The prognostic significance of tumor vascular invasion and its association with plasma Epstein-Barr virus DNA, tumor volume and metabolic activity in locoregionally advanced nasopharyngeal carcinoma.

Parapharyngeal tumor invasion is a known predictor of distant recurrence in stage II-III nasopharyngeal carcinoma (NPC). This study evaluated the prognostic significance of parapharyngeal and cavernous sinus vascular invasion in stage III-IV NPC, and its association with plasma Epstein-Barr virus (pEBV) DNA, disease stage, tumor volume and metabolic activity. Eligible patients underwent magnetic resonance imaging (MRI), 18F-fluorodeoxyglucose (FDG)-positron-emission tomography (PET) and blood sampling for pEBV DNA before undergoing concurrent chemoradiotherapy. Relationship between treatment outcome and tumor vascular invasion was analyzed using Cox regression. Logistic regression was used to analyze the association between vascular invasion and other cofactors. Fifty seven patients with predominantly T3-T4 or N2-N3 stage disease were enrolled. Parapharyngeal invasion was present in 56% and cavernous sinus invasion in 19% of tumors. Multivariate analysis showed that tumor vascular invasion did not predict treatment outcome, while tumor FDG-uptake was the only significant factor that predicted survival and recurrence. Tumor vascular invasion was associated with T-stage, but not pEBV DNA or tumor volume. Parapharyngeal and cavernous sinus invasion were not significant predictors of distant recurrence following chemoradiotherapy in our cohort with locoregionally advanced NPC.