Head and neck cancer treatment delays in 2021: Estimating distributional effects by site, surgery, and p16-positivity

Following decades of policies increasing access to high-quality cancer treatment, the COVID-19 pandemic upended the U.S. healthcare system. The pandemic's disruption likely affected an often-overlooked dimension of quality cancer treatment: timely initiation. Timely treatment initiation is especially critical for head and neck cancer (HNC). We aimed to assess how the treatment interval (diagnosis to treatment initiation) changed in 2021 for different types of HNCs and treatment modalities. We analyzed Surveillance, Epidemiological, End Results (SEER) case data for years 2007–2021. Using ICD site codes, cancers were restricted to oropharynx, oral cavity, other pharynx, larynx. Oropharynx cancers were stratified by Human Papillomavirus (HPV) subtype based on p16-positivity codes. The outcome of interest was a variable measuring the number of days from diagnosis to treatment initiation. Cases were stratified by site and whether they received surgery as first course of treatment. To overcome validity threats from skewed treatment interval data and unobserved heterogeneity, we constructed an unconditional quantile regression model to estimate the effect of treatment in 2021 across the distribution of the treatment interval. 155,273 patients in SEER initiated HNC treatment between 2007 and 2021. The median treatment interval was 29 days (Interquartile Range = 2–48). Among patients not receiving surgery, 2021 was associated with delayed treatment for all sites except oral cavity. For patients receiving surgery, 2021 was only associated with delayed treatment for p16+ Oropharynx cancer. HNC patients overall, but HPV+ Oropharynx cancer patients especially, experienced treatment delays in 2021. These delays, and their consequences, warrant policymaking attention. • Despite the importance of timely care for head and neck cancer patients, disparities persist. • Analyzing a novel SEER days-to-treatment variable, we tested if treatment delays increased in 2021. • From 2007 to 2020, median time-to-treatment was 29 days, but the interquartile range was 2–48 days. • Being diagnosed in 2021 was associated with delayed treatment for all types of head and neck cancer, except oral cavity, patients not receiving surgery. • Only in oropharynx (p16) cancers was a 2021 diagnosis associated with delayed surgery.