Patients with human papillomavirus (HPV) or its surrogate marker p16, positive oropharyngeal squamous cell carcinoma (p16+OPSCC) exhibit favorable overall survival (OS) rates of 70-100% at 3 years. These outcomes are dependent on disease burden and patient characteristics and independent of treatment modality. Significant treatment related side effects exist despite advances in radiotherapy (RT) technology, surgical techniques, and supportive care. In addition to common acute toxicities, the favorable OS of patients with p16+OPSCC potentially places them at increased risk for developing long-term treatment-induced side-effects. Therefore, it is important to establish novel management approaches that maintain excellent current clinical outcomes while effectively reducing acute and long-term side effects.~One such approach of limiting RT-induced toxicity is to decrease the amount of normal tissue that receives radiation through judicious reduction of RT treatment volumes. Treatment of elective nodal volumes increases dose to numerous organs at risk (OARs). Patients with well-lateralized tonsil tumors and limited neck disease can effectively be treated with ipsilateral nodal radiotherapy. However, based on recent phase III trials, contralateral (C/L) elective nodal radiation is performed for the majority of patients with p16+OPSCC increasing acute and long-term toxicities. Therefore, judicious data-driven approaches for decreasing the number of elective ipsilateral and contralateral nodal levels treated is necessary to limit RT-induced side effects. This protocol tests the hypothesis that treating only the high-risk sub-volumes of levels II and III would be effective in maintaining regional control in the elective neck while decreasing xerostomia (dry mouth) and dysphagia (swallowing difficulties).
This is a phase II, non-randomized, therapeutic trial with the primary objective to determine the efficacy of reduced contralateral (C/L) elective nodal treatment volumes in preventing C/L recurrences at 2 years in patients with p16 positive oropharyngeal squamous cell carcinoma undergoing definitive or adjuvant RT.