To evaluate whether historic risk categories and indications for adjuvant therapy in the pre-human papillomavirus (HPV) and pre-transoral surgery (TOS) era were associated with clinically significant relapse rates in HPV+ oropharyngeal squamous cell cancer patients undergoing TOS.

A multi-institutional retrospective review of intermediate- and high-risk HPV+ oropharyngeal squamous cell cancer patients not receiving adjuvant therapy after TOS was performed. Perineural invasion, lymphovascular invasion, T3-T4, or ≥N2 disease were considered to be intermediate-risk factors, and extracapsular extension or positive margins were considered to be high-risk features, according to established risk categories.

Median follow-up was 42.9 months. Among all 53 patients, the 3-year cumulative incidence of relapse was 26.0%. The 3-year cumulative incidence was 11.8% in the 37 intermediate-risk patients and 52.4% in the 16 high-risk patients. On univariate analysis only high-risk status was significantly associated with an increased risk of relapse (hazard ratio 3.9; P=.018). The salvage rate for relapse was 77%, with 10 of 13 patients undergoing salvage therapy.

Risk category was associated with clinically significant relapse rates after TOS alone in HPV+ oropharyngeal cancer, comparable to historical data and traditional indications for adjuvant therapy for all oropharyngeal cancer.