Dopamine agonist therapy in prolactinomas: when can treatment be discontinued?

Formal Synthesis of (-)-Quinagolide: Diastereoselective Ring Expansion via a Bicyclic Aziridinium Ion Strategy to Access the Octahydrobenzo[g]quinoline Architecture

The diastereoselective formal synthesis of (-)-quinagolide, a D₂ receptor agonist, has been achieved. The synthesis started from l-pyroglutamic acid and relied on utilization of (a) a stereospecific catalytic hydrogenation and diastereoselective Horner-Emmons-Michael cascade to obtain functionalized prolinate, (b) a Lewis acid mediated Pummerer cyclization to construct a tricyclic fused ring system, and (c) a diastereoselective ring expansion via a bicyclic aziridinium intermediate to access the required 3-substituted piperidine scaffold.

Long-term Outcome of Microscopic Transsphenoidal Surgery for Prolactinomas as an Alternative to Dopamine Agonists

BACKGROUND

Although long-term dopamine agonist (DA) therapy is recommended as a first-line treatment for prolactinoma, some patients may prefer surgical treatment because of the potential adverse effects of long-term medication, or the desire to become pregnant. This study aimed to determine whether surgical treatment of prolactinomas could be an alternative to DA therapy.

METHODS

In this retrospective study, 96 consecutive patients (74 female, 22 male) underwent primary pituitary surgery without long-term DA treatment for prolactinomas at a single institution from 1990 to 2010. All patients underwent primary surgical treatment in the microscopic transsphenoidal approach (TSA).

RESULTS

The median age and median follow-up period were 31 (16-73) years and 139.1 (12.2-319.6) months, respectively. An initial overall remission was accomplished in 47.9% (46 of 96 patients, 33 macroadenomas, and 13 microadenomas) of patients. DA dose reduction was achieved in all patients after TSA. A better remission rate was independently predicted by lower diagnostic prolactin levels and by a greater extent of surgical resection. Overall remission at the last follow-up was 33.3%, and the overall recurrence rate was 30.4%. The permanent complication rate was 3.1%, and there was no mortality.

CONCLUSION

TSA can be considered a safe and potentially curative treatment for selective microprolactinomas as an alternative to treatment with a long-term DA.

Pediatric prolactinoma: initial presentation, treatment, and long-term prognosis

Prolactinoma is a rare pituitary adenoma secreting prolactin. Studies on diagnostics, treatment, and prognosis in pediatric prolactinoma patients are rare. We analyzed clinical presentation, response to treatment, and prognosis of 27 pediatric prolactinoma patients (10 m/17 f. based on patients' records. Tumors included 6 microadenomas (tumor volume: median 0.2 cm³, range 0.01-0.4 cm³; serum prolactin at diagnosis: median 101 ng/ml, range 33-177 ng/ml), 15 macroadenomas (volume: median 3.3 cm³, range 0.4-25.8 cm³; prolactin: median 890 ng/ml, range 87-8624), and 3 giant adenomas (volume: median 44.5 cm³, range 38.6-93.5 cm³; prolactin: median 4720 ng/ml, range 317-10,400); data for 3 patients were not available. Dopamine agonist treatment (n = 22) was safe and effective, leading to reductions in tumor size (p < 0.01) and prolactin levels (p < 0.01). Threat to vision was the indication for decompressing surgery in three of seven operated patients. No patient was irradiated. Long-term functional capacity was not impaired when compared with other sellar masses (n = 235).

CONCLUSION

In pediatric prolactinoma, diagnosis is based on hyperprolactinemia and imaging. Dopamine agonist treatment is effective and safe. Overall survival and functional capacity as a measure of quality of survival were not impaired, indicating an optimistic prognosis. Surgery should be considered only in emergency situations of threatened visual function, not presenting a fast response to dopamine agonist treatment. Severe side effects of medication and lack of efficacy should be considered as contraindications. What is Known: • In pediatric prolactinoma-a very rare pediatric neuroendocrinological disease-gender-related differences in terms of clinical presentation at initial diagnosis are known. • Due to the rareness of the disease, reports on long-term outcome and prognosis after childhood-onset prolactinoma based on prospective follow-up are not published. What is New: • Dopamine agonist treatment is efficient and safe for tumor volume reduction in pediatric prolactinoma and surgical interventions are recommended only for decompression of the optic chiasm in case of threat to vision. In case of inefficient response to medication, side effects or parental refuse, alternative therapeutic options should be considered. • Quality of life in terms of survival and functional capacity was not impaired in pediatric prolactinoma patients when compared with 235 long-term survivors of different sellar masses.

