Factors determining the remission of microprolactinomas after dopamine agonist withdrawal

Prolactin-secreting tumors, dopamine agonists and pregnancy: a longitudinal experience of a tertiary neuroendocrine center

PURPOSE

Prolactin (PRL)-secreting tumours are associated with infertility and can be reverted by dopamine agonist (DA) therapy. The suspension of DA is recommended once pregnancy is established, as all DAs cross the placenta. The aim of the study was to evaluate the rate of maternal-foetal complications in women treated with cabergoline (CAB) or bromocriptine (BRM) for prolactinoma during gestation and the effect of pregnancy on prolactinoma progression.

METHODS

This was a retrospective observational study involving 43 women affected by prolactinoma who became pregnant during therapy with CAB or BRM for a total of 58 pregnancies. For each patient, medical records were analysed by integrating the data with outpatient or telephone interview.

RESULTS

At the time of conception, 18 women were in the BRM group, while 40 were in CAB group. No differences were found in obstetric or neonatal outcomes between the two groups. There was a significant difference (p = 0.046) in child complications reported in maternal interview found exclusively in the CAB group. No further confounding factors were detected. Disease remission rate after the first pregnancy was 42.9% and the main predictor was a lower PRL nadir before pregnancy (p = 0.023). No difference was detected between the two groups in terms of tumor remission. Breastfeeding did not modify the outcome.

CONCLUSION

Foetal exposure to DAs during the first weeks of embryogenesis is not associated with a greater risk of complications. The transient and mild developmental disorders recorded resolved spontaneously and the prevalence was substantially overlapping with that observed in the general population.

Approach to the Patient With Prolactinoma

Prolactinomas are the most common pituitary tumor histotype, with microprolactinomas being prevalent in women and macroprolactinomas in men. Hyperprolactinemia is among the most common causes of hypogonadotropic hypogonadism in both sexes, prompting medical advice for hypogonadism (infertility, oligo-amenorrhea, impotence, osteoporosis/osteopenia) in both sexes, and for signs and symptoms of mass effects (hypopituitarism, visual loss, optic chiasm compression, cranial nerve deficits, headaches) predominantly in men. Diagnostic workup involves a single prolactin measurement and pituitary imaging, but some laboratory artifacts (ie, the "hook effect" and macroprolactin) can complicate or delay the diagnosis. The treatment of choice for prolactinomas is represented by dopamine agonists, mainly cabergoline, which are able to induce disease control, restore fertility in both sexes, and definitively cure one-third of patients, thus permitting treatment discontinuation. Pregnancy and menopause may promote spontaneous prolactin decline and anticipate cabergoline discontinuation in women. Surgery and/or radiotherapy are indicated in case of resistance to cabergoline not overcome by the increase in drug dose up to the maximally tolerated or the patient's personal choice of surgery. The evidence of resistance to cabergoline in invasive and proliferative tumors may indicate biological aggressiveness, thus requiring alternative therapeutic approaches mainly based on temozolomide use as monotherapy or combined with radiotherapy. In uncontrolled patients, new medical approaches (alternative hormonal treatments, cytotoxic drugs, peptide receptor radionuclide therapy, mTOR/Akt inhibitors, tyrosine kinase inhibitors, or immunotherapy) may be offered but the experience collected to date is still very scant. This article reviews different facets of prolactinomas and discusses approaches to the condition in more common clinical situations.

Withdrawal of dopamine agonist treatment in patients with hyperprolactinaemia: A systematic review and meta-analysis

OBJECTIVE

To estimate the proportion of patients with persistent normoprolactinaemia following dopamine agonist (DA) withdrawal and to identify predictors of successful withdrawal in patients with hyperprolactinaemia.

DESIGN, PATIENTS, AND MEASUREMENTS

A systematic review of observational eligible studies were identified by searching PubMed and Embase. The primary outcome was the proportion of patients with normoprolactinaemia after cessation of DA treatment. Secondary outcome included the proportion of patients with normoprolactinaemia after DA withdrawal using individual patient data. Risk of bias was assessed by using Newcastle-Ottawa Scale. Pooled proportions were estimated using a random effects model in case I²  ≤ 75% or by reporting range of effects if I²  > 75%.

