American Joint Committee on Cancer staging system 7th edition versus 8th edition: any improvement for patients with squamous cell carcinoma of the tongue?

Objective. In this study, we evaluated the 8th edition of American Joint Committee on Cancer (AJCC) staging criteria and lymph node ratio (LNR) to identify patients affected by squamous cell carcinoma of the tongue (SCCT) with a poor prognosis. Study Design. Seventy-three cases of SCCT were analyzed retrospectively. Tumor staging was revised according to the 7th and 8th editions of the AJCC criteria. Depth of invasion (DOI), extranodal extension (ENE), and LNR were evaluated. Results. Twenty-five cases were reclassified: 17 patients received an upstage in the staging score, and in 8 cases in the same stage group, pT or pN was changed. In the pT-upstaged group, 7 patients experienced recurrence, and 8 died. In the pN-upstaged group, 9 patients developed recurrence, and 10 died. The number of disease recurrence or death was higher in the groups of patients who received an upstage in pN and in the staging score (P<.05). The pN-upstaged group showed worse disease-free survival (DFS) and overall survival (OS) (P<.05). LNR was higher in patients with recurrence, and among these, LNR was lower in patients with ENE (P<.05). Conclusions. The 8th edition of the AJCC criteria allows for better stratification of patients with SCCT. The implementation of ENE and LNR to pN classification seems to identify patients with worse DFS and OS.