SS 08 - H&N 3: Addressing High-Risk Challenges Head On: Mitigating Toxicity and Reducing Recurrences
143 - 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
Washington University/B-JH/SLCH Consortium St. Louis, MO
K. Kiser1, A. Apicelli1, R. J. Brenneman2, H. A. Gay3, M. J. Moravan Jr1, N. Rammohan1, R. S. Jackson4, P. Pipkorn4, S. Puram4, D. Adkins5, P. Oppelt5, and W. L. Thorstad1; 1Department of Radiation Oncology, Washington University School of Medicine in St. Louis, St. Louis, MO, 2Banner MD Anderson Cancer Center at Banner North Colorado Medical Center, Greeley, CO, 3Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO, 4Department of Otolaryngology, Washington University School of Medicine in St. Louis, St. Louis, MO, 5Department of Medicine, Division of Oncology, Washington University School of Medicine in St. Louis, St. Louis, MO
Purpose/Objective(s): From 2007 – 2014our institution accrued to a phase II clinical trial omitting contralateral neck radiation therapy in patients with head and neck (HN) carcinomas with a p</span>N0contralateral 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 contralateralrecurrence 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 HNcarcinomastreated with adjuvant ipsilateral radiation therapy after surgical treatment including a bilateral neck dissection with p</span>N0 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 55 patients met cohort inclusion criteria. The cohort median age was 60 years, 80% were male, and 52% were or had been smokers with a median 27.5 pack-year history. Carcinomas arose in the oropharynx (71%), oral cavity (20%) hypopharynx (5%) or from an unknown primary (4%), and most (71%) were p16+. Seventeen patients (31%) had stage IVA or IVB disease. With a median follow-up of 15 months the rates of any recurrence, contralateral recurrence, and contralateral recurrence as a first recurrent site (isolated or synchronous) were 16% (9 events), 7% (4 events), and 5% (3 events), respectively. Contralateral recurrence was associated with pathologic stage IVA and IVB disease (p = 0.003) and oral cavity primary (p = 0.04). Among 36 patients with p16+ oropharyngeal primaries, no contralateral recurrences were observed. In contrast, among 19 patients with p16- oropharynx primaries (3) or another primary site (16), four contralateral recurrences (one oropharynx, three oral cavity) were observed. Conclusion: Despite a relatively short median follow-up, contralateral recurrences after ipsilateral neck radiotherapy were similar to our phase II institutional study. 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.
