- Stomach cancer incidence and mortality rates are higher among African Americans than white Americans.
- The most important risk factor for the disease is infection with the bacterium Helicobacter (H.) pylori, which is more common in African Americans and Hispanics than in non-Hispanic whites, though the vast majority of people with this infection never develop stomach cancer.
- Factors thought to contribute to the disproportionately high rate of cancer in African Americans include structural racism, which refers to the systems, social forces, institutions, ideologies, and processes that interact with one another to generate and reinforce inequities among racial and ethnic groups.
Although stomach cancer is a rare disease, African Americans have a higher risk of developing it than white Americans do.
Incidence rates of stomach cancer are 1.8 times higher in non-Hispanic Black men and 2.2 times higher in non-Hispanic Black women than in white men and women, respectively, according to the American Cancer Society. (These higher rates pertain to non-cardia stomach cancers, which occur outside the portion of the stomach that meets the esophagus.)
A similar disparity exists for stomach cancer mortality. Death rates for the disease are 2.6 times higher in non-Hispanic Black men and 2.3 times higher in non-Hispanic Black women than in white men and women, respectively.
Stomach cancers are diagnosed at roughly the same stage of disease in African Americans and whites. As with most cancers, cancers detected at an early stage can more often be treated successfully.
The good news is that the stomach cancer incidence rates are declining for African Americans as well as whites, with the rates dropping even more sharply for African Americans. Between 2006 and 2015, stomach cancer incidence rates fell 2.1% per year in non-Hispanic Black men and 1.6% per year in non-Hispanic Black women, compared to declines of 2% and 0.7% per year, respectively, in non-Hispanic whites.
Causes of disparities
Factors thought to contribute to the disproportionately high rate of cancer in African Americans include:
- Less access to cancer screening services
- Structural racism, which refers to the systems, social forces, institutions, ideologies, and processes that interact with one another to generate and reinforce inequities among racial and ethnic groups
- Social determinants of health (the environments in which people are born, work, play, worship, as well as factors such as transportation and family support system)
- A shortage of African American physicians in some areas
- Comorbid conditions (more than one illness or disease occurring at the same time)
- Severity of disease presentation (staging at diagnosis)
- Inequitable access to cancer treatment
The most important risk factor for stomach cancer, specifically, is infection with the bacterium Helicobacter (H.) pylori, which is more common in Blacks and Hispanics than in non-Hispanic whites. However, the vast majority of people with this infection never develop stomach cancer, nor the other conditions linked to the bacterium, including ulcers and gastritis, an inflammation of the stomach lining.
Because H. pylori infection usually doesn’t produce any symptoms, most people aren’t tested for it. Testing is generally reserved for people who develop symptoms of a peptic ulcer or other stomach disorder. If H. pylori infection is found, it can be treated with antibiotics.
It isn’t known why African Americans have higher H. pylori infection rates than white Americans, but people who live in crowded conditions and don’t have a reliable supply of clean water tend to be at higher risk. A higher percentage of people from racial and ethnic minority groups live in crowded housing as compared to non-Hispanic white people, according to the U.S. Centers for Disease Control and Prevention. An analysis of data released by the U.S. Environmental Protection Agency also found that there is “is unequal access to safe drinking water, based most strongly on race, a scientific conclusion that mirrors the lived experience of people of color and low-income residents in the United States.”
Additional risk factors
According to the American Cancer Society, other factors that can heighten stomach cancer risk include:
- Excess body weight: According to the American Institute for Cancer Research (AICR), a strong link exists between excess body fat and the risk of 12 different kinds of cancer. We now understand that body fat secretes substances that may make it easier for cancer cells to develop and grow. Any steps taken to reduce weight — or limit weight gain over time — are helpful for managing cancer risk. Strategies that can help with weight management include eating more fruits, vegetables, and whole grains, along with protein from healthy sources like seafood, poultry, beans and soy foods. It’s also important to limit sugary beverages, alcohol, and processed foods, and be physically active most days of the week if possible.