RESULTS

Thirty-two observational studies enroling 1563 patients were included. The proportion of patients with persistent normoprolactinaemia ranged from 0% to 75% (I²  = 84%). Heterogeneity was partly explained by age with more successful withdrawal in patients of higher age. Individual patient data analyses suggested that the proportion of patients with persistent normoprolactinaemia 6 months after DA withdrawal with a low maintenance dose and full regression of the prolactinoma was 87.7% (95% confidence interval [CI] = 60.7-97.1; I²  = 0%) and 58.4% (95% CI = 23.8-86.3; I²  = 75%) for microadenomas and macroadenomas, respectively.

CONCLUSIONS

The proportion of patients with persistent normoprolactinaemia following DA withdrawal treatment varied greatly, partly explained by the mean age of participants of the individual studies. Individual patient data analysis suggested that successful withdrawal was likely in patients with full regression of prolactinomas using a low maintenance dose before cessation.

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.

Hyperprolactinemia after menopause: Diagnosis and management

Most prolactinomas are diagnosed in women of reproductive age and are generally microadenomas. Prolactinomas diagnosed in postmenopausal women are less common and are not usually associated with the typical syndrome induced by prolactin excess, including infertility and oligo-amenorrhea. This implies that the diagnosis of prolactinomas after menopause may be delayed and require greater clinical effort. Limited data are available on the management and prognosis of prolactinomas in postmenopausal women. However, the physiologic decline of prolactin levels during menopause and the lack of fertility concerns, which represent specific indications for medical treatment with dopamine agonists, might require a careful reassessment of therapeutic management in such patients. Postmenopausal women with microprolactinoma may be successfully withdrawn from medical therapy with dopamine agonists, whereas in those with macroprolactinomas greater caution is advisable before dopamine agonists are discontinued, considering the potential, although rare, tumor enlargement. This review focuses on the diagnostic challenges and therapeutic management of prolactinomas in postmenopausal women.

High biochemical recurrence rate after withdrawal of cabergoline in prolactinomas: is it necessary to restart treatment?

PURPOSE

Treatment with dopamine agonists (DA) is highly effective in patients with prolactinomas. In selected patients, discontinuation of DA after several years of successful treatment is possible, however, hyperprolactinemia recurs in 60-80% of them. It is unclear what is the clinical significance of these recurrences and hence, whether or not reinitiation of therapy is necessary.

OBJECTIVES

To evaluate the recurrence rate in prolactinoma patients after DA withdrawal and the necessity to restart treatment.

METHODS

Patients with >2 years of treatment with cabergoline (CBG) who achieved normoprolactinemia and a > 50% reduction in tumor size were included. DA dose was down titrated until withdrawal. Basal tumor size, as well as PRL and gonadal steroid levels were recorded at diagnosis, at withdrawal of DA and every 3-6 months for 1-3 years.

RESULTS

Fifty patients were included (38 women, 34 macroprolactinomas). After withdrawal, 34 (68%) presented recurrence of hyperprolactinemia. PRL levels <5 ng/mL at the time of withdrawal predicted remission (sensitivity 76%, specificity of 63%). CBG was restarted in eight patients (23%) because of the presence of hypogonadism. CBG was withheld in the remaining 26, based on the following arguments: (1) premenopausal women without biochemical hypogonadism, (54%); (2) asymptomatic men under 65 without biochemical hypogonadism (19%); (3) asymptomatic postmenopausal women (19%); (4) asymptomatic men over 65 (8%). After a median follow-up of 30 months, no increase in PRL levels or tumor growth was documented.

CONCLUSIONS

Biochemical recurrence in prolactinomas is very frequent, however, in only a few of these patients reinitiation of DA is necessary.

A Brazilian multicentre study evaluating pregnancies induced by cabergoline in patients harboring prolactinomas

OBJECTIVE

To evaluate the maternal-fetal outcomes of CAB-induced pregnancies in patients with prolactinoma in a large cohort.

METHODS

The prevalence of tumor growth, miscarriage, preterm, low birth weight, congenital malformations and impairment in neuropsychological development in children among women treated with CAB were assessed in a Brazilian multicentre retrospective observational study, RESULTS: We included 194 women with a mean age of 31 (17-45) years, 43.6% presenting microadenomas and 56.4% macroadenomas, at prolactinoma diagnosis. In 233 pregnancies, CAB was withdrawn in 89%, after pregnancy confirmation. Symptoms related to tumor growth occurred in 25 cases, more frequently in macroadenomas. The overall miscarriage rate was 11%, although higher in the subgroup of patients with CAB maintainance after pregnancy confirmation (38% vs. 7.5%). Amongst the live-birth deliveries, preterm occurred in 12%, low birth weight in 6% and congenital malformations in 4.3%. Neuropsychological development impairment was reported in 7% of cases.

