>> P-575: Estimated population-level burden of HPV-positive oropharynx cancers among smokers and never smokers in the United States
19:00 PM - 19:00 PM
1Division of Cancer Epidemiology and Genetics, National Cancer Institute, USA; 2Johns Hopkins University, Baltimore, MD, USA; 3The Ohio State University, Columbus, OH, USA.
Background: The higher prevalence of HPV-positive oropharynx cancer (OPC) among never-smokers than former or current smokers has led to the characterization of HPV-positive OPC as a disease largely of never-smokers. To clarify the population-level burden of HPV-positive OPCs among never, former, and current smokers, we utilized data from several sources to estimate incidence rates, rate ratios (RR), and case counts.
Methods: For each smoking stratum, we calculated HPV-positive OPC incidence as the product of the proportion of OPC cases that are HPV DNA-positive with OPC incidence. The proportion of tumor HPV DNA-positive cases across smoking strata was estimated from case-control data. OPC incidence rates (overall incidence for HPV-positive and HPV-negative) by smoking status were estimated using prospective data from the NIH-AARP cohort. HPV-positive OPC incidences thus estimated were applied to the U.S. population of never, former, and current smokers (NHANES 2007-2008) to calculate HPV-positive OPC cases in these groups. Estimated overall OPC incidence rates were compared to SEER rates to assess calibration.
Results: The proportion of tumor HPV DNA-positive OPC cases was higher among never-smokers (87%) than former (63%) or current (54%) smokers. However, OPC incidence rates in the NIH-AARP cohort were 6.0, 8.3, and 19.5/100,000 person-years, respectively, among never, former, and current-smokers. Consequently, estimated HPV-positive OPC incidence rates were similar among former and never smokers (incidences= 5.2 vs. 5.2/100,000 person-years; RR=1.0; 95%CI=0.4-2.3; p=0.98). Notably, HPV-positive OPC incidence rates were 2-fold higher among current than never-smokers (incidences= 10.7 vs. 5.2/100,000 person-years; RR=2.1; 95%CI=0.9-4.9; p=0.10). In the U.S. during 2007-2008, we estimate that 3,554 HPV-positive OPC cases occurred annually among never-smokers, while 4,902 cases occurred among smokers (2,124 in former and 2,778 in current smokers).
Conclusions: Incidence rates and population-level burden of HPV-positive OPC cases among former and current smokers are at least equivalent and perhaps greater than those among never-smokers.