Outcomes of systemic bevacizumab in radiation-induced optic neuropathy, case series.

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, though the limitations of our study do not allow us to draw this conclusion definitively. Therefore, the risks and potential benefits of using IV bevacizumab should be considered in each individual case.