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

Determining Ideal Management for Patients With Coexisting Prolactinomas and Psychiatric Symptoms: A Systematic Review

OBJECTIVE

Prolactinomas-pituitary tumors that overproduce prolactin-can cause various troublesome symptoms. Dopamine agonists (DAs) reduce prolactin production in the prolactin pathway, making them the first-line treatment for prolactinomas. However, the main side effect of DA treatment, hyperdopaminergia, is an explicit etiology for psychiatric side effects. Psychiatric conditions are often treated with dopamine antagonists, which can induce hyperprolactinemia. This presents a challenge for patients with both a prolactinoma and a preexisting psychiatric condition, as treatment of one condition could worsen the other. This review seeks to identify an adequate therapeutic regimen for patients with coexisting prolactinomas and psychiatric symptoms.

METHODS

This review examined PubMed citations from 1960 to 2023 published in English and involving human subjects. Case reports, case series, and cohort studies involving patients with concomitant prolactinomas and psychiatric symptoms, as validated by brain imaging, serologic prolactin levels, and medical history or chart reports of psychiatric symptoms, were included.

RESULTS

Thematic analysis included 23 reports involving 42 participants; 27 of the 42 patients experienced a significant reduction in prolactin levels and psychiatric symptoms (64%). Treatment of those 42 patients included discontinuing or altering antipsychotic/dopamine antagonist therapy or discontinuing DA therapy to reduce psychiatric symptoms, with surgery or radiation postpharmacotherapy as a last-line strategy. However, in some cases (reported in Tables 2 to 4), either psychiatric or prolactin-related symptoms recurred despite adjustment.

CONCLUSIONS

Clinicians may find it beneficial to prioritize specific antipsychotics (aripiprazole, olanzapine, ziprasidone, or clozapine) over others (risperidone, thioridazine, thiothixene, and remoxipride). Discontinuing DA medication at least periodically until the patient's condition improves may also be advisable. If these 2 initial approaches do not yield a significant improvement in symptom management, surgery or radiation therapy may be considered. As patients may respond differently to these therapies, our study still recommends a patient-centered approach.

The role of surgical management for prolactin-secreting tumors in the era of dopaminergic agonists: An international multicenter report

OBJECTIVE

First-line prolactin-secreting tumor (PST) management typically involves treatment with dopamine agonists and the role of surgery remains to be further explored. We examined the international experience of 12 neurosurgical centers to assess the patient characteristics, safety profile, and effectiveness of surgery for PST management.

METHODS

Patients surgically treated for PST from January 2017 through December 2020 were evaluated for surgical characteristics, outcomes, and safety.

RESULTS

Among 272 patients identified (65.1% female), the mean age was 38.0 ± 14.3 years. Overall, 54.4% of PST were macroadenomas. Minor complications were seen in 39.3% of patients and major complications were in 4.4%. The most common major complications were epistaxis and worsened vision. Most minor complications involved electrolyte/sodium dysregulation. At 3-6 months, local control on imaging was achieved in 94.8% of cases and residual/recurrent tumor was seen in 19.3%. Reoperations were required for 2.9% of cases. On multivariate analysis, previous surgery was significantly predictive of intraoperative complications (6.14 OR, p < 0.01) and major complications (14.12 OR, p < 0.01). Previous pharmacotherapy (0.27 OR, p = 0.02) and cavernous sinus invasion (0.19 OR, p = 0.03) were significantly protective against early endocrinological cure. Knosp classification was highly predictive of residual tumor or PST recurrence on 6-month follow-up imaging (4.60 OR, p < 0.01). There was noted institutional variation in clinical factors and outcomes.

CONCLUSION

Our results evaluate a modern, multicenter, global series of PST. These data can serve as a benchmark to compare with DA therapy and other surgical series. Further study and longer term outcomes could provide insight into how patients benefit from surgical treatment.

Impulse Control Disorders in Patients with Pituitary Tumors Treated with Dopamine Agonists: A Systematic Review

BACKGROUND

The increased prevalence of Impulse Control Disorders (ICDs) in dopamine agonist (DA) treated patients with Parkinson's disease is well described. Despite the frequent use of DAs in the management of pituitary tumors, the relationship between DAs and prevalence of ICDs in patients with pituitary tumours is unclear.

AIMS

To establish the prevalence of ICDs in patients with prolactinoma or acromegaly and determine whether prevalence differs in those on DAs to those treated without.

METHODS

Systematic review of the literature (registered a priori) reporting prevalence of ICDs in patients with prolactinoma or acromegaly (conducted June 2023). A narrative synthesis describing prevalence of ICDs according to assessment method was performed. Prevalence comparisons between patients with prolactinoma or acromegaly treated with DAs, to patients treated without, were summarised.

RESULTS

Studies were largely retrospective, observational and heterogenous, with few patients with prolactinoma and acromegaly treated without DA. Prevalence of ICDs varied between 0-60% in patients with prolactinoma, and from 5-23% in studies with at least five patients with acromegaly. In most studies comparing DA exposed to non-DA exposed cases, DA use was not associated with ICDs.

