LAUSR

OBJECTIVE Oropharynx cancer incidence trends in low socioeconomic (SES) regions of the United States (US) have not been well described. Our objective was to describe tonsil cancer incidence trends in low SES regions, and compare observed trends with those for larynx cancer. MATERIALS AND METHODS Age-adjusted incidence rates and trends for tonsil and larynx squamous cell carcinomas (2000-14) from Surveillance, Epidemiology, and End Results (SEER 18) were evaluated using SEER*Stat and Joinpoint 4.5.0.1. Annual percentage changes (APCs) were compared between low and high SES counties. The laryngeal cancer cohort was included as a comparator reflecting a tobacco-related malignancy. RESULTS Tonsil cancer incidence trends increased at least as much in low SES as in high SES counties (APC/AAPC 4.4, 95%CI 2.4-6.4 versus APC/AAPC 2.9, 95%CI 2.4-3.3). Pairwise comparison confirmed no differences between incidence trends across SES quintiles for tonsil cancer incidence rates. In contrast, age-adjusted incidence rates of larynx cancer decreased in high SES counties (APC/AAPC -2.4, 95%CI -2.4 to -2.0, p < 0.001) and were stable in low SES counties (APC/AAPC -0.9, 95%CI -1.9 to 0.2, p = 0.10). Compared with larynx cancer patients, tonsil cancer patients in low SES regions were significantly more likely to be younger and white. CONCLUSION In low SES US counties, tonsil cancer incidence rates increased from 2000 to 2014, while larynx cancer rates did not change, reflecting diverging trends for larynx and tonsil cancers. Tonsil cancer incidence rates are increasing in most US regions regardless of regional socioeconomic status. Prevention efforts should take these findings into account.