Endocrine Abstracts

Introduction: Pituitary surgery is currently considered the preferred treatment for Cushing’s disease (CD) and achieves remission in 55–85% of patients. Cortisol falls quickly after surgery, so that early post-operative cortisol level has been used as predictor of remission. There’s no agreement about optimal timing for cortisol measurement, with wide variability between centres.

Objective: To assess the value of early post-operative serum cortisol as predictor of remission after pituitary surgery in CD.

Methods: Cross-sectional, retrospective study of patients who underwent pituitary surgery for CD between January/1998 and October/2013. No glucocorticoid replacement therapy was initiated until blood samples were drawn (0800 h the day after surgery).

Results: We evaluated 45 patients, 86.7% (39) female, with a mean age of 38.2±12.9 years at diagnosis. Mean follow-up was 90.4±56.7 months. After surgery, 33 patients (73.3%) achieved cure, 12 patients (26.7%) presented persistent disease. Ten patients relapsed (30.3%), with mean follow-up time until relapse of 64.4±36 months. There were no significant differences in urinary free cortisol, ACTH, serum cortisol and cortisol in the overnight dexamethasone suppression test at diagnosis between patients with and without disease remission after surgery, or between patients with and without disease recurrence. Morning serum cortisol (obtained from 36 patients) the day after surgery was 16.5±18.3 μg/dl, with higher values in patients without cure in comparison with those in remission (27.6±19.3 vs 12.2±16.3; P=0.043). Despite this difference, the postoperative serum cortisol was not a good predictor of remission of CD. The value of ACTH 3 months after surgery was not predictive of disease recurrence.

Conclusion: Serum cortisol measured at 24 h after pituitary surgery was not predictive of remission of CD. A longer interval between surgery and hormonal evaluation may allow a more accurate classification of these patients, including those with later remission.