Stereotactic radiosurgery for recurrent high-grade gliomas: a systematic review

Management of recurrent high-grade glioma (rHGG) is challenging. Contemporary therapeutic approaches include systemic chemotherapy, resection, conventional radiation, and stereotactic radiosurgery (SRS). Stereotactic radiosurgery is increasingly utilized given its low toxicity rates and relative efficacy. As the pace of research on this topic is rapidly evolving, a comprehensive review of the existing literature is necessary.

A systematic review in accordance with the preferred reporting in systematic review and meta-analysis guidelines (PRISMA) was conducted. PubMed and Science Direct databases were queried for articles which reported a primary analysis on a cohort of patients with recurrent gliomas (WHO grade III and IV) treated with SRS. Articles meeting the inclusion criteria and satisfying the quality threshold were included in the final review.

In total 22 articles representing 1,191 patients satisfied the inclusion criteria and quality threshold. The articles spanned a time frame from 1999 to March 2025. Tumor subtypes were distributed as 245 (20.6%) grade III and 946 (79.4%) grade IV. Linear accelerator (LINAC) based SRS was the most frequently utilized SRS platform treating a median tumor volume of 9.9cm³ (range: 1.21-44.0) with a median prescription dose of 16.5 Gy. At one-year, the pooled actuarial survival was 53%. At the time of last radiographic follow up, the pooled local progression and distant progression were 58% and 35% respectively. Grade ≥ 3 toxicity ranged from 0 to 14%.

For patients undergoing SRS for rHGG, overall survival times are consistent with alternative salvage therapies (chemotherapy, resection, and conventional radiotherapy) with relatively low treatment-related toxicity. Certain factors such as age, Karnofsky performance status (KPS), WHO grade, and interval between primary tumor treatment and reccurence/salvage SRS may be important in predicting treatment response.