Optimal timing of post-treatment [18F]fluorodeoxyglucose-PET/CT for patients with head and neck malignancy

The aims of this study were to evaluate the ability of [F]fluorodeoxyglucose (F-FDG)-PET/computed tomography (CT) to identify tumor recurrence, nodal metastases, and distant metastases for surveillance and discuss the optimal timing of F-FDG-PET/CT examination after the completion of treatment for head and neck malignancy.

A total of 319 patients who underwent a post-treatment F-FDG-PET/CT examination for head and neck malignancy were studied. F-FDG-PET/CT findings were compared with the final diagnosis confirmed by histopathological examinations or clinical and radiological follow-up for at least 6 months. Patients were divided into two groups according to the presence or absence of clinical suspicion of recurrent disease. The diagnostic accuracy of F-FDG-PET/CT was analyzed for each group. Patients were also categorized according to the time interval between the completion of treatment and the post-treatment F-FDG-PET/CT examination. Differences in diagnostic accuracy due to the time interval were also evaluated.

The diagnostic accuracy of F-FDG-PET/CT was high for both groups. The overall accuracy of F-FDG-PET/CT performed within 2 months (69%) after the completion of treatment was significantly inferior to that performed after 2 months (93%).

F-FDG-PET should be performed immediately for patients with clinically suspected recurrent disease. In others, it should be performed at later than 2 months after the completion of the treatment.