Prognostic value of metastatic cervical lymph node stiffness in nasopharyngeal carcinoma: A prospective cohort study.

OBJECTIVES:Extracellular matrix stiffness plays an important role in tumorigenesis. In this study, we assessed the prognostic value of metastatic cervical lymph node (CLN) stiffness measured using ultrasound shear wave elastography (SWE) in patients with nasopharyngeal carcinoma (NPC). METHODS:A total of 325 consecutive patients with NPC and CLN metastases were prospectively enrolled in this study. The association between the CLN stiffness and patient characteristics was also evaluated. Survival analysis was performed for 307 patients with stage M0 disease. Distant metastasis-free survival (DMFS) was the primary endpoint. Log-rank test and multivariate analysis were used to explore the prognostic value of CLN stiffness. RESULTS:Eighteen patients developed distant metastases before treatment (stage M1) and had significantly higher CLN stiffness (Pt-test < 0.001) than the other patients (stage M0). For stage M0 patients, those in the high-stiffness group had lower 3-year DMFS (83.3% vs. 91.7%, P = 0.013) and 3-year progression-free survival (PFS) (78.2% vs. 87.9%, P = 0.015) than those in the low-stiffness group. Multivariate analysis identified CLN stiffness and pretreatment Epstein-Barr virus (EBV) DNA as independent prognostic factors for DMFS and PFS. We further established stiffness-EBV risk stratification based on these two factors. The concordance index, receiver operating characteristic curve, and decision curve analyses showed that our risk stratification outperformed the TNM classification for predicting metastasis. CONCLUSION:The stiffness of metastatic CLN is closely associated with the prognosis of patients with NPC. SWE can be used as a pretreatment examination for CLN-positive patients. A multicenter study is required to verify our results.