Hypopituitarism after gamma knife radiosurgery for pituitary adenomas: long-term results from a single-center experience

Abstract

Purpose The aim of this study was to investigate the incidence and risk factors of hypopituitarism after gamma knife radiosurgery (GKRS) for pituitary adenomas in a single center. Methods In this retrospective study, 241 pituitary adenoma patients who underwent GKRS from 1993 to 2016 were enrolled. These patients had complete endocrine, imaging, and clinical data before and after GKRS. The median follow-up time was 56.0 (range, 12.7–297.6) months. Results Fifty patients (20.7%) developed new-onset hypopituitarism after GKRS, including hypogonadism (n = 22), hypothyroidism (n = 29), hypocortisolism (n = 20), and growth hormone deficiency (n = 4). The median time to new-onset hypopituitarism was 44.1 (range, 13.5–141.4) months. The rates of new-onset hypopituitarism were 3%, 11%, 18%, 37%, and 45% at 1, 3, 5, 10, and 15 years, respectively. In univariate analysis, sex (p = 0.012), suprasellar extension (p = 0.024), tumor volume (≥ 5 cm³) (p = 0.002), tumor margin dose (> 16 Gy) (p = 0.028), pre-existing hypopituitarism (p = 0.008), and previous surgery (p = 0.007) were significantly associated with new-onset hypopituitarism. In multivariate analysis, only tumor volume (≥ 5 cm³) and previous surgery were independent risk factors associated with new-onset hypopituitarism (hazard ratio [HR] = 2.149, 95% confidence interval [CI] = 1.190–3.880, p = 0.011 and HR = 1.893, 95% CI = 1.066–3.361, p = 0.029, respectively). Conclusion New-onset hypopituitarism was not uncommon after GKRS for pituitary adenomas. In this study, large tumor volume (≥ 5 cm³) and previous surgery before GKRS were associated with new-onset hypopituitarism.