Background: Dopamine agonists (DA) have excellent result in controlling both hyperprolactinemia and tumor volume in macroprolactinomas. However, even after long term DA treatment, withdrawal of dopamine agonists results in recurrence of hyperprolactinemia in a significant proportion of patients.
Aim: To assess recurrence rate of hyperprolactinemia after DA withdrawal in a large series of patients treated in a tertiary endocrine center.
Patients and methods: 43 patients with macroprolactinomas, treated with DA for at least 2 years, fullfilled the criteria for DA withdrawal: normal serum prolactin (PRL) on minimal DA dose, no visible tumor on MRI/computed tomography or tumor maximum diameter ≤10 mm. PRL was measured by chemiluminecense. Pituitary imaging was performed by computed tomography scan or MRI.
Results: In 18 patients (41.9%) hyperprolactinemia recurred; all reccurences occured in the first year after DA withdrawal, and the majority in the first 6 months. 25 patients (58.1%) showed persistent normal prolactin levels for more than 12 months (median 28 months) after DA withdrawal and were considered curred. In two patients, first attempt to withdrawal DA treatment failed, while the second attempt lead to long term normoprolactinemia.
Conclusion: There is a high rate of recurrence of hyperprolactinemia in macroprolactinomas after DA withdrawal. However, half of patients showed normal prolactin long time after DA withdrawal. A trial of DA withdrawal should be offered to patients responsive to long-term DA treatment with no visible tumor on imaging.