Second Attempt of Cabergoline Withdrawal in Patients with Prolactinomas after a Failed First Attempt: Is it Worthwhile?

Long-term Discontinuation of Dopamine Agonist Treatment in Patients with Prolactinomas Revisited

The most common type of functioning pituitary adenomas is prolactinomas; unlike other types, they are treated medically with dopamine agonists (DA). This treatment aims to normalize PRL levels and decrease tumor size by 50% or more. These objectives are typically achieved by 90% of patients with microprolactinoma, two-thirds of those with macroprolactinomas, and about half of those with giant prolactinomas. Life-long pharmacological treatment implies costs, discomfort, and the possibility of side effects, therefore, it has been suggested that DA discontinuation could be attempted in some patients. Long-term remission seems more likely in who, after 2 years of therapy achieve clinical, biochemical, and imaging remission criteria: no evidence of hypogonadism, a normal PRL level (preferably <5 ng/mL), and a >50% of tumor size reduction. Long-term remission seems to be more likely if the patient has been treated with cabergoline (CBG) for a minimum of 2 years, the PRL levels have normalized, tumor size has decreased by at least 50%, and the DA dose can gradually be tapered down to 0.25-0.5 mg per week. After treatment withdrawal, about 65% of patients experience a recurrence of hyperprolactinemia within the first 12 months of DA discontinuation. Although in most patients in whom DA discontinuation has been attempted, the hyperprolactinemia will recur, not all of them will require re-initiation of treatment. A good clinical judgement is crucial to identify those patients who need life-long treatment.

Diagnosis and management of prolactin-secreting pituitary adenomas: a Pituitary Society international Consensus Statement

This Consensus Statement from an international, multidisciplinary workshop sponsored by the Pituitary Society offers evidence-based graded consensus recommendations and key summary points for clinical practice on the diagnosis and management of prolactinomas. Epidemiology and pathogenesis, clinical presentation of disordered pituitary hormone secretion, assessment of hyperprolactinaemia and biochemical evaluation, optimal use of imaging strategies and disease-related complications are addressed. In-depth discussions present the latest evidence on treatment of prolactinoma, including efficacy, adverse effects and options for withdrawal of dopamine agonist therapy, as well as indications for surgery, preoperative medical therapy and radiation therapy. Management of prolactinoma in special situations is discussed, including cystic lesions, mixed growth hormone-secreting and prolactin-secreting adenomas and giant and aggressive prolactinomas. Furthermore, considerations for pregnancy and fertility are outlined, as well as management of prolactinomas in children and adolescents, patients with an underlying psychiatric disorder, postmenopausal women, transgender individuals and patients with chronic kidney disease. The workshop concluded that, although treatment resistance is rare, there is a need for additional therapeutic options to address clinical challenges in treating these patients and a need to facilitate international registries to enable risk stratification and optimization of therapeutic strategies.

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.

Italian Association of Clinical Endocrinologists (AME) and International Chapter of Clinical Endocrinology (ICCE). Position statement for clinical practice: prolactin-secreting tumors

Prolactinomas are the most frequent pituitary adenomas. Prolactinoma may occur in different clinical settings and always require an individually tailored approach. This is the reason why a panel of Italian neuroendocrine experts was charged with the task to provide indications for the diagnostic and therapeutic approaches that can be easily applied in different contexts. The document provides 15 recommendations for diagnosis and 54 recommendations for treatment, issued according to the GRADE system. The level of agreement among panel members was formally evaluated by RAND-UCLA methodology. In the last century, prolactinomas represented the paradigm of pituitary tumors for which the development of highly effective drugs obtained the best results, allowing to avoid neurosurgery in most cases. The impressive improvement of neurosurgical endoscopic techniques allows a far better definition of the tumoral tissue during surgery and the remission of endocrine symptoms in many patients with pituitary tumors. Consequently, this refinement of neurosurgery is changing the therapeutic strategy in prolactinomas, allowing the definitive cure of some patients with permanent discontinuation of medical therapy.

Treatment of hyperprolactinemia: A single-institute experience

BACKGROUND

Dopamine agonists such as bromocriptine and cabergoline have been found to be an effective treatment for hyperprolactinemia, not only inducing adenoma shrinkage but also lowering serum prolactin levels. Among known dopamine agonists, cabergoline is the drug of choice due to its enhanced tolerability compared with bromocriptine. This study aimed to evaluate cabergoline's effectiveness, along with transsphenoidal surgery, in the treatment of hyperprolactinemia.

