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Stomach cancer, otherwise known as gastric cancer is relatively uncommon in the U.S., where only 22,710 new cases or 1.7% of all cancer cases will be diagnosed this year. However, there are two reasons why preventing gastric cancer is of public health significance. First, gastric cancer disproportionately occurs among individuals of non-white race/ethnic groups. Second, the five-year survival rates of gastric cancer are among the lowest of all cancers. For example, only 23% of individuals diagnosed with gastric cancer this year will live beyond five years. This is in contrast to the five-year survival rates of individuals diagnosed with colon (62%) or breast (87%) cancer.
We know that cigarette smoking is an important risk factor for certain gastric cancers that are located in the proximal or cardia region near the junction of the esophagus and the stomach These cancer are called gastric cardia adenocarcinomas. Smoking may account for up to 45% of all gastric cardia cancers. Gastric cardia cancer is more likely to occur in younger individuals, to be more aggressive and to have worse prognostic factors, compared to non-cardia gastric cancers. The latter, less aggressive type of gastric cancer is primarily caused by Helicobacter pylori infection, which is not common in the U.S., but very common in less developed countries, such as Mexico. Although Hispanics have lower incidence of the most common cancers in the U.S., they have one of the highest incidence rates of infection-related cancers, such as gastric cancer. This is though to be due to the higher prevalence of H. pylori among this population.
The goal of this project is to determine whether the factors associated with increased acculturation, such as increased tobacco use, result in a shift of gastric cancer type among Hispanics in California, or in other words, an increased incidence of the more aggressive, gastric cardia type. To accomplish this goal, we will first evaluate the trends of gastric cardia cancer incidence and mortality among Hispanics living in California, using the statewide, population-based cancer registry. Second, we will conduct a population-based study of newly diagnosed gastric cancer cases in an eight-county region of the California Central Valley. We will collect information on tobacco use, secondhand smoke exposure, acculturation, diet, socioeconomic status and obesity.
We predict the following three outcomes will result from this project: (1) identification of increasing trends of gastric cardia adenocarcimoa among Hispanics; (2) a stronger correlation between cigarette smoking and gastric cardia adenocarcinoma, compared to non-cardia adenocarcinomas; and (3) an association between cigarette smoking and acculturation factors among Hispanic cases of gastric cardia, but not of non-cardia adenocarcinomas. These outcomes will be used to direct future research aimed at reducing risk of developing and preventing deaths due to cancer of the gastric cardia, among the particularly susceptible population of recently acculturated Hispanics. |
