Endocrine Abstracts

Background: Endoscopic surgery (ES) performed in Pituitary Centers of Excellence (PCOE) represents the gold standard treatment for GH-secreting adenomas. However, rate of cure greatly varies according to definition criteria, follow-up duration, various patient and adenoma features, and surgeon ability.

Study aim: To assess short- (3 month) and long-term (≥1 year) outcome and identify predictors of ES, in a large and homogeneous cohort of acromegaly patients.

Subjects and methods: Clinical, radiological, and histological data at enrolment and follow-up of consecutive patients with GH-secreting adenoma, treated by ES at an Italian PCOE, from 1998 to 2020, were retrospectively analyzed.

Results: 291 patients (167 females; mean age at surgery 46.2 ±12.4 years) were included. 195 (67%) had a macroadenoma with invasion of surrounding structures (Hardy-Wilson-Knosp classification) in 92.3% of the cases. According to Trouillas grading, 183 (62.9%) were grade 1a, 35 (12%) 1b, 48 (16.5%) 2a, and 25 (8.5%) 2b. 269 patients were treated by ES and 22 by combined ES-craniotomy. 134 were naïve for treatment; 35 had been treated with surgery; 107 with medical therapy and 21 with radiation therapy. Histological examination revealed 250 GH- (150 sparsely and 99 densely granulated) and 41 GH-PRL-secreting adenomas. At 3-month follow-up, 217 (74.6%) patients presented disease remission, 74 (25.4%) had residual adenoma. At last follow-up (mean duration 67.8±50.4 months; range 12-240.8), 197 patients (67.7%) were cured; 94 (32.3%) had residual adenoma, controlled by medical therapy in 63.8% of the cases. During follow-up, 9 (3%) patients underwent second surgery, 90 (30.9%) received medical therapy and 4 (1.4%) radiation therapy. At last follow-up, 16 (5.4%) suffered from hypopituitarism, 11 (3.7%) from central diabetes insipidus. Surgical complications included cerebrospinal fluid leak (n=35; 12%) and epistaxis (n=2;0.7%). According to multivariate regression analysis, GH <1 μg/l at 48h post-surgery and dense granulation were positive predictors; age <30 years, male gender, tumor invasiveness, Trouillas grade 2b and previous surgery were negative predictors (P<0.0001) of short- and long-term outcome. The chance of developing invasive highly proliferative adenoma (2b) was inversely related to age (P<0.02; OR 6.6 for age <30 vs. >60 years old). Moreover, 2b adenomas increased the risk of complications (P<0.005), independently from gender and histological features.

Conclusions: Our study, performed on the largest available cohort of acromegaly patients, supports the indications of ES in PCOE as first and second line treatment, independently from patient and tumor features, for the overall high chance of cure and very low risk profile.