MON-312 The Effects of Cabergoline in Pre-Surgical and Recurrence Periods of Cushing’s Disease Patients

BACKGROUND: Dopaminergic agonist cabergoline (CAB) has been used in pharmacological treatment of Cushing’s disease (CD). The effect is attributed to the frequent expression of subtype 2 dopamine receptor in corticotropic tumors. However, in vivo studies demonstrated normalization of urinary cortisol (UC) in about 30-40% of cases over the long term, mainly after surgical failure. Objective: To evaluate the effect of CAB as monotherapy in early preoperative period and on recurrence of Cushing’s disease. Methods. A single-center retrospective study was conducted in a tertiary referral center. Twenty-one patients with confirmed CD were included. Median age was 32 years (13-70), 86% female, 10 with microadenomas, 11 with macroadenomas. They were diagnosed from 1986 to 2016 and used CAB as monotherapy either in the preoperative period (n=7, CABi) or in recurrence, before any other treatment (n=14, CABr). It was considered ‘complete response’ a 24h-UC normalization and ‘partial response’ a 24h-UC reduction >50%. UC was obtained on the last follow-up evaluation. Normalization of nocturnal salivary cortisol (NSC) on CAB was evaluated in most cases, as well as the larger tumor diameter by pituitary MRI, before and after CAB treatment. Results: Complete response was achieved in 29% (6/21) of subjects after 14.9±16.4 months of treatment with a mean dose of 2.2±1.0 mg/wweek. Partial response occurred in 9.5% (2/21). NSC normalized in 35% (6/17) and no variation in tumor diameter before and after CAB use was observed (n=13): 6.8±6.8 vs. 7.2±7.1 mm, respectively. There was no normalization of UC in CABi at the end of the treatment whereas in CABr, 43% (6/14) of patients reached complete response. CABi group was treated for 4.7±1.9 months and CABr was treated for 20.1±18.1 months. Both groups were on similar doses of CAB (CABi 2.1±0.9 and CABr 2.3±1.1 mg/w). Interestingly, the difference between the groups’ complete response was evident early on 3 months of treatment: no cases in CABi vs. 60% (6/10) in CABr (p=0.035) despite a lower dose in CABr (1.0 vs. 1.5; p=0.008). Normalization of NSC occurred in 20% in CABi and 42% in CABr. Conclusion. Normalization of UC and NSC occurred in about 30% of total patients, mainly those who used CAB on recurrence of CD. Due to the small number of subjects in CABi group, the absence of hormone control in this group requires further investigation in order to verify the effectiveness of CAB as primary therapy or as preoperative treatment option.