The maximum diameter of cervical lymph node was not a prognostic factor for local-regional advanced nasopharyngeal carcinoma treated with intensity modified radiotherapy

BACKGROUND: Cervical lymph node metastasis was an important prognostic factor. However, the prognosis of the maximum diameter of cervical lymph nodes before treatment has always been controversial. The aim of this study was to analyze the relationship between treatment outcomes and the maximum diameter of lymph nodes (Dmax) in loco-regional advanced nasopharyngeal carcinoma (NPC) after intensity modified radiotherapy. METHODS: From Jan. 2012 to Dec. 2017, 163 patients with locally advanced NPC treated with intensity modified radiotherapy were retrospectively analyzed. The T-stage distribution was 6.7% in T1, 23.3% in T2, 38.7% in T3, and 31.3% in T4. The N-classifications were 6.1% in N0, 23.3% in N1, 47.9% in N2, and 22.7% in N3. TNM stages were III 51.5% and IVa 48.5%. All patients received intensity modified radiotherapy to the nasopharynx and neck. The dose was 66–70.4 Gy, 2–2.2 Gy per fraction over 6–7 weeks to the primary tumor and lymph nodes and 54–60 Gy to clinical target volumes (CTVs). One hundred fifty patients were received induction chemotherapy and/or concurrent chemotherapy. The maximum diameter of the lymph node is measured on the axial or coronal MRI image. RESULTS: The median follow-up time was 31 months (range, 6.1–79.3 months). Six cases developed neck recurrence and 9 cases developed nasopharynx recurrence. The lymph nodes diameter was 0–12 cm, median 2.9 cm. Three-year overall survival (OS) rate was 77.8%. Three-year local failure-free rate (L-FFR), distant failure-free rate (D-FFR) and disease-free survival (DFS) rate were 88.1%, 77.6% and 63.9% respectively. Multivariate analysis showed Dmax was not a prognostic factor for OS, L-FFR, D-FFR, DFS. Both uni- and multivariate analyses demonstrated that N-classification and age is the significant prognostic factor for predicting OS while the maximum diameter of lymph nodes, T-classification, N-classification and AJCC-classification are the significant prognostic factor for predicting OS in univariate analyses in local-regional advanced NPC. CONCLUSIONS: The maximum diameter of the lymph nodes was not a prognostic factor for local-regional advanced NPC treated with intensity modulated radiotherapy.