Stomach cancer, also called gastric cancer, begins when tumors grow in the lining of the stomach. It usually affects people over 65 and is difficult to diagnose early. Smoking, stomach infections and eating a lot of salted or smoked foods can increase your risk. This guide will help you learn more about stomach cancer symptoms, causes, treatment and survival rates.
What Is Stomach Cancer?
Stomach cancer starts in the mucosa, the innermost layer of the stomach wall’s five layers of tissue. As it grows, it spreads to the other four layers: submucosa, muscle, subserosa and serosa.
The good news about stomach cancer is rates are on the decline in the United States. This cancer accounts for only about 1.5 percent of all cancers diagnosed each year, according to the American Cancer Society.
Treatment for stomach cancer depends on how far the cancer has spread. The right regimen may improve quality of life and extend survival time.
- In 2021, there will be about 26,560 new cases of stomach cancer and 11,180 deaths.
- About 60 percent of people diagnosed with stomach cancer are 65 or older.
- More men than women get stomach cancer.
- The overall five-year survival rate is 32 percent.
- Early stage stomach cancer symptoms include nausea, loss of appetite, indigestion, feeling bloated after eating and heartburn.
- Smoking, stomach infections, older age, male gender, eating processed or smoked meats and family history of cancer are risk factors for stomach cancer.
- Treatments for stomach cancer include surgery, radiation therapy, chemotherapy, targeted therapy and immunotherapy.
Signs of Stomach Cancer
People don’t usually notice early stomach cancer symptoms because they resemble symptoms of other health problems. Stomach cancer symptoms are the same in both men and women, although men are more likely to get the disease.
There is no single first sign of stomach cancer, but the first warning signs are usually gastrointestinal problems such as nausea, loss of appetite and abdominal discomfort that lasts for several days.
“People no longer feel hungry and ultimately start losing weight without trying. That’s probably the most concerning symptom.”
- Acid reflux and heartburn
- Feeling bloated after eating
- Loss of appetite
- Stomach discomfort and indigestion
- Blood in the stool
- Difficulty swallowing
- Fluid in the abdomen (ascites)
- Stomach pain
- Sudden, unexpected weight loss
- Yellowing of eye and skin (jaundice)
Causes and Risk Factors
Abnormal cell growth in the stomach lining causes stomach cancer to grow. But each person has different risk factors that increase individual risk for developing the disease.
The most significant risk factor for developing stomach cancer is having a Helicobacter pylori (H. pylori) bacterial infection, according to Moffitt Cancer Center. Long-term infections can cause pre-cancerous changes in the stomach lining.
Some factors, such as age and sex, can’t be controlled. Others, such as lifestyle and diet, can be controlled.
“Having a risk factor does not mean that you will get cancer; not having risk factors doesn't mean that you will not get cancer. Talk with your doctor if you think you may be at risk.”
- Sex – Men are more likely to get stomach cancer than women.
- Age – Risk increases with age and most people with this cancer are in their 60s or older.
- Ethnicity – Asian/Pacific Islanders, Hispanic Americans, Native Americans and African Americans are more likely to get the cancer than non-Hispanic whites.
- Weight – Being obese or overweight increases the chance of upper stomach cancer.
- Diet – Eating a lot of smoked, salted or processed meats increases stomach cancer risk.
- Smoking – Smoking doubles a person’s stomach cancer risk.
- Alcohol – Drinking alcoholic beverages increases stomach cancer risk, especially in people who have three or more drinks a day.
- Previous stomach surgery – People who have had part of their stomach removed may develop stomach cancer many years after surgery.
- Pernicious anemia – Pernicious anemia, a condition that affects the body’s ability to make new red blood cells, may increase gastric cancer risk.
- Family history – People with siblings, parents or children who have had stomach cancer have a higher risk of getting the disease.
- Blood type – People with type A blood are more likely to get stomach cancer.
- Chemical exposure – Some people exposed to chemicals in coal, metal and rubber industries may have an increased risk of stomach cancer.
- Infection with Epstein-Barr virus (EBV) – EBV causes infectious mononucleosis (mono) and it’s found in five to 10 percent of people with stomach cancer.
N-nitrosodimethylamine (NDMA) and Gastric Cancer
High intake of N-nitrosodimethylamine (NDMA), a probable human carcinogen, is linked to an increased risk of gastric cancer.
Certain foods, such as smoked meat, contain NDMA in small amounts. The environment and water also contain NDMA. Ingesting small amounts isn’t typically a problem for most people.
“Low levels of NDMA are commonly ingested in the diet, for example NDMA is present in foods and in water. These low levels would not be expected to lead to an increase in the risk of cancer. However, sustained higher levels of exposure may increase the risk of cancer in humans.”
