumour shrinkage and restoration of gonadal function are achieved in the majority of cases with dopamine agonists. A trial of withdrawal of medical therapy may be considered in many patients with close follow-up. Pituitary surgery and radiotherapy currently have very limited indications. Pregnancies in patients with prolactinomas need careful planning and close monitoring.

Medical causes and consequences of hyperprolactinaemia. A context for psychiatrists

Hyperprolactinaemia is the commonest endocrine disorder of the hypothalamic-pituitary axis and can lead to both short-term sexual dysfunction and galactorrhoea, and long-term loss of bone mineral density. Prolactin is secreted from the anterior pituitary gland under the influence of dopamine, which exerts a tonic inhibitory effect on prolactin secretion. Physiological regulators of prolactin secretion include many different types of 'stress' and sleep. Disruption of the normal control of prolactin secretion results in hyperprolactinaemia from pathological and pharmacological causes. The administration of antipsychotic medication is responsible for the high prevalence of hyperprolactinaemia in people with severe mental illness. Physiological hyperprolactinaemia, such as pregnancy and lactation, should be distinguished from pathological causes to prevent unnecessary investigation and treatment. The causes, consequences and management of hyperprolactinaemia are discussed in this article.

Hyperprolactinemia and prolactinomas

Any process interfering with dopamine synthesis, its transport to the pituitary gland, or its action at the level of lactotroph dopamine receptors can cause hyperprolactinemia. As described in this article, considering the complexity of prolactin regulation, many factors could cause hyperprolactinemia, and hyperprolactinemia can have clinical effects not only on the reproductive axis. Once any drug effects are excluded, prolactinomas are the most common cause of hyperprolactinemia. The most frequent symptom is hypogonadism in both genders. Medical and surgical therapies generally have excellent results, and most prolactinomas are well controlled or even cured in some cases.

Hyperprolactinemia

In several respects prolactin is unique among anterior pituitary hormones. The primary regulation of prolactin secretion is mediated through hypothalamic inhibition, and the diagnosis of hyperprolactinemia can be established without the use of stimulation or suppression tests. Documenting the presence of hyperprolactinemia is not difficult-the challenge is in identifying the cause of the hormone hypersecretion. With immunoradiometric assays falsely low levels of prolactin are occasionally seen in patients with macroadenomas and very high serum prolactin (the hook effect). Macroprolactin should be suspected when a patient with hyperprolactinemia does not present with typical clinical symptoms, and all hyperprolactinemic sera should be screened for macroprolactin. With prolactinomas, prolactin levels generally parallel tumor size. Prolactin secreting macroadenomas are typically associated with levels that exceed 250 microg/l and may exceed 1,000 microg/l. Large non-functioning adenomas also lead to hyperprolactinemia but levels virtually never exceed 94 microg/l. Acquired and isolated prolactin deficiency is rare.

Predictors of remission of hyperprolactinaemia after long-term withdrawal of cabergoline therapy

BACKGROUND

Remission rates of 76, 69.5 and 64.3% have been reported in patients with nontumoural hyperprolactinaemia (NTH), microprolactinoma and macroprolactinoma, respectively, 2-5 years after cabergoline (CAB) withdrawal.

OBJECTIVE

To report the estimated recurrence rate at 24-96 months after CAB withdrawal and indicate predictors of disease remission.

DESIGN

Observational, analytical, prospective.

PATIENTS

Of 381 previously untreated de novo patients with hyperprolactinaemia, 221 (58%) (173 women, 48 men; 27 with NTH, 115 with micro-, and 79 with macroprolactinoma) were studied.

MEASUREMENTS

Using multiple regression analysis the diagnostic accuracy of nadir PRL levels (t = 7.6, P < 0.0001) and nadir maximal tumour diameter at CAB withdrawal (t = 3.9, P < 0.001) was analysed using receiver operating characteristic (ROC) curves.

RESULTS

The recurrence of hyperprolactinaemia was 25.9, 33.9 and 53.1% in patients with NTH, micro- or macroprolactinoma, respectively. To predict the last PRL level after withdrawal, the optimum cut-off of nadir PRL levels at withdrawal was 162 mU/l (5.4 microg/l) [sensitivity (95% CI) 76% (67-84%), specificity 65% (51-77%)] and that of nadir maximal tumour diameter was 3.1 mm [sensitivity 52% (41-63%), specificity 86% (79-91%)]. The patients achieving both nadir PRL levels </= 162 mU/l and maximal tumour diameter </= 3.1 mm (n = 111) at CAB withdrawal had a significantly lower Kaplan-Meier estimate of recurrence of hyperprolactinaemia (20%) at 24-96 months than those who did not fulfil any of these criteria [(n = 38) 90%; P < 0.0001]. Patients achieving nadir PRL levels </= 162 mU/l (n = 26) or maximal tumour diameter </= 3.1 mm during CAB treatment (n = 46) had an estimated recurrence rate of hyperprolactinaemia of 50 and 56%, respectively.

CONCLUSION

Persistent remission of hyperprolactinaemia without any evidence of tumour re-growth after 24-96 months of CAB withdrawal occurred in the majority of patients with NTH and microprolactinoma and in about half of those with macroprolactinoma. Nadir PRL levels and maximal tumour diameter at CAB withdrawal of </= 162 mU/l and </= 3.1 mm predicted remission of hyperprolactinaemia in 80% of patients.

