Long term follow-up of patients with prolactinomas and outcome of dopamine agonist withdrawal: a single center experience.

Dopamine agonists (DA) are the mainstay of treatment for patients with prolactinomas. To describe the efficacy of treatment and the outcomes of DA withdrawal. Retrospective review of electronic medical records of patients with prolactinomas from 1985 to 2009. Seventy-nine patients (17 men/62 women), aged 35.3 ± 1.6 years at diagnosis were studied. The mean follow-up time was 84.7 ± 9.2 months (range 0-336). The mean initial size of microadenomas was 0.74 ± 0.10 cm (range 2.41 ± 0.39) and of macrodenomas 2.41 ± 0.39 cm (range 1.1-8) and serum prolactin (PRL) levels were 112 ± 19 and 263 ± 59 ng/ml, respectively (normal range 0-40). Fifty-one (65%) prolactinomas were micro- and 28 (35%) were macroadenomas. DA led to a decrease in adenoma size in 71% of them, while 53% of microadenomas were not visible during follow-up. In 26 patients, DA withdrawal was decided. After therapy of >24 months and a mean follow-up time of 49 ± 11 months (range 3-168), 15 subjects (58%) showed no recurrence of hyperprolactinemia. Higher remission rates, although not statistically significant, were observed with cabergoline (75%). The mean PRL levels before DA discontinuation were 12.2 ± 2.3 ng/ml (range 0.5-44.7) and after discontinuation they were significantly lower than pre-treatment values. Recurrence of hypeprolactinemia was evident during the first year in all but one patient. Remission rates were not associated with age or size of adenoma at diagnosis, initial or before DA discontinuation PRL levels and duration of treatment. DA withdrawal was followed by remission of hyperprolactinamia in about half of patients after >2 years of treatment.