Early detection of nasopharyngeal carcinoma: performance of a short contrast-free screening MRI.

BACKGROUND:While contrast-enhanced MRI detects early-stage nasopharyngeal carcinoma (NPC) not detected by endoscopic-guided biopsy (EGB), a short contrast-free screening MRI would be desirable for NPC screening programs. This study evaluated a screening MRI in a plasma Epstein-Barr virus (EBV)-DNA NPC screening program. METHODS:EBV-DNA screen positive patients underwent endoscopy and endoscopy-positive patients underwent EGB. EGB was negative if biopsy was negative or was not performed. Patients also underwent a screening MRI. Diagnostic performance was based on histologic confirmation of NPC in the initial study or during a follow-up period of at least 2 years. RESULTS:The study prospectively recruited 354 patients for MRI and endoscopy, 40/354 (11.3%) endoscopy-positive patients underwent EGB. Eighteen had NPC (5.1%) and 336 without NPC (94.9%) were followed-up for a median of 44.8 months. MRI detected additional NPCs in 3/18 (16.7%) endoscopy-negative and 2/18 (11.1%) EGB-negative patients (stage I/II, n = 4; stage III, n = 1). None of the 24 EGB-negative patients who were MRI-negative had NPC. MRI missed NPC in 2/18 (11.1%), one of which was also endoscopy-negative. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of MRI, endoscopy and EGB were 88.9%, 91.1%, 34.8%, 99.4% and 91.0%; 77.8%, 92.3%, 35.0%, 98.7% and 91.5%; 66.7%, 92.3%, 31.6%, 98.1% and 91.0%, respectively. CONCLUSION:A quick contrast-free screening MRI complements endoscopy in NPC screening programs. In EBV-screen-positive patients, MRI enables early detection of NPC that is endoscopically occult or negative on EGB and increases confidence that NPC has not been missed.