Bevacizumab for stereotactic radiosurgery-induced radiation necrosis in patients with non-small cell lung cancer treated with immune check-point inhibitors.

Background: Bevacizumab was shown to be effective in the treatment of brain radiation necrosis (RN) attributed to the use of stereotactic radiosurgery (SRS). Data on its efficacy and safety in non-small cell lung cancer (NSCLC) patients treated with immune check-point inhibitors (ICI) is lacking.

Methods: A multi-center retrospective analysis of all consecutive patients with NSCLC treated with ICI, who received bevacizumab for post-SRS RN between April 2017 and June 2020. Improvement in RN-associated symptoms, RN radiological improvement, and decrease in corticosteroid dose following bevacizumab initiation were assessed.

Results: Thirteen patients were identified. The median time from diagnosis of RN to initiation of bevacizumab was 3 months (range 1.1-7.8 months), and the median number of bevacizumab cycles before assessment was 2 (range, 1-5). Patients continued ICI during treatment with bevacizumab. Improvement in RN-associated symptoms was observed in 11 patients (85%). In ten patients (77%) the daily dose of dexamethasone was decreased. Radiological improvement of RN occurred in all 11 cases available for radiological assessment (100%). Treatment was withheld in two patients for grade 3-4 toxicity. At a median follow up of 11.9 months (range 2.0-35.4 months), one patient experienced a recurrent episode of RN; the estimated median survival since RN diagnosis was 21.9 months (95% CI 3.8-40.2 months).

Conclusion: Treatment with bevacizumab appears to be safe and effective for the treatment of SRS-induced RN in patients with NSCLC treated with ICI. This is the first series to report on the use of bevacizumab in this clinical scenario.