Validation of the eighth edition AJCC staging system in early T1 to T2 oral squamous cell carcinoma.

Background: To validate the newly proposed American Joint Committee on Cancer (AJCC) eighth edition staging in early T1 and T2 oral cavity cancers and its effect in predicting tumour control.
Methods: Retrospective analysis of treatment outcomes of 441 T1 to T2 oral squamous cell carcinoma (OSCC). Overall survival (OS), disease-specific survival (DSS), and tumour control were calculated and compared between the AJCC 7 and 8 staging systems.
Results: The 5-year OS was 78% and 61% for T1 and T2 tumours, respetively (P < 0.001) (AJCC 7) vs 87% and 67% (P < 0.001) (AJCC 8). The 5-year DSS was 78% and 61% for T1 and T2, respectively (P < 0.001) (AJCC 7) vs 89% and 71% (P < 0.001) (AJCC 8). For stages I and II tumours the 5-year OS was 81% and 76%, respectively (P < 0.302) (AJCC 7) vs 87% and 73% (P < 0.017) (AJCC 8). The 5-year DSS was 83% and 82% (P < 0.222) vs 89% and 77% (P < 0.016). With the AJCC eighth edition the 5-year local, regional, and distant control rates for T1 vs T2 tumours were 85% vs 74% (P = 0.003), 95% vs 77% (P = 0.001), and 95% vs 80% (P = 0.014), respectively.
Conclusion: The AJCC 8th staging system provided for more accurate prediction of OS, DSS, and disease control in early oral cavity cancers.
(© 2018 Wiley Periodicals, Inc.)