Purpose:Optic neuropathy is a rare, delayed complication after radiation with no universally accepted treatment modality. We report the outcomes of 6 patients with radiation-induced optic neuropathy (RION) who were treated with systemic bevacizumab.Methods: This is a retrospective series of 6 cases of RION, treated with intravenous (IV) bevacizumab. "Improved" or "worse" visual outcomes were de ned as a change in best corrected visual acuity of ≥3 Snellen lines. Otherwise, the visual outcome was noted as "stable".Results: In our series, RION was diagnosed 8 to 36 months after radiotherapy. IV bevacizumab was initiated as treatment within 6 weeks of the onset of visual symptoms in 3 cases and after 3 months in the other cases. Although no improvement in visual function was observed, stabilization of vision was noted in 4 of the 6 cases. In the other 2 cases, the level of vision declined from counting ngers to no light perception. In 2 cases, bevacizumab treatment was discontinued prior to completion of the planned course due to renal stone formation or worsening of renal disease. One patient developed ischemic stroke 4 months after bevacizumab completion.Conclusion: Systemic bevacizumab may stabilize vision in some patients with RION; however, the risks and potential bene ts of using IV bevacizumab should be considered in each individual case.

Purpose:Optic neuropathy is a rare, delayed complication after radiation with no universally accepted treatment modality. We report the outcomes of 6 patients with radiation-induced optic neuropathy (RION) who were treated with systemic bevacizumab. Methods: This is a retrospective series of 6 cases of RION, treated with intravenous (IV) bevacizumab. “Improved” or “worse” visual outcomes were defined as a change in best corrected visual acuity of ≥3 Snellen lines. Otherwise, the visual outcome was noted as “stable”. Results: In our series, RION was diagnosed 8 to 36 months after radiotherapy. IV bevacizumab was initiated as treatment within 6 weeks of the onset of visual symptoms in 3 cases and after 3 months in the other cases. Although no improvement in visual function was observed, stabilization of vision was noted in 4 of the 6 cases. In the other 2 cases, the level of vision declined from counting fingers to no light perception. In 2 cases, bevacizumab treatment was discontinued prior to completion of the planned course due to renal stone formation or worsening of renal disease. One patient developed ischemic stroke 4 months after bevacizumab completion. Conclusion: Systemic bevacizumab may stabilize vision in some patients with RION; however, the risks and potential benefits of using IV bevacizumab should be considered in each individual case.