Long-term tumor control following gamma-knife radiosurgery of recurrent or residual pituitary adenomas: a population-based cohort study.

Background: Pituitary adenomas (PAs) often require adjuvant Gamma Knife radiosurgery (GKRS) due to partial resection or postoperative recurrence. The purpose of this study was to evaluate the long-term efficacy of GKRS for such cases. Methods: Population-based, observational cohort study of patients who underwent GKRS for postoperative residual or recurrent PAs between 1999 and 2020. We assessed long-term progression-free survival (PFS), identified predictors of tumor growth, and documented adverse radiation events (AREs). Results: 147 patients were included, with a median follow-up time of 8.1 years. Following GKRS, the 5-year and 10-year PFS was 86% and 68%, respectively, with a median PFS of 18.7 years. Somatotrophic adenomas showed a significantly lower risk of tumor progression in the regression analysis (OR 0.11, p = 0.003). Hypopituitarism was the most common ARE, affecting 32% of patients. Conclusion: GKRS is an effective treatment option for recurrent or residual PAs, offering substantial long-term control. However, the risk for AREs, particularly hypopituitarism, is not negligeable. [ABSTRACT FROM AUTHOR]