Cabergoline may act as a radioprotective agent in Cushing's disease.

Abstract

Conventional fractionated radiotherapy (CRT) achieves control of pathological hypercortisolism in 75%-80% of patients with persistent or recurrent Cushing's disease (CD), over a mean period of 18-24months. Medical therapy is recommended as bridge therapy while awaiting RT effect. To determine long-term outcome of CRT and its predictors in CD patients. This is a retrospective case record analysis of 42 patients with CD who received CRT as a treatment modality and had at least 12months post-RT follow-up. The dose delivered was 45Gy in 25 fractions over 5weeks. Demographic details, hormonal evaluation and radiological data were extracted from case records. Dexamethasone suppressed cortisol at cut-off of 1.8µg/dL was used to define remission or recurrence. Possible predictors for remission and recurrence were analysed. The mean age at the time of CRT administration was 23.7±10.7 (range: 12-48) years. A total of 29 (69%) patients achieved remission 26.5±28.5 (median: 18, range: 3-120) months after RT, while 13 (31%) patients had persistent disease at last follow-up. There were no significant predictors of disease remission after CRT. Six (20.7%) patients had recurrence after a documented initial remission. Recurrence occurred 66.6±25.9 (median: 74; range: 18 to 90) months after documented remission. Recurrence of the disease was exclusively seen in patients who received peri-RT cabergoline. Peri-CRT use of cabergoline was significantly associated with increased recurrence rates (P=.016). Use of cabergoline in the peri-CRT period did not affect initial remission after CRT but was associated with increased recurrence after initial remission in CD.