Prolactinoma

There is a variety of tumors affecting the pituitary gland in childhood; some of these tumors (eg craniopharyngioma) are included among the most common central nervous system tumors in childhood. The gene(s) involved in the pathogenesis of these tumors are largely not known; their possible association with other developmental defects or inheritance pattern(s) has not been investigated. The present study serves as a (i) screening/training, and, (ii) a research protocol. As a screening and training study, this protocol allows our Institute to admit children with tumors of the hypothalamic-pituitary unit to the pediatric endocrine clinics and wards of the NIH Clinical Center for the purposes of (i) training our fellows and students in the identification of genetic defects associated with pituitary tumor formation, and (ii) teaching our fellows and students the recognition, management and complications of pituitary tumors As a research study, this protocol aims at (i) developing new clinical studies for the recognition and therapy of pituitary tumors; as an example, two new studies have emerged within the context of this protocol: (a) investigation of a new research magnetic resonance imaging (MRI) tool and its usefulness in the identification of pituitary tumors, and (b) investigation of the psychological effects of cortisol secretion in pediatric patients with Cushing disease. Continuation of this protocol will eventually lead to new, separate protocols that will address all aspects of diagnosis of pituitary tumors and their therapy in childhood. (ii) Identifying the genetic components of pituitary oncogenesis; those will be investigated by (a) studying the inheritance pattern of pituitary tumors in childhood and their possible association with other conditions in the families of the patients, and (ii) collecting tumor tissues and examining their molecular genetics. As with the clinical studies, the present protocol may help generate ideas for future studies on the treatment and clinical follow up of pediatric patients with tumors of the pituitary gland and, thus, lead to the development of better therapeutic regimens for these neoplasms.

This will be a multicenter, prospective, randomized, open-label trial with women harboring microprolactinomas and treatment naïve. The sample will be added consecutively and randomized into 2 unblinded groups: the high dosage group will receive a high cabergoline (CAB) dose for a period of \~6 months vs the standard dosage group, which will use the lowest needed dose of CAB to achieve normoprolactinemia for 2 years. The primary outcome will be remission rate.

Prolactinomas are the most common pituitary adenomas, representing about two-thirds of clinically relevant cases. Their prevalence is around 50 per 100,000 individuals, with an incidence of 3-5 new cases per 100,000 per year and has been rising in recent decades. They may increase morbidity and mortality due to several factors: * Hormone hypersecretion: excess prolactin causes galactorrhea, amenorrhea, and infertility. * Mass effect: macroadenomas can compress adjacent structures, leading to headaches, visual loss, or neurological symptoms. * Treatment complications: medical or surgical treatments may carry risks. A marked sex difference exists, with a male-to-female ratio of 1:5-1:10, and peak diagnosis in women aged 25-44. This disparity disappears after menopause, supporting a potential role of estrogens in tumor development. Lactotrope cells, from which prolactinomas arise, are estrogen-sensitive, unlike other pituitary tumor cells (e.g., somatotrophs, gonadotrophs). A large 2022 prospective cohort (nurses) suggested a possible association between pituitary adenomas and both combined oral contraceptives (COCs) and hormone therapy (HT). However, limitations included self-reported diagnoses, lack of adenoma characterization, and contradictory findings (association with HT but not consistently with COCs). A 2009 case-control study including all adenomas found no link with hormonal contraception, while older studies from the 1980s assessed high-dose contraceptives no longer in use. Microprolactinomas are 4-5 times more frequent than macroprolactinomas (≥10 mm). Distinguishing between the two is essential, as they differ in clinical presentation, prognosis, and sex distribution. Macroadenomas are more common in men, possibly due to delayed diagnosis, as symptoms such as decreased libido are less specific, whereas women often present with amenorrhea or galactorrhea. However, studies suggest tumor size is not directly linked to symptom duration, indicating other factors may explain macroadenoma development. Why some patients develop macro- rather than microadenomas remains unclear. Estrogen exposure is a possible explanation. It is therefore relevant to investigate whether women with macroprolactinomas had greater exposure to endogenous estrogens (early menarche, late menopause, pregnancies, breastfeeding) or exogenous estrogens (contraception, menopausal HT) compared to women with microprolactinomas. The hypothesis is that women with macroprolactinomas were exposed to higher cumulative levels of estrogens before diagnosis than women with microprolactinomas.

This randomized, active-controlled, parallel-arm, single-blind trial is to compare the effects of Dopamine agonists (DA) therapy targeting different established treatment strategies on glucose metabolism assessed by an oral glucose tolerance test.