Avastin is an anti-angiogenic agent and a natural candidate for blocking vascular endothelial growth factor (VEGF) that produces leaky capillaries which are largely responsible for the edema and symptoms of radiation necrosis in the brain. A number of case reports and series have been published.
Seeing responses in patients treated with bevacizumab for their cancers, led to a placebo-controlled, double-blind, phase II trial sponsored by the U.S. Cancer Therapy Evaluation Program in which bevacizumab would be tested specifically for the treatment of radiation necrosis of the brain.
The trial (Gonzalers et al) was limited to those with progressive symptoms, lower-grade primary brain tumors, and head and neck cancers. All of the patients receiving bevacizumab responded almost immediately to treatment, with regression of necrotic lesions evident on magnetic resonance images, while none of the patients receiving the placebo showed a response. The results were striking, and all of the patients who switched from placebo showed a response to bevacizumab as well. So far, responses have persisted over 6 months even after the end of bevacizumab treatment. However, more studies are clearly needed. A recent series notes: " In children with pontine gliomas, bevacizumab may provide both therapeutic benefit and diagnostic information. More formal evaluation of bevacizumab in these children is needed." Another one concludes: "Bevacizumab, alone and in combination with other agents, can reduce radiation necrosis by decreasing capillary leakage and the associated brain edema. Our findings will need to be confirmed in a randomized trial to determine the optimal duration of treatment."
However, there are also reports of worsening necrosis on Avastin. A phase III study is clearly warranted. Until that is done, this remains an investigational approach. There is an ongoing study: The Role of Bevacizumab in the Treatment of Radiation Necrosis in Children With Central Nervous System Tumors NCT01201850. This study is being done to learn about the safety of the study drug bevacizumab(Avastin®), when used to treat radiation necrosis. The primary objective of this study is to test the feasibility of treating CNS tumor patients suffering from radiation necrosis with bevacizumab every 2 weeks.
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Torcuator R, Zuniga R, Mohan YS, Rock J, Doyle T, Anderson J, Gutierrez J, Ryu S, Jain R, Rosenblum M, Mikkelsen T.Initial experience with bevacizumab treatment for biopsy confirmed cerebral radiation necrosis. J Neurooncol. 2009 Aug;94(1):63-8.
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Liu AK, Macy ME, Foreman NK.Bevacizumab as therapy for radiation necrosis in four children with pontine gliomas.Int J Radiat Oncol Biol Phys. 2009 Nov 15;75(4):1148-54
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