Surgical outcomes of medically failed prolactinomas: a systematic review and meta-analysis

Ropinirole for the Treatment of Hyperprolactinemia: A Dose-Escalation Study of Efficacy and Tolerability

CONTEXT

Treatment of hyperprolactinemia with ergoline dopamine agonists (DAs) can be complicated by intolerance and resistance.

OBJECTIVE

This study examines the efficacy and tolerability of the nonergot DA ropinirole for the long-term treatment of hyperprolactinemia.

METHODS

Twelve hyperprolactinemic women were treated with ropinirole in a 6-month, open-label, dose-escalation trial; 7 of the 12 continued treatment in an extension study for up to 17 months. Ropinirole doses were uptitrated to achieve normal prolactin (PRL) levels, restore menses, and eliminate galactorrhea.

RESULTS

Two of the 12 participants were DA naive; 6 of 12 were ergot DA intolerant; and 1 of 12 had known ergot DA resistance. Baseline PRL levels were 126.2 ± 41.4 ng/mL (SEM). Ropinirole was uptitrated from 0.125 to 0.25 mg/h to a median total daily dose (TDD) of 2 mg/d (1-4 mg/d [interquartile range]). PRL normalization was achieved in 50% of the participants (5 with microadenomas and 1 with idiopathic hyperprolactinemia) at a median effective TDD of 1 mg/d. Of the patients achieving PRL normalization, 83% were ergot DA intolerant. A persistent partial biochemical response (PRL reduction >50% from baseline) was achieved in 17% of the participants. During treatment, menses resumed in 67% of amenorrheic patients; galactorrhea resolved in 67%. Mild adverse effects were reported in 92% of participants; however, ropinirole was not discontinued because of intolerance even among the 50% of individuals with a prior history of ergot DA intolerance and resultant medication discontinuation.

CONCLUSION

These data demonstrate the efficacy and tolerability of ropinirole for the treatment of hyperprolactinemia in patients with microprolactinomas and idiopathic hyperprolactinemia and suggest ropinirole may represent a novel therapeutic alternative for treating hyperprolactinemic disorders in patients with ergot DA intolerance.

Stereotactic Radiosurgery Outcomes in Medically and Surgically Failed or Nonsurgical Candidates with Medically Failed Prolactinomas: A Systematic Review and Meta-Analysis

Objective  Prolactinomas are treated with dopamine agonists (DAs) as first-line therapy and transsphenoidal surgery as an alternative approach for medically failed tumors. We sought to summarize the efficacy of stereotactic radiosurgery (SRS) in the medically and surgically failed prolactinomas as well as in nonsurgical candidates with medically failed prolactinomas by systematic review and meta-analysis. Method  A literature search was conducted according to the Preferred Reporting Items for Systematic Review and Meta-Analyses guideline. Results  A total of 11 articles (total N  = 709) met inclusion criteria. Thirty-three percent of patients were able to achieve endocrine remission at a mean follow-up of 54.2 ± 42.2 months with no association between stopping DA and endocrine remission. Sixty-two percent of patients were able to achieve endocrine control with DA therapy and 34% of patients were able to decrease the dose of DA dose when compared with pre-SRS DA dose at the end of the follow-up period. However, 54% of patients required DA at the end of the follow-up to control hyperprolactinemia. Ninety percent of patients were able to achieve radiologic control at the end of the follow-up in comparison to pre-SRS imagings. Furthermore, 26% of patients newly developed hypopituitarism (one or more pituitary hormones) post-SRS throughout the follow-up period. Conclusion  This systematic review and meta-analysis demonstrates SRS as an effective adjunct therapy in medically failed nonsurgical candidates or surgically and medically recalcitrant prolactinomas with a 33% chance of achieving endocrine remission, 62% of patients achieved hormonal control with DA and GKRS (gamma knife radio-surgery), with a 34% chance of decreasing DA dose and 90% chance of achieving radiologic control.

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.

How to manage intolerance to dopamine agonist in patients with prolactinoma

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Refractory lactotroph adenomas

A small subset of lactotroph adenomas is resistant to dopamine agonists (DA) and can also demonstrate aggressive or even malignant behavior. The implicated mechanisms are not clearly defined. Management can be challenging and requires a multidisciplinary approach. In DA resistant prolactinomas, switching to another DA could be the first option to consider. Further strategies include surgery and radiotherapy used alone or in combination. In cases of aggressive or malignant prolactinomas, temozolomide could be offered. Immune checkpoint inhibitors have been also recently proposed as an alternative approach. The place of other treatments (e.g., metformin, selective estrogen modulators, somatostatin analogues, tyrosine kinase inhibitors, inhibitors of mammalian target of rapamycin and peptide radio-receptor therapy) remains to be carefully assessed.

11C-methionine PET aids localization of microprolactinomas in patients with intolerance or resistance to dopamine agonist therapy

PURPOSE

To assess the potential for ¹¹C-methionine PET (Met-PET) coregistered with volumetric magnetic resonance imaging (Met-PET/MR^CR) to inform clinical decision making in patients with poorly visualized or occult microprolactinomas and dopamine agonist intolerance or resistance.

PATIENTS AND METHODS

Thirteen patients with pituitary microprolactinomas, and who were intolerant (n = 11) or resistant (n = 2) to dopamine agonist therapy, were referred to our specialist pituitary centre for Met-PET/MR^CR between 2016 and 2020. All patients had persistent hyperprolactinemia and were being considered for surgical intervention, but standard clinical MRI had shown either no visible adenoma or equivocal appearances.

