Stomach or gastric cancer usually originates from the cells that line the stomach. This may begin as an ulcer or a polyp which may cause no symptoms or can cause pain or bleeding. Most times cancer in the stomach is usually advanced by the time it is detected
The exact cause of stomach cancer is not always known, but may be related to risk factors such as acid reflux, smoking and bacterial infection.
Stomach cancer can occur in the upper part of the stomach (proximal) close to the esophagus or in the body of the stomach. In the United States the incidence of proximal gastric cancer is increasing. Overall stomach cancer is more common in people over age 65 and is more common in men. It also is much more prevalent in Asian countries and Eastern Europe.
The Following Factors Influence the Risk of Developing Stomach Cancer
- Infection with the bacteria Helicobacter Pylori causes inflammation of the inner layer of the stomach which can lead to ulcers and cancer. If detected a Helicobacter pylori infection can be effectively treated with antibiotics.
- Stomach cancer is more common in men than in women.
- Stomach cancer is most commonly diagnosed in people over the age of 65.
- Smoked and salted foods have been shown to increase a person’s chances of developing stomach cancer. A deficiency in the dietary mineral, selenium, may also increase the risk. Eating a diet high in fruits and vegetables (particularly beta-carotene and vitamin C) can decrease this risk.
- Stomach cancer is more common among Asians, Pacific Islanders, Hispanics, and African Americans than Caucasians.
- A very rare autoimmune condition in which the stomach no longer produces acid, making it hard to absorb vitamin B12.
Family cancer syndromes
- Such as hereditary nonpolyopsis colorectal cancer (HNPCC), also known as Lynch syndrome, Peutz-Jeghers syndrome, and familial adenomatous polyposis, all of which increases risk of colorectal cancer and slightly increase stomach cancer risk.
- Of stomach cancer, possibly resulting from E-cadherin mutation.
- Of breast cancer, People carrying mutations of the inherited genes BRCA1 and BRCA2.
Other Risk Factors
- Blood type A (for unknown reasons)
Types of Stomach Cancer
Up to 95 percent of stomach cancers are adenocarcinomas.
These adenocarcinoma cancers are formed in the cells that line the stomach and can be divided into three types.
Non-cardia stomach cancer
This develops from prolonged periods of inflammation and irritation and is commonly associated with chronic infection with Helicobacter pylori (H. pylori) bacteria.
H. pylori is a spiral-shaped bacterium commonly found in the stomach. The bacteria’s shape and the way they move allow them to penetrate the stomach’s protective mucous lining, where they produce substances that weaken the lining and make the stomach more susceptible to damage from gastric acids.
The bacteria can also attach to cells of the stomach, causing stomach inflammation, and can stimulate the production of excess stomach acid. Over time, infection with the bacteria can also increase the risk of stomach cancer.
Although it is not known how H. pylori infection is spread, scientists believe it may be contracted through food and water. According to the National Institutes of Health, approximately 20 percent of people under the age of 40 and half of adults over 60 in the United States are infected, with higher rates in developing countries.
Having H. pylori infection doesn’t necessarily mean you’ll have ulcers or develop stomach cancer.
Diffuse stomach cancer
This type of cancer grows within the stomach wall as individual scattered cells rather than forming a lump or tumor. It can be very difficult to detect using standard endoscopic techniques and often multiple biopsies throughout the stomach are needed. Diffuse stomach cancer sometimes has a genetic cause.
Proximal or gastroesophageal (GE) junction stomach cancer
This type of stomach cancer affects the first part of the stomach and often extends into the area where the stomach and esophagus meet, known as the gastroesophageal junction. Risk factors for this type of cancer include obesity and gastroesophageal reflux disease. This is rapidly increasing in the United States.
Less Common Types of Stomach Cancer
Cancer that begins in the cells of the immune system
Gastrointestinal stromal tumor (GIST)
Cancer of the muscle or connective tissue of the stomach wall
Cancer of the hormone-producing cells of the stomach
Stomach Cancer Stages
A staging system is a way for your doctor to describe the extent of your cancer and then establish a treatment plan.
The system most often used to stage stomach cancer in the United States is the American Joint Commission on Cancer (AJCC) TNM system. This divides cancer stages into 1 and 2 (early), 3 spread to surrounding lymph nodes and 4 to other organs (e.g. lung, liver and peritoneum).
TNM (tumor, node, metastasis) describes the stage of a cancer. This abbreviation summarizes the depth of penetration of the tumor into the stomach wall (T), whether it has spread to nearby lymph nodes (N), and whether it has metastasized, or spread, to other parts of the body (M).
T describes the extent of the primary tumor (how far it has grown into the wall of the stomach and into nearby organs).
N describes the spread to nearby (regional) lymph nodes.
M indicates whether the cancer has metastasized (spread) to distant parts of the body. The most common sites of distant spread of stomach cancer are the liver, the peritoneum (the lining of the space around the digestive organs), and distant lymph nodes. Less common sites of spread include the lungs and brain.
Esophageal and Gastric Cancer Treatment
Multimodality treatment (surgery, chemotherapy and radiation) is often used to treat patients with esophageal and gastric (stomach) cancer. Sequencing of treatment is determined by the stage, size and location of the tumor.Learn About Stomach Cancer Treatment Options