Primary Medical Therapy of Micro- and Macroprolactinomas in Men*

Abstract

The presentation and long-term therapeutic responses of PRL-secreting pituitary tumors in men have been only partially studied. Gender-specific differences in tumor size at clinical presentation and possible differences in tumor biology in men compared to women make it important to determine treatment outcomes of male patients with prolactinomas. We performed a retrospective review of men with prolactinomas medically managed at Massachusetts General Hospital between 1980 and 1997. We identified 46 male patients with prolactinomas managed with medical therapy alone. Twelve patients had microadenomas, defined as a serum PRL level greater than 15 ng/mL and a normal pituitary scan or a tumor smaller than 1 cm. Thirty-four patients had macroprolactinomas, defined by a serum PRL greater than 200 ng/mL and pituitary adenoma larger than 1 cm. Bromocriptine, quinagolide, and/or cabergoline were administered as medical therapy. All patients had at least one follow-up visit, and the most recent serum PRL measurement after initiating dopamine agonist therapy was reported. Baseline clinical characteristics for patients with macroprolactinomas and microprolactinomas showed a larger proportion of patients with macroprolactinomas reporting a history of headache (74% vs. 0%), whereas the prevalence of sexual dysfunction and testosterone deficiency was similar between the two groups. Median serum PRL at presentation was 99 ng/mL (range, 16-385 ng/mL) vs. 1,415 ng/mL (range, 387-67,900 ng/mL), in the microprolactinoma and macroprolactinoma groups, respectively. A normal PRL level was achieved in a similar percentage of men with microprolactinomas vs. macroprolactinomas (83% vs. 79%, respectively). Although the majority of patients in both groups were treated with bromocriptine, a comparable number of patients with microprolactinomas vs. macroprolactinomas achieved a normal PRL level with cabergoline therapy. The response rates for bromocriptine and cabergoline were similar in both groups. No patient with a microprolactinoma required hormone replacement therapy, in contrast to patients with macroprolactinomas, who required thyroid, testosterone, and/or glucocorticoid replacement therapy. No patient had evidence of an increase in tumor size during therapy. In summary, we investigated the clinical presentation and treatment outcome in men with prolactinomas. We found that normalization of serum PRL levels occurs in approximately 80% of men with prolactinomas. Of importance, dopamine agonist administration yielded similar biochemical remission rates in men with microprolactinomas and macroprolactinomas.

Prolactinomas in men: a multicentre and retrospective analysis of treatment outcome

“…This study is one of the largest series of prolactinomas in men with more than 3 months of follow-up reported so far. [6][7][8][9][10][11][12][13][14][15][16] Our survey confirms that the majority (approximately 80%) of men with prolactinomas have macroprolactinomas. This ratio is higher than previously reported (approximately 3:1) by other authors.…”

“…Eight (61·5%) patients were managed with only one drug, four (30·8%) patients with two drugs and one patient with four drugs. Median time on DA therapy and median cumulative dose were 72 (48-180) months and 25 687 (8212-46 870) mg for BC, 74 (51-102) months and 168 (84-488) mg for CB-11 (6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16) months and 30 735 (27 000-34 470) lg for CV and 44 (4-84) months and 100 months and 4800 lg for lisuride. Radiotherapy was used as adjuvant therapy.…”

“…5 The majority (approximately 70%) of prolactin-secreting pituitary tumours in men are macroprolactinomas. 4,6,7 Clinical symptoms in men with prolactinomas usually occur as a result of tumour mass effect (visual field abnormalities and/ or headaches), together with symptoms resulting from hyperprolactinaemia (impotence and decreased libido) associated or not with hypopituitarism. 8 The goals of therapy for men with prolactinomas are to normalize serum prolactin (PRL) levels, restore gonadal and pituitary function, and decrease tumour size, especially in those patients with symptoms derived from tumour mass effect.…”

“…[11][12][13] Long-term clinical behaviour and therapeutic responses of prolactinomas in male patients have not been extensively reported. [7][8][9][10][11][12] To the best of our knowledge, there are no studies that specifically compare the effect of the different therapies on the treatment outcome in these patients. Therefore, our aim was to analyse the treatment outcome in this population undergoing several therapeutic modalities.…”

Recurrence of hyperprolactinaemia following discontinuation of dopamine agonist therapy in patients with prolactinoma occurs commonly especially in macroprolactinoma

“…Serum prolactin also serves as a useful marker of tumour size and response to therapy. 3 The dopamine agonist (DA) therapies, cabergoline and bromocriptine are first-line drugs for patients with prolactinoma. 4 The majority of patients with prolactinoma demonstrate acceptable clinical and biochemical responses to DAs (an acceptable biochemical response being defined as suppression of serum prolactin levels to within the sex-specific normal range).…”