Higher Rates of Inadequate Adjuvant Radiation Dose Among Older Adults with Head and Neck Cancer

Objective: To determine the rate of inadequate radiotherapy and identify risk factors associated with inadequate adjuvant radiotherapy for head and neck cancer among older adults.Methods: A retrospective review of the National Cancer Database (NCDB) was performed to identify patients diagnosed with squamous cell cancer of the head and neck between 2004 and 2017. Patients with a single malignancy, negative surgical margins, no extranodal extension, and receipt of adjuvant radiation without systemic therapy were included in the study cohort. The main outcome of interest was the adjuvant radiation dose received. Participant data were compared using univariable, multivariable, and correlation analyses to evaluate risk factors for inadequate radiation therapy (RT) dosing.Results: Among 7608 patients, 1010 patients (13.3%) received an inadequate radiation dose and 6598 (86.7%) received an adequate dose. Patients living in a higher income zip-code, younger age, and those who received intensity-modulated RT (IMRT) were more likely to receive an adequate radiation dose (p < 0.05). Patients older than 70 and 80 years old had a greater likelihood of receiving an inadequate radiation dose (>= 70 vs. <70: 16.9% vs. 12.5%; p < 0.05 and >= 80 vs. <80: 20.6% vs. 13.0%%; p < 0.05). Similarly, increasing age was negatively correlated with radiation dose (correlation coefficient: -0.05; p < 0.001).Conclusion: A substantial proportion of older patients receiving adjuvant radiation do not complete the full treatment. Older age, year of diagnosis, non-IMRT, and living in a lower-income zip code were associated with early termination of RT. Future studies should examine strategies to improve tolerance of adjuvant RT so that more patients complete the full treatment.