CONCLUSIONS

Our findings confirm previous results of safety in maternal and fetal outcomes in CAB-induced pregnancies; nevertheless, CAB maintenance after pregnancy confirmation was associated with higher miscarriage rate; result that must be further confirmed.

An observational study of pregnancy and post-partum outcomes in women with prolactinoma treated with dopamine agonists

BACKGROUND

In women with prolactinoma medical treatment with dopamine agonists (DA) can restore fertility. A number of studies have established the safety of DA during pregnancy and the impact of pregnancy and lactation on remission of prolactinoma. However, the total number of reported cases remains modest and further evidence is needed.

AIMS

To evaluate the safety of DA during pregnancy and remission of prolactinoma after pregnancy and lactation.

MATERIALS AND METHODS

Retrospective cohort study (2002-2014) of 57 pregnancies in 47 women with prolactinoma who received DA. Neonatal and pregnancy complications were recorded. Prolactin levels and treatment data were collected at the time of diagnosis, pre-conception, during pregnancy and lactation, and post-partum (up to 114 months).

RESULTS

DA treatment was stopped a median of 4.5 weeks after conception in 49 pregnancies (86%). There were 49 live births (86% of pregnancies) and six miscarriages. Six pregnancies had an adverse neonatal outcome including two with congenital malformations. Following 26% of pregnancies women achieved remission after birth or lactation, and 25% of women were in remission at last follow-up. Remission was associated with older maternal age (P = 0.036), a lower prolactin level at diagnosis (P = 0.037), and a smaller adenoma at diagnosis (P = 0.045).

CONCLUSIONS

Successful pregnancy and lactation is common after DA treatment for prolactinoma. Fetal exposure in the first four weeks of pregnancy appears to be generally safe. Encouragingly, post-partum and after lactation a quarter of women had a normal prolactin level without medical treatment.

Cabergoline Withdrawal Before and After Menopause: Outcomes in Microprolactinomas

Natural course of prolactinomas after menopause is not fully elucidated. The aim of this study was to compare recurrence rate after cabergoline withdrawal in premenopausal vs. postmenopausal women with microprolactinoma. Sixty-two women with microprolactinoma treated with cabergoline for at least 1 year and followed for 2 years after drug withdrawal were retrospectively selected. Patients were divided into two groups: 48 patients stopped cabergoline before menopause ("PRE" group), while 14 after menopause ("POST" group). Recurrence was defined by prolactin levels above normal, confirmed on two occasions. Overall, 39/62 women relapsed. Patients who relapsed apparently had higher prolactin before withdrawal (median 216.2, range 21.2-464.3 mIU/L) compared with those in long-term remission (94.3, 29.7-402.8 mIU/L; p < 0.05), and the risk of recurrence seemed lower in POST women (4/14, 29%) than in PRE ones (35/48, 73%, p < 0.005, OR 0.149, 95% CI 0.040-0.558). However, none of the factors (prolactin before withdrawal, menopausal status, treatment duration, complete adenoma regression) showed a correlation with recurrence risk in multivariate analysis. The best strategy able to optimize CBG treatment and withdrawal's outcomes is still to be defined in microprolactinomas. Postmenopausal status cannot reliably predict long-term remission, and follow-up is needed also in women of this age.

The epidemiology, diagnosis and treatment of Prolactinomas: The old and the new

Prevalence and incidence of prolactinomas are approximately 50 per 100,000 and 3-5 new cases/100,000/year. The pathophysiological mechanism of hyperprolactinemia-induced gonadotropic failure involves kisspeptin neurons. Prolactinomas in males are larger, more invasive and less sensitive to dopamine agonists (DAs). Macroprolactin, responsible for pseudohyperprolactinemia is a frequent pitfall of prolactin assay. DAs still represent the primary therapy for most prolactinomas, but neurosurgery has regained interest, due to progress in surgical techniques and a high success rate in microprolactinoma, as well as to some underestimated side effects of long-term DA treatment, such as impulse control disorders or impaired quality of life. Recent data show that the suspected effects of DAs on cardiac valves in patients with prolactinomas are reassuring. Finally, temozolomide has emerged as a valuable treatment for rare cases of aggressive and malignant prolactinomas that do not respond to all other conventional treatments.