METHODS

We retrieved all patients with a diagnosis of prolactinoma who were treated in our hospital during 2000-2018. A total of 208 patients were enrolled in the analysis after applying exclusion criteria. Patients were divided into four groups according to the treatments received. The demographic data, dosage and duration of cabergoline, and serum prolactin levels at different time points were collected for analysis.

RESULTS

Normalization was achieved in 59 patients (83.10%) within a short median duration of 2.80 months among those treated with cabergoline only. Although cabergoline alone was effective and well-tolerated, our data showed that long-term remission rates were more favorable when surgery was involved. The long-term remission rate of all patients enrolled was 53.8% (112 patients among 208 patients). The long-term remission rates for the different treatment groups were 17.8% (8 of 45 patients) in Group 1 (Operation→Drug), 83.3% (5 of 6 patients) in Group 2 (Drug→Operation), 79.0% (68 of 86 patients) in Group 3 (Operation only), and 43.7% (31 of 71 patients) in Group 4 (Drug only).

CONCLUSION

Cabergoline has been demonstrated to be effective and should be considered as a first-line treatment for hyperprolactinemia. In our study, transsphenoidal surgery was also demonstrated to achieve good results compared with medical treatment. Surgical intervention may resurface as an alternative first-line treatment. When used in combination with cabergoline, surgery offers a higher disease remission rate than either drug or operation alone.

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.

Dopamine agonists in prolactinomas: when to withdraw?

Dopamine agonists (DAs) are well recognized as the first-line therapy for prolactinomas due to their efficacy in achieving tumoral shrinkage and normoprolactinemia. However, it remains to be established the best timing to withdraw DAs and in which patients this should be attempted. Studies in the 1980s, mainly using bromocriptine, started to defy the concept that DAs should be regarded as a lifelong therapy considering that sustained normoprolactinemia was attained in a small subset of patients after drug withdrawal. The introduction of the more effective agent cabergoline led to an increase in the percentages of remission. The most recent meta-analysis on the topic stated than remission rates after withdrawal can range from 15% in macroprolactinoma patients treated with bromocriptine to 41% in those with microprolactinomas previously treated with cabergoline. When more stringent criteria were applied before attempting withdrawal, sustained remission ensued in more than 50% of the individuals. Treatment duration for more than 24 months, the achievement of normoprolactinemia, marked reduction (≥ 50%) in tumoral size and DAs tapering till a low maintenance dose (e.g. cabergoline 0.5 mg/week) have been the most consistently identified predictors of success. In addition, a growing amount of evidence suggests that the post-pregnancy/breastfeeding period and menopause are reasonable timings to re-access the need for continuing DAs therapy. Considering that the achievement of sustained normoprolactinemia is still far from being universal after the withdrawal, even in highly selected cohorts, future larger prospective studies should continue to address this issue.

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.

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.

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.

The Role of Isotretinoin Therapy for Cushing's Disease: Results of a Prospective Study

Objective. This prospective open trial aimed to evaluate the efficacy and safety of isotretinoin (13-cis-retinoic acid) in patients with Cushing's disease (CD). Methods. Sixteen patients with CD and persistent or recurrent hypercortisolism after transsphenoidal surgery were given isotretinoin orally for 6-12 months. The drug was started on 20 mg daily and the dosage was increased up to 80 mg daily if needed and tolerated. Clinical, biochemical, and hormonal parameters were evaluated at baseline and monthly for 6-12 months. Results. Of the 16 subjects, 4% (25%) persisted with normal urinary free cortisol (UFC) levels at the end of the study. UFC reductions of up to 52.1% were found in the rest. Only patients with UFC levels below 2.5-fold of the upper limit of normal achieved sustained UFC normalization. Improvements of clinical and biochemical parameters were also noted mostly in responsive patients. Typical isotretinoin side-effects were experienced by 7 patients (43.7%), though they were mild and mostly transient. We also observed that the combination of isotretinoin with cabergoline, in relatively low doses, may occasionally be more effective than either drug alone. Conclusions. Isotretinoin may be an effective and safe therapy for some CD patients, particularly those with mild hypercortisolism.