Reversal of cerebral radiation necrosis with bevacizumab treatment in 17 Chinese patients

Abstract

Background: Bevacizumab has been suggested as a new treatment modality for cerebral radiation necrosis due to its ability to block the effects of vascular endothelial growth factor (VEGF) in leakage-prone capillaries, though its use still remains controversial in clinical practice.

Methods: The use of bevacizumab in 17 patients with symptomatic cerebral radiation necrosis poorly controlled with dexamethasone steroid treatments was examined between March 2010 and January 2012. Bevacizumab therapy was administered for a minimum of two cycles (7.5 mg/kg, at two-week interval) with a median of four bevacizumab injections. Changes in bi-dimensional measurements of the largest radiation necrosis lesions were observed by gadolinium-enhanced and T2-weighted magnetic resonance imaging (MRI). Additionally, dexamethasone dosage, Karnofsky performance status (KPS), adverse event occurrence and associated clinical outcomes were recorded for each patient.

Results: MRI analysis revealed that the average reduction was 54.9% and 48.4% in post-gadolinium and T2-weighted sequence analysis, respectively. Significant clinical neurological improvements were expressed in 10 patients according to KPS values. Dexamethasone reduction was achieved four weeks after initiation of bevacizumab in all patients, with four patients successfully discontinuing dexamethasone treatment. Mild to moderate bevacizumab-related adverse events, such as fatigue, proteinuria and hypertension were observed in three patients. Upon follow-up at 4 to 12 months, 10 patients showed clinical improvement, and 7 patient deaths occurred from tumor progression (5 patients), recurrent necrosis (1 patient), and uncontrolled necrosis-induced edema (1 patient).

Conclusions: These findings suggest bevacizumab as a promising treatment for cerebral radiation necrosis induced by common radiation therapies, including external beam radiotherapy (EBRT), stereotactic radiosurgery (SRS), and fractionated stereotactic radiotherapy (FSRT).

Figure 1

MRI images before (A, B) and after (C, D) bevacizumab treatment in Patient No. 5. Patient No. 5 (Table 1) received two cycles of bevacizumab (7.5 mg/kg, two-week intervals) for brain metastatic tumor from non-small cell lung carcinoma cancer. The patient also received cyberknife treatment system based FSRT with 31.5 Gy in three fractions seven months prior to treatment.