Biological Effective Dose as a Predictor of Hypopituitarism After Single-Fraction Pituitary Adenoma Radiosurgery: Dosimetric Analysis and Cohort Study of Patients Treated Using Contemporary Techniques. Issue 4 (19th January 2021)

• Record Type: Journal Article
• Authors: Graffeo, Christopher S; Perry, Avital; Link, Michael J; Brown, Paul D; Young, William F; Pollock, Bruce E
• Is Part Of: Neurosurgery. Volume 88:Issue 4(2021)
• Page Start: E330
• Page End: E335
• Publication Date: 2021-01-19
• Subjects: Pituitary adenoma -- Stereotactic radiosurgery -- Biological effective dose -- Hypopituitarism -- Complications; Nervous system -- Surgery -- Periodicals; 617.48005
• DOI: 10.1093/neuros/nyaa555
• Languages: English
• ISSNs: 0148-396X

Abstract

Abstract: BACKGROUND: Hypopituitarism is the most frequent complication after pituitary adenoma stereotactic radiosurgery (SRS) and is correlated with increasing radiation to the pituitary gland. Biological effective dose (BED) is a dosimetric parameter that incorporates a time component to adjust for mechanisms of deoxyribonucleic acid repair activated during treatment. OBJECTIVE: To assess mean gland BED as a predictor of post-SRS hypopituitarism, as compared to mean gland dose, in a contemporary cohort study of patients undergoing single-fraction SRS for pituitary adenoma. METHODS: Cohort study of 97 patients undergoing single-fraction SRS from 2007 to 2014. Eligible patients had no prior pituitary irradiation, normal pre-SRS endocrine function, and >24 mo of endocrine follow-up. Cox proportional hazards analysis was used to assess mean gland dose and BED as predictors of new post-SRS hypopituitarism. RESULTS: Median post-SRS follow-up was 48 mo (interquartile range [IQR], 34-68). A total of 27 patients (28%) developed new hypopituitarism at a median 22 mo (IQR, 12-36). Actuarial rates of new endocrinopathy were 17% at 2 yr (95% CI 10%-25%) and 31% at 5 yr (95% CI 20%-42%). On univariate analysis, sex ( P = .02), gland volume ( P = .03), mean gland dose ( P < .0001), and BED significantly predicted new hypopituitarism ( P < .0001). After adjusting for sex and gland volume, BED > 45 Gy2.47 and mean gland dose > 10 Gy were significantly associated increased risk of hypopituitarism (hazard ratio [HR] = 14.32, 95% CI = 4.26-89.0, P < .0001; HR = 11.91, 95% CI = 3.54-74.0, P < .0001). CONCLUSION: BED predicted hypopituitarism more reliably than mean gland dose after pituitary adenoma SRS, but additional studies are needed to confirm these results. Graphical Abstract: