Abstract A28: Incidence trends of lung cancer among Chinese Americans in California, 1990-2010
Authors: Gomez Scarlett Lin , Clarke Christina A. , Yang Juan , Sandler Alan , Lin Shih-Wen 
Published: October 2015

Background: Lung cancer is among the three most commonly occurring cancers among Chinese Americans and the top cause of cancer death. While lung cancer trends have been declining in the overall U.S. population, a recent report indicated that incidence through 2008 has been stable among Chinese American females and males. These trends among Chinese females are particularly noteworthy considering their consistently low prevalence of smoking (&lt;10% ever smokers). A more in-depth and current examination of lung cancer incidence and mortality trends by nativity (US or foreign born) among Chinese Americans may provide insights into the burden and etiology of lung cancer.

Methods: Incidence data from the California Cancer Registry were enhanced with data on patient nativity. Population data were derived from the 1990, 2000, and 2010 U.S. Census. Incidence rates were age-adjusted to the 2000 U.S. standard population. Annual percentage change (APC) statistics (2-sided p-values) based on a linear regression line were used to characterize the magnitude and direction of trends.

Results: 8167 lung cancers were diagnosed among Chinese in California from 1990-2010; the majority, 7,265 (89%) were foreign-born, with 79% of them born in China, followed by 7.4% from Taiwan, 5.1% from Hong Kong, and 2.8% from Vietnam. Over the 1990-2010 period, the relative proportion of all lung cancers that were non small-cell lung cancer (NSCLC) increased slightly; the proportions of squamous cell and large cell cancers declined, while the proportion of adenocarcinomas increased. There was also an increase in the proportion of NOS (not otherwise specified) NSCLC.

Among both Chinese males and females, lung cancer incidence rates declined steadily from 1990-2010 (-1.4% per year (95% CI: - 2.1 to -0.8) among males and -1.0% per year (95% CI: -1.6 to -0.3) among females), with rates of decline more rapid after 2000. . Among males, statistically significant declines were observed for small cell, total NSCLC, squamous cell, and large cell carcinomas. Among females, statistically significant declines were observed for total NSCLC and squamous cell carcinoma.

From 1990-2004, among females, incidence decreased non-statistically among US-born (APC = -2.8 (95% CI: -9.1 to 4.0)) but was stable among foreign-born (APC = -0.4 (95% CI: -1.7 to 1.0)). By histology, a statistically significant decreasing trend was observed for squamous cell carcinoma and increasing trend for NOS NSCLC among foreign-born females. Among males, overall incidence increased non-statistically among US-born (APC = 2.1 (95% CI: -4.9 to 9.7), but decreased significantly among foreign-born (APC = -1.7 (95% CI: -2.9 to -0.6)).. Statistically significant decreasing trends were observed for total NSCLC, squamous cell, and large cell carcinoma among foreign-born males.

Conclusions: Although incidence of lung cancer is declining overall and for certain histologies among Chinese American males and females, contrasting patterns were seen when stratified by nativity, with decreasing trends seen among foreign-born males but suggestion of increasing trends among US-born males, and stable rates among foreign-born females but suggestion of decreasing trends among US-born females. In the US, the prevalence of cigarette smoking has been shown to increase with subsequent generations among females, but decrease among males, counter to the observed incidence patterns by nativity. Further research is needed to identify additional risk factors beyond smoking in these populations, particularly given the high burden of disease. Given the generally low prevalence of cigarette smoking in Chinese American women, as well as the general lack of decline in rates over time for most subtypes, especially adenocarcinoma, these incidence patterns may point to genetic or biological factors inherent to the Chinese female population.

Citation Format: Scarlett Lin Gomez, Christina A. Clarke, Juan Yang, Alan Sandler, Shih-Wen Lin. Incidence trends of lung cancer among Chinese Americans in California, 1990-2010 [abstract]. In: Proceedings of the Thirteenth Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2014 Sep 27-Oct 1; New Orleans, LA. Philadelphia (PA): AACR; Can Prev Res 2015;8(10 Suppl): Abstract nr A28.