Application of the Eighth Edition American Joint Committee on Cancer Staging System for HPV-Related Oropharyngeal Cancer Treated With Transoral Robotic Surgery.

OBJECTIVE:Analyze patients treated with transoral robotic surgery (TORS) in the context of the eighth edition of the American Joint Committee on Cancer (AJCC) staging system. METHODS:Retrospective cohort study including 110 human papillomavirus-related oropharyngeal cancer (HPV+OPC) patients with a minimum 1-year follow-up treated with TORS between 2007 to 2016. Kaplan-Meier methods were used to estimate 3-year disease-free survival and assess differences in recurrence. RESULTS:One hundred and ten patients with a median follow-up of 54 months were analyzed. Of those, 85% of patients were male, with a median age of 60. Twenty-two percent of patients received no adjuvant therapy; 43% received adjuvant radiation; and 35% underwent adjuvant chemoradiation. Extracapsular spread was identified in 24% of patients. Overall survival was 100%, with estimated 3-year disease-free survival (DFS) (95% confidence interval) of 87% (77, 93). Under the seventh edition of the AJCC, 5% of patients were stage I; 11% were stage II; 26% were stage III; and 57% were stage IVa. Twenty-seven patients (25%) were upstaged on final pathology, whereas 15 patients (14%) were downstaged. Under the eighth edition of the AJCC, 94% of patients were stage I for both clinical and pathologic staging systems. Six patients (6%) were upstaged on final pathology, whereas six patients (6%) were downstaged. No factors demonstrated statistical significance for DFS. Within pathologic stage I, Kaplan-Meier estimates for DFS did not reach statistical significance. CONCLUSION:The majority of patients undergoing TORS for HPV + OPC are stage I under the eighth edition of the AJCC staging system, with limited pathologic re-staging compared with the prior system. Oncologic outcomes are favorable for this group. No clinicopathologic features are significant for DFS within pathologic stage I. LEVEL OF EVIDENCE:2b. Laryngoscope, 128:1133-1139, 2018.