A popular explanation for the decrease in the number of stomach cancer diagnoses in the United States and other countries involves improved nutrition due to the proliferation of refrigeration during the past century, which has fostered an increase in the availability of fresh foods at the expense of the once-common pickled, dried and smoked fare that heads the list of dietary risk factors.
Another explanation focuses on the broader use of antibiotics in developed countries, which may play a beneficial role in reducing the stomach-dwelling Helicobacter pylori bacteria, a co-factor in the development of stomach carcinoma and a cause of stomach infection in many developing countries where substandard hygiene conditions exist.
Being aware of and/or mitigating the following risk factors may help prevent stomach cancer:
- Diet: The intake of foods preserved through pickling, salting and drying appears to increase the likelihood of stomach cancer, whereas eating substantial quantities of fruits, vegetables and whole-grain foods likely reduces the risk. Men who are very overweight or obese appear to have a higher risk of cancer in the part of the stomach nearest the esophagus. Scientists are not sure whether obesity increases a woman’s risk of stomach cancer.
- Helicobacter pylori: Infection of the stomach by H. pylori bacteria, a common cause of ulcers, is believed to significantly increase one’s cancer risk.
- Tobacco and alcohol abuse: According to the American Cancer Society, tobacco use causes about one-third of all cancer deaths in the United States, and both smoking and drinking excessive amounts of alcohol appear to increase the likelihood of cancer in the upper part of the stomach.
- Genetic disposition: Immediate family members of those diagnosed with stomach cancer are at increased risk for developing the disease. Other genetic risk factors include hereditary non-polyposis colon cancer (HNPCC) syndrome and Li-Fraumeni syndrome, conditions that result in a predisposition to cancer. Having type A blood appears to slightly increase the risk for stomach cancer.
- Medical Conditions: People with pernicious anemia are 5 to 10 percent more likely to develop stomach cancer. Those with chronic stomach inflammation and intestinal polyps are also at increased risk for the disease.
- Gender: The majority of stomach cancer patients are male.
- Age: Most individuals who develop stomach cancer are older than 55 years of age.
- Ethnicity: In the U.S., stomach cancer occurs more frequently in Hispanic Americans and African Americans than in non-Hispanic whites, and it is most common in Asian/Pacific Islanders.
- Environment: Because the number of stomach cancer cases varies dramatically from one part of the world to another, there may be an environmental component to stomach cancer risk that goes beyond nutrition. It is known that workers in the rubber, metal, coal and timber industries, as well as those who have been exposed to asbestos fibers, have a higher risk for stomach cancer.