Tracking changes in age distribution of head and neck cancer in the United States from 1975 to2016

Introduction: Several independent studies report an alarming increase in patients younger than 40 being diagnosed with squamous cell carcinoma. There is currently a lack of available data clearly tracking changes in the age distribution of head and neck cancer (HNC) within the United States. This study attempts to elucidate any trends in oral cavity, oropharynx, larynx and hypopharynx cancer age distribution in the United States population from 1975 to 2016. Unlike previous studies, this paper does not track incidence but rather reports proportional changes of prevalence within age cohorts over time. Methods: This is a retrospective chart review centred on data from the Surveillance, Epidemiology, and End Results (SEER) Program of the National Cancer Institute (NCI). Each decade interval from 1975 to 2016 displays the proportion of HNC patients, classified by primary tumour subsite, within each age cohort. Results: Mean age at diagnosis increased for all subsites except oropharynx. Oropharyngeal cancer was the only subsite to show a decrease in the mean age at diagnosis. In addition, oropharyngeal cancer was the only subsite to demonstrate an overall increase in proportional prevalence, largely due to increased incidence in middle-age (40–59 years) patients. Cancers of the oral cavity were the only subset to show a true increase in the proportion of young (0–39 years) patients, but its mean age at diagnosis still increased. When stratifying by gender, the proportion of young patients in female HNC cases is higher than the young male proportion. Conclusion: Overall, this study demonstrates an increased proportion of older HNC patients that is consistent with the ageing population. Oral cavity cancer demonstrated a true increase in the proportion of young patients, likely due to the increased incidence of young women diagnosed with this cancer. Oropharyngeal cancer was the only subsite to show a decrease in the mean age at diagnosis. The increased proportion of middle-age patients with oropharyngeal cancer likely reflects the increase in HPV-related cancers.