Prognostic value of midtreatment FDG-PET in oropharyngeal cancer.

BACKGROUND Prognostic metabolic imaging indices are needed for risk stratification for patients with locally advanced oropharyngeal cancer. METHODS We retrospectively examined pretreatment and midtreatment fluorodeoxyglucose-positron emission tomography (FDG-PET) parameters in patients with locally advanced oropharyngeal cancer who were treated with definitive chemoradiation. RESULTS A total of 74 patients were evaluated. Pretreatment metabolic tumor volume (MTV) using threshold of 50% standardized uptake value (SUV) maximum (MTV50% ) was associated with progression-free survival (PFS; p = .003; hazard ratio [HR] = 1.57 per 10 cc; 95% confidence interval [CI] = 1.17-2.11) and overall survival (OS; p = .01; HR = 1.36 per 10 cc; 95% CI = 1.07-1.74). Midtreatment MTV using a threshold of SUV 2.0 (MTV2.0 ) was associated with PFS (p < .001; HR = 1.24 per 10 cc; 95% CI = 1.10-1.39) and OS (p = .009; HR = 1.21 per 10 cc; 95% CI = 1.05-1.39). Nodal total lesion glycolysis (TLG) velocity >5% decrease/week was associated with improved PFS (p = .04; HR = 0.37; 95% CI = 0.15-0.95). CONCLUSION Metabolic response during chemoradiation is associated with survival in locally advanced oropharyngeal cancer and may aid with risk-adapting treatment. © 2016 Wiley Periodicals, Inc. Head Neck 38: First-1478, 2016.