Lymph Node Ratio as a Prognostic Factor for Oral Tongue Squamous Cell Carcinoma: A Retrospective Study

Background Oral squamous cell carcinoma (OSCC) incidence and its mortality have increased recently. The oral part of the tongue is one of the commonest sites for OSCC. Apart from Tumour-Node-Metastasis (TNM) staging, lymph node ratio (LNR) has been implicated as one of the useful predictors for the better clinical outcome of the disease. The aim of the present study was to assess the LNR as a prognostic factor for patients having oral tongue squamous cell carcinoma (OTSCC). Materials and methods It is a retrospective study of 122 patients with OTSCC who were managed primarily by surgery with curative intent from January 2014 to December 2016. The mean lymph node ratio was measured and compared with various parameters of clinical outcome such as five-year overall survival (OS), five-year disease-free survival (DFS), locoregional failure (LRF) within three years, and distant metastasis (DM) within five years using Kruskal-Wallis Test followed by Mann-Whitney Post Hoc Test. The association of LNR with other tumor characteristic features like perineural invasion, extra-nodal extension (ENE), and histopathological grading was also elicited. Results The study population's mean age was 50.5 ± 11.77 years. Among them, 85 were males and 37 were females. On comparing the mean LNR value with patient status after primary treatment, the patients with minimal LNR value had statistically significant five-year OS and five-year DFS (p< 0.001). High mean LNR values were associated with other adverse features like perineural invasion and ENE, which were statistically significant (p<0.001). Receiver operator characteristics (ROC) curve analysis for the LNR parameter for determining the cut-off (0.02) between OS and DFS had 86% sensitivity and 40% specificity. Conclusion The LNR could be an important prognosis factor for OTSCC that helps in determining better clinical outcomes.

Comparison of Different Staging Systems Applied to a Cohort of Patients With Oral Tongue and Floor of the Mouth Cancer

Purpose: The present work compares the effects produced by the application of the 7th edition of the tumor node metastasis (TNM) staging system (TNM7), 8th Edition (TNM8) with its two subsequent revisions, and pN-N+ classification on a cohort of patients with oral tongue and floor of the mouth cancer. Methods: A monocentric cohort of 148 patients was retrospectively analyzed. Patients were staged according to the TNM7, TNM8 and revisions, and pN-N+ classification. Stage migration was assessed and overall survival (OS) analyzed with the Kaplan-Meier method. The pT, pN, and stage stratification was evaluated with univariate and multivariate Cox regression and comparing adjacent categories with the log-rank method. Results: pT3-T4a categories showed significant differences in comparison to pT1-T2 for each staging metric employed in both uni- and multivariate analysis. When comparing adjacent pT categories, OS was significantly different only between pT2 and pT3 categories of the TNM8. Disproportionate patient distribution among pN categories was observed in the TNM8, and stratification was scarce. Conversely, in the pN-N+ classification the difference between pN2 and pN3a categories was significant. Only stage IVa reached statistical significance in TNM7, whereas stage III and above were significant in TNM8 and revisions in both uni- and multivariate analysis. However, no significant difference was noted comparing adjacent stages. Conclusion: The TNM8 pT classification differentiated low- from high-risk diseases. Nonetheless, it failed to separate pT1 from pT2 and pT3 from pT4a categories. Conversely, although TNM8 nodal staging was inaccurate, the number of metastatic lymph nodes was more valuable.

Prognostic performance of the American Joint Committee on Cancer 8th edition of the TNM staging system in patients with early oral tongue cancer

BACKGROUND

The 8th edition of the American Joint Committee on Cancer's (AJCC) staging system for oral cavity cancer incorporates pathological features. We aimed to assess whether these changes results in better risk stratification of patients with early oral tongue squamous cell carcinoma (OTSCC).

METHODS

Overall survival (OS) and disease-specific survival (DSS) of 244 patients were calculated using the Kaplan-Meier method. Multivariate analysis with stepwise selection was performed using Cox proportional hazards regression.

RESULTS

Sixty-two patients (25%) were upstaged using the 8th edition. Multivariate analysis revealed that overall stage using the 8th edition of the AJCC staging system but not using the 7th edition was a significant predictor for both OS and DSS. The 8th edition had lower Akaike information criterion and improved concordance index values compared with the 7th edition.

CONCLUSION

The 8th edition of AJCC allows better risk stratification and more precise counseling of patients with OTSCC who were previously considered at low risk.