In April 2020, FDA requested all ranitidine products be removed from the market after it found levels of NDMA in ranitidine could increase over time, especially when stored at high temperatures.
A study published in 2021 by Gerald McGwin in Cancers “provided direct support for the assertion that NDMA contaminated ranitidine is associated with the occurrence of gastrointestinal cancer.”
Doctors use a variety of tests to diagnose stomach cancer and see how far it has spread. How far a cancer has spread, or its stage, helps determine treatment options and survival rates.
Tests for stomach cancer include physical examinations, blood tests and taking tissue or fluid samples.
During a biopsy, doctors remove small amounts of tissue for a pathologist to examine under a microscope. This is the only definitive way to diagnose cancer. A pathologist will look for abnormal cells in a sample of stomach tissue to diagnose disease.
During an endoscopy doctors insert a thin, lighted tube called an endoscope into the mouth to examine the stomach and bowel. During the exam, the patient is under mild sedation.
During the endoscopy the doctor can check for signs of cancer and take a tissue sample to send to the lab.
Imaging tests use radiation, radio waves or magnetic fields to create pictures of the stomach and internal organs to diagnose cancer and see how far it has spread.
- X-ray – An x-ray is a way to create a picture of the structures inside of the body using a small amount of radiation.
- Barium swallow – Patients swallow barium liquid that makes tissues, organs and abnormalities easier to see on an x-ray.
- Computed tomography (CT or CAT) scan – A CT scan uses radiation to create detailed, 3-D images of tumors or abnormalities. CT scans can measure a tumor’s size. Doctors may or may not administer a special contrast dye intravenously or orally. This dye can make tumors easier to see.
- Magnetic resonance imaging (MRI) – Instead of radiation, an MRI uses magnetic fields to make detailed images of the body and measure the tumor’s size. Injected contrast medium dye can help doctors see more detail.
Doctors use laparoscopy to find out if the cancer has spread to the lining of the abdominal cavity or liver. During this minimally invasive surgery, the doctor inserts a thin, flexible, lighted tube called a laparoscope into the abdominal cavity to look for tumors.
It’s more effective than imaging scans at finding cancer that has spread to these areas.
Stomach Cancer Prognosis
A stomach cancer prognosis is an estimate of a person’s chances for survival and how well treatment may go. Many factors go into estimating prognosis. These include the type of cancer, the cancer’s stage, a person’s age and general health.
“If the 5-year relative survival rate for a specific stage of stomach cancer is 70%, it means that people who have that cancer are, on average, about 70% as likely as people who don’t have that cancer to live for at least 5 years after being diagnosed.”
Researchers use five-year survival rates derived from data in the National Cancer Institute’s database to determine prognosis. This data compares people with the same type and stage of cancer with the general population to see how likely it is that a person will survive five years after stomach cancer diagnosis.
Ask your doctor to determine your prognosis, these are just guidelines.
- Overall survival rate – 32 percent
- Tumor hasn’t spread outside the stomach (localized) – 70 percent
- Tumors have spread to nearby lymph nodes or structures outside the stomach (regional) – 32 percent
- Tumors have spread to far away organs and body parts – 6 percent
Stages of Stomach Cancer
About 90 to 95 percent of all stomach cancers are adenocarcinomas that start in the mucosa, the innermost stomach lining.
Intestinal adenocarcinomas have a better prognosis and may respond to targeted therapy. Diffuse adenocarcinomas spread more quickly and are difficult to treat but are less common.
Most stomach cancers start in the innermost layer of the stomach wall called the mucosa. Doctors use the TNM system to stage stomach cancer.
T stands for tumor, N stands for node and M stands for metastasis. Doctors evaluate how deeply the main tumor has spread (T), if the tumor has reached lymph nodes (N) and if the cancer has spread to other parts of the body (M). They then stage each tumor from Stage 0 to Stage IV based on the TNM system.
The cancer hasn’t spread past the mucosa into other layers of the stomach. It’s also called carcinoma in situ.
Stage IA and IB
The stage IA tumor has grown into the mucosa and may have spread to the submucosa. At this stage, it hasn’t spread to lymph nodes.
Stage IB tumors have spread into the mucosa, may have spread to the submucosa and may or may not have spread to one or two lymph nodes.
Stage IB tumors that haven’t spread into lymph nodes have spread into the muscle layer.
Stage IIA and IIB
Stage IIA cancers have three possible conditions.
- Spread into the submucosa and three to six lymph nodes, or
- Spread into the stomach muscle layer and one or two lymph nodes, or
- Spread into the subserosa with no lymph node involvement.