Impact of menopause on outcomes in prolactinomas after dopamine agonist treatment withdrawal

OBJECTIVE

Discontinuation of dopamine agonist (DA) treatment in women with prolactinoma after menopause is a potential approach; studies systematically assessing long-term outcomes are lacking. Our aim was to investigate the natural history of prolactinoma in this group.

DESIGN/PATIENTS

Retrospective cohort study of women with prolactinoma diagnosed before menopause and who after menopause were not on DA.

RESULTS

Thirty women were included. Twenty-eight received DA (median duration 18 years, median age at DA withdrawal 52 years). At last assessment (median follow-up 3 years) and compared with values 6-12 months after stopping DA, Prolactin (PRL) increased in 15%, decreased but not normalized in 33% and was normal in 52%; PRL levels or visible adenoma on imaging before DA withdrawal, treatment duration and presence of macro-/microadenoma at diagnosis were not predictors of normoprolactinaemia at last review, whereas PRL values 6-12 months after stopping DA were. Adenoma regrowth was detected in 2/27 patients (7%), who showed gradual increase in PRL. Comparison with 28 women who had DA withdrawal before their menopause revealed lower risk of hyperprolactinaemia recurrence in the postmenopausal group (HR:0.316, 95% CI: 0.101-0.985, P < .05). Two women with microprolactinoma diagnosed in perimenopausal period had not been offered DA; PRL decreased (but not normalized) during observation of 1 and 8 years.

CONCLUSIONS

Prolactin normalized over time in nearly half of the women and serum PRL 6-12 months after DA withdrawal is useful predictor. Nonetheless, 7% of the patients demonstrated adenoma regrowth which, given the life expectancy postmenopause, necessitate regular monitoring of the cases with persistent hyperprolactinaemia.

Controversial issues in the management of hyperprolactinemia and prolactinomas - An overview by the Neuroendocrinology Department of the Brazilian Society of Endocrinology and Metabolism

Prolactinomas are the most common pituitary adenomas (approximately 40% of cases), and they represent an important cause of hypogonadism and infertility in both sexes. The magnitude of prolactin (PRL) elevation can be useful in determining the etiology of hyperprolactinemia. Indeed, PRL levels > 250 ng/mL are highly suggestive of the presence of a prolactinoma. In contrast, most patients with stalk dysfunction, drug-induced hyperprolactinemia or systemic diseases present with PRL levels < 100 ng/mL. However, exceptions to these rules are not rare. On the other hand, among patients with macroprolactinomas (MACs), artificially low PRL levels may result from the so-called "hook effect". Patients harboring cystic MACs may also present with a mild PRL elevation. The screening for macroprolactin is mostly indicated for asymptomatic patients and those with apparent idiopathic hyperprolactinemia. Dopamine agonists (DAs) are the treatment of choice for prolactinomas, particularly cabergoline, which is more effective and better tolerated than bromocriptine. After 2 years of successful treatment, DA withdrawal should be considered in all cases of microprolactinomas and in selected cases of MACs. In this publication, the goal of the Neuroendocrinology Department of the Brazilian Society of Endocrinology and Metabolism (SBEM) is to provide a review of the diagnosis and treatment of hyperprolactinemia and prolactinomas, emphasizing controversial issues regarding these topics. This review is based on data published in the literature and the authors' experience.

Optimal timing of dopamine agonist withdrawal in patients with hyperprolactinemia: a systematic review and meta-analysis

PURPOSE

Dopamine agonists (DAs) are recommended as first-line treatment for patients with hyperprolactinemia. Generally, it is accepted that patients with hyperprolactinemia do not need lifelong medication, but the optimal timing for DA withdrawal has not been determined. The aim of this systematic review and meta-analysis is to assess the impact of DA withdrawal on the clinical outcomes of patients with hyperprolactinemia, and to explore possible factors affecting successful DA withdrawal.

METHODS

The databases of PubMed, Cochrane and EMBASE were searched up to May 2016.

RESULTS

The proportion of patients with persisting normoprolactinemia after DA withdrawal reached 36.6% in a random effects model (95% CI, 29.4-44.2%; I-squared: 82.5%). Data of stratified analysis showed that the success rate of drug withdrawal was high in patients using cabergoline (CAB) as the only treatment (41.2%; 95% CI 32.3-50.4%) and those using CAB over 24 months (48.7%; 95% CI 38.9-58.5%), especially in patients with idiopathic hyperprolactinemia (73.2%; 95% CI 55.6-87.7%). In addition, patients who received a low maintenance dose of CAB, and had a significant reduction in tumor size (over 50%) before withdrawal, were more likely to achieve success (51.5 and 49.4%, respectively).

