Neurosurgery and Neuroscience

Objectives: To examine the relationship between the speed of peripheral cortisol level drop following pituitary surgery for Cushing disease (CD) and long-term CD recurrence.

 

Design: A retrospective study of patients presenting to our centre between 2007 and 2018.

 

Methods: We reviewed our centre’s database to identify all patients with confi rmed pituitary-driven CD. The target cortisol level for remission of CD was defined as, less than 50 nmol/l.

 

Results: We identified 148 patients (43 males and 105 females, age range: 17–84 years). Twenty patients were excluded due to being lost to follow-up. Median follow-up from diagnosis was 59 months (range: 4–126 months). Patients who achieved the target cortisol of <50 nmol/l within 48 h had a recurrence rate of 2.1% during the followup period. Patients who achieved that level within 48 to 96 h had a recurrence rate of 10%, and those who achieved this level after 96 h had recurrence rate of 33.3%. Interestingly, we identified 13 patients who attained long term CD remission during follow-up with a persistent cortisol level of >50 nmol/l post operatively (range: 59–270 nmol/l).

 

Conclusions: The speed of reduction in peripheral cortisol levels correlates with long term CD control. This can be used as a predicting factor to guide the treating physicians in counselling patients with CD. In addition, some individuals with cortisol levels above 50 nmol/l are in long term remission, suggesting a need to reconsider this threshold value.