Stomach Cancer Facts

“Providing the best available treatment options for every one of my gastric cancer patients — and offering hope, whether it is with curative surgery or combination of therapies — I find that to be the most enriching part of my day.”

YANGHEE WOO, M.D., SURGEON

What Is Stomach Cancer?

Stomach cancer — also called gastric cancer — is a rare disease in the United States, however it is a leading cause of cancer death worldwide. Nearly 1 million patients worldwide will be diagnosed with stomach cancer this year. About 26,000 of those cases will be diagnosed in the United States, according to the American Cancer Society.

Types of Stomach Cancer

• Adenocarcinoma is the most common type of stomach cancer; it starts in the inner lining of the stomach, called the mucosa. Between 90 to 95 percent of stomach cancers are adenocarcinomas.

The two types of gastric adenocarcinoma include:

• Intestinal type is usually found in the lower portions of the stomach. This type tends to arise from chronic inflammation — with a well described malignant transformation of normal mucosa – and has a strong association with H. pylori infection.
• Diffuse type is an aggressive form of cancer in which cells (that never come together to form tumors) scattered throughout the stomach grow and spread rapidly. This form is more commonly found in the upper portions of the stomach or involves the entire stomach. Some patients with inherited conditions are predisposed to developing diffuse type gastric cancer.

Less Common Stomach Cancers

• Gastrointestinal stromal tumors start in special cells found in the wall of the gastrointestinal tract, called the interstitial cells of Cajal. This type of tumor — whether benign (not cancerous) or malignant (cancerous) — is commonly found in the stomach.
• Carcinoid tumors are tumors that start in hormone-making cells in the stomach. Most of the time they do not spread to other parts of the body.
• Lymphomas are cancers that typically start in immune system cells but can also start in the stomach wall.
• Other rare cancers can start in the stomach, including squamous cell carcinoma, small cell carcinoma and leiomyosarcoma.

How Stomach Cancer Develops

The stomach is a large pouch – shaped like a “J” – that connects the esophagus to the intestines, and is where the food you eat is partially digested before being passed through to the small intestine. It expands and contracts and has the capacity to hold a large volume of food and fluids.

Stomach cancer develops when cancer-causing substances from foods come into contact with the layers lining the stomach, or when a condition that causes inflammation (an abnormally sustained immune response) changes the character of the stomach lining. There a few conditions that may lead to this disease:

• Helicobacter pylori infection, or H. pylori, is a type of bacteria that causes stomach infection. It may be involved with changes to cells that turn them from normal to cancer.
• Chronic atrophic gastritis creates problems in the immune system, causing it to attack cells in the stomach wall. This condition is related to H. pylori infection and may lead to cancer, but it is not known exactly how.
• Intestinal metaplasia leads to changes to cells that line the stomach, so that they resemble cells in the intestine. This condition is suspected to play a role in stomach cancer.
• Intestinal dysplasia are premalignant lesions that may transform into cancer over time if left untreated.

What Increases Your Risk of Stomach Cancer?

Things that put you at higher risk for getting stomach cancer are called risk factors. Since the main role the stomach plays in the body is digesting food, an important risk for developing this type of cancer is related to what you eat. Other things like genetics, age and whether you smoke also play a role. Some major risk factors for getting stomach cancer include:

• H. pylori, a type of bacterial infection affecting the inner lining of the stomach that can lead to inflammation (an immune system response that lingers for too long) and peptic ulcers. It is found in most stomach cancer patients.
• Diets high in salted, pickled, fermented, smoked and preserved foods.
• Family history of gastric cancer.
• Genetic syndromes such as hereditary diffuse gastric cancer (caused by a mutation in a gene called CDH1), familial adenomatous polyposis, Li-Fraumeni syndrome, Lynch syndrome, juvenile-polyposis syndrome, Peutz-Jeghers syndrome, and hereditary breast and ovarian cancer syndrome.

Other risk factors:

• Male gender is a major factor — men are twice as likely as women to get stomach cancer.
• Race and ethnicity increase your risk of stomach cancer, especially if you are Korean-American, African-American, Hispanic or in another Asian group.
• Certain medical conditions like chronic atrophic gastritis, pernicious anemia, intestinal metaplasia and gastric polyps can increase your risk of stomach cancer.
• Obesity or being overweight may increase your risk of stomach cancer.
• Previous stomach surgery, including having part of your stomach removed for reasons other than cancer, increases risk.
• Industrial chemical exposure that comes from working in dusty and/or high temperature processing environments — or being exposed to certain chemicals like chromium — is associated with a higher risk of developing stomach cancer.
• Smoking cigarettes is linked to an increased risk of developing stomach cancer.
• Blood type A is associated with an increased risk of stomach cancer.
• Age is a risk factor for stomach cancer — most people are diagnosed in their late 60s or older.

Stomach Cancer Symptoms

During early stages, stomach cancer may not cause any symptoms, or they may not be specific — like indigestion or stomach discomfort that does not go away. Since these symptoms mimic other, less serious conditions, many people may dismiss them.

Early stomach cancer symptoms

• Indigestion
• Reduced appetite
• Heartburn
• Mild nausea

Later stomach cancer symptoms

Symptoms may be different during later stages and can affect other parts of the body — like the liver, lungs and bones. Stomach cancer that is advanced may block the stomach or intestines. Later symptoms may include:

• Sticky, dark or bloody stool
• Anemia
• Unexplained weight loss
• Excessive belching
• Vomiting
• Jaundice (yellowing eyes or skin)
• Fluid build-up in the abdomen
• Trouble swallowing
• Feeling bloated even after not eating much
• Pain or burning in the belly (stomach, abdomen)

Other medical conditions, like peptic ulcers and gastritis, share these symptoms. If you are treated for these conditions and symptoms like bloating, heartburn or indigestion do not go away, you may need further consultation to rule out stomach cancer.

Stomach Cancer Prevention

Quitting smoking, maintaining a healthy weight and avoiding smoked, pickled, preserved and salted foods may lower your risk. Eating a diet rich in fruits and vegetables may also reduce risk and, as with many cancers, being physically active and avoiding processed foods and meats helps.

Studies are ongoing to find out if things like antibiotic treatment and eating an antioxidant-rich diet could thwart one of the biggest risks for stomach cancer: H. pylori.