2590 - Incidence of Radiation Necrosis with Immunotherapy in the Management of Brain Metastasis: A Systematic Review and Meta-Analysis
Presenter(s)
R. Neill1, M. Fis Loperena1, V. Dreyer1, P. Harris2, S. Goyal3, and L. Daggubati4,5; 1The George Washington University School of Medicine and Health Sciences, Washington, DC, 2The George Washington University Hospital, Washington, DC, 3Department of Radiation Oncology, George Washington University School of Medicine and Health Sciences, Washington, DC, 4Department of Neurosurgery, George Washington University School of Medicine and Health Sciences, Washington, DC, 5The George Washington University Medical Faculty Associates, Washington, DC
Purpose/Objective(s): Cerebral radiation necrosis is an adverse, inflammatory reaction following radiotherapy which can lead to a variety of clinical consequences, including cognitive impairment, focal deficits, and seizures. Various studies have reported mixed results on whether use of immunotherapy is associated with increased radiation necrosis following radiation therapy for the treatment of brain metastases. This study investigates this comparative incidence via a systematic review and meta-analysis.
Materials/Methods: Following a literature review, search parameters for a systematic review were identified and relevant studies were sorted based on selection criteria to be included in meta-analysis following PRISMA guidelines. Data analysis was performed in statistical software and spreadsheet software. Targeted reports for analysis sought to quantify the risk of radiation necrosis with immunotherapy in treating brain metastases. A logistic regression was coupled with pooled estimates calculating odds ratios for dichotomous outcomes with corresponding 95% confidence intervals; findings were translated into illustrative tables and figures.
Results: 36 articles were included for final analysis from 1,892 abstract screenings. A total of 4,731 cases were statistically analyzed with 814 total cases of radiation necrosis, 499 with the immunotherapy group and 315 with radiation alone. Summative analysis revealed an increased incidence of radiation necrosis when immunotherapy is coupled with radiation therapy (21.9%), versus radiation therapy alone (12.8%). Logistic regression indicated a 91% greater odds of radiation necrosis with immunotherapy versus radiation therapy alone (OR 1.91 with 95% CI 1.64 to 2.23 and p<0.001).
Conclusion: The use of immunotherapy was associated with increased incidence of radiation necrosis following radiation for treatment of brain metastases compared to radiation therapy without immunotherapy. Future studies are needed to further assess potential mechanisms for these differentiated outcomes and assess the risks and benefits of adding immunotherapy into treatment plans.