Criteria for medical as opposed to surgical treatment of prolactinomas.

The treatments for both true and pseudoprolactinomas are reviewed. True prolactinomas, usually characterized by pituitary lesions and circulating levels of prolactin in excess of 2 U/l (100 micrograms/l), are best treated with a dopamine agonist such as bromocriptine. Administration of 50 mg of a repeatable bromocriptine depot preparation (Parlodel-LAR, Sandoz, Basel, Switzerland), results in a prompt reduction of circulating prolactin levels to within normal limits over 48 h in a patient with macroadenoma. Bromocriptine treatment results in a reduction of circulating prolactin in 80% of patients and tumour shrinkage in about two-thirds. Patients with macroadenomas treated successfully with dopamine agonists should be given pituitary radiotherapy to provide long-term ablation of the prolactin-secreting cells and facilitate a gradual cessation of drug. Tumours which are not responsive to dopamine agonists should undergo trans-sphenoidal surgery. Pseudoprolactinomas usually associated with circulating prolactin levels < 2 U/l (100 micrograms/l) are caused by a peripituitary tumour which obstructs the flow of dopamine into the pituitary. Treatment with dopamine agonists reduces prolactin levels but does not result in tumour shrinkage and so the treatment of choice is trans-sphenoidal surgery. Surgery is also indicated in patients with intolerance to dopamine agonists.