Contralateral Neck Recurrence Rates in Head and Neck Carcinomas after Primary Surgery, Bilateral Neck Dissection, a Pathologically Negative Contralateral Neck, and Adjuvant Ipsilateral Neck Radiation

Abstract

Purpose/Objective(s)

From 2007 – 2014 our institution accrued to a phase II clinical trial omitting contralateral neck radiation therapy in patients with head and neck (HN) carcinomas with a pN0 contralateral neck following primary surgical treatment and bilateral neck dissection. After that trial’s contralateral neck recurrence rate resulted at only 3%, contralateral neck radiotherapy omission became an institutional practice. In the present study of similar patients treated since the trial’s publication, we hypothesized that contralateral recurrence rates have remained persistently low.

Materials/Methods

Clinical records and radiation plans of HN radiotherapy patients at a single institution were reviewed, and a cohort of patients was identified with oral cavity, oropharynx, hypopharynx, larynx, or unknown primary HN carcinomas treated with adjuvant ipsilateral radiation therapy after surgical treatment including a bilateral neck dissection with pN0 contralateral lymph nodes. Clinical variables for these patients were abstracted and tested for associations with recurrence events using nonparametric statistical tests.

Results

Records for 858 patients treated with HN radiotherapy from 2020 – 2023 were reviewed, and 58 patients met cohort inclusion criteria. The cohort median age was 60.5 years, 79% were male, and 53% were or had been smokers with a median 24 pack-year history. Carcinomas arose in the oropharynx (71%), oral cavity (21%) hypopharynx (5%) or from an unknown primary (3%), and most (71%) were p16+. Eighteen patients (31%) had stage IVA or IVB disease. With a median follow-up of 16 months the rates of any recurrence, contralateral recurrence, and contralateral recurrence as a first recurrent site (isolated or synchronous) were 19% (11 events), 12% (7 events), and 10% (6 events), respectively. Contralateral recurrence was associated with pathologic stage IVA and IVB disease (P < 0.001) and oral cavity primary (P = 0.02). Among 38 patients with p16+ oropharyngeal primaries, no contralateral recurrences were observed. In contrast, among 20 patients with p16- oropharynx primaries (3) or another primary site (17), seven contralateral recurrences (35%; two oropharynx, five oral cavity) were observed.

Conclusion

Despite a relatively short median follow-up, contralateral recurrences after ipsilateral neck radiotherapy were overall more frequent than hypothesized. Most were a site of first recurrence. However, contralateral recurrences were primarily driven by oral cavity primaries and stage IVA and IVB disease, for whom treatment intensification with adjuvant bilateral neck radiotherapy may be warranted. In the subset of patients with p16+ oropharyngeal primaries, the contralateral recurrence rate remained low.