Long-term remission and recurrence rate in a cohort of Cushing's disease: the need for long-term follow-up.

OBJECTIVE: Transsphenoidal surgery is the procedure of choice in Cushing disease (CD), with immediate post-operative remission rates ranging between 59 and 94% and recurrence rates between 3 and 46%, both depending upon the definition criteria and the duration of the follow-up. Our aim was to assess the rate of remission, recurrence and persistence of the disease after the first treatment and to identify predictors of remission in the CD population of our center.
METHODS: Retrospective cohort study of the patients diagnosed of CD and with follow-up in our center between 1974 and 2011. We analyzed 41 patients (35 women and 6 men) with a mean age at diagnosis of 34 ± 13 years. The mean follow-up was 14 ± 10 years (range 1-37 years) and the median of follow-up period was 6.68 years.
RESULTS: Thirty-five (85.4%) patients underwent transsphenoidal surgery as first treatment option. Histopathological evidence of a pituitary adenoma was registered in 17 (48.5%) patients. Thirty-two (78%) patients achieved disease remission after the first treatment, 21 (65.6%) of them presented disease recurrence. Persistent disease was observed in 9 (22%) patients. Twelve (29.3%) subjects developed post-surgical adrenal insufficiency, 7 of which (70%) achieved stable remission. Two parameters were found to be significant predictors of remission after the first treatment: age at disease diagnosis and the development of adrenal insufficiency (cortisol <3 μg/dl) in the immediate post-operative state.
CONCLUSIONS: We report a high recurrence rate, at least partially attributable to the long follow-up time. Early post-surgery adrenal insufficiency predicts remission. Hypopituitarism was also very prevalent, and strongly associated with radiotherapy. These results lead us to the conclusion that CD needs a life-long strict follow-up.