Surgical indication after bromocriptine therapy on giant prolactinomas: effects and limitations of the medical treatment.

Bromocriptine (BC) is now an accepted primary therapeutic agent for patients with microadenoma. But, for patients with large or giant prolactinomas, the treatment choice is controversial. This report focuses on long-term results of the BC effect on 10 giant prolactinomas (maximum diameter more than 40 mm and the serum PRL level more than 1000 ng/ml) with particular emphasis on cases that needed surgical intervention due to unsatisfactory results from BC therapy alone. BC was effective in 6 cases (60%). They had the serum PRL level normalized in less than one year, with BC maintenance doses between 5-15 mg/day. MRI revealed complete or nearly total disappearance of the tumor. Discontinuation of the medicine was achieved in one patient. In the remaining 4 cases, surgery was needed for various reasons: 1) BC resistant prolactinomas in 2 cases, 2) large hematomas in one of the previous cases, 3) regrowth of tumor size, despite the nearly normalized PRL level due to bulk increase in non-secretory adenomatous portion in 1 case, and 4) intolerable side effect in 1 case. BC is effective even for giant prolactinomas in 60% of cases. But, this therapy needs surgical intervention more often than microadenomas. Surgical indications and timing should be decided on based on closer follow-up of neuroimaging and visual evaluation as well as the serum PRL level.