Comparison of the 8th and 9th version tumor-nodes-metastasis staging systems in human papilloma virus-associated oropharyngeal carcinoma: A stepwise reclassification.

PURPOSE: The Union for International Cancer Control (UICC)/American Joint Committee on Cancer (AJCC) 9th version Tumor-Nodes-Metastasis (TNM) staging incorporates iENE to improve prognostic accuracy in human papilloma virus-associated (HPV) oropharyngeal carcinoma. We evaluated the impact of iENE on reclassification and associated clinical outcomes in HPV oropharyngeal carcinoma in a retrospective study.

MATERIAL AND

METHODS

Patients with HPV oropharyngeal carcinoma with positive lymph-nodes at diagnosis and treated with curative-intent chemoradiotherapy were included. Pre-treatment MRI images were reviewed by a head and neck radiologist to assess for iENE. All patients were (re)staged according to the 8th and the 9th TNM versions. Disease-free survival (DFS) was compared between cases with and without iENE and across clinical nodal categories.

RESULTS

Twenty-six consecutive patients with HPV oropharyngeal carcinoma with positive nodes were analyzed. All patients completed the planned treatment and achieved a clinical complete response at 3 months post-therapy. iENE was identified in 16 patients (61.5%). The presence of iENE was associated with lower 2-year DFS: 68.8% (95% CI 0.41-0.86) versus 100% (95% CI not estimable) (p = 0.048). Reclassification using the 9th TNM edition improved prognostic discrimination compared with the 8th edition (p = 0.043). The 2-year DFS rates by 9th edition clinical nodal stage were 100% (95% CI not estimable), 75% (95% CI 0.41-0.91) and 66.7% (95% CI 0.19-0.90) for clinical nodal 1, 2 and 3, respectively, compared to 82.9% (95% CI 0.56-0.94), 71.4% (95% CI 0.26-0.92) and 100% (calculated at 12 months) for the 8th edition.

CONCLUSION

The 9th TNM version seems to improve DFS stratification in HPV oropharyngeal carcinoma after definitive chemoradiotherapy.