Accuracy of Late-Night Salivary Cortisol in Evaluating Postoperative Remission and Recurrence in Cushing's Disease

• Published in: The journal of clinical endocrinology and metabolism 2015-10, Vol.100 (10), p.3770-3777
• Main Authors: Amlashi, Fatemeh G, Swearingen, Brooke, Faje, Alexander T, Nachtigall, Lisa B, Miller, Karen K, Klibanski, Anne, Biller, Beverly M.K, Tritos, Nicholas A
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Aged; Aged, 80 and over; Circadian Rhythm; Female; Follow-Up Studies; Humans; Hydrocortisone - analysis; Male; Middle Aged; Pituitary ACTH Hypersecretion - diagnosis; Pituitary ACTH Hypersecretion - surgery; Postoperative Period; Recurrence; Remission Induction; Retrospective Studies; Saliva - chemistry; Sensitivity and Specificity; Young Adult
• ISSN: 0021-972X; 1945-7197
• DOI: 10.1210/jc.2015-2107

Context: Late-night salivary cortisol (LNSC) is well-validated in the diagnosis of Cushing's disease (CD). The accuracy of LNSC during follow-up of patients undergoing transsphenoidal surgery (TSS) has not been fully characterized. Objectives: We examined the accuracy of LNSC in establishing remission and identifying recurrence in postoperative patients with CD. Design: This is a retrospective study. Patients: Records of patients with CD who underwent TSS by a single neurosurgeon in our tertiary center (2005–2014) were analyzed (N = 224). Patients were selected for further investigation (n = 165) if there was at least one available LNSC test obtained after TSS (either within 3 months or during long-term follow-up). Extracted data included demographic and clinical characteristics, magnetic resonance imaging and laboratory data (morning serum cortisol, 24-hour urine free cortisol [UFC], LNSC) . Main Outcomes and Measures: Remission was defined as nadir morning serum cortisol less than 5 mcg/dl and nadir 24-hour UFC less than 23 mcg. Recurrence was considered definite if confirmed surgically or prompted radiotherapy. Results: Surgical remission occurred in 89% of 89 patients with available LNSC data. LNSC, obtained within 3 months of TSS, established remission with 94% sensitivity and 80% specificity at a cutpoint of 1.9 nmol/l (area under the curve [AUC] = 0.90). At a median follow-up of 53.5 months, LNSC established recurrence (75% sensitivity and 95% specificity) at a cutpoint of 7.4 nmol/l (AUC = 0.87), and 24-hour UFC established recurrence (68% sensitivity and 100% specificity) at a cutpoint of 1.6-fold above normal (AUC = 0.82). Conclusions: LNSC may accurately establish remission after TSS and identify recurrence more accurately than 24-hour UFC during long-term follow-up.