Role of whole-body ¹⁸F-FDG PET/CT in screening for metastases in newly diagnosed sinonasal malignancies

OBJECTIVE. The aim of this study is to assess the utility of pretreatment whole-body ¹⁸F-FDG PET/CT in screening for distant metastasis (DM) and regional lymphatic metastasis (LM). MATERIALS AND METHODS. Eighty-nine consecutive patients with untreated sinonasal malignant lesions (32 women and 57 men; mean age, 62 years) underwent whole-body FDG PET/CT between January 2009 and August 2017. A retrospective analysis was performed to determine the presence of DM and LM. Any suspected metastases were confirmed by histopathologic analysis or clinical and imaging follow-up in the subsequent 12 months. The statistics were verified by comparing FDG PET/CT results with a reference standard. RESULTS. Overall, the frequency of DM was 24% (21/89), of which 81% (17/21) were identified by whole-body FDG PET/CT. The sensitivity and specificity of FDG PET/CT in predicting DM were 81% (95% CI, 62-95%) and 99% (95% CI, 82-100%), respectively. The most common DM sites were the lungs (n = 6; 28%) and bones (n = 5; 24%), followed by the liver (n = 2; 10%), brain (n = 1; 5%), and spinal canal (n = 1; 5%), with six patients (28%) having DMs at multiple sites. Overall, the frequency of LM according to the reference standard was 20%, of which 83% (15/18) were confirmed with FDG PET/CT. The sensitivity and specificity of FDG PET/CT in detecting LM were 83% (95% CI, 68-97%) and 96% (95% CI, 77- 100%), respectively. CONCLUSION. Our study showed that whole-body FDG PET/CT can be used as a screening tool for the detection of DM and LM in sinonasal neoplasms and could be performed as part of the routine pretreatment evaluation of metastatic workup.