RESULTS

In all 13 patients Met-PET/MR^CR demonstrated a single focus of avid tracer uptake. This was localized either to the right or left side of the sella in 12 subjects. In one patient, who had previously undergone surgery for a left-sided adenoma, recurrent tumor was unexpectedly identified in the left cavernous sinus. Five patients underwent endoscopic transsphenoidal selective adenomectomy, with subsequent complete remission of hyperprolactinaemia and normalization of other pituitary function; three patients are awaiting surgery. In the patient with inoperable cavernous sinus disease PET-guided stereotactic radiosurgery (SRS) was performed with subsequent near-normalization of serum prolactin. Two patients elected for a further trial of medical therapy, while two declined surgery or radiotherapy and chose to remain off medical treatment.

CONCLUSIONS

In patients with dopamine agonist intolerance or resistance, and indeterminate pituitary MRI, molecular (functional) imaging with Met-PET/MR^CR can allow precise localization of a microprolactinoma to facilitate selective surgical adenomectomy or SRS.

Resistant prolactinomas: a case series of 26 patients

PURPOSE

Prolactin (PRL)-secreting tumors are the most common functional pituitary adenomas. They usually respond to dopamine agonist (DA) treatment, with PRL normalization and adenoma shrinkage. Our aim was to characterize patients with prolactinoma resistant to DA treatment.

METHODS

This retrospective case series included patients diagnosed with DA-resistant prolactinomas between 1993-2017 in three medical centers. Resistance was defined as PRL levels above three times the upper limit of normal (ULN) despite a weekly dose of ≥2 mg cabergoline (CAB). Clinical and biochemical information, and response to treatment, were retrieved from medical records.

RESULTS

Twenty-six patients were identified; 20 males. Of 25 macroadenomas, three were giant tumors (>40 mm) and 15 (57.7%) were invasive. The mean age at diagnosis was 31.8 ± 14.9 years (range: 13-62). The median maximal CAB dose was 3.5 mg/week (IQR, 2.5-5). Half the patients received only CAB in escalating doses, nine received CAB and underwent transsphenoidal surgery, and four underwent surgery and radiotherapy in addition to CAB treatment. PRL levels at baseline between patients treated only with CAB and those operated were (91.6 [51.1-296.7] vs. 73.1 [22.6-170.9] XULN p = 0.355), and under maximal CAB dose PRL levels between patients treated only with CAB and those operated were similar (5.77 [1.27-11.27] vs 5.27 (2.9-26) XULN p = 0.317). At the last visit patients who received combined therapy achieved lower PRL levels than those treated with DA only (5.22 [1.7-21.6] vs 1.1 [0.44-3.99] XULN p = 0.017) PRL normalization was attained in seven patients and levels below 3 × ULN in fourteen patients; the overall response was 56%.

CONCLUSIONS

Resistant prolactinomas usually require a multi-modal treatment strategy. We were able to control 14/25 (56%) of resistant tumors.

Dopamine Agonist-Resistant Microprolactinoma—Mechanisms, Predictors and Management: A Case Report and Literature Review

Objective: Prolactinomas are the most common type of functional, hormone-secreting pituitary adenomas that account for about 40% of total pituitary adenomas. Typical clinical presentations include loss of menstrual periods (amenorrhea) and galactorrhoea in women and sexual dysfunction in men. Prolactinomas are preferentially treated with dopamine agonists and respond to such therapy with hormonal normalisation and tumour shrinkage. However, about 10–20% of prolactinomas are resistant to dopamine agonists. The management of dopamine agonist-resistant prolactinomas poses a therapeutic challenge and includes several possible approaches. Design and Methods: In this study, we present a case report of a woman diagnosed with microprolactinoma at the age of 27 who did not fully respond either to treatment with dopamine agonists nor to transsphenoidal surgery. This was followed by a review of literature on the current state of knowledge about the mechanisms, predictors, and management of dopamine agonist-resistant prolactinomas on the basis of recent scientific literature published up to November 2021 and searches of the PubMed, Google Scholar, and Web of Science databases. Results and Conclusions: The exact mechanisms underlying dopamine agonists’ resistance in lactotroph tumours are not fully understood, yet refractory prolactinomas pose a great challenge in everyday clinical practice. Several predictive factors that contribute to poor response to medical treatment have been identified, among them the elevated Ki-67 index. Recently, various alternative medical treatments have been considered, but their usefulness remains to be evaluated. A return of menses can serve as a first clinical indication of successful medical treatment.

Dopamine agonist therapy for prolactinomas: do we need to rethink the place of surgery in prolactinoma management?

The current treatment paradigm for prolactinomas involves dopamine agonist (DA) therapy as the first-line treatment, with surgical resection reserved for cases where there is DA failure due to resistance or intolerance. This review highlights how DA therapy can be optimised to overcome its increasingly recognised pitfalls, whilst also addressing the potential for expanding the use of surgery in the management of prolactinomas. The first part of the review discusses the limitations of DA therapy, namely: DA resistance; common DA side effects; and the rare but serious DA-induced risks of cardiac valvulopathy, impulse control disorders, psychosis, CSF rhinorrhoea and tumour fibrosis. The second part of the review explores the role of surgery in prolactinoma management with reference to its current second-line position and recent calls for surgery to be considered as an alternative first-line treatment alongside DA therapy. Randomised trials comparing medical vs surgical therapy for prolactinomas are currently underway. Pending these results, a low surgical threshold approach is herein proposed, whereby DA therapy remains the default treatment for prolactinomas unless there are specific triggers to consider surgery, including concern regarding DA side effects or risks in vulnerable patients, persistent and bothersome DA side effects, emergence of any serious risks of DA therapy, expected need for long-term DA therapy, as well as the traditional indications for surgery. This approach should optimise the use of DA therapy for those who will most benefit from it, whilst instituting surgery early in others in order to minimise the cumulative burden of prolonged DA therapy.