PRIMARY OBJECTIVE:~I. To describe the rate of manifestation of an occult primary tumor in the pharyngeal axis or delayed nodal recurrence in a un-dissected and/or non-irradiated neck at 2 years after study registration in patients treated with mucosal sparing (and unilateral neck, if applicable) radiotherapy after resection using transoral surgery for head and neck cancer of unknown primaries (HNCUP).~SECONDARY OBJECTIVES:~I. To describe the rates and severity of acute and late toxicities and PEG dependence attributable to mucosal sparing radiotherapy after resection using transoral surgery by assessment of grade 3 or higher adverse events National Cancer Institute (NCI)-Common Terminology Criteria for Adverse Events (CTCAE) version (v.) 5.0 criteria.~II. To describe the overall survival, recurrence-free survival (manifestation of an occult primary in the pharyngeal axis, nodal recurrence in a treated (surgery/radiation therapy [RT]) neck, delayed lymph node metastasis in an untreated neck (surgery/RT), and distant failure associated with mucosal sparing radiotherapy.~III. To describe swallowing function changes (assessed via swallowing study) associated with transoral surgery and adjuvant mucosal sparing radiotherapy.~OUTLINE:~Patients who have recurrence or progression during treatment or observation have medical charts reviewed every 6 months for 5 years. Patients who complete adjuvant treatment are followed for observation 3 days after radiation therapy, 1 month after radiation therapy, every 3 months after radiation therapy for 2 years, every 6 months for 1 year, and then annually for 2 years.
This early phase I trial evaluates the clinical outcome of mucosal sparing adjuvant radiotherapy after surgical exploration in HPV+ head and neck cancer of unknown primaries. The purpose of this research is to assess if radiation treatment to the neck only for tumors with unclear original locations after careful surgical evaluation will lead to historical rates of disease control while reducing side effects and toxicity from treatment.