Dopamine agonist for the rapid improvement of visual field defects in giant and macro-prolactinomas

To evaluate effect of first-line dopamine agonist (DA) therapy as an alternative to surgery for visual field defect (VFD) recovery in giant and macro-prolactinoma.

In this retrospective study, 125 patients with giant and macro-prolactinoma, except those with a history of previous surgery or radiotherapy, were evaluated. Those who underwent visual field examinations using the Humphrey Visual Field analyser upon initial assessment and after treatment were included for analysis. Twelve patients with VFD were included. The effects of DA therapy on both VFD and tumor size were evaluated within the first three months.

There were twelve patients analysed: three females and nine males, five giant and seven macroprolactinomas; eight patients received cabergoline (CAB) and four patients received bromocriptine (BRC). The mean adenoma diameter was 35±13mm (range 15-60), and the mean PRL level was 3,523ng/dL (range 312-11,703). Eight patients (67%) complained of blurred vision, while four patients (33%) reported no visual symptoms. After a median duration of three weeks, the VFD completely resolved in ten patients (83%) but only partially improved in two (17%). The mean initial doses of CAB and BRC that provided VFD improvement were 0.5±0.2mg/week and 6.3±1.4mg/day, respectively. After a mean duration of 2.2±0.9months, the mean decrease in adenoma size was 43.6±24.5% (range 10-95%).

The use of DA as a first-line treatment for at least one month before deciding on surgery is recommended in giant and macro-prolactinomas with VFD. Surgery should be considered only in cases with DA resistance or persistent visual impairment despite medical therapy.