The prognostic value of pretreatment FDG-PET parameters in HPV-associated oropharynx cancer

(18)Fluorodeoxyglucose positron-emission tomography (FDG-PET) has shown prognostic value in oropharynx cancer but data regarding patients with known human papillomavirus (HPV) status is limited. If prognostic, FDG-PET may play a role in the identification of patients suitable for treatment de-intensification. Patients with stage III-IVB squamous cell carcinoma of the oropharynx treated with definitive chemoradiation with known HPV status were identified. Clinical and PET parameters were compared between HPV-positive and HPV-negative patients and evaluated for prognostic value via Cox proportional hazards univariate and multivariate regression. Seventy patients were identified (58 HPV-positive, 12 HPV-negative) with a median follow-up of 41.5 months. HPV-negative tumors were associated with increased metabolic activity at the primary site but smaller cervical lymph nodes compared to HPV-positive tumors. Univariate and multivariate analysis identified the nodal maximum standard uptake value (SUVmax) as a predictor of disease-free (DFS) and overall survival (OS) among HPV-positive patients independent of other commonly used prognostic factors such as smoking and nodal stage. Pretreatment SUVmax in the nodal volume is a simple parameter that retains prognostic value in the HPV-era. Increased PET activity portends inferior DFS and OS and may be used in conjunction with other known prognostic factors, to identify patients inappropriate for treatment de-intensification strategies in the future.