Long-term management of prolactinomas

Prolactinomas are a frequent cause of gonadal dysfunction and infertility, especially in young women. The regulation of prolactin secretion and the efficacy of dopamine agonists in the therapy of prolactinomas are well established. The current challenges in management of prolactinomas are related to follow-up after successful therapy. Issues and questions to be addressed in this approach to long-term management of prolactinomas include the frequency of radiographic monitoring, effect of pregnancy and menopause, safety of estrogen in women taking oral contraceptives, and the potential for discontinuation of dopamine agonist therapy.

Current evaluation of amenorrhea

Amenorrhea is the absence or abnormal cessation of the menses. Primary and secondary amenorrhea describe the occurrence of amenorrhea before and after menarche, respectively.

[Treatment of pituitary gland hyperfunction: from acromegaly to prolactinoma]

Evidence based drug therapy is currently available for the treatment of prolactinomas and growth hormone secreting adenomas (acromegaly). Dopamine agonists such as bromocriptine, quinagolide or cabergoline represent the standard therapy for the treatment of micro- and macro-prolaktinomas. In pregnancy, more differentiated, individual and patient-adapted therapeutic procedures have to be considered. Transsphenoidal adenomectomy is the treatment of choice for patients suffering from acromegaly. If biochemical cure (defined by normalized IGF-1 serum levels or by a GH nadir <1 microg/l during a 3-h oral glucose tolerance test) cannot be achieved, somatostatin analogues such as octreotide and lanreotide are effective. In some cases, dopamine agonists can be added. In therapy-resistant cases, growth hormone receptor antagonists can be used.

Advances in the treatment of prolactinomas

Prolactinomas account for approximately 40% of all pituitary adenomas and are an important cause of hypogonadism and infertility. The ultimate goal of therapy for prolactinomas is restoration or achievement of eugonadism through the normalization of hyperprolactinemia and control of tumor mass. Medical therapy with dopamine agonists is highly effective in the majority of cases and represents the mainstay of therapy. Recent data indicating successful withdrawal of these agents in a subset of patients challenge the previously held concept that medical therapy is a lifelong requirement. Complicated situations, such as those encountered in resistance to dopamine agonists, pregnancy, and giant or malignant prolactinomas, may require multimodal therapy involving surgery, radiotherapy, or both. Progress in elucidating the mechanisms underlying the pathogenesis of prolactinomas may enable future development of novel molecular therapies for treatment-resistant cases. This review provides a critical analysis of the efficacy and safety of the various modes of therapy available for the treatment of patients with prolactinomas with an emphasis on challenging situations, a discussion of the data regarding withdrawal of medical therapy, and a foreshadowing of novel approaches to therapy that may become available in the future.

Guidelines of the Pituitary Society for the diagnosis and management of prolactinomas

In June 2005, an ad hoc Expert Committee formed by the Pituitary Society convened during the 9th International Pituitary Congress in San Diego, California. Members of this committee consisted of invited international experts in the field, and included endocrinologists and neurosurgeons with recognized expertise in the management of prolactinomas. Discussions were held that included all interested participants to the Congress and resulted in formulation of these guidelines, which represent the current recommendations on the diagnosis and management of prolactinomas based upon comprehensive analysis and synthesis of all available data.

Development of a macroprolactinoma in association with hormone replacement therapy in a perimenopausal woman with presumed idiopathic hyperprolactinemia

OBJECTIVE

To describe a 48-year-old woman with presumed idiopathic hyperprolactinemia, who was found to have a macroprolactinoma after receiving hormone replacement therapy for almost 3 years.

METHODS

We present a detailed case report, including a chronologic summary of clinical and laboratory findings as well as the drug history of our patient. The related literature is also reviewed.

RESULTS

Premenopausal women with idiopathic hyperprolactinemia or microprolactinomas (<1 cm) are treated with dopamine agonists if fertility is desired or galactorrhea is bothersome. Otherwise, estrogens and progestational agents may be prescribed to regularize menses and prevent osteoporosis. Several case reports of prolactinoma formation or enlargement after exposure to exogenous estrogens have been published. In our patient, a perimenopausal woman with presumably idiopathic long-standing hyperprolactinemia, a macroprolactinoma developed within 3 years after initiation of hormone replacement therapy for management of perimenopausal symptoms. The only clue for ordering a pituitary imaging study in this case was a substantial increase in the level of the serum prolactin. Treatment with cabergoline normalized the patient's serum prolactin level and considerably decreased the size of her pituitary adenoma.

CONCLUSION

It is postulated that exogenous estrogens could have an important role in tumor development or growth in some patients with idiopathic hyperprolactinemia. Therefore, it is recommended that women with idiopathic hyperprolactinemia or microprolactinomas treated with estrogens be considered for concomitant therapy with dopamine agonists. In all cases, serum prolactin levels should be diligently monitored.

The effect of MR contrast medium dose on pituitary gland enhancement, microlesion enhancement and pituitary gland-to-lesion contrast conspicuity

INTRODUCTION

The purpose of this study was to compare the differences in gland enhancement, microlesion enhancement and gland-lesion contrast ratio in patient groups in which half-dose (HD), standard-dose (SD) and double-dose (DD) contrast medium was used in pituitary MR imaging.

