TY - JOUR T1 - <sup>18</sup>F-FDG PET/CT Is an Early Predictor of Pathologic Tumor Response and Survival After Preoperative Radiochemotherapy with Bevacizumab in High-Risk Locally Advanced Rectal Cancer JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 1560 LP - 1568 DO - 10.2967/jnumed.118.222604 VL - 60 IS - 11 AU - Antonio Avallone AU - Luigi Aloj AU - Biagio Pecori AU - Corradina Caracò AU - Alfonso De Stefano AU - Fabiana Tatangelo AU - Lucrezia Silvestro AU - Vincenza Granata AU - Francesco Bianco AU - Carmela Romano AU - Francesca Di Gennaro AU - Alfredo Budillon AU - Antonella Petrillo AU - Paolo Muto AU - Gerardo Botti AU - Paolo Delrio AU - Secondo Lastoria Y1 - 2019/11/01 UR - http://jnm.snmjournals.org/content/60/11/1560.abstract N2 - There is an unmet need for predictive biomarkers of the clinical benefit of antiangiogenic drugs. The aim of the present study was to prospectively evaluate the value of 18F-FDG PET/CT performed during and after preoperative chemoradiotherapy with bevacizumab for the prediction of complete pathologic tumor regression and survival in patients with MRI-defined high-risk locally advanced rectal cancer. Methods: Sixty-one patients treated in a nonrandomized phase II study (BRANCH) with concomitant or sequential (4 d before chemoradiotherapy) administration of bevacizumab with preoperative chemoradiotherapy were included. 18F-FDG PET/CT was performed at baseline, 11 d after the beginning of chemoradiotherapy (early), and before surgery (late). Metabolic changes were compared with pathologic complete tumor regression (TRG1) versus incomplete tumor regression (TRG2–TRG5), progression-free survival, cancer-specific survival, and overall survival. Receiver-operating-characteristic curves were calculated for those 18F-FDG PET/CT parameters that significantly correlated with TRG1. Results: Early total-lesion glycolysis and its percentage change compared with baseline (ΔTLG-early) could discriminate TRG1 from TRG2–TRG5. Only receiver-operating-characteristic analysis of ΔTLG-early showed an area under the curve greater than 0.7 (0.76), with an optimal cutoff at 59.5% (80% sensitivity, 71.4% specificity), for identifying TRG1. Late metabolic assessment could not discriminate between the 2 groups. After a median follow-up of 98 mo (range, 77–132 mo), metabolic responders (ΔTLG-early ≥ 59.5%) demonstrated a significantly higher 10-y progression-free survival (89.3% vs. 63.6%, P = 0.02) and cancer-specific survival (92.9% vs. 72.6%, P = 0.04) than incomplete metabolic responders. Conclusion: Our results suggest that early metabolic response can act as a surrogate marker of the benefit of antiangiogenic therapy. The findings provide further support for the use of early 18F-FDG PET/CT evaluation to predict pathologic response and survival in the preoperative treatment of patients with locally advanced rectal cancer. ΔTLG-early showed the best accuracy in predicting tumor regression and may be particularly useful in guiding treatment-modifying decisions during preoperative chemoradiotherapy based on expected response. ER -