Pretreatment ADC Histogram Analysis as a Prognostic Imaging Biomarker for Patients with Recurrent Glioblastoma Treated with Bevacizumab: A Systematic Review and Meta-analysis
R. Kurokawa, A. Baba, M. Kurokawa, A. Capizzano, O. Hassan, T. Johnson, Y. Ota, J. Kim, A. Hagiwara, T. Moritani, A. Srinivasan
Abstract
<h3>BACKGROUND:</h3> The mean ADC value of the lower Gaussian curve (ADC<sub>L</sub>) derived from the bi-Gaussian curve-fitting histogram analysis has been reported as a predictive/prognostic imaging biomarker in patients with recurrent glioblastoma treated with bevacizumab; however, its systematic summary has been lacking. <h3>PURPOSE:</h3> We applied a systematic review and meta-analysis to investigate the predictive/prognostic performance of ADC<sub>L</sub> in patients with recurrent glioblastoma treated with bevacizumab. <h3>DATA SOURCES:</h3> We performed a literature search using PubMed, Scopus, and EMBASE. <h3>STUDY SELECTION:</h3> A total of 1344 abstracts were screened, of which 83 articles were considered potentially relevant. Data were finally extracted from 6 studies including 578 patients. <h3>DATA ANALYSIS:</h3> Forest plots were generated to illustrate the hazard ratios of overall survival and progression-free survival. The heterogeneity across the studies was assessed using the Cochrane <i>Q</i> test and I<sup>2</sup> values. <h3>DATA SYNTHESIS:</h3> The pooled hazard ratios for overall survival and progression-free survival in patients with an ADC<sub>L</sub> lower than the cutoff values were 1.89 (95% CI, 1.53–2.31) and 1.98 (95% CI, 1.54–2.55) with low heterogeneity among the studies. Subgroup analysis of the bevacizumab-free cohort showed a pooled hazard ratio for overall survival of 1.20 (95% CI, 1.08–1.34) with low heterogeneity. <h3>LIMITATIONS:</h3> The conclusions are limited by the difference in the definition of recurrence among the included studies. <h3>CONCLUSIONS:</h3> This systematic review with meta-analysis supports the prognostic value of ADC<sub>L</sub> in patients with recurrent glioblastoma treated with bevacizumab, with a low ADC<sub>L</sub> demonstrating decreased overall survival and progression-free survival. On the other hand, the predictive role of ADC<sub>L</sub> for bevacizumab treatment was not confirmed.