Prospective study of tailoring whole-body dual-modality [18F] fluorodeoxyglucose positron emission tomography/computed tomography with plasma Epstein-Barr virus DNA for detecting distant metastasis in endemic nasopharyngeal carcinoma at initial staging

Abstract

Purpose To evaluate which patients with nasopharyngeal carcinoma (NPC) obtained the greatest benefits from the detection of distant metastasis with [18F]fluorodeoxyglucose positron emission tomography and computed tomography (PET/CT) combined with plasma Epstein-Barr virus (EBV) DNA levels. Patients and Methods Consecutive patients with NPC were prospectively enrolled. PET/CT, conventional work-up (CWU), and quantification of plasma EBV DNA were performed before treatment. The accuracy of these strategies for distant metastases was assessed. The costs of the diagnostic strategies were compared. Results Eighty-six (14.8%) of the 583 eligible patients were found to have distant metastases; 71 patients (82.6%) by PET/CT and 31 patients (36.0%) by CWU. In the multivariable analysis, advanced N stage (odds ratio, 2.689; 95% CI, 1.894 to 3.818) and pretreatment EBV DNA level (odds ratio, 3.344; 95% CI, 1.825 to 6.126) were significant risk factors for distant metastases. PET/CT was not superior to CWU for detecting distant metastases in very low-risk patients (N0-1 with EBV DNA < 4,000 copies/mL; P = .062), but was superior for the low-risk patients (N0-1 with EBV DNA ≥ 4,000 copies/mL and N2-3 with EBV DNA < 4,000 copies/mL; P = .039) and intermediaterisk patients (N2-3 disease with EBV DNA ≥ 4,000 copies/mL; P