Current management of prolactinomas

Abstract

Prolactinomas constitute the largest group of pituitary adenomas in autopsy series. However, their relative incidence in recent surgical series is much less impressive since medical treatment with dopamine agonists is routinely employed, which in many cases leads to tumor shrinkage and normalization of prolactin levels. The clinical symptoms of hyperprolactinemia are menstrual dysfunction and galactorrhea in women and loss of libido and potency in men. Prolactinomas may present also as space occupying sellar mass lesions impinging on the adjacent structures like the pituitary gland, cavernous sinus and optic nerves. The standard primary treatment is medical by dopamine agonists. Prolactinomas are the prototype of tumors, the growth of which can be reliably and safely inhibited by specific drugs other than cytostatic chemotherapy. These unfortunately have side effects, like orthostatic hypotension, nausea and vomiting. The effects induced by dopamine agonists are suppressive but not tumoricidal. Thus, the therapeutic effect is only maintained as long as the drug is administered. Consequently, in most cases, treatment has to be continued life-long with a few exceptions, in whom normoprolactinemia persists even after discontinuation of dopamine agonists. Main indications of surgery in prolactinomas are intolerance of the medication, and tumors not responding to dopamine agonists. Occasionally, these may ultimately require radiation therapy. nobreak Remission rates in large series of surgically treated prolactinomas vary between 54% and 86%. In our consecutive series of 540 surgically treated prolactinomas, the normalization rate after transsphenoidal surgery basically depended on the preoperative prolactin levels, tumor size and extension. The remission rate of 82% in microprolactinomas with initial prolactin levels < 200ng/ml would even in small adenomas make one consider surgical treatment as an interesting alternative to long-term medical treatment.