Background: Positron emission tomography/computed tomography (PET/CT) in staging of advanced oropharyngeal squamous cell carcinoma (OPSCC) and at 3 months posttreatment (PETpost) is often utilized to assess response. The significance of lymph node vs primary site treatment response is incompletely understood.
Methods: We reviewed 230 patients treated with radiation therapy. PETpost response was graded at primary and nodal sites and correlated with survival.
Results: Median age was 58, and 83% were p16-positive. Median follow-up was 24.3 months. Nodal response at PETpost predicted improved 2-year local recurrence-free survival (LRFS) (93% vs 72%, P =.004), 2-year disease-free survival (DFS) (80% vs 61.3%, P =.021), and 2-year overall survival (OS) (89% vs 83%, P =.051), while primary response only predicted improved 2-year LRFS (91% vs 76% P = .035).
Conclusion: In OPSCC patients, both nodal and primary response at 3 months on PET/CT predicted for improved LRFS, but only nodal response predicted DFS and OS.
Keywords: Oropharyngeal squamous cell carcinoma (OPSCC); PET/CT response assessment; head and neck cancers (HNC); human papilloma virus (HPV); intensity-modulated radiation therapy (IMRT); positron emission tomography/computed tomography (PET/CT).
© 2020 Wiley Periodicals, Inc.