CONCLUSION

The success rate of DA withdrawal has increased in recent years. Further, the success rate of CAB withdrawal was higher than that of bromocriptine, especially in patients with a duration of treatment longer than 24 months. Conclusively, the probability of success was higher in patients who received low-dose CAB maintenance treatment and those who achieved a significant reduction in tumor size before withdrawal.

Best candidates for dopamine agonist withdrawal in patients with prolactinomas

PURPOSE

Dopamine agonist (DA) therapy is recommended as the first-line treatment for prolactinomas. However, it requires long treatment duration, and a high recurrence rate after DA withdrawal has been reported. We aimed to elucidate the predictors for long-term remission following DA withdrawal and propose the best candidates who can achieve complete remission after DA withdrawal.

METHODS

In a retrospective cohort study, we included 89 patients with prolactinoma who have withdrawn DAs with normal prolactin (PRL) levels at Seoul National University Hospital, from 2000 to 2016. Patient's data were retrieved from the electronic medical records.

RESULTS

The median age and median treatment duration of the study patients were 33 (15-73) years and 69.5 (8.3-277.4) months, respectively. The recurrence rate after drug withdrawal was 57.3% during the 23.9 (3.0-176.8) month follow-up period. Age, gender, baseline PRL level, and baseline maximum tumor diameter were similar between the remission and recurrence group. In the Cox-proportional hazard model analysis, the significant predictors for remission were nadir PRL level of <1 ng/dL (hazard ratio [95% confidence interval] = 0.37 [0.18-0.74]), invisible tumors on magnetic resonance imaging (MRI) (0.42 [0.24-0.74]), and treatment duration of >72 months (0.54 [0.30-0.96]). Of the subjects who met all the three criteria, 66.7% achieved long-term remission.

CONCLUSIONS

Patients who have no tumor visible on MRI, have a nadir PRL level <1 ng/dL during drug treatment, and received drug treatment for >6 years may be the best candidates for DA withdrawal.

Prolactinoma management: predictors of remission and recurrence after dopamine agonists withdrawal

OBJECTIVE

Prolactinomas are the most common functional pituitary tumour. Dopamine agonists (DA) are its principal treatment. The criteria that should guide therapy withdrawal and the factors that influence disease remission or relapse are not yet fully established. Our purpose is to evaluate the proportion of patients who attempted DA withdrawal, and to identify the factors that influence clinicians to try it. In addition, we aim to study the factors that are involved in prolactinoma remission/relapse after therapy withdrawal.

METHODS

We retrospectively evaluated 142 patients with prolactinoma diagnosis who had been treated exclusively with DA. Firstly, the patients were divided in two groups, according to whether DA withdrawal had been attempted, or not, and the factors that might predict clinicians' decision to discontinue the therapy were then analysed. Secondly, patients who attempted withdrawal were further divided into two subgroups, based on their remission or relapse status and predictors of remission were evaluated.

RESULTS

DA withdrawal was attempted in 35.2% of our patients. Females, subjects with lower initial serum prolactin (PRL) levels, those with microadenomas and those with longer treatment duration all had a higher probability of seeing their therapy discontinued. In the withdrawal group, the remission rate was 72%. Macroprolactinomas relapse more often than microprolactinomas (p < 0.05). The recurrence group had higher median initial serum PRL levels and a lower mean duration of therapy, however these variables did not reach statistical significance.

CONCLUSION

We found a low percentage of attempt of withdrawal of DA therapy in the subjects with prolactinoma. Our data confirms that DA therapy can be discontinued with a high remission rate. Tumour size was the main variable that affected the withdrawal outcome in our patients.

Recurrence of hyperprolactinemia following dopamine agonist withdrawal and possible predictive factors of recurrence in prolactinomas

BACKGROUND

The optimal duration of cabergoline (CAB) treatment of prolactinomas that minimizes recurrences is not well established. 2011 Endocrine Society Guidelines suggested that withdrawal may be safely undertaken after 2 years in patients achieving normoprolactinemia and tumor reduction.

MATERIALS

We analyzed 74 patients (mean age = 46.9 ± 14.4, M/F = 19/55, macro/micro = 18/56) bearing a prolactinoma divided in 3 groups: group A (23) treated for 3 years, group B (23) for a period between 3 and 5 years, and group C (28) for a period >5 years. CAB therapy was interrupted according to Endocrine Society Guidelines. Prolactin (PRL) levels were measured 3, 6, 12 and 24 months after withdrawal. Recurrence was defined with PRL levels ≥30 ng/ml.

