
According to the American Cancer Society, stomach cancer is responsible for approximately 1.5% of all US cancer cases diagnosed every year. "In the United States, stomach cancer screening tests are only for people with a high risk of stomach cancer," says oncologist Bassam Sonbol, MD. "Your risk could be high if stomach cancer runs in your family. You could have a high risk if you have a genetic syndrome that can cause stomach cancer. Examples include hereditary diffuse gastric cancer, Lynch syndrome, juvenile polyposis syndrome, Peutz-Jeghers syndrome and familial adenomatous polyposis. In other parts of the world where stomach cancer is much more common, tests to detect stomach cancer are used more widely."
One of the most significant risk factors for stomach cancer is age. "Stomach cancer more commonly affects older people," says Dr. Sonbol. "The average age of those diagnosed with stomach cancer is 68. Around 60% of cases occur in patients older than 65, and there is a slightly higher lifetime risk of stomach cancer in men. However, it can affect anyone. Stomach cancer tends to develop slowly over time, usually over many years. What happens is small changes occur in the DNA of the stomach cells, telling them to over multiply and then they accumulate, forming abnormal growth called tumors. There are several known risk factors that could increase your risk of developing stomach cancer, for instance, smoking doubles your risk of stomach cancer, family history of stomach cancer, infection with H. pylori, long-term stomach inflammation, gastroesophageal reflux disease, or stomach polyps. Eating a diet high in salty and smoked foods or low in fruits and vegetables can be also a risk. And there is some correlation between higher weight and risk, as well."
"Stomach cancer treatment is most likely to be successful if the cancer is only in the stomach," says Dr. Sonbol. "The prognosis for people with small stomach cancers is quite good. Many can expect to be cured." Here are five symptoms of stomach cancer, according to experts. Read on—and to ensure your health and the health of others, don't miss these Sure Signs You've Already Had COVID.
Weight Loss

Unexplained weight loss is often one of the earliest signs that something might be wrong health-wise, and should never be ignored. "For many people with cancer, this unexplained weight loss is one of the first indications of the disease," says Munveer Bhangoo, MD, a hematologist and oncologist at Scripps MD Anderson Cancer Center. "Someone who loses this amount of weight without a clear reason should see their physician to determine what is causing it."
Some types of cancer are more likely to cause weight loss than others—for example, cancers where eating is made difficult. Because cancer cells may need more energy than healthy cells, the body is burning more calories at rest which can lead to weight loss. "People no longer feel hungry and ultimately start losing weight without trying," says Daniel Joyce, MBBCh. "That's probably the most concerning symptom."
Swollen Stomach

Having a swollen stomach could be a sign of stomach cancer, experts say. "Your provider may be able to feel a mass in your stomach during a physical exam depending on how advanced the cancer is," says the Cleveland Clinic. "More often, however, symptoms involve recognizing sensations in your stomach. Your stomach may frequently feel swollen, full or painful. The pain may start as mild and then get more intense as the disease progresses."
Certain types of food may increase the risk of stomach cancer. "Stomach cancer risk is increased in people whose diets include large amounts of foods preserved by salting, such as salted fish and meat and pickled vegetables," says the American Cancer Society. "Eating processed, grilled, or charcoaled meats regularly appears to increase risk of non-cardia stomach cancers. Eating few or no fruits likely increases the risk of stomach cancer. On the other hand, eating lots of fresh fruits (especially citrus fruits) and raw vegetables appears to lower the risk of stomach cancer. "
Abdominal Pain

Unexplained, persistent stomach pain could be a symptom of gastric cancer, experts say, especially when the pain is localized towards the top of the stomach. "Stomach cancer doesn't always cause symptoms in its early stages," says Dr. Sonbol. "When they happen, symptoms might include indigestion and pain in the upper part of the belly. Symptoms might not happen until the cancer is advanced. Later stages of stomach cancer might cause symptoms such as feeling very tired, losing weight without trying, vomiting blood and having black stools."
Cancer that spreads can lead to a bloated belly, doctors say. "Stomach cancer that spreads to other parts of the body is called metastatic stomach cancer," Dr. Sonbol says. "It causes symptoms specific to where it spreads. For example, when cancer spreads to the lymph nodes it might cause lumps you can feel through the skin. Cancer that spreads to the liver might cause yellowing of the skin and whites of the eyes. If cancer spreads within the belly, it might cause fluid to fill the belly. The belly might look swollen."
Heartburn

Heartburn is a common symptom of stomach cancer, experts say. "If there's a large cancer growth at the stomach's exit point, fluid can accumulate and the path of least resistance can be back up the food pipe/esophagus," says Dr. Joyce. Certain factors can make heartburn worse, which can again raise the risk of cancer. "There's a problem with obesity in the US. That causes more acid reflux in the esophagus, which leads to a condition called Barrett's esophagus, and that can ultimately lead to cancer."
According to Johns Hopkins Medicine, Barrett's esophagus is where "some people's bodies attempt to heal the damage by replacing the esophagus' lining with tissue very similar to the small intestine." So, while chronic heartburn doesn't necessarily mean you have cancer, it can be dangerous if left untreated. "It's not normal to have recurrent daily heartburn," says gastroenterologist Marcia "Mimi" Canto, MD, MHS. "Diagnosing Barrett's esophagus and treating it before it can progress is a scientifically proven way to prevent cancer."
Nausea and Vomiting

Nausea and vomiting could be an early sign of stomach cancer, and there many or may not be blood visible. "As the early symptoms of stomach cancer are similar to those of many other conditions, the cancer is often advanced by the time it's diagnosed," says NHS Scotland. "It's therefore important to get any possible symptoms of stomach cancer checked by your GP as soon as possible."
Another risk factor for stomach cancer is previous surgery. "Stomach cancers are more likely to develop in people who have had part of their stomach removed to treat non-cancerous diseases such as ulcers," says the American Cancer Society. "This might be because the stomach makes less acid, which allows more harmful bacteria to be present. Reflux (backup) of bile from the small intestine into the stomach after surgery might also add to the increased risk. These cancers typically develop many years after the surgery."