METHODS

Pituitary gland enhancement and microlesion enhancement were measured and gland-lesion contrast ratios were calculated in 18 patients receiving HD (0.05 mmol/kg), 9 receiving SD (0.1 mmol/kg) and 13 receiving DD (0.2 mmol/kg) contrast medium. Gland enhancement and microlesion enhancement over baseline were determined employing DICOM region of interest measurements and compared after normalization to temporal lobe white matter. Contrast ratios and differences were also calculated and compared.

RESULTS

Gland enhancement and lesion enhancement were greater with larger contrast medium doses (gland: HD 50%, SD 99%, DD 132%; microlesion: HD 19%, SD 54%, DD 86%). The gland-lesion contrast ratios were similar with the three doses (25.6%), reflecting expected similar fractional contrast medium distributions in spite of different doses. The signal difference between gland and microlesion, therefore, was a fixed percentage of gland enhancement (DeltaS approximately 26%) with greater signal differences with larger contrast medium doses.

CONCLUSION

Greater gland-to-lesion signal differences with larger contrast medium doses would likely improve pituitary microlesion visualization and margin characterization aiding in microlesion detection as well as preoperative planning.

Current treatment issues in female hyperprolactinaemia

High prolactin levels can occur as a physiological condition in females who are pregnant or lactating. As a pathological condition, hyperprolactinaemia is associated with gonadal dysfunction, infertility and an increased risk of long-term complications including osteoporosis. The most frequent cause of persistent hyperprolactinaemia is the presence of a micro- (<10mm diameter) or macroprolactinoma (>/=10mm). These pituitary tumours may produce an excessive amount of prolactin or disrupt the normal delivery of dopamine from the hypothalamus to the pituitary; prolactin secretion from the pituitary is inhibited by dopamine released from neurones in the hypothalamus. Medications including anti-psychotics can induce hyperprolactinaemia, while idiopathic hyperprolactinaemia accounts for 30-40% of cases. The prevalence of hyperprolactinaemia is difficult to establish as not all sufferers are symptomatic or concerned by their symptoms and may remain undiagnosed. Symptoms of hyperprolactinaemia include signs of hypogonadism, with oligomenorrhoea, amenorrhoea and galactorrhoea frequently observed. Pharmacological intervention should be considered the first line therapy and involves the use of dopamine agonists to reduce tumour size and prolactin levels. Bromocriptine has the longest history of use and is a well-established, inexpensive, safe and effective therapy option. However, bromocriptine requires multiple daily dosing and some patients are resistant or intolerant to this therapy. The two newer dopamine agonists, quinagolide and cabergoline, provide more effective and better tolerated treatments compared with bromocriptine and may offer effective therapies for bromocriptine-resistant or intolerant patients. Quinagolide can be used until pregnancy is confirmed and may result in improved compliance in females wishing to become pregnant. For patients with hyperprolactinaemia, pregnancy is safe and can frequently be beneficial, inducing a decrease in prolactin levels. There does not appear to be any increased risk of abortion, malformations or multiple births in pregnancies achieved with bromocriptine and this dopamine agonist can be used safely during pregnancy. Surgery should be considered only in certain circumstances, and for the majority of patients, dopamine agonists will be sufficient to alleviate symptoms and restore normal prolactin levels.

Drug Insight: cabergoline and bromocriptine in the treatment of hyperprolactinemia in men and women

Prolactinoma is the most frequent pituitary tumor histotype. Men generally have macroadenomas whereas women generally have microadenomas. The major objectives of treating prolactinomas are to suppress excessive hormone secretion and its clinical consequences, to remove the tumor mass while preserving the residual pituitary function, and possibly to prevent disease recurrence or progression. Primary therapy of prolactinomas is based on use of dopamine-receptor agonists. Bromocriptine induces normalization of prolactin levels in 80-90% of patients with microprolactinomas and approximately 70% of those with macroprolactinomas. Tumor-mass shrinkage and improvement of visual-field defects are found in the majority of treated macroprolactinomas, but bromocriptine often causes side effects. Cabergoline is very effective and well tolerated in more than 90% of patients with either microprolactinomas or macroprolactinomas. Cabergoline treatment also induces tumor shrinkage in the majority of patients with macroprolactinomas. Tumor shrinkage is more evident if patients have not previously been treated with other dopamine agonists. Fewer results are available for men than for women, but there is no evidence that men are less responsive to dopamine agonists than are women.

Hyperprolactinaemia in 271 women: up to three decades of clinical follow-up

OBJECTIVE

To characterize women with hyperprolactinaemia at diagnosis and to assess the effect of treatment after long duration of the disease.

DESIGN

Retrospective chart review.

PATIENTS AND MEASUREMENTS

Two hundred and seventy-one women with hyperprolactinaemia at the Karolinska University Hospital, Stockholm, Sweden between 1974 and 2002 were evaluated retrospectively. Criterion for inclusion was elevated S-PRL (> or = 20 microg/l) found on at least two occasions. Secondary hyperprolactinaemia was excluded. The patients were followed for a median time period of 111 (6-348) months. Two hundred and forty patients were treated with dopamine agonists, 17 underwent surgery, seven received radiotherapy and seven were followed without treatment.