RESULTS

Groups did not differ in pretreatment PRL levels (123.2 ± 112.1, 120.9 ± 123.8, 176.6 ± 154.0), pituitary deficit (4, 17, 17 %), mean CAB weekly dose (0.7 ± 0.4, 0.6 ± 0.3, 0.7 ± 0.4) and PRL levels before withdrawal (17.1 ± 19.6, 11.4 ± 8.8, 13.8 ± 13.5). Recurrence occurred within 12 months in 34 patients (45.9 %), without significant differences among groups. Neuroradiological evaluation showed a significantly higher presence of macroadenoma in group C (13, 17 and 39 %, respectively). Recurrence rate of hyperprolactinemia did not depend on sex, tumor size or CAB dose but it was significantly correlated with PRL levels at diagnosis and before withdrawal (p = 0.03). Finally, patients with pituitary deficit at diagnosis showed a significantly higher recurrence rate (p = 0.03).

CONCLUSIONS

The study provides additional evidence that prolonging therapy for more than 3 years does not reduce recurrence rate. In particular, recurrence risk was similar in micro- and macroadenomas, and higher in patients with pituitary deficits at diagnosis.

THERAPY OF ENDOCRINE DISEASE: Surgery in microprolactinomas: effectiveness and risks based on contemporary literature

Microprolactinomas are the most common pituitary adenomas. In symptomatic patients, dopamine agonists are the first-line treatment of choice; when cabergoline is used, biochemical control rates between 85 and 93% have been reported. Long-term treatment is needed in most of the cases with compliance, patient convenience, and potential adverse effects representing areas requiring attention. Based on the literature published in the past 15 years, transsphenoidal surgery can lead to normal prolactin in the postoperative period in usually 71-100% of the cases with very low postoperative complication rates. Surgical expertise is the major determinant of the outcomes, and it may be a cost-effective option in young patients with life expectancy greater than 10 years (provided it is performed by experienced surgeons at high volume centers with confirmed optimal outcomes). Larger series of patients with adequate follow-up could further validate the place of transsphenoidal surgery (particularly through the endoscopic approach for which long-term results are currently limited) in the management algorithm of patients with microprolactinoma.

Withdrawal of dopamine agonist therapy in prolactinomas: In which patients and when?

PURPOSE

The aim of the study was to assess the effect of dopamine agonist (DA) withdrawal, the current recurrence rate of hyperprolactinemia, and possible factors that predict recurrence in patients with prolactinoma.

METHODS

We evaluated DA withdrawal in 67 patients with prolactinoma (50 female/17 male) who received DA treatment for at least 2 years and showed normalization of prolactin (PRL) levels and tumor disappearance or ≥50 % tumor shrinkage, retrospectively. Accordingly, patients were divided into two groups as remission and recurrence groups, and factors that predict recurrence were evaluated.

RESULTS

The overall remission rate was 46 %; the remission ratios were 65 % in microprolactinomas and 36 % in macroprolactinomas. Remission rates were 39 % in the bromocriptine withdrawal group and 55 % in the cabergoline withdrawal group. The maximum tumor diameter and baseline PRL levels were significantly higher in the recurrence group (p = 0.001 and p = 0.003, respectively). The mean duration of DA therapy was significantly longer in the remission group (88.7 ± 48.1 and 66.7 ± 30.4 months, respectively, p = 0.026).The mean time to recurrence was 5.3 ± 3.2 months. The mean PRL levels at recurrence time were significantly lower than baseline PRL levels (p = 0.001).

CONCLUSION

The most important predictors of recurrence were maximum tumor diameter and baseline PRL levels in this study. The remission rate in our study group was higher, which was thought to be associated with the longer duration of DA treatment and that our patients were selected according to certain criteria. Despite these positive results, close monitoring is necessary for detection of early and late recurrence, especially within the first year after DA withdrawal.

