Intracavitary irradiation with phosphorus-32 for cystic craniopharyngiomas: a systematic review and single-arm meta-analysis.

Cystic craniopharyngiomas (CPs) are benign tumors and due to the anatomic position next to critical neurological structures remains a therapeutic challenge. In order to prevent bigger complications, the intracavitary irradiation with phosphorus-32 (³²P) emerged as a minimally invasive strategy to control cystic components and delay or avoid external-beam radiotherapy. A systematic search of publications was conducted in databases including PubMed, Embase, and the Cochrane Library, covering studies published up to July 2025. The risk of bias was assessed using the ROBINS-I tool, as recommended by Cochrane. Data analysis was performed using RStudio (version 2025.05.0). Eight studies comprising 285 patients were included. The pooled complete cyst reduction rate was 25.62% (95% CI 13.47–43.26, I² = 84.1%), partial reduction was 53.32% (95% CI 45.31–61.16, I² = 45.7%), and cyst volume increase was 12.88% (95% CI 4.42–32.10, I² = 79.8%). Visual improvement was reported in 59.63% (95% CI: 35.32–79.98; I² = 82.5%) of patients for visual acuity and 68.82% (95% CI: 42.41–86.87; I² = 87.9%) for visual fields. The pooled neurological complication rate was 4.88% (95% CI 2.72–8.62, I² = 0%), and the 5-year overall survival was 92.26% (95% CI 79.15–97.39, I² = 75.4%). The intracavitary irradiation with ³²P may represent a therapeutic option for cystic craniopharyngiomas, showing encouraging results across clinical, radiological and safety outcomes. However, more and larger studies are needed to confirm its efficacy and safety.