Prognostic value of pretreatment F-FDG PET/CT and human papillomavirus type 16 testing in locally advanced oropharyngeal squamous cell carcinoma.

Purpose: Human papillomavirus type 16 (HPV-16) positivity is associated with favourable survival in oropharyngeal squamous cell carcinoma (OPSCC). We report here a study of the prognostic significance of F-FDG PET/CT functional parameters and HPV-16 infection in OPSCC patients. Methods: We retrospectively analysed 60 patients with stage III or IV OPSCC who had had a pretherapy F-FDG PET/CT scan and had completed concurrent chemoradiotherapy ( n = 58) or curative radiotherapy ( n = 2). All patients were followed up for ≥24 months or until death. We determined total lesion glycolysis (TLG) and the maximal standardized uptake values (SUV) of the primary tumour and neck lymph nodes from the pretherapy F-FDG PET/CT scan. Optimal cut-offs of the F-FDG PET/CT parameters were obtained by receiver operating characteristic (ROC) curve analyses. Pretherapy tumour biopsies were studied by polymerase chain reaction to determine HPV infection status. Results: The pretherapy tumour biopsies were positive for HPV-16 in 12 patients (20.0 %). Cox regression analyses revealed HPV-16 positivity and tumour TLG >135.3 g to be independently associated with overall survival ( p = 0.027 and 0.011, respectively). However, only tumour TLG >135.3 g was independently associated with progression-free survival, disease-free survival and locoregional control ( p = 0.011, 0.001 and 0.034, respectively). A scoring system was formulated to define distinct overall survival groups using tumour TLG and HPV-16 status. Patients positive for HPV-16 and with tumour TLG ≤135.3 g experienced better survival than those with tumour TLG >135.3 g and no HPV infection ( p = 0.001). Conclusion: Tumour TLG was an independent predictor of survival in patients with locally advanced OPSCC. A scoring system was developed and may serve as a risk stratification strategy for guiding therapy. [ABSTRACT FROM AUTHOR]