2025 Proffered Presentations
S018: PREDICTORS OF BIOCHEMICAL REMISSION AFTER TRANSSPHENOIDAL SURGERY IN A LARGE COHORT OF ACROMEGALY PATIENTS
Kaasinath P Balagurunath, BA1; Christopher S Hong, MD1; Jakob V Gerstl, MBBS1; Ryan Chreneck, MD1; Sean Lyne, MD1; Noah L Nawabi, BS1; Rania A Mekary, PhD2; Timothy R Smith, MD, PhD1; 1Brigham and Women's Hospital; 2School of Pharmacy, Massachusetts College of Pharmacy and Health Sciences (MCPHS) University
Introduction: The criteria for biochemical remission in Acromegaly patients has changed numerous times over the past decade. The latest criteria set in 2022 by the Acromegaly Consensus Conference defined remission as an IGF-1 level less than 1.3 times the age normalized upper limit of normal. Since the release of these guidelines, no large-scale retrospective studies have examined the outcomes, lesion characteristics, and factors predictive of biochemical remission in patients with the latest guidelines.
Objectives: To characterize the clinical outcomes and factors predictive of biochemical remission in patients with symptomatic acromegaly receiving transsphenoidal surgery (TSS), as defined by the most recent guidelines.
Methods: In this single institution, retrospective study, a large cohort of 158 patients diagnosed with operative acromegaly were examined. 38 patients were excluded as IGF-1 testing was performed less than 12 weeks postoperatively. The lesion, surgical, clinical, and endocrinological characteristics at baseline and postoperatively were tracked for the remaining 120 patients. Hormone values were determined at baseline and up to 3 years postoperatively. Pituitary adenoma size, location, and dimensions were determined using preoperative magnetic-resonance-imaging (MRI) and computerized-tomography (CT) imaging. T tests and chi-square tests were not performed due to the high type-1 error rate. A multivariate logistic regression model was created to identify the factors predictive of biochemical remission failure.
Results: A total of 120 patients receiving TSS for pituitary adenomas from 2008-2024 were included, 91 of which achieved biochemical remission (75.8%). The most common preoperative symptoms were headache (46.7% vs 27.6%, in patients who achieved vs failed to achieve biochemical remission), visual loss (20.9% vs 13.8% respectively), and acromegalic bone changes (69.2% vs 69% respectively). Moreover, preoperative obesity occurred at a higher rate in those who achieved remission (23% vs 0%). Patients who failed remission tended to have higher raw IGF-1 levels preoperatively compared to those who attained remission (732 ± 313 vs 278 ± 313 respectively), and experienced higher rates of GH hypersecretion (93.1% vs 78.4%). Those who failed remission also tended to have higher GH levels and IGF-1 levels postoperatively, and experienced a lower percentage reduction in raw IGF-1 levels.
The majority of tumors were intrasellar (88% vs 96.4% in those who attained vs failed remission), macroadenomas (75.8% vs 72.4%). Nearly all patients (98.3%) received endoscopic surgery. Postoperatively, the rates of complications such as SIADH (7.7% vs 6.9% in patients with vs without remission) and transient Diabetes Insipidus (9.9% vs 6.9%) were largely similar.
Multiple logistic regression demonstrated that surgical and lesion characteristics such as gross total resection, size, and suprasellar location were not significantly associated with an increased risk of remission failure. Among endocrinologic characteristics, the magnitude of preoperative IGF-1 and the percentage change in IGF-1 were associated with an increased risk of remission failure (Odds ratios of 1.001 and 1.021 respectively).
Conclusions: Overall, tumors which failed to achieve biochemical remission displayed distinctive preoperative endocrinological characteristics, however tumor size and location were not necessarily predictive of worse postoperative outcomes.
