Long-term efficacy of bromocriptine in macroprolactinomas and giant prolactinomas in men.

We prospectively analyzed presentations and long-term therapeutic responses to bromocriptine (BRC) in 29 newly diagnosed men with macroprolactinomas including 14 patients with 'giant prolactinoma'. Clinical symptoms, prolactin (PRL) levels and tumor size on MRI were measured before BRC and sequentially thereafter. The duration of follow-up were 6 to 96 (30.7 +/- 14.4) months. Pretreatment PRL ranged between 124 and 29200 ng/mL (1698 +/- 857.1) and tumor volume was between 2.81 and 132 cm(3) (21.1 +/- 24.3). Baseline PRL levels did not correlated with tumor volume (r = 0.45, P > 0.05). Significant decrease (P = 0.0003) in PRL, at least 96% of the pretreatment value from 1698 +/- 857.1 ng/mL to 42.4 +/- 30.6 ng/mL occurred in 26 patients. Persistent normalization of PRL levels (< 16 ng/mL) for at least 6 months was achieved in 12 patients (40.8%). Twenty-two patients (74.8%) achieved significant tumor shrinkage (P = 0.005) at study completion. An improvement in visual field defects (VFD) and restoration of libido and potency was observed in 40% and 33.3%, respectively. Trans-sphenoidal / trans-frontal pituitary surgery was performed in 9 patients (31%) for various reasons: pituitary apoplexy in 1, CSF rhinorrhea in 2, increasing prolactin in spite of BRC therapy in 3, and intolerant /resistant to BRC in 3 patients. These data suggest that, in male macro- and giant prolactinomas, dopamine agonists represent the first-line therapy effective in reducing PRL, restoration of libido and potency, improvement of VFD and determining tumor shrinkage.