| Objective:The 8th edition of the AJCC Cancer Staging Manual published by the American Joint Committee on Cancer is the latest tumor staging standard and has a profound impact on the clinical treatment strategies for all types of cancer.The new edition of the manual has significant changes compared with the 7th edition.Two important variables,extranodal extension and depth of invasion,were included in the TNM staging of oral cancer.Our study aimed to evaluate the influence of extranodal extension on TNM staging and prognosis of oral cancer.Additionally,we further verified the feasibility of the 8th edition of tumor TNM staging system in guiding clinical treatment and improving prognosis stratification of oral cancer.Methods:Patients with primary oral squamous cell carcinoma who received operation in the Affiliated Hospital of Qingdao University between January 2014 and June 2017 were enrolled in this study.All patients were performed by N staging and TNM staging according to the 7th edition of AJCC TNM staging criteria and the 8th edition,respectively.The changes of the new and old editions were analyzed and compared.The SPSS26.0 statistical analysis software was used to analyze the curves of overall survival and disease-specific survival.The difference in survival curves between groups was compared by Log-rank test.The forecast exactitude and data matching performance of the new and old staging system models were compared by the concordance index and the Akaike Information Criteria.COX proportional hazard regression model was used to evaluate the hazard ratio.P<0.05 was regarded as statistically significant.Results:In all,485 patients who were diagnosed with oral squamous cell carcinoma met the inclusion criterion,including 328 males(67.63%)and 157 females(32.37%)with an average age of 67.3 years old and a median age of 68 years old(29～95 years).The median follow-up time was 46 months(1～105 months).Among the primary sites of oral cancer,the tongue mucosa was 150,accounting for 30.93%.The gingival mucosa and the sublingual mucosa took the proportion of 21.44% and 21.03%,respectively.The pathological data showed that 69 of 167 patients with lymph node metastasis presented ENE positive,accounting for 41.32%(69/167).There was no significant difference in the incidence of ENE among different primary sites of oral cancer(P<0.05).ENE correlated with pathological N staging,nodal number and maximum diameter of metastatic lymph nodes(P<0.05).However,ENE was not associated with pathological T staging,the degree of tumor differentiation or depth of invasion(P>0.05).Compared with the 7th staging standard,the pathological N staging was changed in69 patients with positive ENE in new staging standard.Moreover,the pathological TNM staging was changed in 67 patients with positive ENE according to the 8th staging standard.5-year survival rate of patients with positive ENE(OS: 27.1%,DSS: 31.2%)was significantly lower than that of those with negative ENE(OS: 72.2%,DSS: 78.0%).The difference was statistically significant by Log-rank test,P < 0.05.The Akaike Information Criterion of the 8th version of AJCC staging system was less than those of the 7th version.The COX multivariate regression analysis showed that ENE and pTNM were independent prognostic factors for patients,particularly in patients with higher grade stage(P<0.05).Conclusions:Compared with AJCC 7,the prognosis of patients with oral squamous cell carcinoma can be assessed more precisely and legitimately by AJCC 8 model.The new edition of TNM staging system may provide a more scientific guiding significance to clinical practice.As an independent factor to evaluate the prognosis of oral cancer,the inclusion of extranodal extension has significantly changed the TNM staging of oral cancer.ENE index can reflect the status of patients more accurately and objectively,which is of great significance for treatment decision and prognosis evaluation of oral cancer. |
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