Dopamine agonists (DAs), used as first line therapy in patients with macroprolactinomas, and antipsychotics have opposite effects on dopamine receptors (D2R). In patients with severe psychiatric conditions treated with antipsychotics, the rare occurrence of a macroprolactinoma, particularly with optic chiasm compression, represents a therapeutic challenge. Indeed, on one hand, antipsychotics by their antagonistic effect on D2R, could decrease or even abolish the effects of DAs on prolactinomas; on the other hand, DAs could make antipsychotics ineffective and lead to psychiatric exacerbation. Our retrospective study aimed at evaluating the efficacy and psychiatric safety of DAs prescribed for the treatment of large macroprolactinomas in patients whose underlying psychiatric disorder necessitated antipsychotics. Endocrinological and psychiatric data on 18 patients were obtained from charts from 12 centers in France and Belgium. Results are expressed as median value (interquartile range). Each of the 18 patient received DAs. Nine had also pituitary surgery (most often because of insufficient tumoral response) and two had radiotherapy. The median decrease of PRL levels, under DA, was −94.7 (30.6) % for the 8 patients treated with DAs only [from an initial median level of 1247 (13012) ng/ml to a minimal level of 42 (244) ng/ml, P=0.008], −85.5 (16.5) % for the 7 patients treated before surgery [3850 (8831) ng/ml to 141 (1510) ng/ml, P=0.03] and −18 (62.75)% for the 6 patients treated after surgery [1664 ng/ml (1473) to 1215 ng/ml (3094), P=0.56]. The median decrease of prolactinoma largest diameter was −28 (23.5) % for patients only treated with DAs [from an initial median diameter of 27 (22.5) mm to 24 (11.75) mm after treatment; P=0.02] and it almost did not change in the patients who had surgery. Nevertheless, DA treatment allowed optic chiasm decompression in 82% of the patients. Five patients (28%) were admitted for psychiatric relapse while they were receiving DAs (but 3 of them had stopped their antipsychotic treatment at that time). Moreover, 89% of them had a history of one or more psychiatric admissions compared to 11% among those who did not have any relapse (P=0.0034). Even if DAs efficacy on PRL levels and tumoral volume in macroprolactinoma patients under antipsychotic drugs is less impressive than that observed usually, it may be considered as satisfactory for half of them, particularly in case of optic chiasm compression. Psychiatric symptoms exacerbation was unusual. DAs may therefore be used as antitumoral treatment of macroprolactinoma in patients receiving antipsychotics.
18 - 21 May 2019
European Society of Endocrinology