Prediction of Survival by [18F]Fluorodeoxyglucose Positron Emission Tomography in Patients With Locally Advanced Non–Small-Cell Lung Cancer Undergoing Definitive Chemoradiation Therapy: Results of the ACRIN 6668/RTOG 0235 Trial

Purpose In this prospective National Cancer Institute–funded American College of Radiology Imaging Network/Radiation Therapy Oncology Group cooperative group trial, we hypothesized that standardized uptake value (SUV) on post-treatment [ 18 F]fluorodeoxyglucose positron emission tomography (FDG-PET) correlates with survival in stage III non–small-cell lung cancer (NSCLC).Patients and Methods Patients received conventional concurrent platinum-based chemoradiotherapy without surgery; postradiotherapy consolidation chemotherapy was allowed. Post-treatment FDG-PET was performed at approximately 14 weeks after radiotherapy. SUVs were analyzed both as peak SUV (SUV peak ) and maximum SUV (SUV max ; both institutional and central review readings), with institutional SUV peak as the primary end point. Relationships between the continuous and categorical (cutoff) SUVs and survival were analyzed using Cox proportional hazards multivariate models.Results Of 250 enrolled patients (226 were evaluable for pretreatment SUV), 173 patients were evaluable for post-treatment SUV analyses. The 2-year survival rate for the entire population was 42.5%. Pretreatment SUV peak and SUV max (mean, 10.3 and 13.1, respectively) were not associated with survival. Mean post-treatment SUV peak and SUV max were 3.2 and 4.0, respectively. Post-treatment SUV peak was associated with survival in a continuous variable model (hazard ratio, 1.087; 95% CI, 1.014 to 1.166; P = .020). When analyzed as a prespecified binary value (≤ v > 3.5), there was no association with survival. However, in exploratory analyses, significant results for survival were found using an SUV peak cutoff of 5.0 (P = .041) or 7.0 (P < .001). All results were similar when SUV max was used in univariate and multivariate models in place of SUV peak .Conclusion Higher post-treatment tumor SUV (SUV peak or SUV max ) is associated with worse survival in stage III NSCLC, although a clear cutoff value for routine clinical use as a prognostic factor is uncertain at this time.