Abstract B13: Gastric cancer disparities in Latino populations in Texas, South Texas, and United States
Authors: Munoz Edgar , Westin Gustavo Figueiredo , Long-Parma Dorothy , Suarez Lucina , Ramirez Amelie G. 
Published: October 2015

Gastric cancer (GC) is the second-leading cause of cancer-related deaths in most Western countries. US Hispanics have higher rates of GC compared to the general population. The purpose of this study was to comprehensively compare Latinos to non-Hispanic white (NHW) for all primary gastric malignant tumor incidence and trends from 1995 to 2010, in the US, TX and STX. This includes incidence rates for all GC, Gastric Adenocarcinomas (GCA) by anatomic location and morphologic type, and Gastric Non-Epithelial Tumors (GNET). This analysis will provide a population comparison for incidences of gastric malignancies at regional, state and national levels among Latinos and NHW, yielding a clear snapshot of existing GC disparities which can be used to generate novel interventions and programs.

Methods: Data were collected from SEER and the Texas Cancer Registry. SEER*Stat software v 8.1.5 (SEER*Stat, 2014, National Cancer Institute) generated 1995-2010 average annual age-specific, age-adjusted, and three-year moving averages of GC, GCA, and GNET incidence rates, rate ratios (RR), annual percent changes (APCs) and 95% confidence intervals (CI) for Latino and NHW populations in the SEER, TX and STX datasets. APCs were derived using weighted least squares point-estimation; trends were tested for statistical significance using SEER*Stat.

Results: Incidence rates of GC were higher in Latino than NHW men in all three geographic populations analyzed. Latinas likewise showed higher rates than NHW women. Rates were similar for both genders across all Latino populations. The male-to-female ratio was approximately 2.1 for Latinos and 1.7 for NHW, and was similar in all populations. In terms of rate ratios (RR), TX and STX displayed the greatest ethnic disparities. The largest RR for GC was in STX, comparing Latino vs. NHW men (2.31; 95% CI=2.17-2.46; p&lt; 0.001). STX also had the largest RR for Latinas vs. NHW women (2.78; 95% CI: 2.51-3.08; p&lt; 0.001).

Because GCA accounts for the majority of GC, GCA incidence rates and RR were analyzed in more detail by stomach site and histology type. Intestinal was the most common type at both cardia and non-cardia sites (63%), followed by diffuse (22%) and other epithelial (OET) carcinomas (14 %). Type distributions were similar in all populations. Cardia GCA incidence rates were higher in NHW, particularly for intestinal type. In contrast, Latinos had higher incidence rates at non-cardia sites in all populations. Antrum/pylorus site had the highest rates of non-cardia GCA for intestinal and diffuse types. In this location, the most significant disparities were seen in intestinal type in TX (RR 4.28; 95% CI: 3.74-4.89) and STX (4.38; 95% CI: 3.25-5.98). The greatest disparity in the curvature site was the diffuse type in TX for both men (5.51; 95% CI: 4.04 – 7.55; p&lt;0.05) and women (4.42; 95% CI: 3.27-5.97; p&lt;0.05).

Conclusions: Our study provided a comprehensive overview of the ethnic differential distribution of gastric epithelial and non-epithelial tumors in US, TX and STX populations, as well as a detailed evaluation of GCA by histology type and stomach site. GC disparities between Latinos and NHW are more prominent in TX and STX. Latinos are at higher risk of developing GCA and GNET. Additional research is needed to further explore different contributors to these disparities.

Citation Format: Edgar Munoz, Gustavo Figueiredo Westin, Dorothy Long-Parma, Lucina Suarez, Amelie G. Ramirez. Gastric cancer disparities in Latino populations in Texas, South Texas, and United States. [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 B13.