Prolactinoma and pregnancy: From the wish of conception to lactation

Prolactinoma is a common cause of infertility in young women and treatment with dopamine agonists (DA) allows restoration of fertility in over 90% of the cases. Both bromocriptine and cabergoline have shown a good safety profile when administered during early pregnancy. In particular, data on exposure of the fetus or embryo to cabergoline during the first weeks of pregnancy have now been reported in more than 900 cases, and do indicate that cabergoline is safe in this context. There is no increase in the frequency of spontaneous miscarriage, premature delivery, multiple births or neonatal malformations, and follow-up studies of the children for up to 12years after fetal exposure to cabergoline did not show any physical or developmental abnormalities. These women should therefore continue DA treatment until pregnancy has been initiated. Treatment discontinuation is recommended at that time in women with microprolactinoma or non-compressive macroprolactinoma. For microprolactinomas, the risk of symptomatic tumour enlargement during pregnancy is very low (2-3%). It is higher for macroprolactinomas (20-30%) and careful follow-up is advised, including MRI without contrast injection if symptoms or visual disturbances develop. If a symptomatic tumour enlargement does occur, reinitiation of the dopamine agonist (BRC or CAB) is indicated rather than surgery. Breast-feeding has no harmful effect on tumour growth and DA treatment, if still needed, may be postponed as long as breast-feeding is desired. Finally, about 40% of women with a microprolactinoma or an intermediate size macroprolactinoma may be in prolonged remission after one or more pregnancies.

Evaluation of atherosclerosis after cessation of cabergoline therapy in patients with prolactinoma

OBJECTIVE

The aim of the study was to determine whether atherosclerotic risk markers exist at the moment and after withdrawal of cabergoline (CAB) therapy in patients who had taken a suitable dose of CAB therapy for a suitable period of time before cessation of CAB.

METHODS

This study was designed as prospective cross-sectional. Out of a total of 115 patients with prolactinoma, 42 non-obese women with microprolactinoma, who met the Pituitary Society criteria (2006) for the withdrawal of long-term CAB therapy, and 30 healthy patients participated in our study. The number of patients excluded from the study were as follows: 34 patients with tumor shrinkage of less than 50%; 10 who received DA treatments for less than 2 years; 9 who were treated with bromocriptine; and 20 who had diabetes mellitus, hypertension, hyperlipidemia, obesity, renal disease, coronary arterial disease, or were tobacco smokers. The patients were evaluated for anthropometric, metabolic, and inflammatory parameters at the time of cessation of CAB therapy and at the 3rd and 12th months after the withdrawal of CAB therapy. Endothelial dysfunction was determined by flow-mediated dilation (FMD) of the brachial artery and carotid intima media thickness (IMT), which were assessed by high resolution ultrasonography (USG) by the same practitioner.

RESULTS

At the moment of cessation of CAB therapy, the FMD percentage in patients with prolactinoma was worse than that in healthy controls (p=0.0029). After the withdrawal of CAB treatment, fibrinogen (p=0.036), mean platelet volume (MPV) (p<0.001), carotid IMT (p=0.041), and high-density lipoprotein cholesterol (HDL C) (p=0.048) were worse in the relapse patients than those in the remission patients. Furthermore, only MPV values were found to be significantly related to a relapse of hyperprolactinemia among all atherosclerotic risk markers [area under the curve: 0.830 (95% CI 0.685-0.974) (p<0.001)].

CONCLUSION

Unfavorable cardiovascular risk profiles are a problem for patients with prolactinoma during cessation and after CAB withdrawal.

Current drug withdrawal strategy in prolactinoma patients treated with cabergoline: a systematic review and meta-analysis

BACKGROUND

Cabergoline is a recommended first-line dopamine agonist for prolactinoma treatment, which is withdrawable for some cases. However, the optimal withdrawal strategy and the accurate recurrence rate associated with cabergoline withdrawal remains uncertain.

OBJECTIVE

To assess the current recurrence rate of hyperprolactinemia and possible favorable factors associated with cabergoline withdrawal in prolactinoma patients.

METHOD

The databases of PubMed, EMBASE, and Web of Science were searched up to May 2014 to identify studies containing data of recurrent hyperprolactinemia in prolactinoma patients after cabergoline withdrawal. Meta-analysis, including sensitivity analysis, meta-regression analysis, and subgroup analysis were performed.

RESULTS

When the patients who received cabergoline withdrawal were pooled, it was found that the hyperprolactinemia recurrence rate was 65% by a random effects meta-analysis [95% confidence interval 55-74%]. In a random effects meta-regression adjusting for optimal withdrawal strategies, CAB dose reduced to the lowest level before withdrawal was associated with treatment success (p = 0.006), whereas CAB treatment longer than 2 years showed no trend of effect (p = 0.587). Patients who received the lowest CAB dose and presented a significant reduction in tumor size before withdrawal were more likely to achieve the best success (p < 0.001).

