Effects of Neuroanatomic Structural Distances on Pituitary Function After Stereotactic Radiosurgery: A Multicenter...

Area of Science:

• Neurosurgery
• Radiation Oncology
• Endocrinology

Background:

• Delayed hypopituitarism is a common complication following stereotactic radiosurgery (SRS) for pituitary adenomas.
• Preserving anterior pituitary function after SRS is crucial for patient outcomes.

Purpose of the Study:

• To investigate the relationship between the distance of neuroanatomic structures from the radiation target and anterior pituitary function preservation after SRS.
• To identify predictive factors for anterior pituitary function preservation following SRS for pituitary adenomas.

Main Methods:

• Retrospective review of the International Radiosurgery Research Foundation database (2002-2021).
• Analysis of 487 adult patients with pituitary adenomas treated with SRS and >6 months follow-up.
• Measurement of distances between hypothalamic-pituitary axis structures and SRS target volumes using MRI; multivariable logistic regression and AUROC analyses.

Main Results:

• A larger distance between the pituitary stalk center and tumor margin isodose was a positive predictor of pituitary function preservation (aOR=1.162, P=.005).
• Pre-SRS hypopituitarism and larger treatment volumes were near negative predictors.
• An optimal distance of ≥3.95 mm predicted function preservation, with an AUROC of 0.620. For smaller treatment volumes (<2.34 mL), an optimal distance of ≥2.95 mm yielded an AUROC of 0.719.

Conclusions:

• A distance of ≥3.95 mm between the pituitary stalk and tumor margin isodose predicts anterior pituitary function preservation after SRS for pituitary adenomas.
• For smaller treatment volumes (<2.34 mL), a distance of ≥2.95 mm is optimal.
• These distances may be modifiable during trans-sphenoidal resection to enhance pituitary function preservation.