Lymph Node Metastasis And Prognostic Value Of Nasopharyngeal Carcinoma Based On 2008 Cervical Lymph Node

Background: Nasopharyngeal carcinoma(NPC)is a unique tumor in China,and the number of cases is the highest in the world.Unlike nasopharyngeal carcinoma(NPC)in aboard,more than 90% of NPC patients in China are poorly differentiated and undifferentiated carcinomas(WHO II + III).Based on the1992 stage of nasopharyngeal carcinoma,the 2008 stage of NPC has been promulgated and carried out by the Committee of clinical staging of nasopharyngeal carcinoma(NPC)in China,after more than 1 years of discussion.There are many studies on the characteristics of cervical lymph node metastasis and its correlation with the value of prognosis.However,different scholars have different conclusions about the N staging indicators(such as maximum diameter,envelope,invasion,etc.).Objective: To retrospectively analyze the lymph node metastasis and prognostic value in patients with nasopharyngeal carcinoma after radical radiotherapy,and to provide some references for further discussion of N staging and N staging.Materials/Methods: The 324 patients from Jan.2005 to Dec.2010 were recruited retrospectively to analysis.After diagnosed as non-metastatic NPC,all of them were treated with IMRT.CT/MRI images were obtained before treatment.The CT/MRI images of all patients were analyzed retrospectively to evaluate the imaging features and prognostic value of cervical lymph node metastasis.The patients were followed up for a long time,and the OS,DFS,DMFS and RRFS were calculated.Kaplan-Meier method was used for survival analysis,and COX regression model was used for multivariate analysis?Result: The median follow-up time was 66 months(6-134 months).The 5years of LRFS(local recurrence free survival)rate was 93.5%;5 years of NRFS(nodal recurrence free survival)rate was 97.4%;5 years of DMFS(distant metastasis free survival)rate was 73.4%,5 years of DFS(distant free survival)rate was 69.1%,5 years of OS(overall survival)was 79.2%.The most common lymph node metastasis mainly includes level II and retropharyngeal lymph node,respectively 62.5%,93.1%,followed by level III,level VA,level IV,levelVB transfer rate gradually decreased,respectively 18.7%,8.5%,5.8% and4.4%.Retropharyngeal lymph node positive mainly exists in the lateral group.The results were consistent with the general rule of lymph node metastasis,that is from top to bottom,step by step,and jump metastasis rate was low,accounting for 1.7%.The number of patients with bilateral lymph node metastasis was 53.4%,and the proportion of patients with necrotic lymph nodes was about 40.4%,while that of patients with extracapsular invasion was about52%.In univariate analysis,lymph node diameter greater than 3cm and 6cm,extracapsular extension and lymph node involvement is the factor of side effects to DFS(distant free survival)and DMFS(distant metastasis free survival)(P<0.05).Lymph node necrosis also affects DFS(disease-free survival).The lower cervical involvement(i.e.,below the cricoid cartilage)had no significant predictive value for survival.In multivariate analysis,the results suggest that T stage,age,and unilateral / bilateral lymph node status have significant impact on DFS(distant free survival)(P<0.05);T stage and age are independent prognostic factors for DMFS(distant metastasis free survival)(P<0.05)Conclusion: The result illustrates the characteristics of cervical lymph node metastasis of nasopharyngeal carcinoma,and the lymph node diameter greater than 3cm,extracapsular extension and lymph node involvement is the factor of side effects to DFS(distant metastasis free survival)and DMFS(distant metastasis free survival)important factors.Lymph node necrosis can affect DFS(disease-free survival),However,the involvement of the lower cervical region(i.e.,the area below the cricoid cartilage)had no significant effect on the prognosis.