Contralateral Neck Recurrence Rates After Ipsilateral Neck Adjuvant Radiation in Head and Neck Carcinomas with a Pathologically Negative Contralateral Neck

Abstract

AbstractIntroductionIn 2019 we published a phase II trial of ipsilateral neck adjuvant radiation therapy in head and neck (HN) carcinoma patients with a pathologically negative (pN0) contralateral neck after bilateral neck dissection. The five-year contralateral neck recurrence rate was 3%. Here we present the recurrence rate in patients subsequently treated by this trial’s paradigm.MethodsPatients were selected who would have been eligible for our phase II trial: all had oropharynx, hypopharynx, oral cavity, or unknown primary carcinomas without prior HN cancer or major HN surgeries, underwent primary resection including bilateral neck dissection with a pN0 contralateral neck, and underwent adjuvant intensity modulated radiation therapy (IMRT) that spared the contralateral neck.ResultsFifty-five patients met cohort inclusion criteria. Thirty-nine cancers arose from the oropharynx, 11 from the oral cavity, three from the hypopharynx, and two from an unknown primary. With a median follow-up of 15 months there were nine recurrences (16%), four contralateral neck recurrences (7%), and one isolated contralateral neck recurrence (2%). No contralateral neck recurrences occurred in patients with p16+ oropharyngeal primaries despite that most (73%) arose from the base of the tongue. In contrast, three contralateral neck recurrences occurred in patients with advanced stage oral cavity primaries.ConclusionThe contralateral neck recurrence rate in HN carcinoma patients with a pN0 contralateral neck treated by adjuvant ipsilateral neck IMRT was similar to the 3% rate observed in our phase II trial. However, this paradigm may be inadequate for patients with locally advanced oral cavity primaries.