Outcomes of endoscopic transsphenoidal pituitary surgery in patients with Cushing's disease: A retrospective review.

Background: Cushing's disease (CD) is a rare endocrine disorder associated with significant morbidity and increased mortality if left untreated. Endoscopic transsphenoidal surgery (ETSS) is the preferred first-line treatment; however, reported remission and recurrence rates vary widely due to differences in biochemical remission criteria and follow-up duration. This study aimed to evaluate surgical outcomes, remission rates using standard and strict biochemical criteria, recurrence, and postoperative complications following ETSS for CD at a tertiary referral center. Methods: This retrospective analysis included 82 patients with confirmed CD who underwent ETSS between January 2015 and July 2025. Diagnosis was established using standard biochemical tests, with inferior petrosal sinus sampling where clinically indicated. Postoperative remission was assessed using two criteria: (1) standard remission - early morning serum cortisol <138 nmol/L within 7 days of surgery and (2) strict remission - postoperative day-3 serum cortisol <50 nmol/L. Patients with persistent hypercortisolism were managed with early repeat ETSS, radiotherapy, or medical therapy. Postoperative complications, endocrine deficits, and recurrence were analyzed. Results: The cohort comprised 58 females and 24 males, with a median age of 33.6 years (range 14-71). Preoperative MRI identified microadenomas in 64 patients and macroadenomas in 18 patients. Using standard criteria, remission after initial ETSS was achieved in 70 of 82 patients (85.4%), increasing to 90.2% (74/82) after inclusion of early repeat ETSS. Using strict criteria, early biochemical remission was observed in 56 patients (68.3%) following initial surgery. Persistent hypercortisolism was noted in 12 patients (14.6%), of whom six underwent early repeat ETSS, achieving remission in 66% by standard criteria. Transient diabetes insipidus (DI) occurred in 26.8% and permanent DI in 9.8% of patients. No cases of cerebrospinal fluid leak, meningitis, vascular injury, or postoperative visual deterioration were observed. During short-term follow-up, recurrence was documented in two patients, both with macroadenomas. Median follow-up duration was 4 months. Conclusion: ETSS provides high remission rates with minimal surgical morbidity in patients with CD. Remission rates are significantly influenced by the biochemical criteria applied, with higher rates observed using standard Endocrine Society definitions compared to stricter postoperative cortisol thresholds. Microadenomas demonstrate superior surgical outcomes. While early biochemical remission rates were high, the relatively short median follow-up limits assessment of long-term recurrence and durability of remission, underscoring the need for extended surveillance.