- Smoking: Smoking is the leading cause of cancer worldwide, causing almost 6 million deaths each year according to the AICR. There are no good forms of smoking, including vaping which still contains harmful chemicals. For help quitting smoking, you can call the national Smokers’ Helpline (1-800-QUIT-NOW) for programs in your state or talk with a medical professional to learn more. The number for the Massachusetts Smokers’ Helpline is 1-800-TRY-TO-STOP (1-800-879-8678). See Quitting Smoking for additional resources.
- Alcohol consumption: Strong evidence points to alcohol consumption raising your risk of several types of cancer, including colorectal, regardless of whether you’re drinking beer, wine, or liquor. The AICR recommends women consume no more than one drink per day, and men no more than two. One drink is a 12-ounce beer, 5-ounces of wine or 1.5-ounces of liquor. Less is even better. Measure your pour at home so you know whether your serving is larger than recommended.
- A diet high in red and processed meat: Research suggests that eating more than 12-18 ounces of cooked red meat per week increases the risk of colorectal cancer. Red meat includes beef, pork, and lamb. A 3-ounce serving is about the size of a deck of cards, so aim for no more than four to six “decks of cards” of cooked red meat weekly. The AICR especially recommends staying away from processed meats like ham, hot dogs, bologna, salami, bacon, and sausages (including those made from chicken and turkey). Limit these to only occasional use.
It is important to acknowledge that not everyone has the same access to cancer risk reduction strategies, and many factors play a role.
Dana-Farber research in stomach cancer
Dana-Farber investigators have played a seminal role in genomically characterizing diffuse gastric cancer, an aggressive form of the disease that disproportionately affects lower socioeconomic and immigrant populations. In a recent study, Dana-Farber scientists and an international team of collaborators found that a protein pathway called the RHOA pathway plays a critical role in the disease. In laboratory studies, the team found that mouse models of diffuse gastric cancer with a mutation in RHOA-Y42C were sensitive to agents inhibiting the FAK protein — a sign that FAK could represent a strong therapeutic target for diffuse gastric cancer. Dana-Farber investigators are now in discussions with several pharmaceutical companies to design a clinical trial testing FAK inhibition in patients.
Research by Dana-Farber scientists has led to the identification of four subtypes of stomach cancers, highlighting the complexity of the disease and potentially leading to more precise treatments.
Nilay Sethi, MD, PhD, is exploring how environmental factors may interact with genetic mutations to cause tumor development in animal models. In a recent study, he demonstrated how early mutations in the P53 gene interacted with environmental factors like dietary carcinogens and inflammation to promise premalignancy in stomach tissue.
In a clinical trial, the antibody-drug conjugate trastuzumab deruxtecan showed promising results in patients with advanced stomach cancer or cancer of the gastroesphageal junction (the area where the stomach meets the esophagus). As part of this landmark work, Peter Enzinger, MD, is participating in a phase II trial testing the conjugate in patients with HER2-positive stomach cancer that cannot be surgically removed or has metastasized.
Dana-Farber researchers have discovered that a subset of stomach and esophageal cancers harbor extra copies of the KRAS gene. Follow-up studies showed a combination of drugs inhibiting the SHP2 and MEK proteins works against such tumors. Based on these findings, Kimmie Ng, MD, MPH, is leading a multi-institutional phase I clinical trial testing SHP2 inhibition in patients with KRAS-amplified tumors, including gastric and esophageal cancers.
A phase III clinical trial is comparing a combination of the drugs zolbetuximab and chemotherapy to chemotherapy plus a placebo in patients with a genetic subtype of stomach or gastroesophageal cancer that has spread or isn’t treatable with surgery.
About the Medical Reviewer
Dr. Enzinger received his college and medical degrees from Brown University in Providence, RI. He completed his Internal Medicine residency at the University of Rochester and his Medical Oncology and Hematology fellowship at Memorial Sloan-Kettering Cancer Center (Cornell University) in New York City. Additionally, he served as a Fogarty Fellow (Experimental Cell Biology) at Hopital St. Louis and the Universite Paris VII. He is board-certified in both Internal Medicine and Medical Oncology.