Ling Huang1, Yun Zhang2, Yifei Liu3, Haojiang Li4, Shunxin Wang5, Shaobo Liang6, Jian Zhou7, Chunyan Cui8, Yin Sun9, Minyuan Chen10, Shuoyu Xu11, Jianjun Li12, Lizhi Liu13. 1. Department of Endoscopy, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangzhou 510060, China. Electronic address: huangling@sysucc.org.cn. 2. Department of Radiology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangzhou 510060, China. Electronic address: zhangyun@sysucc.org.cn. 3. Department of Radiology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangzhou 510060, China. Electronic address: liuyf1@sysucc.org.cn. 4. Department of Radiology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangzhou 510060, China. Electronic address: lihaoj@sysucc.org.cn. 5. Zhongshan School of Medical, Sun Yat-sen University, China. Electronic address: wangshx23@mail2.sysu.edu.cn. 6. Department of Radiation Oncology, Cancer Center, The First People's Hospital of Foshan Affiliated to Sun Yat-sen University, China. Electronic address: liangshb@sysucc.org.cn. 7. Department of Radiology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangzhou 510060, China. Electronic address: zhoujian@sysucc.org.cn. 8. Department of Radiology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangzhou 510060, China. Electronic address: cuichy@sysucc.org.cn. 9. Department of Radiation Oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangzhou 510060, China. Electronic address: sunying@sysucc.org.cn. 10. Department of Nasopharyngeal Cancer, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangzhou 510060, China. Electronic address: chenmy@sysucc.org.cn. 11. Department of Radiology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangzhou 510060, China. Electronic address: xushuoy@sysucc.org.cn. 12. Department of Endoscopy, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangzhou 510060, China. Electronic address: lijj@sysucc.org.cn. 13. Department of Radiology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangzhou 510060, China. Electronic address: liulizh@sysucc.org.cn.
Abstract
BACKGROUND AND PURPOSE: Metastasis laterality is used for N classification of cervical lymph nodes, but not retropharyngeal lymph nodes (RLNs). This study explored the prognostic value of laterality of RLN metastasis to provide suggestions for a better N standard classification. MATERIALS AND METHODS: This retrospective study evaluated 1225 patients with new biopsy-confirmed nasopharyngeal carcinoma (NPC). Univariable and multivariable Cox regression models were used to assess overall survival (OS), progression-free survival (PFS), and distant metastasis-free survival (DMFS). A new N classification system was developed and compared to the 8th AJCC system. Kaplan-Meier methods with log-rank tests were used to compare OS, PFS, and DMFS between our proposed N stage and the AJCC N stages. RESULTS: The incidence of RLN metastasis was 38.7% (unilateral) and 27.5% (bilateral). In the N1 subgroup, metastasis laterality was associated with significant differences in the 5-year rates of OS (89.4% vs. 82.6%, p = 0.016), DMFS (91.5% vs. 82.9%, p = 0.004), and PFS (80.3% vs. 71.2%, p = 0.016). However, no significant differences in these outcomes were observed when we compared N2 disease to N1 bilateral RLN metastasis. Multivariate analysis confirmed that bilateral RLN metastasis independently predicted OS, DMFS, and PFS. The proposed classification broadened the differences in OS, DMFS, PFS between N1 and N2 disease. CONCLUSION: Patients with NPC and unilateral RLN metastasis had better survival than did patients with bilateral RLN metastasis. Upgrading cases with bilateral RLN metastasis from N1 to N2 may help improve prognostication using the 8th AJCC system.
BACKGROUND AND PURPOSE: Metastasis laterality is used for N classification of cervical lymph nodes, but not retropharyngeal lymph nodes (RLNs). This study explored the prognostic value of laterality of RLN metastasis to provide suggestions for a better N standard classification. MATERIALS AND METHODS: This retrospective study evaluated 1225 patients with new biopsy-confirmed nasopharyngeal carcinoma (NPC). Univariable and multivariable Cox regression models were used to assess overall survival (OS), progression-free survival (PFS), and distant metastasis-free survival (DMFS). A new N classification system was developed and compared to the 8th AJCC system. Kaplan-Meier methods with log-rank tests were used to compare OS, PFS, and DMFS between our proposed N stage and the AJCC N stages. RESULTS: The incidence of RLN metastasis was 38.7% (unilateral) and 27.5% (bilateral). In the N1 subgroup, metastasis laterality was associated with significant differences in the 5-year rates of OS (89.4% vs. 82.6%, p = 0.016), DMFS (91.5% vs. 82.9%, p = 0.004), and PFS (80.3% vs. 71.2%, p = 0.016). However, no significant differences in these outcomes were observed when we compared N2 disease to N1 bilateral RLN metastasis. Multivariate analysis confirmed that bilateral RLN metastasis independently predicted OS, DMFS, and PFS. The proposed classification broadened the differences in OS, DMFS, PFS between N1 and N2 disease. CONCLUSION:Patients with NPC and unilateral RLN metastasis had better survival than did patients with bilateral RLN metastasis. Upgrading cases with bilateral RLN metastasis from N1 to N2 may help improve prognostication using the 8th AJCC system.