- Spread into the submucosa and seven to 15 nearby lymph nodes, or
- Spread to the muscle layer and three to six nearby lymph nodes, or
- Spread to the subserosa and to one or two nearby lymph nodes, or
- Spread to the serosa and spread to one to six nearby lymph nodes.
Stage IIIA, IIIB and IIIC
Stage IIIA tumors have four possible conditions.
- Spread to the muscle wall and seven to 15 nearby lymph nodes, or
- Spread to the subserosa and three to six lymph nodes, or
- Spread to the serosa and one to six nearby lymph nodes, or
- Spread to nearby organs including liver, colon, spleen, pancreas abdominal wall, adrenal glands, small intestine, back of the abdomen or kidney.
Stage IIIB tumors have three possible conditions.
- Spread to the submucosa or muscle layer and to 16 or more nearby lymph nodes, or
- Spread to the subserosa or serosa and seven to 15 lymph nodes, or
- Spread out of the stomach to nearby organs and to one to six nearby lymph nodes.
Stage IIIC tumors have two possible conditions.
- Spread to the subserosa or serosa and 16 or more nearby lymph nodes, or
- Spread from the stomach to nearby organs and seven or more nearby lymph nodes.
Stage IV stomach cancer has spread to other distant parts of the body such as the lungs and lymph nodes and the tissue lining the abdominal wall.
Treatment options depend on the stomach cancer stage. Each has its own side effects. Doctors may recommend a combination of treatments.
Endoscopic Mucosal Resection
In very early stage cancers, doctors can use a non-surgical technique called endoscopic mucosal resection. Doctors pass a flexible, lighted tube called an endoscope through the mouth and into the stomach to remove cancerous tissues or masses.
This procedure can also take samples of tissue for further lab tests.
Doctors use surgery to cut tumors out of the stomach. Surgery is most effective in early stage cancer that hasn’t spread.
In early stage stomach cancer, doctors perform a partial gastrectomy to remove part of the stomach and lymph nodes.
If the cancer has spread to the outer stomach wall, doctors may prescribe radiation and chemotherapy along with surgery. Depending on how far the cancer has spread a doctor may perform a total gastrectomy, removal of the entire stomach. This is major surgery and can have serious side effects. Make sure you discuss the risks and benefits with your doctor.
Surgery isn’t recommended for cancer that has spread to lymph nodes and multiple, distant organs.
Radiation therapy uses high-energy particles to destroy cancer cells in the stomach. External-beam radiation therapy — radiation given from a machine outside the body — is the type of therapy most often used to treat stomach cancer.
Side effects include skin reactions, fatigue and stomach problems.
Chemotherapy uses intravenous or oral drugs to kill cancer cells. These drugs stop cancer growth, slow cancer growth or reduce the severity of cancer symptoms.
- Taxotere (docetaxel)
- Eloxatin (oxaliplatin)
- Efudex (fluorouracil)
- Taxol (paclitaxel)
Side effects include risk of infection, nausea, fatigue, vomiting, appetite loss, hair loss and diarrhea. These side effects may vary and get worse depending on the medication dose, but they usually go away after treatment.
Targeted therapy identifies specific proteins and genes that help a cancer survive and grow. Then it blocks their spread, helping to limit damage to healthy cells. Targets for stomach cancer include human epidermal growth factor receptor 2 (HER2) and anti-angiogenesis therapy.
HER2-targeted therapy with trastuzumab and chemotherapy may be an option for people with later stage cancer.
Anti-angiogenesis therapy targets the tumor’s ability to make new blood vessels. This therapy starves the tumor. Treatment with ramucirumab (Cyramza) may be an additional option for people whose tumor grew during chemo.
Immunotherapy is also called biologic therapy and is designed to help the body’s immune system fight cancer. Keytruda (pembrolizumab) might help advanced cancer patients with certain tumor markers.
Side effects of immunotherapy include flu-like symptoms, skin reactions, weight changes and diarrhea.
While people can’t control all risk factors for stomach cancer, they can make certain lifestyle changes that may reduce their risk.
“There’s no doubt that the data supports a diet that’s rich in fresh vegetables, minimal fruit and minimal meat, especially processed meat. Avoiding these toxic foods will not only decrease a person’s risk for cancer development, but also the digestive symptoms from eating them.”
- If you are overweight or obese, talk to your doctor about losing weight
- Incorporate more fresh fruits and vegetables into your diet
- Reduce or limit the amount of smoked, preserved and salty foods, especially those that contain nitrites
- Stop smoking
- Avoid alcohol
- Ask your doctor if you need gastric cancer screening
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