The impact of different volumetric thresholds to determine progressive disease in patients with recurrent glioblastoma treated with bevacizumab.

Early appearing new lesions were associated with poor OS. Lowering the volumetric threshold for PD at both first and second follow-up improved survival prediction. However, the additional number of patients categorized as PD by lowering the threshold was very low. The per-RANO added change in nonenhancing volumes to the analyses was of limited value.