High biochemical recurrence rate after withdrawal of cabergoline in prolactinomas: is it necessary to restart treatment?

Abstract

Treatment with dopamine agonists (DA) is highly effective in patients with prolactinomas. In selected patients, discontinuation of DA after several years of successful treatment is possible, however, hyperprolactinemia recurs in 60-80% of them. It is unclear what is the clinical significance of these recurrences and hence, whether or not reinitiation of therapy is necessary. To evaluate the recurrence rate in prolactinoma patients after DA withdrawal and the necessity to restart treatment. Patients with >2 years of treatment with cabergoline (CBG) who achieved normoprolactinemia and a > 50% reduction in tumor size were included. DA dose was down titrated until withdrawal. Basal tumor size, as well as PRL and gonadal steroid levels were recorded at diagnosis, at withdrawal of DA and every 3-6 months for 1-3 years. Fifty patients were included (38 women, 34 macroprolactinomas). After withdrawal, 34 (68%) presented recurrence of hyperprolactinemia. PRL levels <5 ng/mL at the time of withdrawal predicted remission (sensitivity 76%, specificity of 63%). CBG was restarted in eight patients (23%) because of the presence of hypogonadism. CBG was withheld in the remaining 26, based on the following arguments: (1) premenopausal women without biochemical hypogonadism, (54%); (2) asymptomatic men under 65 without biochemical hypogonadism (19%); (3) asymptomatic postmenopausal women (19%); (4) asymptomatic men over 65 (8%). After a median follow-up of 30 months, no increase in PRL levels or tumor growth was documented. Biochemical recurrence in prolactinomas is very frequent, however, in only a few of these patients reinitiation of DA is necessary.