MMDA-13 IMPACT OF BEVACIZUMAB DOSING ON EDEMA RESPONSE IN PATIENTS WITH RADIATION NECROSIS
Sydney Schultz, Jason Barreto, Carolyn Mead-Harvey, Ugur SenerAbstract
Background
Bevacizumab is a treatment for radiation necrosis; the optimal dosing remains inadequately studied.
Methods
Retrospective review of adult patients with primary central nervous system (CNS) tumors or brain metastasis treated with bevacizumab for radiation necrosis from 6/29/2021 to 7/31/2024. Primary outcome was to compare edema response with two different bevacizumab doses: 7.5 mg/kg and 10 mg/kg. Edema response was classified according to the following groups: (1) increase of edema, >105% of baseline; (2) constant edema, 75%-105% of baseline; (3) slight decrease of edema, 25%-75% of baseline; (4) large decrease of edema, <25% of baseline.
Results
104 patients were evaluated (median age 59 years, 56% male); 53 patients in the 7.5 mg/kg group and 51 patients in the 10 mg/kg group. Tumor type varied significantly across dosing groups (p < 0.001). In the 7.5 mg/kg group, tumor type was primary CNS (n = 23, 43%), lung (n = 14, 26%), breast (n = 8, 15%), melanoma (n = 4, 8%) and other (n = 4, 8%). In the 10 mg/kg group, tumor type was primary CNS (n = 43, 84%), lung (n = 2, 4%), melanoma (n = 2, 4%) and other (n = 4, 8%). Median number of bevacizumab doses administered was 4. There was a statistically significant difference in distribution of edema response across all response levels favoring bevacizumab 10 mg/kg (p = 0.032). When edema response was dichotomized (large decrease vs other), the difference remained statistically significant (p = 0.015).
Conclusion
Bevacizumab 10 mg/kg was more efficacious in terms of edema response; this result is impacted by the significantly higher incidence of primary CNS tumors in the 10 mg/kg dosing group.