CONCLUSIONS

Our meta-analysis shows that hyperprolactinemia recurs after cabergoline withdrawal in a majority of patients. The probability of success favors patients who have achieved normoprolactinemia and considerable reduction in tumor size by low dose of cabergoline treatment. In addition, our study further suggests that a beneficial strategy is associated with tapering CAB dose before withdrawal but not with CAB treatment duration longer than 2 years.

Challenges and controversies in the treatment of prolactinomas

Recent studies have reported a higher prevalence of pituitary tumors than previously thought. Among these tumors, prolactinomas occur in up to 66% of cases. Since the mid-1980s, the widespread use of dopamine agonists has facilitated the management of the majority of prolactinomas, allowing biological and tumoral control in most cases. The less frequent cases of resistant prolactinomas remain challenging despite a multimodal therapy approach. The understanding of genetic alterations in familial and aggressive pituitary tumors provides new perspectives in the management of some prolactinomas. Genetic screening should be considered, particularly in familial cases but also in young patients with macroprolactinomas, as some mutations can predict potential aggressiveness.

Outcome of prolactinoma after pregnancy and lactation: a study on 73 patients

CONTEXT

Prolactinoma is the most frequent pituitary tumour among women of child-bearing age. Only a few studies have addressed the outcome of prolactinoma after pregnancy.

OBJECTIVE

To study remission, defined as prolactin normalization without medical treatment, after pregnancy and lactation in women with prolactinoma.

PATIENTS AND METHODS

A retrospective study conducted in 2 Belgian academic centres including 73 patients (54 microprolactinomas and 19 macroprolactinomas) with 104 pregnancies continuing beyond first trimester. Dopamine agonists were stopped in early pregnancy in all treated cases. Prolactin level and adenoma size at pituitary magnetic resonance imaging (MRI) were recorded before pregnancy and throughout follow-up.

RESULTS

Thirty of 73 women (41%) were in remission after a median follow-up of 22 months after delivery or cessation of lactation. Adenoma size at diagnosis was smaller in women in remission (5 vs 8 mm). There was a nonsignificant higher rate of remission for microprolactinomas than for macroprolactinoma (46% vs 26%). The first pituitary MRI after pregnancy and lactation showed no tumour and a decreased adenoma size in 23% and 39% of women, respectively. MRI normalization was associated with remission. The number of pregnancies per woman as well as breastfeeding and its duration did not influence remission rate.

CONCLUSION

More than 40% of women with previous diagnosis of prolactinoma have normal PRL level without medical treatment for a median follow-up of 22 months after pregnancy and lactation. The likelihood of remission is associated with a smaller initial adenoma size and normalization of pituitary MRI after pregnancy.

Long term follow-up of patients with prolactinomas and outcome of dopamine agonist withdrawal: a single center experience

Dopamine agonists (DA) are the mainstay of treatment for patients with prolactinomas. To describe the efficacy of treatment and the outcomes of DA withdrawal. Retrospective review of electronic medical records of patients with prolactinomas from 1985 to 2009. Seventy-nine patients (17 men/62 women), aged 35.3 ± 1.6 years at diagnosis were studied. The mean follow-up time was 84.7 ± 9.2 months (range 0-336). The mean initial size of microadenomas was 0.74 ± 0.10 cm (range 2.41 ± 0.39) and of macrodenomas 2.41 ± 0.39 cm (range 1.1-8) and serum prolactin (PRL) levels were 112 ± 19 and 263 ± 59 ng/ml, respectively (normal range 0-40). Fifty-one (65%) prolactinomas were micro- and 28 (35%) were macroadenomas. DA led to a decrease in adenoma size in 71% of them, while 53% of microadenomas were not visible during follow-up. In 26 patients, DA withdrawal was decided. After therapy of >24 months and a mean follow-up time of 49 ± 11 months (range 3-168), 15 subjects (58%) showed no recurrence of hyperprolactinemia. Higher remission rates, although not statistically significant, were observed with cabergoline (75%). The mean PRL levels before DA discontinuation were 12.2 ± 2.3 ng/ml (range 0.5-44.7) and after discontinuation they were significantly lower than pre-treatment values. Recurrence of hypeprolactinemia was evident during the first year in all but one patient. Remission rates were not associated with age or size of adenoma at diagnosis, initial or before DA discontinuation PRL levels and duration of treatment. DA withdrawal was followed by remission of hyperprolactinamia in about half of patients after >2 years of treatment.

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.