Abstract LB160: Oral cancer incidence among smokers and smokeless tobacco users compared to nonusers of tobacco products - contemporary analysis of cancer registry data
Authors: Noggle Brendan , Cheng Hui , Sarkar Mohamadi 
Published: June 2022

Abstract
Tobacco use has been identified as a risk factor for oral cancer (oral cavity and pharynx). However, the differential oral cancer risk among users of cigarettes and smokeless tobacco (ST) products has not been well studied. In this study, we estimate oral cancer incidence among adult males who were current smokers that had never used ST products (SM), ST users who had never smoked (STU), and nonusers of cigarettes or ST products (NON) using data from state-wide cancer registries and national surveys. Oral cancer incidence rates were estimated using Colorado, Florida, North Carolina, and Texas cancer registries from the years 2014 through 2017 (the most recent 4 years of available data). State-specific population counts by tobacco use status were estimated from the Tobacco Use Supplement to the Current Population Survey. Missing values in tobacco use status in cancer registry data were imputed either by assuming missing at random (MR) or using multiple imputation (MI). Poisson regression was used to estimate incidence rate ratios (IRR) by state and age group. A random-effect meta-analysis approach was used to summarize estimates by state and age groups while considering potential heterogeneity using the Mantel-Haenszel model. Cases of oral cancer among adult males 35 years and older with tobacco use data numbered 19,536 in the geographies studied over the covered period. Assuming MR, the pooled oral cancer IRR relative to NON were 1.0 (95% CI = 0.7 to 1.3) for STU and 3.4 (95% CI = 3.0 to 3.9) for SM, resulting in an IRR of 3.5 (95% CI = 2.5 to 4.9) for SM relative to STU. The corresponding MI-based estimates relative to NON were 1.4 (95% CI = 1.1 to 1.9) for STU and 3.6 (95% CI = 3.2 to 4.1) for SM, resulting in an IRR of 2.6 (95% CI = 2.0 to 3.3) comparing SM relative to STU. These estimates should be considered in the context of certain limitations, such as the estimates were not adjusted for other potential confounding variables (e.g., alcohol intake and other lifestyle factors, duration of tobacco use, and other tobacco product use) due to the lack of such information in data sources. Our population estimates based on state cancer registry data demonstrate that current ST users had a substantially lower oral cancer risk than current smokers. While causal relationships cannot be concluded, the large sample size in this contemporary analysis suggests that oral cancer risks among smokers may be reduced by switching to ST products; however, quitting all tobacco use is the optimal path for reducing oral cancer risks.
Citation Format: Brendan Noggle, Hui Cheng, Mohamadi Sarkar. Oral cancer incidence among smokers and smokeless tobacco users compared to nonusers of tobacco products - contemporary analysis of cancer registry data [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr LB160.