Single-center retrospective trial of bevaciumab for radiation necrosis after stereotactic radiosurgery for brain metastasis

Stereotactic radiosurgery (SRS) for brain metastases (BMs) can induce radiation necrosis (RN). A retrospective study at Rabin Medical Center (Petach Tikva, Israel) evaluated bevacizumab for SRS-induced RN. The cohort included 23 patients with a total of 31 RN lesions after SRS for BMs. Immediately after completion of bevacizumab treatment, 15 patients (65.2%) had complete or partial response, while 13 (56%) improved clinically. Greater than 50% of reduction in volume was observed in 84% of target lesions. At 12 months, among 13 patients still evaluable, three continued to improve, and four remained stable. During a median 15 months of follow-up, 11 patients experienced regrowth of the target lesion; median time to progression was 7 months. Five patients underwent bevacizumab re-challenge, but only two responded. The authors conclude that bevacizumab for the treatment of SRS-induced RN was associated with a high initial response rate, significant lesion reduction, and prolonged clinical improvement. However, with longer follow-up there was a high rate of lesion regrowth and poor response to bevacizumab re-challenge.