The Impact of Surgical Resectability on Outcomes for Patients Undergoing Primary Radiation Treatment for Human Papillomavirus-Related Oropharyngeal Cancer

Abstract

Primary radiation therapy with or without chemotherapy (RT/CRT) is the most common treatment for oropharyngeal squamous cell carcinomas (OPSCC), but there has been an increase in transoral surgery (TOS) for T1-2 tumors. Because only a subset of T1-2 tumors are TOS-favorable, nonrandomized comparisons between RT/CRT and TOS could be confounded by indication. We aimed to compare outcomes of potential TOS-candidates versus non-TOS candidates, among patients who underwent RT/CRT for early T-stage OPSCC. For patients treated with RT/CRT for early-stage human papilloma virus positive OPSCC between 2014 and 2018, pretreatment imaging was reviewed by 3 head and neck surgeons, blinded to outcomes, to assess primary-site appropriateness for TOS, and extracapsular extension (ECE) was scored by a head and neck neuroradiologist. We compared outcomes based on surgical favorability pertaining to (1) the primary site tumor alone and (2) the primary site and an absence of ECE. Kaplan-Meier estimates for overall survival (OS), disease-specific survival (DSS), and recurrence-free survival (RFS) were compared using the log-rank test, with Cox regression used for multivariable modeling. One hundred and forty-three patients were evaluated, of which 121 were male (84.6%), the median age was 59.4 years, and all of them were p16 positive (100%). The primary site was TOS-favorable in 115 of 143 (80.4%). Patients with TOS-favorable primary site experienced superior 5-year OS (89.8% vs 71.2%, P=.017), DSS (90.4% vs 63.4%, P=.022), and RFS (83% vs 49.4%, P=.04) compared with TOS-unfavorable patients. Similarly, patients with a TOS-favorable primary site and no ECE on imaging 101 of 143 (70.6%), had improved OS, DSS, and RFS (P < .05) compared with TOS-unfavorable patients. In this first study to assess surgical favorability as a prognostic factor among patients with T1/2 p16+ OPSCC, patients with TOS-favorable early-stage OPSCC have better outcomes than TOS-unfavorable patients. This provides valuable prognostic information for patients, and also suggests the risk of confounding by indication in nonrandomized comparisons of treatment modalities.