Prolactinoma management: predictors of remission and recurrence after dopamine agonists withdrawal.

OBJECTIVE: Prolactinomas are the most common functional pituitary tumour. Dopamine agonists (DA) are its principal treatment. The criteria that should guide therapy withdrawal and the factors that influence disease remission or relapse are not yet fully established. Our purpose is to evaluate the proportion of patients who attempted DA withdrawal, and to identify the factors that influence clinicians to try it. In addition, we aim to study the factors that are involved in prolactinoma remission/relapse after therapy withdrawal.

METHODS: We retrospectively evaluated 142 patients with prolactinoma diagnosis who had been treated exclusively with DA. Firstly, the patients were divided in two groups, according to whether DA withdrawal had been attempted, or not, and the factors that might predict clinicians' decision to discontinue the therapy were then analysed. Secondly, patients who attempted withdrawal were further divided into two subgroups, based on their remission or relapse status and predictors of remission were evaluated.

RESULTS: DA withdrawal was attempted in 35.2% of our patients. Females, subjects with lower initial serum prolactin (PRL) levels, those with microadenomas and those with longer treatment duration all had a higher probability of seeing their therapy discontinued. In the withdrawal group, the remission rate was 72%. Macroprolactinomas relapse more often than microprolactinomas (p < 0.05). The recurrence group had higher median initial serum PRL levels and a lower mean duration of therapy, however these variables did not reach statistical significance.

CONCLUSION: We found a low percentage of attempt of withdrawal of DA therapy in the subjects with prolactinoma. Our data confirms that DA therapy can be discontinued with a high remission rate. Tumour size was the main variable that affected the withdrawal outcome in our patients.