COMPARISON OF THE 7TH AND 8TH EDITIONS OF THE UICC TNM STAGING SYSTEM FOR ORAL CAVITY CARCINOMA IN THE PREDICTION OF DISEASE SPECIFIC SURVIVAL

Abstract

Background The eighth edition TNM staging system introduced depth of invasion into T staging and extracapsular metastatic spread into N staging for oral cavity carcinomas. Objective Compare the seventh and eighth editions of the Union for International Cancer Control TNM staging systems for oral cavity carcinoma in the prediction of disease-specific death using a local cohort. Methods One hundred cases of oral squamous cell carcinoma with at least 5 years of follow-up data were retrieved and staged by the seventh and eighth edition TNM staging systems. Correlation with disease-specific survival was examined by construction of Kaplan-Meier curves and application of log-rank tests for trends or Gehan-Breslow-Wilcoxon tests. Results T staging by the seventh edition did not correlate significantly with disease-specific survival, whereas T staging by eighth edition did correlate significantly. N stage correlated with disease-specific survival for both the seventh and eighth editions. Overall staging by the seventh edition did not correlate significantly with disease-specific survival. Overall staging by the eighth edition did correlate significantly with disease-specific survival. Significantly reduced disease-specific survival was seen for N0 cases with a depth of invasion greater than 5 mm. For N positive cases, a depth greater than 5 mm did not show a significant impact on disease-specific survival. Node positive cases with extracapsular spread showed significantly worse survival than those without. Conclusions The findings support depth of invasion as a prognostic factor for N0 cases and extracapsular spread as a prognostic factor for N positive cases of oral squamous cell carcinoma. The eighth edition TNM staging system introduced depth of invasion into T staging and extracapsular metastatic spread into N staging for oral cavity carcinomas. Compare the seventh and eighth editions of the Union for International Cancer Control TNM staging systems for oral cavity carcinoma in the prediction of disease-specific death using a local cohort. One hundred cases of oral squamous cell carcinoma with at least 5 years of follow-up data were retrieved and staged by the seventh and eighth edition TNM staging systems. Correlation with disease-specific survival was examined by construction of Kaplan-Meier curves and application of log-rank tests for trends or Gehan-Breslow-Wilcoxon tests. T staging by the seventh edition did not correlate significantly with disease-specific survival, whereas T staging by eighth edition did correlate significantly. N stage correlated with disease-specific survival for both the seventh and eighth editions. Overall staging by the seventh edition did not correlate significantly with disease-specific survival. Overall staging by the eighth edition did correlate significantly with disease-specific survival. Significantly reduced disease-specific survival was seen for N0 cases with a depth of invasion greater than 5 mm. For N positive cases, a depth greater than 5 mm did not show a significant impact on disease-specific survival. Node positive cases with extracapsular spread showed significantly worse survival than those without. The findings support depth of invasion as a prognostic factor for N0 cases and extracapsular spread as a prognostic factor for N positive cases of oral squamous cell carcinoma.