AJCC 8th Versus AJCC 7th as a Prognostic Indicator in Buccal Mucosal Squamous Cell Carcinoma.

Abstract

American Joint Committee for Cancer (AJCC) staging manual has been recently updated with 8th edition which led to an immense shift in the tumor, node, and composite stages, in comparison to the previous staging. This was mainly due to the incorporation of depth of invasion (DOI) and extranodal extension (ENE) in staging. The impact of new staging system is widely studied as combined subsites in oral cancer. This study is to focus on a single subsite of oral cavity which is known for its poor prognosis. We evaluated 109 patients who had buccal mucosal squamous cell carcinomas (BSCC) who underwent treatment, with a curative intend, between 2014 and 2015. Clinical records were reviewed and the tumors were re-staged as per 8th edition of AJCC; disease-free survival (DFS) was also analyzed. Our study population had a mean age of 54.5 ± 10.35years and male to female ratio of 4:1. During a median follow-up of 41months, 35 patients (32.1%) developed recurrence. There was a statistically significant shift in stages between AJCC 7th edition against AJCC 8th edition leading to 34% upshift in T-stage, 43.1% upshift in N-stage, eventually leading to a 23.9% upshift in the composite stage. Tumors which got upgraded due to upshift in nodal stage had a poor survival (p= 0.002). Newer staging system is easy to use in clinical practice. Around a quarter of the BSCC got upstaged with the introduction of the newer staging system. But it was surprising to note that there were no statistically significant differences in DFS between the tumors of the same composite stages with regard to the two staging systems.