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Survival outcome of early versus delayed bevacizumab treatment in patients with recurrent glioblastoma.
Abstracts that were granted an exception in accordance with ASCO's Conflict of Interest Policy are designated with a caret symbol (^).
Background: Bevacizumab (BEV) is widely used for treatment of patients with recurrent glioblastoma (GB). Differences in outcome between early versus delayed BEV treatment of recurrent GB are not well defined. We examined the relationship between the time of start of BEV treatment and outcomes in patients with recurrent GB. Methods: In this retrospective chart review derived from our longitudinal database, we identified patients with recurrent GB between 2001 and 2011, who were treated with BEV alone or BEV-containing regimens. Data was analyzed to determine overall survival (OS) from time of diagnosis and progression free survival (PFS) from time of BEV start. Early BEV was defined as start of BEV treatment at first recurrence, while delayed BEV was defined as start of treatment at second recurrence or later. Results: A total of 298 patients with recurrent GB who received BEV were identified, of whom 149 patients received early BEV, 134 patients received delayed BEV, and 15 patients who were excluded because they received BEV upfront. There were no significant differences in the age, sex, performance status and extent of resection between patients treated with early BEV and those treated with delayed BEV. The median time from diagnosis to first recurrence was more than 6 months (mos.) for both groups (6.5 mos. for early BEV and 7.6 mos. for delayed BEV, p = 0.01). The median time from diagnosis to start of BEV was 7.9 mos. for patients with early BEV and 15.6 mos. for patients with delayed BEV (p<0.001). There was no significant difference in PFS between patients that received early BEV and those that received delayed BEV (5.73 mos. vs. 4.33 mos., p = 0.07). Patients who were treated with delayed BEV had longer OS when compared to those treated with early BEV (25.9 mos. vs. 19.7 mos., p = 0.0002). Conclusions: In patients with recurrent GB, there was no significant difference in PFS between early and delayed BEV; however, patients treated with delayed BEV have longer OS when compared to those treated with early BEV. These results indicate that delaying treatment with BEV is not detrimental and may be associated with a favorable survival outcome.