Stomach cancer starts when abnormal cells in the stomach lining start growing. In the earliest stages, cancer usually doesn’t cause any symptoms or signs. This is because it grows slowly over years, and the changes in the lining are often so gradual that people don’t notice them. Even when symptoms do show up, they may feel like common gastrointestinal (GI) issues such as stomach viruses or ulcers. Because of this, most cases of stomach cancer aren’t diagnosed until they reach advanced stages. Then, they tend to spread to other parts of the body before they’re found and treated.
Symptoms of stomach cancer may include nausea and vomiting, especially when the person is throwing up solid food soon after eating. Sometimes the vomit may contain blood. Blood in the stool is also common. The stools can look black or tar-like, because of bleeding from the stomach and upper part of the small intestine. The blood may make the person feel tired and weak, because it cuts off oxygen to the tissues in the stomach and bowels.
When the cancer gets to the deeper parts of the stomach, it may bleed there too. This can cause a feeling of fullness in the stomach before the person finishes eating (early satiety). It can also lead to blood in the stool or urine. The blood may be bright red, which means the bleeding is fresh. But it can also be dark brown, or even black, if the cancer has been there for a long time.
Stomach cancer can also spread to lymph nodes and other tissues in the abdomen. Symptoms from this can include a feeling of pressure in the belly, pain when swallowing, and enlarged liver and spleen. The cancer can also cause diarrhea or constipation.
The causes of stomach cancer aren’t completely known. But it’s thought that most people who get the disease have a combination of risk factors. These include:
There are a few tests that can help doctors find out if a person has stomach cancer or not. These include:
If a doctor thinks you might have stomach cancer, they may order other tests. These include an upper endoscopy, which involves a thin tube with a camera being inserted into your mouth and into the stomach. This test can be used to take a biopsy (a sample of the tissue) of any areas that seem unusual.
Another test they might do is a CT scan or an MRI. These are both images of the inside of your body that can help doctors find out if you have stomach cancer or not. They can also find out how far the cancer has spread. If it hasn’t spread, treatment might be easier. But if it has, you might need more intensive treatments.
