RT Journal Article SR Electronic T1 Prognostic value of pre-and post-induction chemotherapy FDG PET/CT in locally advanced oropharyngeal cancer patients. JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 1286 OP 1286 VO 61 IS supplement 1 A1 Hyukjin Yoon A1 Ie Ryung Yoo A1 Soo Jin Kwon A1 Sun Ha Boo A1 Seunggyun Ha YR 2020 UL http://jnm.snmjournals.org/content/61/supplement_1/1286.abstract AB 1286Background: The role of induction chemotherapy in locally advanced oropharyngeal cancer is still debatable. This study aims to assess the role of FDG PET/CT performed pre-and post-induction chemotherapy in prognosis of locally advanced oropharyngeal carcinoma patients. Methods: Twenty five locally advanced oropharyngeal carcinoma patients who underwent FDG PET/CT before and after 1~3 cycles of platinum-based induction chemotherapy were included. Tumor response was assessed with follow-up PET/CT using the Hopkins criteria. Also, metabolic parameters for primary tumor and lymph nodes were measured at baseline PET/CT. Treatment response and baseline PET/CT parameters were analyzed for overall survival (OS) and progression-free survival (PFS). Sub-group analysis was done according to HPV status, if status was known. Results: Median follow-up was 43.5 months. On whole group analysis, non-responders (n = 13) on follow-up PET/CT had a tendency for earlier progression compared the responders (n = 12). On multivariate analysis, primary tumor MTV was an independent predictor for OS (Odds ratio 4.8, p = 0.020). 18 patients had information on HPV status. In patients with positive HPV (n = 13) there was a tendency for less progression and death in responders (n = 6, 0 progression, 1 death) than in non-responders (n=7, 3 progression, 3 deaths). Conclusions: In locally advanced oropharyngeal carcinoma patients, response evaluation of induction chemotherapy with FDG PET/CT using Hopkins criteria may provide information for survival prognosis, especially in HPV positive cases. Primary tumor MTV on baseline PET/CT can be also be a biomarker for prognosis.