All About Gastric (Stomach) Cancer: The Basicsby Erin L. Boyle Health Writer
You, or a loved one, have recently – or months or years ago – received the news: a diagnosis of gastric (stomach) cancer.
Or maybe you’ve heard about this cancer, had it in your family, and are curious about it.
What should you know about gastric cancer? Most importantly, what IS gastric cancer?
Here are the facts and figures about it, including what it is, risk factors, symptoms, tests, treatment, and prognosis.
What is gastric cancer?
According to the National Cancer Institute (NCI), gastric cancer is cancer of the stomach. Cancerous cells form in the lining of the organ. The stomach wall is composed of three layers of tissue: the mucosal (innermost) layer, the muscularis (middle) layer, and the serosal (outermost) layer.
The stomach, of course, helps us digest food and pass waste out of the body. It’s located in the upper abdomen and is shaped like the letter “J.” The stomach itself has five parts.
“Food moves from the throat to the stomach through a hollow, muscular tube called the esophagus. After leaving the stomach, partly-digested food passes into the small intestine and then into the large intestine,” the NCI explains.
Ever wondered what “GI,” “GE,” and “GEJ” mean in relation to the stomach? The gastrointestinal (GI) tract is an important part of the body’s digestive system and includes the stomach, small intestine, and large intestine (colon). GE stands for gastroesophageal (GE) junction (also known as GEJ), which is the lower part of the esophagus that connects to the first part of the stomach, called the “cardia.” GEJ tumors are increasingly common, with about half of gastric carcinomas occurring here.
So, the long and short of it is: because the stomach is connected to other organs, its location and function impact other cancer types, too.
“The esophagus and stomach are continuous with each other,” explains Veena Shankaran, M.D., a medical oncologist who specializes in caring for patients with gastrointestinal malignancies at Seattle Cancer Care Alliance. She focuses on treating cancers of the esophagus and stomach.
Almost all — 90 to 95 percent — of gastric cancers are “adenocarcinomas,” starting in the cell lining of the mucosal layer, which makes and releases mucus and other fluids. When this cancer type metastasizes, or advances, it spreads beyond this layer. This cancer type can occur in the stomach and esophagus.
Other types of gastric cancer are gastrointestinal carcinoid tumors, gastrointestinal stromal tumors, and lymphomas. Stromal tumors of the stomach start in the supporting connective tissue, and are tested for and treated differently than adenocarcinomas, according to the NCI.
“Cancers of the lower esophagus and gastroesophageal junction are typically different pathologically than cancers of the upper- or mid-esophagus,” Dr. Shankaran says. “The former are usually adenocarcinoma while the latter are squamous cell cancers.”
“So, gastric and distal esophagus/gastroesophageal junction adenocarcinomas are usually lumped together for treatment and in thinking about clinical trials,” she says.
Who has gastric cancer?
Both men and women, but more men. They’re twice as likely as women to be diagnosed with this cancer, the NCI reports. Other risk factors for gastric cancer include:
Age. If you’re over 50, there’s a “sharp increase” in stomach cancer rates, the American Cancer Society (ACS) reports. Most people are diagnosed in their late 60s and 80s.
Ethnicity. Stomach cancer is more common in Hispanic Americans, African Americans, and Asian/Pacific Islanders than in non-Hispanic whites. “Black men are more than twice as likely as white men to die from stomach cancer,” the NCI says.
Inherited cancer syndromes. Genetics can play a role in elevating your risk of gastric cancer. Hereditary diffuse gastric cancer, caused by mutations in the CDH1 gene, is rare, but has a 70 percent to 80 percent lifetime stomach cancer risk. Other genetic syndromes associated with gastric cancer include hereditary non-polyposis colorectal cancer (HNPCC) or Lynch syndrome, which increases both your risk of colorectal cancer and stomach cancer; familial adenomatous polyposis (FAP), which includes the development of polyps in the colon, stomach, and intestines, raising the risk of colorectal cancer and slightly raising the risk of gastric cancer; and BRCA1 and BRCA2 mutations.
