Prognostic Value and Staging Classification of Retropharyngeal Lymph Node Metastasis in Nasopharyngeal Carcinoma Patients Treated with Intensity-modulated Radiotherapy

Abstract

BackgroundThe development of intensity-modulated radiotherapy (IMRT) has revolutionized the management of nasopharyngeal carcinoma (NPC). The purpose of this study was to evaluate the prognostic value and classification of TNM stage system for retropharyngeal lymph node (RLN) metastasis in NPC in the IMRT era.Material and MethodsWe retrospectively reviewed data from 749 patients with biopsy-proven, non-metastatic NPC. All patients received IMRT as the primary treatment. Chemotherapy was administered to 86.2% (424/492) of the patients with stage III or IV disease.ResultsThe incidence of RLN metastasis was 64.2% (481/749). Significant differences were observed in the 5-year disease-free survival (DFS; 70.6% vs. 85.4%, P<0.001) and distant metastasis-free survival (DMFS; 79.2% vs. 90.1%, P<0.001) rates of patients with and without RLN metastasis. In multivariate analysis, RLN metastasis was an independent prognostic factor for disease failure and distant failure (P = 0.005 and P = 0.026, respectively), but not for locoregional recurrence. Necrotic RLN metastases have a negative effect on disease failure, distant failure and locoregional recurrence in NPC with RLN metastasis (P = 0.003, P = 0.018 and P = 0.005, respectively). Survival curves demonstrated a significant difference in DFS between patients with N0 disease and N1 disease with only RLN metastasis (P = 0.020), and marginally statistically significant differences in DMFS and DFS between N1 disease with only RLN metastasis and other N1 disease (P = 0.058 and P = 0.091, respectively). In N1 disease, no significant differences in DFS were observed between unilateral and bilateral RLN metastasis (P = 0.994).ConclusionsIn the IMRT era, RLN metastasis remains an independent prognostic factor for DFS and DMFS in NPC. It is still reasonable for RLN metastasis to be classified in the N1 disease, regardless of laterality. However, there is a need to investigate the feasibility of classifying RLN metastasis as N1a disease in future by a larger cohort study.

Prognostic value of pretreatment 18F-FDG PET-CT for nasopharyngeal carcinoma patients.

“…It is possible that LN metastasis correlates better with distant metastasis-free survival (DMFS). [30,31] Since the data included in our analysis did not contain DMFS values, this hypothesis has to be verified with further studies. Hung et al [34] suggested that the SUVmax of the LNs in the neck region is an independent prognostic factor for DMFS in NPC patients treated with intensity-modulated radiation therapy (IMRT).…”

“…Patients with primary tumors characterized by a high SUV value before treatment have been demonstrated to have poor survival rates in cases of head and neck squamous cell carcinoma, lung cancer, esophageal cancer, and cervical cancer. [17][18][19]30] Another study involving meta-analysis of HNC patient data concluded that primary tumors with a high MTV or TLG before treatment are associated with worse patient survival rates. [12] The use of SUV, MTV, and TLG parameters for predicting disease prognosis is worthy of systematic evaluation in both HNC and head and neck squamous cell carcinoma (HNSCC), based on studies cited above.…”

“…[30][31][32] A recent meta-analysis survey has suggested that PET-CT is a highly reliable diagnostic tool for detecting LN metastasis. [33] Prognostic efficacy of SUV, MTV, TLG parameters of LNs before treatment has been studied by many investigators, but there have been conflicting conclusions.…”

Radiation-Induced Changes in Structural Network in Patients with Nasopharyngeal Carcinoma

“…However, it occurs much more frequently in Southeast Asia and China. In Southern China, NPC is one of the most common malignant tumors and the incidence of NPC is approximately 30-80 per 100,000 per year [3]. Because of the special lesion location, nasopharyngeal carcinoma is not suitable for surgical treatment and radiotherapy play a crucial part in NPC therapy.…”

Identify the radiotherapy-induced abnormal changes in the patients with nasopharyngeal carcinoma

“…However, it exists much more frequently in Southeast Asia and China. In Southern China, NPC is one of the most common malignant tumor and the incidence of NPC is approximately 30-80 per 100,000 per year [1]. Because of the special lesion location, nasopharyngeal carcinoma is not suitable for surgical treatment and radiotherapy plays a crucial part in NPC therapy.…”