RESULTS

Mean age at diagnosis was 31 (+/- 9.5) years and median PRL level was 72 (25-3500) microg/l. Menstrual disturbances were present in 87% of the women of reproductive age and 47% had galactorrhoea. Microadenomas were found in 63%, macroadenomas in 8% and idiopathic hyperprolactinaemia in 29%. Patients with menstrual disturbances had higher PRL levels than women with normal menstrual function (P < 0.001). We found no differences in PRL levels between patients with or without galactorrhoea (P = 0.578). At the end of clinical follow-up, menstrual cycle was normalized in 94% and galactorrhoea disappeared in 94%. In the medically treated patients, median PRL levels decreased from 70 (25-3100) to 13 (0-89) microg/l, (P < 0.0001). Normalization of PRL level was achieved in 71% of the patients and 80% showed a total or partial degree of tumour shrinkage. In the surgically treated patients, 53% had normal PRL levels without medication at follow-up.

CONCLUSION

Medical treatment was effective in correcting hypogonadism, normalizing PRL levels and reducing tumour size in the majority of the patients after short-term treatment and also in the long run. However, the possibility of transsphenoidal surgery in specific cases must be considered.

Quand et comment traiter une hyperprolactinémie ?

Hyperprolactinemia affects the gonadotropic axis. Its results in women include amenorrhea, menstrual disorders and galactorrhea; in men, the frequency of macroadenomas tends to lead to problems related to sexual performance or tumor volume. Radioimmunoassays make diagnosis easy. Secondary causes of hyperprolactinemia, drug reactions in particular, must be ruled out before MRI exploration to look for a pituitary tumor. First-line treatment of prolactin adenomas is based on the use of dopaminergic agonists, especially cabergoline, because of their excellent efficacy and the risk of relapse following surgery. For patients who wish to become pregnant, the dopaminergic agonist must be continued during pregnancy for those with macroadenoma and withdrawn for women with microadenoma. When hyperprolactinemia is induced by anti-psychotic agents, treatment requires an in-depth assessment.

Current evaluation of amenorrhea

Amenorrhea is the absence or abnormal cessation of the menses. Primary and secondary amenorrhea describe the occurrence of amenorrhea before and after menarche, respectively.

Current evaluation of amenorrhea

Amenorrhea is the absence or abnormal cessation of the menses. Primary and secondary amenorrhea describe the occurrence of amenorrhea before and after menarche, respectively.

From galactorrhea to osteopenia: rethinking serotonin-prolactin interactions

The widespread use of the selective serotonin reuptake inhibitors (SSRIs) has been accompanied by numerous reports describing a potential association with hyperprolactinemia. Antipsychotics are commonly known to elevate serum prolactin (PRL) through blockade of dopamine receptors in the pituitary. However, there is little awareness of the mechanisms by which SSRIs stimulate PRL release. Hyperprolactinemia may result in overt symptoms such as galactorrhea, which may be accompanied by impaired fertility. Long-term clinical sequelae include decreased bone density and the possibility of an increased risk of breast cancer. Through literature review, we explore the possible pathways involved in serotonin-induced PRL release. While the classic mechanism of antipsychotic-induced hyperprolactinemia directly involves dopamine cells in the tuberoinfundibular pathway, SSRIs may act on this system indirectly through GABAergic neurons. Alternate pathways involve serotonin stimulation of vasoactive intestinal peptide (VIP) and oxytocin (OT) release. We conclude with a comprehensive review of clinical sequelae associated with hyperprolactinemia, and the potential role of SSRIs in this phenomenon.

Withdrawal of long-term cabergoline therapy for tumoral and nontumoral hyperprolactinemia

BACKGROUND

Whether the withdrawal of treatment in patients with nontumoral hyperprolactinemia, microprolactinomas, or macroprolactinomas is safe and effective has been unclear. We performed an observational, prospective study of cabergoline (a dopamine-receptor agonist) withdrawal in such patients.

METHODS

The study population included 200 patients--25 patients with nontumoral hyperprolactinemia, 105 with microprolactinomas, and 70 with macroprolactinomas. Withdrawal of cabergoline was considered if prolactin levels were normal, magnetic resonance imaging (MRI) showed no tumor (or tumor reduction of 50 percent or more, with the tumor at a distance of more than 5 mm from the optic chiasm, and no invasion of the cavernous sinuses or other critical areas), and if follow-up after withdrawal could be continued for at least 24 months.

RESULTS

Recurrence rates two to five years after the withdrawal of cabergoline were 24 percent in patients with nontumoral hyperprolactinemia, 31 percent in patients with microprolactinomas, and 36 percent in patients; with macroprolactinomas. Renewed tumor growth did not occur in any patient; in 10 female patients (22 percent) and 7 male patients (39 percent) with recurrent hyperprolactinemia, gonadal dysfunction redeveloped. In all diagnostic groups, prolactin levels at the time of recurrence were significantly lower than at diagnosis (P<0.001). The Kaplan-Meier estimated rate of recurrence at five years was higher among patients with macroprolactinomas and those with microprolactinomas who had small remnant tumors visible on MRI at the time of treatment withdrawal than among patients whose MRI scans showed no evidence of tumor at the time of withdrawal (patients with macroprolactinomas, 78 percent vs. 33 percent, P=0.001; patients with microprolactinomas, 42 percent vs. 26 percent, P=0.02).

