Failure Patterns After Salvage Stereotactic Radiosurgery for Recurrent High-Grade Gliomas

Overview

This study analyzed failure patterns and outcomes following salvage stereotactic radiosurgery (SRS) for recurrent high-grade gliomas (HGG). It identified clinical and demographic factors influencing treatment efficacy and failure locations, providing insights into patient selection for salvage SRS.

Background

High-grade gliomas are aggressive primary brain tumors with poor prognosis and high recurrence rates despite standard treatment involving surgery, radiotherapy, and chemotherapy. Management of recurrent HGG is challenging due to prior treatments and proximity to critical brain regions. Salvage stereotactic radiosurgery has emerged as a potential reirradiation strategy, but its efficacy is uncertain given the infiltrative nature of HGG. Understanding failure patterns after SRS can guide optimal patient selection and treatment planning.

Data Highlights

The study included adult patients with WHO Grade III and IV gliomas treated with single-fraction Gamma Knife SRS for recurrence. Failure locations were categorized as in-field, marginal, regional, or distant based on MRI imaging relative to the prescription isodose line. Survival outcomes including progression-free survival, overall survival, and local failure-free survival were analyzed using Kaplan-Meier and multilevel mixed-effects regression models accounting for intra-patient clustering.

Key Findings

• Salvage SRS was performed on recurrent HGG lesions with target volumes defined by MRI enhancement.
• Failure patterns were classified by distance from the treated volume: in-field, marginal (<2 cm), regional (2–5 cm), and distant (>5 cm).
• Multilevel mixed-effects models accounted for multiple lesions per patient and identified factors associated with failure risk and location.
• Local failure-free survival and progression-free survival were key endpoints, with competing-risks regression assessing the impact of dose and age.
• Results suggested that certain clinical and demographic factors may predict which patients derive the most benefit from salvage SRS.

Clinical Implications

Salvage SRS can be a viable option for selected patients with recurrent high-grade gliomas, particularly when considering lesion characteristics and patient factors such as age and prior treatments. Understanding failure patterns helps tailor treatment volumes and doses to maximize local control while minimizing toxicity. Multidisciplinary evaluation remains critical to optimize outcomes.

Conclusion

This study provides valuable insights into failure patterns after salvage SRS for recurrent HGG, highlighting the importance of patient selection and treatment planning to improve disease control. Further research is needed to refine predictive factors and optimize salvage strategies.

References

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