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

Context 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 18‐24 months. Medical therapy is recommended as bridge therapy while awaiting RT effect. Objective To determine long‐term outcome of CRT and its predictors in CD patients. Design, Setting and Patients This is a retrospective case record analysis of 42 patients with CD who received CRT as a treatment modality and had at least 12 months post‐RT follow‐up. The dose delivered was 45 Gy in 25 fractions over 5 weeks. Demographic details, hormonal evaluation and radiological data were extracted from case records. Dexamethasone suppressed cortisol at cut‐off of 1.8 µg/dL was used to define remission or recurrence. Possible predictors for remission and recurrence were analysed. Results 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). Conclusion 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.