Addition of 18F-FDG PET/CT to Clinical Assessment Predicts Overall Survival in HNSCC: A Retrospective Analysis with Follow-up for 12 Years

F-18-FDG PET/CT is used in the follow-up of patients with head and neck squamous cell cancer (HNSCC). However, its impact on clinical decision making and patient outcome is not fully established. The objective of this study was to determine the prognostic value of F-18-FDG PET/CT for overall survival (OS) of HNSCC patients when performed in addition to clinical assessment between 4 and 24 mo after treatment. Methods: This was a retrospective study at a single tertiary center. The institutional review board approved this study, and the requirement to obtain informed consent was waived. The study included 134 biopsy-proven HNSCC patients with 227 follow-up PET/CT scans. The primary outcome measure was OS. Median follow-up was 40 mo (range, 7-145 mo). Survival is presented as Kaplan-Meier plots with Mantel-Cox log-rank test. The multivariate Cox model included clinical covariates. Results: Of the 227 PET/CT scans, 41(18%) were positive for tumor and 186 (82%) were negative for tumor. PET/CT identified recurrence in 5% (9/194) of scans performed without prior clinical concern and ruled out tumor in 51.5% (17/33) of scans performed to evaluate clinical suspicion or uncertainty of recurrence. The median survival of PET-positive and -negative groups from the date of the scan was 20 and 30.5 mo, respectively (P < 0.0001). There was a significant difference in OS from the scan date between patients who had a positive PET/CT result for tumor and those who had a negative result (log-rank, P < 0.0001), with a hazard ratio of 29.74. Human papillomavirus status (P = 0.001) and PET/CT result (P = 0.04) were the only factors significantly associated with OS, adjusted for all other covariates. Conclusion: F-18-FDG PET/CT performed between 4 and 24 mo after treatment adds value to clinical assessment at the time of the study, especially when there is clinical suspicion or uncertainty, and can serve as a prognostic marker of OS in HNSCC.