CONCLUSIONS

Cabergoline can be safely withdrawn in patients with normalized prolactin levels and no evidence of tumor. However, because the length of follow-up in our study was insufficient to rule out a delayed increase in the size of the tumor, we suggest that patients be closely monitored, particularly those with macroprolactinomas, in whom renewed growth of the tumor may compromise vision.

Hyperprolactinemia: pathophysiology and management

Hyperprolactinemia is commonly found in both female and male patients with abnormal sexual and/or reproductive function or with galactorrhea. If serum prolactin levels are above 200 microg/L, a prolactin-secreting pituitary adenoma (prolactinoma) is the underlying cause, but if levels are lower, differential diagnoses include the intake of various drugs, compression of the pituitary stalk by other pathology, hypothyroidism, renal failure, cirrhosis, chest wall lesions, or idiopathic hyperprolactinemia. When a pituitary tumor is present, patients often have pressure symptoms in addition to endocrine dysfunction, such as headaches, visual field defects, or cranial nerve deficits. The large majority of patients with prolactinomas, both micro- and macroprolactinomas, can be successfully treated with dopaminergic drugs as first-line treatment, with normalization of prolactin secretion and gonadal function, and with significant tumor shrinkage in a high percentage of cases. Surgical resection of the prolactinoma is the option for patients who may refuse or do not respond to long-term pharmacological therapy. Radiotherapy and/or estrogens are also reasonable choices if surgery fails. In patients with asymptomatic microprolactinoma no treatment needs to be given and a regular follow-up with serial prolactin measurements and pituitary imaging should be organized. Currently, the most commonly used dopamine agonists are bromocriptine, pergolide, quinagolide and cabergoline. When comparing the plasma half-life, efficacy and tolerability of these drugs, cabergoline seems to have the most favorable profile, followed by quinagolide. Ifprolactin levels are well controlled with dopamine agonist therapy, gradual tapering of the dose to the lowest effective amount is recommended, and in a number of cases medication can be stopped after several years. Evidence to date suggests that cabergoline and quinagolide appear to have a good safety profile for women who wish to conceive, but hard evidence proving that dopamine agonists do not provoke congenital malformations when taken during early pregnancy is currently only available for bromocriptine. Once pregnant, dopamine agonist therapy should be immediately stopped, unless growth of a macroprolactinoma is likely or pressure symptoms occur. At our institution patients with symptomatic prolactinomas, both micro- and macroadenomas, are treated with cabergoline as the first-line aproach. In the small group of patients who do not respond to this treatment, or who refuse long-term therapy, surgery is offered. Radiotherapy is given if both pharmacologic therapy and surgery fail.

Predictive value of serum prolactin levels measured immediately after transsphenoidal surgery

OBJECT

Prolactin-secreting pituitary adenomas may be managed by surgery, medication, radiotherapy, or observation. The authors reviewed a consecutive series of patients who were followed for at least 5 years after surgery to assess the prognostic significance of preoperative factors (tumor size and prolactin level) and an immediate postoperative factor (prolactin level obtained the morning after surgery) on long-term hormonal outcome, thereby clarifying the indications for surgical removal of tumor, the definition of successful treatment outcomes, and the nature of "recurrent" tumors.

METHODS

Between 1979 and 1991, 241 patients with prolactinomas underwent transsphenoidal resection. Nineteen patients were lost to follow-up review, whereas the remaining 222 patients underwent measurement of their prolactin levels on postoperative Day 1 (POD 1), at 6 and 12 weeks, and every 6 months thereafter for a minimum of 5 years. On POD 1, prolactin levels in 133 patients (Group 1) were lower than 10 ng/ml, in 43 patients (Group 2) between 10 and 20 ng/ml, and in 46 patients (Group 3) higher than 20 ng/ml. At 6 and 12 weeks, normal prolactin levels (< or = 20 ng/ml) were measured in 132 (99%) of the 133 patients in Group 1 but only in 32 (74%) of the 43 patients in Group 2. By 5 years postoperatively, normal levels of prolactin were still measured in 130 patients (98%) in Group 1 compared with only five patients (12%) in Group 2. No patient with a prolactin level lower than 3 ng/ml on POD 1 was found to have an elevated hormone level at 5 years. The likelihood of a long-term chemical cure was greater for patients with microadenomas (91% cure rate) than for those with macroadenomas (33%). Preoperative prolactin levels also correlated with hormonal outcome.

CONCLUSIONS

Prolactin levels lower than 10 ng/ml on POD 1 predict a long-term chemical cure in patients with microadenomas (100% cure rate) and those with macroadenomas (93% cure rate). In contrast, a cure is not likely to be obtained in patients with normal levels ranging between 10 and 20 ng/ml on POD 1 if they harbor macroadenomas (0% cure rate). A recurrence reported several years after surgery probably represents the presence of persistent tumor that was not originally removed. If the initial operation was performed by an experienced surgeon, however, reoperation is not likely to yield a chemical cure.

