Clinical significance of anaemia associated with prolactin-secreting pituitary tumours in men

Prolactinomas in males: any differences?

CONTEXT

Prolactinomas in men are usually large and invasive, presenting with signs and symptoms of hypogonadism and mass effects, including visual damage. Prolactin levels are high, associated with low testosterone, anemia, metabolic syndrome and if long-standing also osteoporosis.

RESULTS

Medical treatment with the dopamine agonist, cabergoline, became the preferred first-line treatment for male prolactinomas as well as for giant tumors, leading to prolactin normalization in ~ 80% of treated men, and tumor shrinkage, improved visual fields and recovery of hypogonadism in most patients. Multi-modal approach including surgery and occasionally radiotherapy together with a high-dose cabergoline is saved for resistant and invasive adenomas. Experimental treatments including temozolomide or pasireotide may improve clinical response in men harboring resistant prolactinomas.

CONCLUSIONS

Compared to other pituitary adenomas, secreting and non-secreting, where pituitary surgery is the recommended first-line treatment, men with prolactinomas will usually respond to medical treatment with no need for any additional treatment.

Hypopituitarism patterns and prevalence among men with macroprolactinomas

PURPOSE

Men with prolactin-secreting tumors usually harbor macroadenomas. The degree of pituitary dysfunction may vary among different adenoma size subgroups, as is recovery after treatment. Our study purpose was to characterize hypopituitarism and recovery after treatment in men with macroprolactinomas.

METHODS

A retrospective study, including a consecutive group of 81 men with pituitary macroadenomas (≥10 mm) and hyperprolactinemia (>7×ULN). Patients were divided into three categories according to adenoma size at presentation: 10-19 mm (group A), 20-39 mm (group B), and ≥40 mm (group C). We compared total testosterone, gonadotropins, cortisol, thyroid hormones and hemoglobin levels at presentation and after treatment.

RESULTS

Eighty-one patients were included; 24, 31 and 26 patients in groups A, B and C, respectively. Pretreatment hypogonadism prevalence was 75.0, 93.5 and 90.9% (p = 0.046; A vs B and C), central hypocortisolism - 0, 6.9 and 33.3% (p = 0.005), and central hypothyroidism - 6.7, 17.9 and 26.1% (NS) in groups A, B and C, respectively. Only 26.7% of all patients presented with hypocortisolism and/or hypothyroidism (42.9% in group C). Anemia (Hb < 13.5 g%) was detected in 31.3, 57.1 and 80.0% in groups A, B and C, respectively (p = 0.04). Larger adenoma diameter correlated strongly with lower FT4 levels following treatment (r = -0.42, p = 0.043).

CONCLUSIONS

Macroprolactinomas in men caused partial hypopituitarism, affecting testosterone in all adenoma size groups and cortisol more in patients with larger adenomas. However, most of the men did not have pituitary hormones affected, beside testosterone. Most patients recovered central hypocortisolism but not hypothyroidism following treatment.

Macroprolactinoma: a diagnostic and therapeutic update

Prolactinomas are the most common type of pituitary adenomas. Macroprolactinomas are the name used for these tumors when their size is ≥ 1 cm. These tumors commonly cause symptoms due to the excessive production of prolactin as well as complaints caused by tumor mass and compression of neural adjacent structures. Clinical diagnosis and assessment of macroprolactinoma are based on the measurement of serum prolactin concentrations and the morphological evaluation of the pituitary gland by magnetic resonance imaging. Dopamine agonists are the first-line treatment modality, with cabergoline being preferred to bromocriptine, because of its better tolerance and feasibility of administration. Cabergoline therapy has been reported to achieve normalization of prolactin levels and gonadal function and reduction of tumor volume in >50% of patients with macroprolactinoma. Resistance or intolerance to dopamine agonists are the main indications for transsphenoidal adenomectomy in patients with macroprolactinoma. External radiation therapy has been used in patients with poor response to medical and surgical procedures. Clinically significant tumor growth may occur during pregnancy in women with macroprolactinomas, especially if they have not received prior surgical or radiation therapy. Visual fields should be assessed periodically during pregnancy and therapy with dopamine agonists is indicated if symptomatic tumor growth occurs. Cystic and giant prolactinomas as well as the rare cases of malignant prolactinomas have special peculiarities and entail a therapeutic challenge.