Staging and Treatment Implications of the 7th Vs. 8th AJCC Staging System for Oral Cancer

Abstract

The eighth edition of the American Joint Committee on Cancer TNM staging has integrated depth of infiltration (DOI) into the T staging and extra-nodal extension (ENE) or Extracapsular spread (ECS) into the N staging as prognostic factors. Multiple studies have shown that ENE or ECS have been associated with worse survival outcomes and recurrence rates (1). DOI is indirectly correlated to poorer survival outcomes and recurrence rates by predicting nodal metastasis (2). This study intends to look at the potential change of management caused by the new staging system. An IRB approval by North Memorial Medical Center was granted for a retrospective chart review from 2014-2017 looking at 100 patients that were managed for oral squamous cell carcinoma using the seventh edition TNM staging system in the hospital. The same cohort of patients were then restaged using the eighth edition and comparison of management strategies based on the National Comprehensive Cancer Network guidelines was performed to evaluate if any staging discrepancies also translated to a difference in management. The individual components of the new staging system were also analyzed to see which impacted staging and management more frequently. Results showed a 14.3% overall rate of upstaging and an 8.6% overall rate in change of management leading to additional adjunctive treatment, DOI was involved in 40% of upstaging and no change in management, ENE/ECS positivity was involved in 60% of upstaging and 100% in change of management. No patients were downstaged using the eighth edition. We concluded that while DOI was involved in upstaging it has a less of an impact on management as compared to upstaging caused by ENE/ECS.