Objective: Surveillance of lung cancer by histology type is important for monitoring population trends that have implication for etiology and prevention, clinical diagnosis, prognosis and choice of targeted therapies. This study provides a comprehensive and recent description of disparities in histologic lung cancer incidence rates and trends for U.S. adults.

Methods: Histologic lung cancer incidence was analyzed from CDC's National Program of Cancer Registries (NPCR) and the National Cancer Institute's Surveillance, Epidemiology and End Results (SEER) Program. Standardized rates and trends were calculated for men and women by age, race/ethnicity, and U.S. Census region. Rate ratios were examined for differences in rates between men and women, and annual percent change was calculated to quantify changes in incidence rates over time.

Results: Adenocarcinoma and squamous cell carcinoma were the two most common histologic subtypes. Adenocarcinoma rates continued to increase in men and women, and squamous cell rates increased in women only. All histologic subtype rates for white women exceeded rates for black women, and histologic rates for black men exceeded those for white men, except for small cell carcinoma where rates were higher among white men. Among both men and women, the rate for Hispanics was nearly half the rate for non-Hispanic (NH) blacks and NH whites. Men had higher incidence rates than women for race and ethnic groups, but the relative size of this difference by sex was higher for NH blacks, NH Asian/Pacific Islanders and Hispanics compared with NH whites. The relative difference in incidence rates between men and women was slightly lower for NH American Indian/Alaska Native (AI/AN) populations than for whites. Differences between men and women living in the West were less pronounced compared to those living in other Census regions.

Conclusion: The variations observed by race and ethnicity, continuing rise in incidence rates of lung adenocarcinoma, and rise of squamous cell cancer rates in women suggest more research is needed to comprehensively understand factors that may be contributing to observed differences in lung cancer histology. Identification of these factors acting in addition to, or in synergy with cigarette smoking, may provide public health agencies with guidance for targeted messages to groups at higher risk.

Citation Format: Keisha Houston, S. Jane Henley, Jun Li, Mary C. White, Thomas B. Richards. Disparities in lung cancer incidence rates and trends by histologic type in the United States, 2004-2009. [abstract]. In: Proceedings of the Seventh AACR Conference on The Science of Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; Nov 9-12, 2014; San Antonio, TX. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2015;24(10 Suppl):Abstract nr B63.