Use of micro-positron emission tomography with (18)F-fallypride to measure the levels of dopamine receptor-D2 and (18)F-FDG as molecular imaging tracer in the pituitary glands and prolactinomas of Fischer-344 rats

Dopamine receptor-D2 (DRD2) is the most important drug target in prolactinoma. The aim of this current study was to investigate the role of using micro-positron emission tomography (micro-PET) with (18)F-fallypride and (18)F-fluorodeoxyglucose ((18)F-FDG) as molecular imaging tracer in the pituitary glands and prolactinomas of Fischer-344 (F344) rats and detect the difference of the levels of DRD2 in the pituitary glands and prolactinomas of F344 rat prolactinoma models. Female F344 rat prolactinoma models were established by subcutaneous administration of 15 mg 17β-estradiol for 8 weeks. The growth of tumors was monitored by the small-animal magnetic resonance imaging and micro-PET. A series of molecular biological experiments were also performed 4 and 6 weeks after pump implantation. The micro-PET molecular imaging with (18)F-fallypride revealed a decreased expression of DRD2 in F344 rat prolactinoma models, but the micro-PET molecular imaging with (18)F-FDG presented an increased uptake in the prolactinoma compared with the pituitary gland. A decreasing trend of levels of DRD2 in F344 rat prolactinoma models was also detected by molecular biological experiments. From this, we can conclude that micro-PET with (18)F-fallypride and (18)F-FDG can be used to assess tumorigenesis of the prolactinomas in vivo and molecular imaging detection of DRD2 level in prolactinoma may be an indication of treatment effect in the animal experiment.

[Clinical guidelines for diagnosis and treatment of prolactinoma and hyperprolactinemia]

OBJECTIVE

To provide practical and up to date recommendations for evaluation, differential diagnosis, and treatment of prolactinoma and hyperprolactinemia in various clinical settings.

PARTICIPANTS

Members of the Neuroendocrinology Working Group of the Spanish Society of Endocrinology.

METHODS

Recommendations were formulated according to the Grading of Recommendations, Assessment, Development, and Evaluation system (GRADE) to describe both the strength of recommendations and the quality of evidence. A systematic search was made in Medline (Pubmed) for each subject, and authors' considerations were added in areas where the literature provided scarce evidence. Finally, recommendations were jointly discussed by the Working Group.

CONCLUSIONS

The document provides evidence-based practical and updated recommendations for diagnosis and management of hyperprolactinemia and prolactinoma, including drug-induced hyperprolactinemia, treatment options for prolactinoma (drugs, surgery, and radiotherapy), prolactinoma in pregnancy, adverse effects of dopaminergic agents, and drug-resistant and malignant prolactinomas.

2012 update in the treatment of prolactinomas

New information has been provided over the last years regarding treatment of prolactinomas and will be reviewed in this update. Medical treatment with a dopamine agonist (DA) remains the cornerstone of therapy and cabergoline is the first choice, due to its high efficacy and good tolerability profile. Prolonged remission after discontinuation of DA may be observed if treatment has been given for at least two years, normal prolactin has been obtained with a low dose and tumoral diameter has been reduced by at least 50%. Although the risk of restrictive cardiac valve disease is low at the standard doses of cabergoline used for the treatment of hyperprolactinaemia, long-term echocardiographic surveillance is however indicated, in particular in resistant patients who need higher doses of cabergoline (2.0 mg/week or more). Neurosurgical treatment of prolactinomas is less effective than medical therapy and recurrence of hyperprolactinaemia is frequent. Besides classical indications such as drug intolerance, resistance or acute complications, new indications have emerged such as young patients with a high likelihood of complete tumour resection and who do not wish to take prolonged medical treatment, or patients who require high doses of cabergoline, in whom surgical debulking may significantly improve postoperative hormonal control. Finally, recent data indicate that cabergoline is safe for the developing foetus and for the mother, and therefore should not be preventively withdrawn in a young woman wishing to become pregnant.

Treatment for prolactinomas and hyperprolactinaemia: a lifetime approach

BACKGROUND

Prolactinomas are the most common hormone-secreting pituitary tumours and are amenable to medical therapy with dopamine agonists. Indication for treatment will most commonly result from hypogonadism, infertility or symptoms related to tumour size. Thus, both diagnosis and treatment will essentially depend on the patients' stage of life, namely prepubertal, reproductive or postreproductive stage. This review will focus on a lifespan-dependent diagnosis and treatment for prolactinoma and hyperprolactinaemia.

METHODS

PubMed, the Cochrane Library, the Web of Science and EMBASE were searched electronically. No restriction was made with respect to language. Relevant current articles will be included in this review.

RESULTS

Prevalence of prolactinomas and clinical symptoms are age group-specific, and treatment of first choice is dopamine agonists over the whole lifespan. Open questions in the treatment for hyperprolactinaemia include optimal choice and duration of pharmacological treatment. In addition, concerns have been raised on the safety of dopamine agonists since a reported association of valvular heart disease with dopaminergic treatment in patients with Parkinson's disease.

CONCLUSIONS

Clinical presentation and consequences of hyperprolactinaemia and prolactinoma will differ in the specific stages of reproductive life and require an adequate lifetime-dependent diagnostic and therapeutic approach.