Long-term follow-up of prolactinomas: normoprolactinemia after bromocriptine withdrawal

Bromocriptine (BRC) and other dopamine agonist drugs are the first-choice treatment for prolactinomas. However, the major disadvantage is the need for prolonged therapy. We retrospectively studied 131 patients [62 microprolactinoma (MIC), 69 macroprolactinoma (MAC)], who achieved serum prolactin (PRL) normalization during BRC use. Twenty-seven percent of them (31% MIC and 69% MAC) underwent previous surgery. Twenty-seven patients (20.6%: 25.8% MIC and 15.9% MAC) persisted with normoprolactinemia after a median time of 44 months of BRC withdrawal. The median time of BRC use was 47 months. There were no statistically significant differences regarding age, gender, BRC initial dose, length of BRC use, tumor size, pregnancy during treatment, previous surgery, or radiotherapy among patients who persisted with normoprolactinemia and those who did not, using both univariate and multivariate analysis. BRC-induced prolactinoma cell alterations are highly controversial; and so, whether the mechanism of PRL normalization after BRC withdrawal is related to BRC use or whether it is attributable to natural history is a matter for debate. A periodic assessment of PRL levels during BRC (and other dopamine-agonist drugs) withdrawal is recommended to avoid the unnecessary maintenance of therapy in a subset of patients with prolactinomas.

Medical management of prolactin-secreting pituitary adenomas

Prolactinomas are a common cause of reproductive/sexual dysfunction. Once other causes of hyperprolactinemia have been excluded with a careful history and physical examination, routine chemistries, a pregnancy test and a TSH, imaging with MRI or CT will delineate the size and extent of the tumor. Medical therapy is the initial treatment of choice. When infertility is the primary indication for treatment, bromocriptine use has an extensive safety experience and is preferred. However, for other indications, cabergoline appears to be more efficacious and better tolerated. Transsphenoidal surgery remains an option, especially for patients with microadenomas, when medical therapy is ineffective.

Current management of prolactinomas

Prolactinomas constitute the largest group of pituitary adenomas in autopsy series. However, their relative incidence in recent surgical series is much less impressive since medical treatment with dopamine agonists is routinely employed, which in many cases leads to tumor shrinkage and normalization of prolactin levels. The clinical symptoms of hyperprolactinemia are menstrual dysfunction and galactorrhea in women and loss of libido and potency in men. Prolactinomas may present also as space occupying sellar mass lesions impinging on the adjacent structures like the pituitary gland, cavernous sinus and optic nerves. The standard primary treatment is medical by dopamine agonists. Prolactinomas are the prototype of tumors, the growth of which can be reliably and safely inhibited by specific drugs other than cytostatic chemotherapy. These unfortunately have side effects, like orthostatic hypotension, nausea and vomiting. The effects induced by dopamine agonists are suppressive but not tumoricidal. Thus, the therapeutic effect is only maintained as long as the drug is administered. Consequently. in most cases, treatment has to be continued life-long with a few exceptions, in whom normoprolactinemia persists even after discontinuation of dopamine agonists. Main indications of surgery in prolactinomas are intolerance of the medication, and tumors not responding to dopamine agonists. Occasionally, these may ultimately require radiation therapy. Remission rates in large series of surgically treated prolactinomas vary between 54% and 86%. In our consecutive series of 540 surgically treated prolactinomas, the normalization rate after transsphenoidal surgery basically depended on the preoperative prolactin levels, tumor size and extension. The remission rate of 82% in microprolactinomas with initial prolactin levels <200 ng/ml would even in small adenomas make one consider surgical treatment as an interesting alternative to long-term medical treatment.

Disorders of prolactin secretion

Prolactinomas are a common cause of reproductive/sexual dysfunction. Once other causes of hyperprolactinemia have been excluded with a careful history and physical examination, routine chemistries, and an assay for TSH, MR imaging, or CT will delineate the size and extent of the tumor. Medical therapy is the initial treatment of choice. When infertility is the primary indication for treatment, bromocriptine use has an extensive safety record and is preferred. For other indications, cabergoline seems to be more efficacious and better tolerated. Transsphenoidal surgery remains an option, especially for patients with microadenomas, when medical therapy is ineffective.

Growth potential of female prolactinomas

BACKGROUND

The indications for treatment in female patients with small prolactinomas and mild or no symptoms are controversial. The aim of this study was to investigate whether we can predict the growth potential of a given small prolactinoma.

METHODS

The proliferation potential of 25 female prolactinomas and 5 prolactin-containing adenomas found incidentally at autopsy was determined immunohistochemically using the Ki-67 (MIB-1) antibody. The results were compared according to age, clinical and endocrine findings, and tumor volume.

RESULTS

Small prolactinomas (<1.0 cm(3)) with mild hyperprolactinemia (<150 ng/mL) showed significantly low proliferation potential irrespective of age, resembling prolactin-containing adenomas found at autopsy. The patients tended to present with mild symptoms and rarely had estrogen deficiency.

CONCLUSION

These findings indicate that female patients with a small prolactinoma, mild hyperprolactinemia, and no symptoms or those who do not desire fertility may have no specific reason for treatment, but can be followed by serum prolactin level and serial magnetic resonance imaging.

Long-term follow-up of 246 hyperprolactinemic patients

BACKGROUND

We wanted to evaluate the very long-term effects of bromocriptine on prolactin (PRL) levels and pituitary tumor size in a large cohort of hyperprolactinemic patients.

METHODS

We conducted a retrospective cohort study in the Department of Endocrinology from Necker Hospital in Paris, France. Two hundred and forty-six patients consulted primarily for menstrual disorders, with diagnosis of hyperprolactinemia. Patients were followed-up for 99.9+/-3.6 months. One hundred and ninety-one were treated with bromocriptine, 32 underwent surgery, and 23 received no treatment.