Family ties. In addition to these genetic risk factors, if your mother, father, sister, or brother had stomach cancer, you’re at a heightened risk for it too.
Diet. According to the NCI, eating a diet that includes a lot of salted, smoked foods, and not many fruits and vegetables can be a risk factor for gastric cancer.
Smoking. Cigarette smoking raises your risk.
Your location. Gastric cancer is far more common around the world than in the United States: it’s the fourth most common cancer in the world but is not in the current top 10 most common cancers in the U.S. Japan, China, Southern and Eastern Europe, and South and Central America have higher rates of gastric cancer. It’s less common in Northern and Western Africa, South Central Asia, and North America.
Helicobacter pylori (H. pylori) infection. Have you had this infection? It puts you at a higher risk of developing gastric cancer. It’s also more prevalent in other parts of the world, particularly Japan, South Korea, Russia, which ties it back to the geographical risk of having the cancer type, Dr. Shankaran says.
What are the symptoms?
Only about 10 percent to 20 percent of early stage gastric cancer cases are diagnosed in the United States. This cancer type is often not diagnosed until later stages because people mistake the symptoms for other issues, especially if they are young or don’t have a history of stomach cancer in their family, or they don't have any symptoms.
Dr. Shankaran shared a list of symptoms:
Trouble swallowing (for tumors in the upper part of the stomach/lower esophagus)
Pain after eating in the upper abdomen
Dark/black appearing stools
Vomiting undigested food after meals
Unintentional weight loss
If you are experiencing any of these, see your doctor.
What are the tests?
So you go to your doctor, and your doctor thinks further tests are needed, based on your potential risk factors and/or possible symptoms, to determine if you have gastric cancer.
What happens next?
You undergo tests and procedures that could include:
Physical exam and history: This exam looks at the whole body for changes, including lifestyle and any physical changes.
Blood chemistry studies: This procedure uses a blood sample to measure amounts of different substances in your body to determine disease.
Complete blood count (CBC): A procedure using a blood sample to test for red blood cells, white blood cells, platelets, and hemoglobin (the protein that carries oxygen).
Upper endoscopy: A procedure that looks inside the esophagus, stomach, and duodenum (the first part of the small intestine) for any abnormalities. It’s performed using an endoscope, which is a thin, lighted tube that goes down the mouth and into the throat to the esophagus.
Barium swallow or upper GI series: X-rays of the esophagus and stomach taken after you drink a liquid that contains barium, a silver-white metallic compound, to coat the esophagus and stomach.
CT scan (CAT scan): According the NCI, this procedure is a series of images, taken with X-rays, of areas inside the body. It's also called computed tomography, computerized tomography, or computerized axial tomography.
Biopsy: Removing cells or tissues to examine by microscope to check for signs of cancer. Stomach biopsies are often done during an endoscopy.
What are the treatments?
The treatment of gastric cancer differs by staging, or severity of cancer, as well as cancer type and location. Chemotherapy, surgery (a “gastrectomy,” which is partial or whole removal of the stomach or “esophagogastrectomy,” which is partial or whole removal of the esophagus and the top of stomach), and radiation therapy are among the treatment types for the cancer.
“The location of the tumor within the stomach often significantly affects the type of surgery performed — esophagostomy versus partial gastrectomy vs. total gastrectomy. For GEJ tumors, preoperative chemoradiation is commonly used,” Dr. Shankaran says.
What is the prognosis?
The prognosis — or likely course — for gastric cancer shows why it’s so important for early detection of the disease. The five-year survival rate for stomach cancer is 30.6 percent. Advanced metastatic stomach cancer, or stage 4 gastric/stomach cancer, does not have a good outlook: “long remissions are uncommon,” the NCI reports. The most common sites of the spread of advanced gastric cancer are the liver, lungs, peritoneum, abdominal lymph nodes, and bones, Dr. Shankaran says.
Meaning: it’s best to know the risk factors and symptoms of gastric cancer, and see your doctor when you have questions and concerns.