Long-term outcome of patients with macroprolactinomas initially treated with dopamine agonists

Dopamine agonists are the first line therapy for the treatment of prolactinomas. The aim of this study was to assess the outcome of macroprolactinomas during long-term follow-up after initial treatment with dopamine agonists. Retrospective follow-up study. We included 72 consecutive patients (age 39+/-17 years, men 46%) diagnosed with macroprolactinoma, and initially treated with dopamine agonists between 1980 and 2004. Initial presentation included headache in 49%, and visual field defects in 38% of the patients. Nine patients were already treated with dopamine agonists at presentation. Median prolactin level of the untreated patients was 460 microg/L (range 96-35,398 microg/L) at presentation. Hypopituitarism, other than hypogonadism, was present in 6% of the patients. Mean duration of follow-up was 10.2+/-6.1 years. Additional transsphenoidal surgery was necessary in 35% of the patients, because of resistance and/or intolerance of dopamine agonists. Postoperative radiotherapy was provided to 18% of all patients. During long-term follow-up, normoprolactinemia was present in 85% of the patients, but biochemical remission (normal prolactin levels in the absence of dopamine agonists) was present in only 22% of the patients. Tumor shrinkage was evident on MRI in 57% of the patients. Hypopituitarism developed in 39% of the patients, especially in those who received additional surgery with or without radiotherapy. Dopamine agonists are effective in normalizing prolactin values, and inducing tumor shrinkage. However, in one-third of the patients, additional therapy was necessary due to dopamine agonist resistance and/or intolerance, associated with a high incidence of hypopituitarism