RESULTS

The mean initial plasma PRL level was 135.0+/-20.2 ng/ml. Presence of an adenoma was detected in 60% of our patients and comprised a microadenoma in 64% of cases. Compared to oligomenorrheic women, amenorrheic patients had significantly higher levels of PRL and larger pituitary tumor size. In the bromocriptine group, PRL levels decreased from 99.6+/-7.9 to 20.0+/-1.5 ng/ml (p=0.00001). The medical treatment was associated with disappearance of the adenoma in 45% of the women and with stabilization of pituitary tumor size in 40% of patients. Surgery led to disappearance of the adenoma in almost all cases, but failed to definitively cure hyperprolactinemia.

CONCLUSION

In this large-scale retrospective study, the medical treatment of mild hyperprolactinemia was shown to be effective and sufficient after 9 years of follow-up.

Tratamento medicamentoso dos tumores hipofisários. Parte I: prolactinomas e adenomas secretores de GH

O recente desenvolvimento de novas drogas, particularmente os análogos da somatotastina (SRIFa), representou um grande progresso na terapia dos tumores hipofisários. Os SRIFa mostram-se bastante eficazes na normalização dos níveis de GH e IGF-1 em acromegálicos e podem ser uma alternativa para a cirurgia transesfenoidal, mas seu uso como terapia primária da acromegalia fica limitado pelo pequeno efeito dessas drogas na redução das dimensões do tumor. Os resultados preliminares com os antagonistas do receptor de GH, como o pegvisomant, são bastante animadores. Tais drogas permitem a normalização do IGF-1 e melhora clínica em mais de 80% dos casos; entretanto, não causam redução tumoral. Agonistas dopaminérgicos (DA) representam a terapia de escolha para microprolactinomas sintomáticos e macroprolactinomas, permitindo normalização dos níveis da prolactina e redução do volume do adenoma na maioria dos pacientes. Podem também ser eventualmente eficazes em acromegálicos, sobretudo naqueles com adenomas co-secretores de prolactina e níveis não muito elevados de GH e IGF-1. Devido a sua maior eficácia e melhor tolerabilidade, a cabergolina representa o DA de escolha para o manuseio dos prolactinomas e da acromegalia.

Pituitary incidentalomas

The optimal strategy for hormonal screening of a patient with any incidentally discovered pituitary mass is unknown. The authors' review of the endocrinologic literature supports the view that such patients are at slightly increased risk for morbidity and mortality. This risk implies a benefit of early diagnosis for at least for some of the disorders, suggesting the importance of case finding. Nevertheless, the data in Table 1 illustrate that clinically diagnosed hormone-secreting pituitary tumors are far less common than incidentalomas. Clinically, one cannot accurately determine the approximately 0.5% of patients with incidentaloma who are at increased risk among the vast majority who are not. Given the limitations of diagnostic tests, effective hormonal screening requires a sufficiently high pretest probability to limit the number of false-positive results. This condition is met to varying degrees in the patient with a small incidentally discovered pituitary mass but no signs or symptoms of hormone excess. Even the more common lesions, such as prolactinoma, are relatively rare. [table: see text] Subjecting patients to unnecessary testing and treatment is associated with risk. In addition to its initial cost, testing may result in further expense and harm as false-positive results are pursued, producing the "cascade effect" described by Mold and Stein as a "chain of events (which) tends to proceed with increasing momentum, so that the further it progresses the more difficult it is to stop." The extensive evaluations performed for some patients with incidentally discovered masses may reflect the unwillingness of many physicians to accept uncertainty, even in the case of an extremely unlikely diagnosis. This unwillingness may be driven, in part, by fear of potential malpractice liability, the failure to appreciate the influence of prevalence data on the interpretation of diagnostic testing, or other factors. The major justification for further evaluation of these patients is not so much to avoid morbidity and mortality for the rare patient who truly is at increased risk but to reassure patients in whom further testing is negative and the physician. Physicians must take care not to create inappropriate anxiety in patients by overemphasizing the importance of an incidental finding unless it is associated with a realistic clinical risk. The authors' recommendations are based on currently available information to minimize the untoward effects of the cascade. As evidence accumulates, these recommendations may need to be revised. The benefit of the diagnosis of an adrenal or pituitary disorder must be considered in the context of the patient's overall condition. Additional studies are needed to analyze the clinical utility of hormonal screening for these common radiologic findings. Data from these studies can be used to identify critical gaps in knowledge and to adopt the epidemiologic methods of evaluation of evidence that have been applied to preventive measures. One must be careful to recognize lead-time bias, in which survival can appear to be lengthened when screening simply advances the time of diagnosis, lengthening the period of time between diagnosis and death without any true prolongation of life; and length bias, which refers to the tendency of screening to detect a disproportionate number of cases of slowly progressive disease and to miss aggressive cases that, by virtue of rapid progression, are present in the population only briefly. Physicians must avoid the pitfalls of overestimation of disease prevalence and of the benefits of therapy resulting from advances in diagnostic imaging. Clinical judgment based on the best available evidence should be complemented and not replaced by laboratory data.

