Who Is at Risk for Stomach Cancer?

A Keck Medicine of USC expert explains the risk factors of stomach cancer and what you can control.

Stomach cancer affects only 3% of people in the United States. But when it is detected, it’s typically in more advanced stages because there are no routine screening protocols for early detection of stomach cancer as there are for breast cancer or colon cancer.

This makes understanding risk factors and symptoms of stomach cancer crucial for early detection, says Sharon Shiraga, MD, an upper-gastrointestinal surgeon with Keck Medicine of USC.

If you have a family history of gastrointestinal cancer or any of the risk factors below, knowing what to look for can help you make informed decisions about your health and when to seek medical attention.

Family history is the biggest risk factor for stomach cancer

Most stomach cancers are sporadic, meaning they develop due to random genetic mutations or environmental factors rather than predictable causes. “It’s nothing you’ve done,” Dr. Shiraga reassures patients.

The biggest risk factor for stomach cancer is family genetics. For this reason, “If you have somebody in your family who had early onset of cancer anywhere in the gastrointestinal tract, you need to have a conversation with your doctor and think about screening early,” Dr. Shiraga says.

Learn as much as you can about your family’s history of stomach cancer. Many people only have fragments of family medical information — “Granddad died of some kind of stomach cancer” or “There’s digestive cancer in the family.” Even these incomplete details, however, give your doctor important clues about your risk, she says.

Since there are no official screening guidelines for stomach cancer, your doctor can create an individualized plan for appropriate monitoring.

Demographics can also affect stomach cancer risk

Other factors, such as demographics and medical history, can also influence the risk of stomach cancer.

In terms of demographics, people of Asian and South American descent face higher rates of stomach cancer than those of European descent. Dr. Shiraga notes that patterns of stomach cancer in these demographics could result from regional dietary practices.

Conditions that cause persistent stomach inflammation can lead to cellular changes that may become cancerous over time. Examples include:

• Chronic gastritis: Long-term stomach inflammation is often linked to dietary habits or H. pylori infection.
• Stomach ulcers: Stomach ulcers are particularly concerning when they don’t heal properly. When chronic ulcers don’t improve, doctors may suggest removing them before they can become cancerous, Dr. Shiraga says.
• Gastroesophageal reflux disease (GERD): GERD, or acid reflux, happens when stomach acid repeatedly irritates the esophagus. “Inflammation is likely the first step,” Dr. Shiraga notes. “As it gets more advanced, it causes ulceration, and after that it can become cancer at the esophageal gastric junction.” For chronic acid reflux lasting five to ten years, many doctors recommend an upper endoscopy to monitor the esophagus for adverse tissue changes.

Are there any stomach cancer risk factors you can control?

While family and health history are the biggest determinants, making other healthy lifestyle changes can boost your health and outlook in general.

Maintaining a healthy weight is important. “The biggest modifiable risk factor of stomach cancer is obesity,” Dr. Shiraga notes. “Excess abdominal fat tends to be more hormonally active and associated with cancer. Having less abdominal fat will help decrease inflammation in your body.”

Regular exercise and a Mediterranean-style diet — rich in fruits, vegetables and fiber and limiting processed foods, excessive salt and preserved meats — can also reduce risk. “It’s about not doing too much of anything; it’s about diversifying,” Dr. Shiraga advises.

Don’t smoke. Cigarette smoke contains 7-10 known carcinogens that increase your body’s inflammatory state, which can increase the risk of all sorts of cancer, including stomach cancer, Dr. Shiraga says.

Finally, be aware of H. pylori infections. People from Asia, South America or other regions with higher H. pylori infection rates should discuss screening with their doctor. H. pylori stomach infection is treatable when detected. If one household member is found to have an H. pylori infection, the whole family should be checked, Dr. Shiraga says.

What symptoms should prompt medical attention?

“We do not have standard guidelines to screen for upper gastrointestinal cancers,” Dr. Shiraga says. Instead, patients can empower themselves by being aware of any new symptoms. Watch for these warning signs:

• Unintentional weight loss: Dr. Shiraga says this is often the first sign of gastrointestinal cancer.
• Loss of appetite: This can occur because your body’s regulatory systems may be disrupted.
• Persistent stomach pain: Pay attention especially to pain that is unrelated to meals or stress.
• Changes in stool: “Bad-smelling, inky, dark stool” is a risk sign to watch for, Dr. Shiraga says.

“If you notice any of these changes, you need to talk to your provider as soon as possible,” she continues. Don’t let embarrassment delay your care; remember that there’s nothing doctors haven’t seen before.

Be proactive when it comes to stomach cancer

To guard yourself against stomach cancer, be your own advocate, Dr. Shiraga says. Take active steps to monitor your health and focus on what you can control — a healthy weight, balanced diet, no smoking and managing chronic digestive conditions with proper medical care.

Most importantly, Dr. Shiraga emphasizes balance: while you can’t control everything, focus on the modifiable factors. Live a healthy life with a healthy diet and exercise, and there’s much less need for concern.

Stay informed, make healthy choices and maintain open communication with your health care provider. Knowledge about stomach cancer isn’t meant to create fear; it’s meant to empower you to recognize when medical attention is needed.

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