RT Journal Article SR Electronic T1 Response to Early Treatment Evaluated with 18F-FDG PET and PERCIST 1.0 Predicts Survival in Patients with Ewing Sarcoma Family of Tumors Treated with a Monoclonal Antibody to the Insulinlike Growth Factor 1 Receptor JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 735 OP 740 DO 10.2967/jnumed.115.162412 VO 57 IS 5 A1 Hyun O, Joo A1 Luber, Brandon S. A1 Leal, Jeffrey P. A1 Wang, Hao A1 Bolejack, Vanessa A1 Schuetze, Scott M. A1 Schwartz, Lawrence H. A1 Helman, Lee J. A1 Reinke, Denise A1 Baker, Laurence H. A1 Wahl, Richard L. YR 2016 UL http://jnm.snmjournals.org/content/57/5/735.abstract AB The aim of this study was to assess the prognostic and predictive value of early quantitative 18F-FDG PET to monitor therapy with an antibody to the insulinlike growth factor 1 receptor (IGF-1R antibody) in patients with Ewing sarcoma family of tumors (ESFT). Methods: 18F-FDG PET images at baseline and approximately 9 d after initiation of IGF-1R antibody therapy in 115 patients with refractory or relapsed ESFT were prospectively obtained as part of the Sarcoma Alliance for Research through Collaboration trial. Responses were centrally evaluated by PERCIST 1.0 in 93 patients. The 9-d PET responses were correlated to overall survival (OS), progression-free survival (PFS), and clinical benefit after 6 wk of therapy based on clinical observation and CT response by World Health Organization anatomic criteria. Results: The median OS was 8.1 mo (95% confidence interval, 6.4–10.0 mo). When PERCIST was used, patients with progressive metabolic disease showed shorter OS (median, 4.7 mo) than patients without progression (median, 10.0 mo; P = 0.001). Progressive metabolic disease on day-9 PET was associated with a significantly higher risk of death (hazard ratio, 2.8; 95% confidence interval, 1.5–5.5). Changes in 18F-FDG uptake after 9 d of therapy had an area under the curve of receiver-operating characteristic of 0.71 to predict 1-y OS. The area under the curve was 0.63 to predict progression at 3 mo and 0.79 to predict clinical benefit after 6 wk of therapy. Conclusion: Treatment response by quantitative 18F-FDG PET assessed by PERCIST 1.0 as early as 9 d into IGF-1R antibody therapy in patients with ESFT can predict the OS, PFS, and clinical response to therapy.