Patterns in lung cancer incidence rates and trends by histologic type in the United States, 2004-2009

Objective: The examination of lung cancer by histology type is important for monitoring population trends that have implications for etiology and prevention, screening and clinical diagnosis, prognosis and treatment. We provide a comprehensive description of recent histologic lung cancer incidence rates and trends in the USA using combined population-based registry data for the entire nation. Materials and methods: Histologic lung cancer incidence data 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: Trend analysis demonstrate that overall rates have decreased, but incidence has remained stable for women aged 50 or older. 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. Histologic rates for black men exceeded those for white men, except for small cell carcinoma. The incidence rate for Hispanics was nearly half the rate for blacks and whites. Conclusion: The continuing rise in incidence of lung adenocarcinoma, the rise of squamous cell cancer in women, and differences by age, race, ethnicity and region points to the need to better understand factors acting in addition to, or in synergy with, cigarette smoking that may be contributing to observed differences in lung cancer histology. Published by Elsevier Ireland Ltd.