Vance, Mary Lee

BACKGROUND: Delayed hypopituitarism is the most common complication after stereotactic radiosurgery (SRS) for pituitary adenomas. OBJECTIVE: To investigate the relationship between neuroanatomic structure distances from the radiation target and anterior pituitary function preservation after SRS through multicenter study. METHODS: We retrospectively reviewed the International Radiosurgery Research Foundation database from January 2002 to December 2021 for adult patients undergoing SRS for pituitary adenomas with >6 months of follow-up. Distances between centers or edges of hypothalamic-pituitary axis structures and SRS target volumes were measured using MRI. The primary outcome was anterior pituitary function preservation. Predictors were analyzed using multivariable logistic regression and area under the receiver operating curve (AUROC) curve analyses. RESULTS: Four hundred eighty-seven patients were categorized by preservation (n = 384) and no preservation (n = 103) of anterior pituitary function. The mean margin dose was 19.1(6.2) Gy. Larger distance from the center of the stalk to the tumor margin isodose was a positive predictor (adjusted odds ratio [aOR] = 1.162 [1.046-1.291], P = .005), while pre-SRS hypopituitarism (aOR = 0.646 [0.405-1.031], P = .067) and larger treatment volume (aOR = 0.965 [0.929-1.002], P = .061) were near negative predictors of the primary outcome. An interaction between the treatment volume and center stalk to margin isodose distance was found (aOR = 0.980 [0.961-0.999], P = .045). Center stalk to margin isodose distance had an AUROC of 0.620 (0.557-0.693), at 3.95-mm distance. For patients with treatment volumes of <2.34 mL, center stalk to margin isodose distance had an AUROC of 0.719 (0.614-0.823), at 2.95-mm distance. CONCLUSION: Achieving a distance between the center of the pituitary stalk and the tumor margin isodose ≥3.95 mm predicted anterior pituitary function preservation. For smaller treatment volumes <2.34 mL, the optimal distance was ≥2.95 mm. This may be modifiable during trans-sphenoidal resection to preserve pituitary function.

Abstract Objective: The aim was to formulate practice guidelines for endocrine evaluation and treatment of pituitary incidentalomas. Consensus Process: Consensus was guided by systematic reviews of evidence and discussions through a series of conference calls and e-mails and one in-person meeting. Conclusions: We recommend that patients with a pituitary incidentaloma undergo a complete history and physical examination, laboratory evaluations screening for hormone hypersecretion and for hypopituitarism, and a visual field examination if the lesion abuts the optic nerves or chiasm. We recommend that patients with incidentalomas not meeting criteria for surgical removal be followed with clinical assessments, neuroimaging (magnetic resonance imaging at 6 months for macroincidentalomas, 1 yr for a microincidentaloma, and thereafter progressively less frequently if unchanged in size), visual field examinations for incidentalomas that abut or compress the optic nerve and chiasm (6 months and yearly), and endocrine testing for macroincidentalomas (6 months and yearly) after the initial evaluations. We recommend that patients with a pituitary incidentaloma be referred for surgery if they have a visual field deficit; signs of compression by the tumor leading to other visual abnormalities, such as ophthalmoplegia, or neurological compromise due to compression by the lesion; a lesion abutting the optic nerves or chiasm; pituitary apoplexy with visual disturbance; or if the incidentaloma is a hypersecreting tumor other than a prolactinoma.