Low Incidence of New-Onset Hypopituitarism After High-Precision Stereotactic Radiation Therapy of Sellar and Perisellar Lesions.

PURPOSE: Radiation therapy-induced hypopituitarism (RIH) is a common complication of radiation therapy, even if the pituitary gland is not the primary target but lies within the irradiation field. This study aimed to investigate the impact of high-precision radiation therapy for benign sellar and perisellar tumors, using radiosurgery or fractionated/hypofractionated stereotactic radiation therapy with the Novalis System (Brainlab), on functional pituitary integrity.

METHODS AND MATERIALS: Fifty-six patients who underwent stereotactic radiation therapy for meningiomas of the sellar or perisellar region of the skull base (n = 36) or pituitary adenomas (n = 20) were recruited between 2013 and 2021 at a single radiooncologic clinic. Fractionated stereotactic radiation therapy was the main irradiation technique (n = 42), followed by hypofractionated stereotactic radiation therapy (n = 4) and stereotactic radiosurgery (n = 10). Irradiation data were assessed retrospectively, and radiation exposure to the pituitary was measured by dose-volume histograms. Each patient received an endocrine diagnostic workup, including a comprehensive functional pituitary analysis.

RESULTS

The median age was 57 years (IQR, 50-63 years), and 42 of 56 patients (75%) were women. RIH was present in 10.7% (n = 6) of patients after a median follow-up of 83.5 months. Gonadotroph function was affected in 7.1% (n = 4) of patients, followed by corticotroph, thyreotroph, somatotroph, and lactotroph function, each at 1.8% (n = 1). Only 1 patient received hormonal replacement for RIH at the study visit.

CONCLUSIONS

Awareness of radiation therapy-induced damage to the pituitary gland is essential in the follow-up after radiation therapy of the surrounding structures of the hypothalamic-pituitary axis. High-precision fractionated stereotactic radiation therapy holds a low risk of RIH after irradiation of benign lesions of the sellar and perisellar region.