Performance of whole-body ¹⁸ F-FDG PET/CT as a posttreatment surveillance tool for sinonasal malignancies

Purpose: To determine the diagnostic utility of posttreatment surveillance whole-body ¹⁸ F-FDG PET/CT in detecting local tumor recurrence (R), regional lymph-node metastasis (LM), and distant metastasis (DM) in asymptomatic sinonasal cancer patients. Methods: Eighty consecutive patients (53 men, 27 women; mean age, 60 years; range, 28–92 years) who had undergone 197 posttreatment whole-body ¹⁸ F-FDG PET/CT examinations for sinonasal malignancies between January 2009 and August 2017 were retrospectively reviewed. ¹⁸ F-FDG PET/CT findings were categorized as positive or negative for R, LM, and DM, separately. Outcomes of ¹⁸ F-FDG PET/CT scans were compared with the final diagnosis confirmed by histological analysis or follow-up period for a minimum 12 months. The diagnostic accuracy of scans was calculated for each site using contingency tables. Impact on the management of ¹⁸ F-FDG PET/CT examinations was additionally evaluated. Results: ¹⁸ F-FDG PET/CT scans identified 37/44 of local recurrences, 21/23 of LMs, and 30/37 of DMs. For local recurrence, sensitivity, specificity, positive predictive value, and negative predictive value were 84% (68–97%), 95% (80–100%), 84% (68–97%), and 95% (80–100%), respectively. For LM, the respective values were 91% (75–100%), 99% (83–100%), 91% (75–100%), and 99% (83–100%). For DM, the values were 81% (64–97%), 99% (85–100%), 97% (81–100%), and 96% (81–100%), respectively. ¹⁸ F-FDG PET/CT accounted for a change in management of 85% patients with recurrences. Conclusions: Whole-body ¹⁸ F-FDG PET/CT is a suitable surveillance tool for sinonasal malignancies in detecting locoregional and distant recurrences in asymptomatic patients without any evidence of recurrence on regular follow-up and endoscopy during the posttreatment period.