Endocrine Abstracts

Transsphenoidal surgery (TSS) to resect a corticotroph adenoma is the first-line treatment for Cushing’s disease (CD); remission rates of up to 80% have been reported in cases of microadenomas. Endocrine Society guidelines define post-operative biochemical remission as morning serum cortisol <138 nmol/L within seven days of surgery. Our practice is to use a cut-off of <50 nmol/L at day 3 post-op to indicate biochemical remission. If serum cortisol on day 3 is 50–138 nmol/L, serial measurements are taken daily to determine if cortisol will fall further, and assessment for improvement/resolution of clinical signs of hypercortisolemia made, before repeat TSS is considered. Twenty-nine endoscopic endonasal TSS were performed in 27 patients with CD between January 2012 and April 2018. Patients with previous TSS prior to the study period were excluded. Twenty-one (78%) were female, median (range) age 37 (8–75) years. Pre-operative tumour localisation was determined on MRI in 17 of 27 patients; 15 microadenoma and 2 macroadenoma (1 with cavernous sinus invasion). Twenty-five patients (93%) underwent IPSS. Postoperative remission rates for initial surgery were 85% (23/27) when Endocrine Society cut-offs were used, 83% (24/29) when all TSS were included, and 88% (22/25) in patients with microadenoma/hyperplasia. Using a stricter cut-off of day 3 cortisol <50 nmol/L, overall remission rate was 61%. Four patients (15%) had persistent hypercortisolemia after initial TSS, two proceeded to second TSS, one received radiotherapy and metyrapone, and another underwent bilateral adrenalectomy. Remission rate after second TSS was 50% (1/2); the patient with persistent disease received radiosurgery and cabergoline. There was no statistical difference in rates of remission in those patients with or without tumour target on pre-operative MRI (15/17 vs 8/10, P=0.6). Eleven of 27 patients (41%) undergoing initial surgery developed transient DI, and 6 (22%) permanent DI. There were no cases of CSF leak requiring lumbar drain or meningitis. Post-operatively, there were four cases of TSH deficiency, and three cases of gonadotrophin deficiency (pre-menopausal). Seven patients were treated with GH. There were no cases of recurrence of CD; six patients recovered their HPA axis, at a median (range) follow-up of 25 (19-79) months. In conclusion, our series demonstrates satisfactory remission rates post-TSS for CD when Endocrine Society criteria are used, 85%, with higher rates for microadenomas/corticotroph hyperplasia, 88%. Permanent DI was the most common complication, occurring in 1 in 5 patients. Longer follow-up is required to determine recurrence rate, which is time dependent.