Award Date

5-1-2016

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Environmental and Occupational Health

First Committee Member

Paulo S. Pinheiro

Second Committee Member

Michelle Chino

Third Committee Member

Timothy Bungum

Fourth Committee Member

Amei Amei

Number of Pages

122

Abstract

Part I

Cancer incidence disparities exist among specific Asian American populations. However, the existing reports exclude data from large metropoles like Chicago, Houston, and New York. Moreover, incidence rates by subgroup have been underestimated due to the exclusion of Asians with unknown subgroup. Cancer incidence data for 2009 to 2011 for eight states accounting for 68% of the Asian American population were analyzed. Race for cases with unknown subgroup was imputed using stratified proportion models by sex, age, cancer site, and geographic regions. Age-standardized incidence rates were calculated for 17 cancer sites for the six largest Asian subgroups. Our analysis comprised 90,709 Asian and 1,327,727 non-Hispanic white cancer cases. Asian Americans had significantly lower overall cancer incidence rates than non-Hispanic whites (336.5 per 100,000 and 541.9 for men, 299.6 and 449.3 for women, respectively). Among specific Asian subgroups, Filipino men (377.4) and Japanese women (342.7) had the highest overall incidence rates while South Asian men (297.7) and Korean women (275.9) had the lowest. In comparison to non-Hispanic whites and other Asian subgroups, significantly higher risks were observed for colorectal cancer among Japanese, stomach cancer among Koreans, nasopharyngeal cancer among Chinese, thyroid cancer among Filipinos, and liver cancer among Vietnamese. South Asians had remarkably low lung cancer risk. Overall, Asian Americans have a lower cancer risk than non-Hispanic whites, except for nasopharyngeal, liver and stomach cancers. The unique portrayal of cancer incidence patterns among specific Asian subgroups in this study provides a new baseline for future cancer surveillance research and health policy.

Part II

Globally, Asian countries bear a disproportionate gastric cancer burden. Asian Americans, the fastest growing minority population in the US, show not only higher incidence of gastric cancer compared to non-Hispanic whites (NHWs), but also significantly higher survival. Benefiting from more uniform staging and treatment practices within the US, we examine for the first time the heterogeneity in the Asian American population, which may elucidate the causes of these disparities. SEER data from 2000 to 2012 were used to calculate 5-year survival estimates for NHWs and the six largest Asian ethnicities. Multivariate analyses were performed to identify critical prognostic factors and survival disparities between Asian groups and NHWs. We analyzed 33,313 NHW and 8,473 Asian gastric cancer cases. All Asian groups had significantly higher 5-year survival than NHWs, at 29.8%. Among Asians, Koreans and Vietnamese had the highest and lowest survival, 45.4% and 35.7%, respectively. The Korean survival advantage was largely attributable to relatively high proportions of localized stage and low proportions of cardia tumors. After adjusting for major prognostic factors, the survival disadvantage of NHWs, while attenuated, remained significant in comparison to all Asian groups (HR: 1.33; 95% CI: 1.24-1.43; reference: Korean). The survival disparities within the Asian groups vanished with adjustment. This study characterizes distinctive gastric cancer survival patterns among the six major Asian groups and NHWs in the US. The causes of the survival disadvantage for NHWs remain elusive. The observed survival disparity affecting NHW in relation to Asians points to the need for increased awareness of gastric cancer screening and treatment options of NHWs, who account for the majority of cases.

Disciplines

Epidemiology

Language

English

Available for download on Sunday, May 14, 2017


Included in

Epidemiology Commons

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