FRI299 Efficacy And Safety Of Endoscopic Transsphenoidal Resection For Prolactinoma: A Retrospective Case-series

Disclosure: I.M. Zandbergen: None. K. Huntoon: None. T.G. White: None. F. de Vries: None. B. Moclair: None. W.R. Van Furth: None. I.C. Pelsma: None. A. Dehdashti: None. N.R. Biermasz: None. D.M. Prevedello: None. Introduction Endoscopic transsphenoidal surgery (ETSS) for prolactinoma is mainly reserved for patients with dopamine agonist (DA) resistance, intolerance, or apoplexy. Surgery as a first-line treatment remains a topic of debate. Therefore, published patient cohorts are often not representative for the total population, and lack long-term follow-up. High remission rates (overall 67%, microprolactinoma up to 90%) have been reported, with recurrence in 5-20%, and low complication rates. This study aimed to assess clinical efficacy and safety of ETSS in prolactinoma patients. Study design Multicenter retrospective chart review of 137 surgically treated prolactinoma patients (mean age 38.2±13.7 years; 61.3% female) from three tertiary care centers from the USA and the Netherlands. Clinical characteristics and outcomes of surgery, including long-term (>2 years postoperatively) biochemical remission, resolution of hypogonadism and visual deficiencies, and recurrence and complication rates were assessed. Main results Median highest preoperative prolactin levels -available for 115 patients- were 168.5 µg/L (97.5 - 836.5 µg/L) and were higher for males (996.4 µg/L (158.6 - 2145.0 µg/L) vs females 128.5 µg/L (83.7 - 223.0 µg/L), P<0.001). The cohort consisted of 56 (40.9%) microprolactinomas, 69 (50.4%) macroprolactinomas, and 7 (5.1%) giant prolactinomas, whereas in 5 (3.6%) patients no adenoma was detectable by MRI. Males had more macroprolactinomas: 38 (71.7%) vs 31 females (36.9%), P<0.001; and giant prolactinomas: 7 (13.2%) vs 0 females (0.0%), P<0.001. Pituitary deficiencies -available for 135 patients- were present in 51 (37.8%) patients, with 8 (5.9%) having panhypopituitarism, and 43 (31.9%) had deficiencies of LH and 41 (30.4%) in FSH. Males more often showed any pituitary deficiency: 32 (61.5%) vs 19 females (22.9%), P<0.001, with correspondingly higher rates of deficiencies of all pituitary axes. Most often reported indication for surgery was DA intolerance 59 (43.1%) patients; males 14 (26.4%) vs females 45 (53.6%), P=0.006, with complete resection being the intent of surgery in 109 (79.6%) patients (males 33, 62.3%; vs females 76, 90.5%, P<0.001). With a median follow-up of 28.0 (15.0 - 55.5) months, long-term DA free remission was achieved in 87 (63.5%) patients. Males had lower remission rates: 25 (47.2%) vs 62 females (73.8%), P=0.002, with similar median follow-up for males and females. Occurring in 29 (21.2%) patients, transient DI was the most frequently reported surgical complication, similar for males and females. Conclusions In this multinational retrospective case-series of 137 prolactinoma patients who underwent ETSS, with relatively high proportions of macroprolactinoma and KNOSP 3-4, long-term remission rates were 63.5%. Both preoperative clinical characteristics and remission rates were significantly different between males and females. Presentation: Friday, June 16, 2023