Long-Term Outcomes After Gamma Knife Radiosurgery Treatment of Craniopharyngiomas: A Swedish Nationwide Cohort With a Mean Follow-Up of 21 Years.

Background and objectives: Craniopharyngiomas are rare intracranial tumors associated with a high recurrence rate. Gamma Knife radiosurgery (GKRS) is a widely used modality to treat these tumors, either as primary or secondary treatment. Long-term control is desired, yet available evidence on the long-term efficacy of GKRS remains unknown because of the limited follow-up periods in existing studies. The aim of this study was to assess long-term outcomes of GKRS-treated craniopharyngiomas in a nationwide consecutive cohort.

Methods: All patients with craniopharyngiomas who were treated by GKRS at the Karolinska University Hospital between 1968 and 2010 were included. Progression-free survival (PFS), overall survival (OS), and potential predictors of tumor growth and survival were assessed.

Results: A total of 44 patients were included. Follow-up times ranged from 4 to 55 years, with a mean of 21 years and a median of 19 years. PFS was 64% at 5 years, 50% at 10 years, 45% at 20 years, and 40% at 30 years. No growth occurred after 30 years in patients who had been progression free until that point. 69% of recurrences required further treatment. OS was 91% at 5 years, 79% at 10 years, 64% at 20 years, and 64% at 30 years. Tumor volume was an independent predictor of tumor growth (OR 1.69, P = .020), and age (OR 1.07, P = .018) and tumor volume (OR 1.21, P = .049) were independent predictors of survival.

Conclusion: GKRS demonstrates sustained long-term efficacy in treating craniopharyngiomas, with a PFS rate of 40% at 30 years and no tumor growth observed beyond this point. Initial tumor volume should be assessed when planning GKRS treatment and follow-up of craniopharyngioma patients because it is a significant predictor of both tumor growth and OS.