OR23-03 Post-Operative Day One Morning Cortisol Value as a Biomarker to Predict the Recurrence of Cushing Disease

Tumor removal by transsphenoidal surgery (TSS) is the first line treatment for Cushing disease (CD). However, recurrence is relatively common. A one week post-operative (post-op) nadir cortisol has been used as a biomarker to predict recurrence(1). We identified 299 CD patients from our longitudinal multidisciplinary clinic or our institutional RPDR search tool who met biochemical diagnostic criteria(1) and had undergone TSS between May 2008 and May 2018, to evaluate post-op cortisol levels as biomarkers to predict long-term remission and to characterize clinical features of Cushing syndrome. Predictors of recurrence were identified with logistic regression, using recurrence as the dependent variable, and a Kaplan-Meier survival curve analysis was performed to compare long-term remission after TSS among the 202 patients who reached initial remission and had at least 1 year of follow-up. The post-op day 1 morning (AM) cortisol had significant association with CD recurrence (OR=1.025, 95%CI:1.002-1.048, p=0.032). The time to recurrence was significantly longer in patients with post-op day 1 AM cortisol <5 μg/dL. In contrast, one week post-op nadir cortisol (OR=1.081, 95%CI: 0.989-1.181, p=0.086), urinary free cortisol (OR=1.032,95%CI: 0.994-1.07, p=0.098), or late night salivary cortisol (OR=1.383, 95%CI:0.841-2.274, p=0.201) had no significant correlation with recurrence. There were no significant differences in time to recurrence for post-op day 2 AM cortisol <5 μg/dL. Among patients who developed post-op adrenal insufficiency, recurrence was significantly lower if glucocorticoid replacement continued for more than one year. In addition, tumor proliferative index (MIB-1) had a significant correlation with recurrence (OR=1.287, 95%CI:1.106-1.498, p=0.001). The most common symptoms and signs of initial presentation of CD were weight gain (91.6%), central obesity (79.6%), menstrual disorders (77.9%), round face (65.9%), hypertension (63.2%), mood disorders (60.2%), dorsocervical fat deposition (59.9%), supraclavicular fat deposition (59.9%), osteoporosis (58.9%), fatigue (58.2%), bruising (55.9%) and facial hirsutism (54.2%). Most of the best discriminating CD features did not have high sensitivity, such as purple striae (31.4%), facial plethora (33.4%) and proximal muscle weakness (30.8%). Our data show that post-op day one morning cortisol level above 5 μg/dL had significant association with recurrence. In contrast, the one week post-op nadir cortisol level had no significant value to predict recurrence. Our data also suggest that nonspecific symptoms and signs of CD are more common than stereotypical signs. Reference: Nieman LK, et al. Treatment of Cushing’s Syndrome: An Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab 2015; 100:2807-2831