Background: Favorable outcomes for human papillomavirus-associated oropharyngeal cancer have led to interest in identifying a subgroup of patients with the lowest risk of disease recurrence after therapy. De-intensification of therapy for this group may result in survival outcomes that are similar to those associated with current therapy but with less toxicity. To advance this effort, this study analyzed the outcomes of oropharyngeal cancer patients treated with or without systemic therapy.
Methods: This was a retrospective study of patients with oropharyngeal cancer treated between 1985 and 2012. The criteria for inclusion were ≤10 pack-years of cigarette smoking and stage III/IVA cancer limited to T1-3, N1-N2b, and T3N0 disease. A survival analysis was performed with the primary endpoint of progression-free survival (PFS).
Results: The cohort included 857 patients. Systemic therapy was given to 439 patients (51%). The median survival was 80 months. The 2-year PFS rate was 91%. When the analysis was limited to 324 patients irradiated without systemic therapy, the 2- and 5-year PFS rates were 90% and 85%, respectively. Furthermore, for these 324 patients, the 5-year PFS rates for T1, T2, and T3 disease were 90%, 83%, and 70%, respectively. The 5-year PFS rate for patients treated with systemic therapy for T3 disease was 77% (P = .07).
Conclusions: According to the low-risk definition currently established in cooperative trials, the patients had a 2-year PFS rate approximating 90%. When patients who were treated with radiation alone were evaluated, no compromise was observed in this high rate of PFS, which is higher than the 2-year PFS thresholds used in current cooperative trials. Cancer 2016;122:1702-7. © 2016 American Cancer Society.
Keywords: human papillomavirus (HPV); oropharyngeal cancer; radiation; treatment de-intensification.
© 2016 American Cancer Society.