Addition of tumour infiltration depth and extranodal extension improves the prognostic value of the pathological TNM classification for early-stage oral squamous cell carcinoma

AIMS: In the 8th edition of the American Joint Committee on Cancer (AJCC) TNM staging Manual, tumor infiltration depth and extranodal extension are added to the pathological classification for oral squamous cell carcinoma. Currently available 8th TNM validation studies are lacking patients with conservative neck treatment, while changes in the classification especially affect patients with small tumors. This study's aim was to determine the potential impact of the changes within the 8th edition pTNM classification on the prognosis and treatment strategy of oral squamous cell carcinoma in a well-defined series of pT1-T2 patients with a long-term follow-up.

METHODS AND RESULTS: 211 first primary pT1-T2 oral squamous cell carcinoma patients, with surgical resection as primary treatment were analyzed retrospectively. 173 patients received a neck dissection and 38 patients had a frequent clinical neck assessment. Long-term follow-up (median: 64 months) and reassessed tumor infiltration depth were available. Classification according to the 8th edition criteria resulted in 36% total upstaging with the T classification and 16% with N classification. T3 restaged patients (n=30, 14%) had lower 5-year disease specific survival rates compared to T2 staged patients (81% versus 67%, p = 0.042). Postoperative (chemo)radiotherapy could have been considered in another 7 (3%) patients based on the 8th edition criteria.

CONCLUSIONS: Addition of tumor infiltration depth and extranodal extension within the 8th TNM classification leads to the identification of oral squamous cell carcinoma patients with a worse prognosis who might benefit from an improved postoperative treatment strategy. This article is protected by copyright. All rights reserved.