Stomach cancer, also known as gastric cancer, starts when cells in the stomach begin to grow uncontrollably. This type of cancer tends to develop slowly over many years.
Before cancer develops, pre-cancerous changes often occur in the inner lining of the stomach. However, these early changes rarely cause any symptoms, which is why the changes generally go undetected.
It is unclear what exactly causes stomach cancer. However, studies show¹ that the main cause of stomach cancer is a genetic mutation in the cells of the stomach. This causes the cells to grow rapidly and eventually form a tumor.
Whether you're concerned about being at risk of stomach cancer or just curious, read on to learn about the types of stomach cancer, the risk factors, prevention tips, and screening guidelines.
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There are various types of stomach cancers. Here are the three most common types you should know about.
The most common type of stomach cancer is adenocarcinoma. In fact, about 90% to 95% of stomach cancers² are adenocarcinomas. These types of cancers develop from the gland cells in the innermost lining of the stomach.
There are two main types of adenocarcinomas: intestinal and diffuse. An intestinal adenocarcinoma has a relatively better prognosis because these cancer cells are more likely to undergo gene change, making targeted drugs more successful.
Diffuse adenocarcinomas generally spread more quickly. However, it is less likely to occur than intestinal.
This type of stomach cancer begins in cells in the stomach or other parts of the digestive tract that act either like nerves or endocrine cells. Most neuroendocrine tumors grow slowly and do not spread to other organs. But it's important to keep in mind that some tumors can spread quickly.
This type of stomach cancer begins in the immune system cells called lymphocytes. While they usually start in other parts of the body, they can also start in the stomach wall. The treatment and outlook for this type of cancer depend on the type of lymphoma.
There are a variety of factors that can increase the risk of stomach cancer. While some risk factors such as age and family history can't be changed, other risk factors like smoking can.
Even if you have one or more risk factors, this does not mean that you will get stomach cancer. In fact, many people with one or more risk factors do not get cancer. On the other hand, some individuals with no risk factors can get the disease.
Let's take a look at some common risk factors of stomach cancer.
Males have an increased risk of getting stomach cancer. Several types of cancers, including stomach, liver, and colon, are more common in men than women. In fact, growing evidence suggests³ that the risk difference is based on basic biological differences between men and women.
While stomach cancer can occur in younger people, the risk increases as you age⁴. Most people who are diagnosed with stomach cancer are typically in their 60s, 70s, and 80s.
In the U.S., stomach cancer is more prevalent⁵ in Hispanic Americans, African Americans, and Asian Americans compared to non-Hispanic white Americans.
Helicobacter pylori infection
H. pylori is an infection that occurs in your stomach. H. pylori is a fairly common infection, and most people with the bacteria will never develop stomach cancer. However, this bacteria is considered a significant risk factor for stomach cancer. This is especially true for cancers in the lower part of the stomach.
Nonetheless, long-term infection of this particular germ can lead to atrophic gastritis and other pre-cancerous changes of the stomach's inner lining.
Being overweight or obese
Individuals who are overweight or obese have an increased risk⁶ of stomach cancer. This specifically increases the risk for stomach cancer in the upper part of the stomach near the esophagus.
Your diet is another crucial risk factor to consider. Studies show⁷ that individuals who eat large amounts of food preserved by salting, like salted fish and meat, have an increased risk of stomach cancer.
In addition to this, eating processed, grilled, or charcoal meats regularly can increase the risk of non-cardia (main part of the stomach) stomach cancers. Lastly, having a diet that incorporates little to no fruit can increase the risk of stomach cancer.
In contrast, eating many fresh fruits (especially citrus fruits) and raw vegetables can lower the risk of stomach cancer.
Alcohol and tobacco use
There is evidence that suggests⁸ excessive alcohol use increases the risk of stomach cancer. More specifically, individuals who have three or more drinks a day are at a greater risk.
Smoking increases the risk of stomach cancer, and for cancers in the upper part of the body near the esophagus.
Previous stomach surgery
Stomach cancer is more likely to develop⁹ in individuals who have had part of their stomach removed to treat other conditions such as ulcers. This could be due to the stomach producing less acid, which allows for harmful bacteria to grow.
Specific cells in the stomach lining usually create a substance called intrinsic factor (IF). This is needed for the body to absorb vitamin B12 from foods; and, those without enough IF may end up with a vitamin B12 deficiency. Unfortunately, this can impact the body's ability to produce red blood cells, leading to other problems.
This condition is known as pernicious anemia. It's important to note that other autoimmune conditions and stomach surgery can cause this condition. Regardless of the cause, pernicious anemia can increase your risk of stomach cancer.
Inherited cancer syndromes
In some cases, people inherit gene mutations from their parents, leading to certain conditions that increase their risk of stomach cancer, such as:
Hereditary Diffuse Gastric Cancer
Familial adenomatous polyposis
If you want to learn how to reduce your risk of stomach cancer, the good news is that you have options. Even if you have one or more risk factors, there are changes you can begin making right now to lower your risk. For instance, it's important to get adequate physical activity. This can lower your chance of being overweight or obese and improve your overall health.
Additionally, be sure to include a diet rich in a variety of fresh fruits and vegetables as well as a food palette that incorporates whole grains. Be sure to limit your intake of red and processed meats, sugar-sweetened beverages, and foods that are highly processed. Smoking can increase your risk of stomach cancer as well, so it's important to quit smoking if you haven't already.
At the moment, there is no standard or routine screening for stomach cancer. However, several stomach cancer screenings have been studied and found effective in finding stomach cancer early. These screenings include:
Barium-meal gastric photofluorography (Barium Swallow)
Serum pepsinogen levels (currently being studied)
Stomach cancer is becoming less prevalent in the United States. It is one of few cancers that develop slowly over time. If you're concerned that you are at risk of stomach cancer, the first step is arming yourself with the proper education to protect your health and lower your risk if possible.
There are a variety of stomach cancer risk factors that individuals should be aware of. While there are some risk factors that you can't change, there are few you can take control of by adopting a better lifestyle and habits.
In addition to this, it's important to take advantage of cancer screenings. This is especially important if stomach cancer runs in your family or you have one or more risks associated with stomach cancer.
For any additional concerns, be sure to discuss them with your doctor.
Hereditary Diffuse Gastric Cancer | Cancer.Net
What Is Stomach Cancer? | American Cancer Society
Stomach Cancer Incidence and Mortality by Age group, New York State Excl New York City, 2014-2018 | New York State - Department of Health
Study gauges specific site stomach cancer risks among ethnic groups | Vanderbilt University Medical Center
Preservation and processing of foods | World Cancer Research Fund
Stomach Cancer Causes | Stanford Health Care