CONCLUSIONS

Reported prevalence of ICDs in patients with prolactinoma and acromegaly varies considerably. Given ICDs were reported to be highly prevalent in some studies, clinicians should be mindful of these potentially serious disorders. ICD screening tools validated for use in patients with pituitary tumors combined with prospective studies including appropriate controls, are necessary to accurately establish prevalence of ICDs and true impact of DAs in their development.

Surgery as first-line treatment for prolactinoma? Discussion of the literature and results of a consecutive series of surgically treated patients

Initial treatment for prolactinoma is usually conservative with dopamine agonists. However, the duration of treatment is often lifelong and can be associated with significant side effects. Surgical outcomes are usually favorable and treatment complications low, raising the question whether surgical therapy should be included earlier in the treatment of prolactinoma. The aim of this study was to analyze the outcome of surgical resection of prolactinomas at our institution, to compare it with other published surgical and conservative series and to discuss the role of surgery in modern prolactinoma therapy. The authors reviewed a database of single-center consecutively operated prolactinoma cases and analyzed the extent of resection (EOR), endocrinological and neurological outcomes, and complications. Thirty patients were analyzed. Mean patient age was 37.2 ± 15.5 years (range 16-76) and consisted of 17 (56.7%) females and 13 (43.3%) males. Twenty-one patients (70%) failed medical therapy, the main reasons being intolerable side effects in 11 cases (52.4%) and insufficient response in 10 cases (47.6%). Nine patients (30%) received no medical treatment prior to surgery, of which five (55.6%) were operated because of pituitary apoplexy, two (22.2%) because of acute visual deterioration and two (22.2%) refused medical treatment and opted for surgery as first-line treatment. Of the 30 operated tumors, 56.7% (n = 17) were microadenomas, 30% (n = 9) were macroadenomas (≥ 10 mm), and 13.3% (n = 4) were giant adenomas (≥ 40 mm). GTR was achieved in 75% (n = 21) of cases. The overall remission rate was 63.3%. MRI showed a residual tumor in seven patients (25%), typically with invasive growth. Postoperative CSF leaks did not occur. Mean follow-up was 34.9 ± 60.3 months (range 0-246 months). Endocrine remission was defined as a morning fasting basal PRL level of 22.3 < ng/mL and measured at the last available follow-up. Postoperative Prolactine levels were missing in three patients. Our analysis describes a highly selected sample with a disproportionate number of larger, invasive tumors and emergency cases. Nevertheless, the results are satisfactory and comparable with other published series. The consistently good results of transphenoidal surgery, especially for microprolactinomas, have led to a greater acceptance of surgery in the treatment of prolactinomas in recent years. The timing of surgery in each individual case must be determined by a multidisciplinary team to ensure the best possible outcome.

Cabergoline-associated valvulopathy of the tricuspid valve in the treatment of prolactinoma

Cabergoline-associated valvulopathy (CAV) is defined by the echocardiographic triad of moderate or severe regurgitation, valvular thickening and restricted valvular motion. While it is a well-described complication of dopamine agonist therapy in Parkinson's disease, only three convincing cases of CAV have previously been described in the treatment of prolactinoma, with none involving the tricuspid valve. We describe a case of CAV affecting the tricuspid valve, ultimately resulting in the patient's death. The novel finding of CAV affecting the tricuspid valve suggests a possible link between confirmed cases of CAV and the echocardiographic surveillance studies of cabergoline-treated prolactinoma patients which have mostly demonstrated subclinical tricuspid valve changes. The risk of CAV, although small, prompts a mindful prescription of dopamine agonist therapy for prolactinomas and consideration of measures to minimise cabergoline exposure. The cumulative cabergoline doses and duration of therapy associated with CAV in published cases exceed what has been evaluated in case series and surveillance studies, underscoring the importance of case reports in understanding CAV.

Treatment of Prolactinoma

Prolactinomas are the commonest form of pituitary neuroendocrine tumor (PitNET), representing approximately half of such tumors. Dopamine agonists (DAs) have traditionally been the primary treatment for the majority of prolactinomas, with surgery considered the second line. The aim of this review is to examine the historical and modern management of prolactinomas, including medical therapy with DAs, transsphenoidal surgery, and multimodality therapy for the treatment of aggressive prolactinomas and metastatic PitNETs, with an emphasis on the efficacy, safety, and future directions of current therapeutic modalities. DAs have been the mainstay of prolactinoma management since the 1970s, initially with bromocriptine and more recently with cabergoline. Cabergoline normalizes prolactin in up to 85% of patients and causes tumor shrinkage in up to 80%. Primary surgical resection of microprolactinomas and enclosed macroprolactinomas performed by experienced pituitary neurosurgeons have similar remission rates to cabergoline. Aggressive prolactinomas and metastatic PitNETS should receive multimodality therapy including high dose cabergoline, surgery, radiation therapy (preferably using stereotactic radiosurgery where suitable), and temozolomide. DAs remain a reliable mode of therapy for most prolactinomas but results from transsphenoidal surgery in expert hands have improved considerably over the last one to two decades. Surgery should be strongly considered as primary therapy, particularly in the setting of microprolactinomas, non-invasive macroprolactinomas, or prior to attempting pregnancy, and has an important role in the management of DA resistant and aggressive prolactinomas.