2025 Poster Presentations
P236: IMPACT OF LESION SIZE ON POSTOPERATIVE OUTCOMES IN A LARGE SINGLE INSTITUTIONAL COHORT OF SOMATOTROPH TUMORS RECEIVING TRANSSPHENOIDAL SURGERY
Sean Lyne, MD; Kaasinath P Balagurunath, BA; Christopher S Hong, MD; Jakob Gerstl, MBBS; Ryan Chrenek, MD; Noah L Nawabi, BS; Rania A Mekary, PhD; Timothy R Smith, MD, PhD; Brigham and Women's Hospital
Introduction: Somatostatin analogue administration is a first line treatment used to shrink tumor volume prior to, or after transsphenoidal surgery. Despite their widespread usage, there is a subset of tumors which remain large, and require intervention through transsphenoidal surgery (TSS). There has been a lack of data on the preoperative and postoperative endocrinological characteristics and response to TSS on the basis of lesion size in acromegaly patients.
Objectives: To characterize the clinical characteristics and postoperative outcomes in acromegaly patients receiving transsphenoidal surgery for macroadenomas versus microadenomas.
Methods: In this single institution, retrospective study, a large cohort of 158 acromegaly patients who had received TSS for acromegaly were examined. Lesions at least 1 centimeter in maximum diameter were considered macroadenomas. Radiological, surgical, clinical, and endocrinological characteristics at baseline and postoperatively were tracked. 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 determine whether granulation pattern was predictive of postoperative outcome.
Results: Among the 158 patients with data available, 112 (70.9%) had macroadenomas and 46 (29.1%) had microadenomas. The rates of common preoperative symptoms were largely similar in large versus small tumors, such as headache (41.1% vs 39.1%) and acromegalic-bone changes (75.1% vs 73.9). Unsurprisingly, tumor induced visual field or visual acuity deficits were more common in macroadenomas (23.2% vs 13%). The rates of preoperative comorbidities and medication prescription were largely similar between groups.
Preoperatively, macroadenomas experienced higher rates of preoperative hyperprolactinemia (26.5% vs 12.8%), hypocortisolism (17.5% vs 4.7%), and hypothyroidism (23.6%). However, rates of preoperative hypercortisolism were higher in patients with microadenomas (16.3% vs 4.9%). Postoperatively, hypercortisolism and hypoprolactinemia remained the most common types of endocrine dysfunction. The majority of lesions included were intrasellar, with suprasellar-extension being more common in large lesions (48.1% vs 0%). Unsurprisingly, the maximum diameter (1.8 ± 0.7 cm vs 0.7 ± 0.2 cm) and lesion volume (2.8 ± 3.6 cm vs 0.2 ± 0.1 cm) were higher in the macroadenoma group. Tumor histology, including hormone co-staining and the MIB index, was largely similar between groups. Nearly all patients received endoscopic TSS (98.7% overall), and the most common Sellar reconstruction method was nasal packing.
Despite a lower rate of gross total resection in macroadenomas (79.5% vs 93.5%), the rates of biochemical remission (76.7% vs 73.3%) and recurrence (10.7% vs 8.7%) rates were largely similar between groups. Multivariate logistic regression demonstrated that large lesion size was not associated with a greater odds of developing complications such as a CSF leak, dysnatremia, recurrence, or failure of biochemical remission
Conclusion: Overall, despite differences in preoperative hormone dysfunction and gross total resection rates, lesion size was not associated with a greater risk of developing postoperative complications or failure to achieve biochemical remission.
