Researchers have explored the impact of immune checkpoint inhibition and single-fraction stereotactic radiosurgery on radiation necrosis in patients with non–small cell lung cancer (NSCLC) brain metastases, according to a novel study published by Lehrer et al in the Journal of Neuro-Oncology.
Study Methods and Results
In the new multi-institutional retrospective cohort study, the researchers recruited 395 patients with a median age of 67 years who had 2,540 brain metastases and were treated with immune checkpoint inhibition and single-fraction stereotactic radiosurgery across four countries. The median margin stereotactic radiosurgery dose was 19 Gy, but 36.5% of the patients had a V12 Gy ≥ 10 cm3.
In a multivariate analysis, the researchers found that V12 Gy ≥ 10 cm3 was a significant predictor of developing any-grade radiation necrosis and symptomatic radiation necrosis. After a follow-up of 1 year, the cumulative incidence of any-grade radiation necrosis and symptomatic radiation necrosis for all of the patients involved in the study was 4.8% and 3.8%, respectively. For concurrent and nonconcurrent groups, the cumulative incidence of any-grade radiation necrosis was a respective 3.8% vs 5.3% and 3.8% vs 3.6% for symptomatic radiation necrosis.
“The risk of any-grade radiation necrosis and symptomatic radiation necrosis following single-fraction stereotactic radiosurgery and immune checkpoint inhibition for [NSCLC] brain metastases increases as V12 Gy exceeds 10 cm3,” explained senior study author Manmeet S. Ahluwalia, MD, MBA, FASCO, Chief of Medical Oncology, Chief Scientific Officer, Deputy Director, and the Fernandez Family Foundation Endowed Chair of Cancer Research at the Miami Cancer Institute. “Concurrent immune checkpoint inhibition and stereotactic radiosurgery do not appear to increase this risk,” he added.
Conclusions
“One of the key findings of the study is that immune checkpoint inhibition, when administered together with stereotactic radiosurgery, does not increase the risk of radiation necrosis. We did, however, find a relationship between the volume of the brain area that is targeted during radiation and radiation necrosis,” emphasized Dr. Ahluwalia. “[R]adiosurgical planning techniques should aim to minimize V12 Gy. In addition, the study suggests that treatment with immune checkpoint inhibitors can continue when radiation necrosis occurs,” he concluded.
Disclosure: The research in this study was organized by the International Radiosurgery Research Foundation. For full disclosures of the study authors, visit link.springer.com.