Medical treatment of prolactinomas

Prolactinomas are a common cause of reproductive and sexual dysfunction. Once other causes of hyperprolactinemia have been excluded with a careful history, physical examination, routine chemistries, and a TSH, MR imaging or computerized tomography will delineate the size and extent of the tumor. Medical therapy is the initial treatment of choice. When infertility is the primary indication for treatment, bromocriptine use has an extensive safety experience and is preferred. For other indications, however, cabergoline appears to be more efficacious and better tolerated. Transsphenoidal surgery remains an option, especially for patients with microadenomas, when medical therapy is ineffective.

Hormonal replacement therapy in menopausal women with a history of hyperprolactinemia

Hyperprolactinemia is involved in almost 30% of infertility problems. At the onset of menopause, prolactin levels often decrease; however, no data are available regarding the course of hyperprolactinemia after menopause with hormonal replacement therapy (HRT). A retrospective study was undertaken in our department to evaluate the potential role of estrogens in women with a history of hyperprolactinemia. Twenty-two patients, with hyperprolactinemia before menopause, were followed-up. Group I included 11 patients who withdrew bromocriptine treatment when menopause was confirmed. These patients were placed on HRT with no other medication administered. HRT was a combination of percutaneous estradiol gel and an oral progestin. Group II included 7 women treated by bromocriptine before menopause and after menopause concomitantly with HRT. Group III included 4 patients who did not receive HRT or other treatments once menopause was diagnosed. The mean serum prolactin level was unchanged in Group I (22.8+/-21.7 before and 22.8+/-16.1 ng/ml after HRT) while it increased but not significantly from 8.1+/-5.2 to 16.0+/-11.7 ng/ml in Group II. The mean duration of HRT was 42.8+/-23.8 (7-81) and 37.3+/-31.0 (6-99) months in Group I and II respectively. In Group III patients, PRL levels decreased spontaneously from 61.2+/-39.8 to 33.0+/-34.7 ng/ml. In conclusion, in this population of menopausal patients with a history of moderate hyperprolactinemia, HRT did not seem to affect plasma prolactin levels.

Prolactinomas in male and female patients: a comparative clinicopathologic study

OBJECTIVE

To explore the basis of the gender-based differences in endocrine and surgical findings in patients with prolactinoma (prolactin cell adenoma) as well as in their clinical outcome.

MATERIAL AND METHODS

In young or reproductive-age female patients, older women (beyond 40 years of age), and male patients, we systematically studied the following factors: operative and endocrine features (tumor size, invasiveness, preoperative serum prolactin level, and biochemical outcome), specific biologic variables (mitotic index, MIB-1 labeling index, and p27 immunoreactivity), and hormone receptor status (estrogen and progesterone receptor proteins as well as dopamine D2 receptor messenger RNA).

RESULTS

Of the various factors assessed, the preoperative prolactin level and MIB-1 labeling index were lower in young female patients in comparison with older female and particularly male patients. Hormone levels were also positively associated with mitotic activity as well as the MIB-1 labeling index. Although invasion was infrequent in microadenomas of young female patients, no statistically significant differences in tumor size or invasiveness were noted among the three patient groups. Absence of differences in invasiveness may, in part, be explained by artifacts of case selection.

CONCLUSION

The basis for the observed differences in proliferative activities in tumors of the three study groups is not readily apparent but may reflect differences in the endocrine milieu or the effect of sex steroid hormone receptors, tumoral vascularity, or specific growth factors.

Growth-hormone and prolactin excess

The treatment of acromegaly and hyperprolactinaemia has been improved by the availability of effective and well-tolerated slow-release somatostatin analogues and dopamine agonists with long-lasting activity, such as cabergoline. The use of these drugs has extended the possibility of treatment to patients who would have responded poorly to the previously available compounds, such as octreotide or bromocriptine, and to those who were intolerant to pharmacotherapy. Moreover, the improvement in the management of acromegaly has enabled the reversal, at least partly, of cardiomyopathy and sleep apnoea, two important risk factors for morbidity and mortality in these patients.

Treatment of prolactinomas

The objectives of the treatment of hyperprolactinaemia are to suppress excessive hormone secretion and its clinical consequences, to remove tumour mass, to preserve the residual pituitary function and to prevent disease recurrence or progression. Prior to the advent of pharmacotherapy, therapy usually consisted of surgical resection and/or pituitary irradiation. In microprolactinomas, trans-sphenoidal surgical resection normalizes prolactin (PRL) levels, restores normal menses and produces the disappearance of galactorrhoea in a great majority of patients, but normalization of serum PRL levels varies from 35-70%. In macroprolactinomas, trans-sphenoidal surgery is less successful with only 32% of patients appearing to be cured initially. However, the recurrence rate is 19%, and the long-term cure rate is only 26%. In more than 80% of the patients with microprolactinoma, suppression of PRL levels and tumour shrinkage can be achieved with bromocriptine therapy given at doses of 2.5-5 mg per day. In 5-10% of the patients, the appearance of side-effects (nausea, dizziness and postural hypotension) is a limiting factor in continuing the treatment. Dopaminergic compounds cause notable tumour shrinkage in most macroprolactinomas. Treatment with cabergoline, a selective and long-lasting dopamine 2-receptor agonist at weekly doses of 0.5-2 mg has been shown to be effective both in normalizing PRL levels and in inducing tumour shrinkage. Pharmacotherapy with dopamine (DA) agonists is an appropriate first-line treatment for both micro- and macroprolactinomas. Surgery should be recommended for those patients who are severely intolerant of or resistant to DA agonists.