Among US Hispanics, stomach cancer has incidence and mortality rates that are more than double the rates observed among non-Hispanic white (NHW) individuals, for both men and women. Disparities in the incidence rates by stomach anatomic subsites have been reported between Hispanics and NHW, suggesting differences in the prevalence of various risk factors between these two populations. Moreover, the decline in mortality due to stomach cancer among Hispanics has been reported to be smaller than among other ethnic groups. Given the heterogeneity among US Hispanics, analyses of cancer clinical characteristics and survival patterns among the major Hispanic subgroups are warranted.

We investigated the frequency of demographic and clinical characteristics of stomach cancer patients and survival rates of Hispanics living in California taking into account subgroups defined by the following country or regions of origin: Mexico, Caribbean (Cuba, Puerto Rico, Dominican Republic), South or Central America, and “other”, which includes Hispanics of no identified origin. Using data from the California Cancer Registry (CCR), we identified 8,268 invasive stomach cancer cases diagnosed during 2000-2010 and defined as Hispanic according to the NAACCR Hispanic Identification Algorithm (NHIA). We identified country of origin using information from NHIA registry variables ‘birthplace’ and ‘Spanish origin’, and also searched Death Records to identify cases of Hispanic origin, for a total of 4,891 cases (59%) of Mexican origin, 1,384 cases (17%) of South or Central American origin, 257 cases (3%) of Caribbean origin, and 1,736 cases (21%) of other/no identified origin. We also included 12,997 NHW for comparisons.

Overall, the frequencies of stomach cancer by anatomical subsites were statistically significantly different between Hispanics and NWH for both males and females (p<0.001). Compared to NHW, Hispanics had lower frequency of cardia stomach cancer (among males, 53% in NHW versus 22% in Hispanics and in females 28% in NHW versus 14% in Hispanics). Among Hispanic males, frequency of cardia stomach cancer was lowest among those of South or Central American origin (20%) and Mexican origin (21%). In contrast, frequencies of tumors of the antrum (24% in males, 27% in females) or body (24% in males and 27% in females) were higher among Hispanics compared to NHW (antrum: 13% males, 21% females; body: 15% males, 23% females).

Hazard ratios from Cox regression models adjusted for age, gender, SES, nativity, stage, anatomical subsite, and type of treatment received, using data from 2004-2010, showed that being of Mexican origin is associated with greater risk of cancer death compared to being NHW (HR = 1.3; 95% CI = 1.2-1.4; p<0.001). In contrast, being Hispanic of ‘other or no-identified country of origin’ was associated with reduced risk of cancer death compared to being NHW (HR = 0.5; 95% CI = 0.5-0.6; p = 0.01).

Our findings highlight the importance of taking into account the heterogeneity within the Hispanic population when studying cancer patterns, as this may help understand cancer determinants and clinical characteristic in this minority population.

Citation Format: Mariana C. Stern, Afsaneh Barzi, JuanJuan Zhang, Dennis Deapen, Lihua Liu. Disparities in stomach cancer characteristics and survival among Hispanics in California. [abstract]. In: Proceedings of the Sixth AACR Conference: The Science of Cancer Health Disparities; Dec 6–9, 2013; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2014;23(11 Suppl):Abstract nr B47. doi:10.1158/1538-7755.DISP13-B47

©2014 American Association for Cancer Research.
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