Everything You Need to Know About Stomach Cancer
Medically Reviewed by Madeline Hubbard, RN, BSN
Everything You Need to Know About Stomach Cancer
Stomach cancer, also known as gastric cancer, is a fairly uncommon form of cancer in the United States, accounting for 1.5% of all cancers diagnosed each year. This disease primarily affects people above the age of 65 years old and is more common in men than in women. Over the past decade, the rate of new stomach cancer cases in the United States has dropped by just over a percent per year.
Experts suggest this may be due to improvements in food storage and diet choices, along with a decline in the occurrence of certain gastrointestinal bacteria that are commonly associated with stomach cancer. Learning about stomach cancer and its risk factors, symptoms, treatment options and more can help you become more proactive about managing your health or better prepare for care if you or a loved one receive a diagnosis.
What Is Stomach Cancer?
Stomach cancer originates and develops in your stomach. There are several different parts of your stomach, and this type of cancer may occur in one or more of these sections. Additionally, different symptoms and outcomes can develop with stomach cancer, depending on the section or sections of your stomach where it develops.
There are four main subtypes of stomach cancer:
- Adenocarcinoma. This type of stomach cancer develops in cells that are located in the innermost lining of your stomach, which is known as the mucosa. According to the American Cancer Society, about 90 to 95% of cancerous stomach tumors are adenocarcinomas.
- Lymphoma. This type of stomach cancer develops in immune cells located in the wall of your stomach. These cells are known as lymphocytes.
- Carcinoid tumors. This type of stomach cancer begins in your stomach’s endocrine, or hormone-producing, cells. Unlike some other types of stomach tumors, carcinoid tumors typically don't spread to other organs.
- Gastrointestinal stromal tumors. These are the rarest types of stomach tumors. Gastrointestinal stromal tumors start in the nervous system cells located in the wall of your stomach. They may develop in any part of your gastrointestinal tract, but most occur in the stomach.
Signs, Symptoms and Stages of Stomach Cancer
Cancer symptoms are often nonspecific, meaning you can attribute them to other health conditions that also cause them. However, if you experience any of the following symptoms regularly, you should contact your primary care physician for further evaluation. Some key symptoms of stomach cancer include:
- Abdominal pain
- A feeling of fullness in the stomach area
- Dark stool
- Vomiting, particularly bloody vomit
- Loss of appetite
- Difficulty swallowing that worsens over time
- Excessive belching
- Feeling bloated after eating
- Unintentional weight loss
- A general decline in health
Symptoms that are particularly specific to stomach or gastrointestinal cancers include:
- Indigestion. Many patients in the early stages of developing stomach cancer experience mild or severe forms of indigestion. Symptoms may include heartburn, slight nausea, a loss of appetite or a bloated feeling after meals. These symptoms aren't exclusive to stomach cancer, but consistent symptoms of indigestion should prompt you to consult with a physician to determine the cause, especially if you have other risk factors for stomach cancer. Common risk factors include a diet high in salty or smoked foods, smoking tobacco, a history of gastroesophageal reflux disease (GERD) and a family history of stomach cancer.
- Stomach pain. As stomach tumors grow, some patients experience more serious symptoms that result in pain or discomfort. Stomach pain is the most common symptom, but tumors may be accompanied by vomiting, unintended weight loss or blood in the stool. Some people also experience difficulty swallowing, constipation or diarrhea, swelling in the stomach or a yellow tint to their eyes and skin (also known as jaundice).
- Chronic fatigue. People with stomach cancer often experience chronic fatigue or exhaustion as a primary symptom. Although chronic fatigue is not the sole symptom of stomach cancer, it could be a sign that cancerous cells have developed in the lining of the stomach, leading to fatigue and general feelings of weakness.
Stomach cancer is also staged, meaning doctors assign it a level that indicates how advanced the cancer has become. A cancer’s stage also tells medical professionals how much cancer is in someone’s body and how far it has spread around their body. Assigning a stage can help doctors determine the best course of treatment for cancer.
- Stage 0 of stomach cancer is the earliest stage and is diagnosed when the cancer has not grown beyond cells that line the stomach. When cancer is detected at this stage, also known as carcinoma in situ, the survival rate is much higher, as long as treatment is administered before the cancer has a chance to spread.
- Stage 1A of stomach cancer is also an early-detection stage of this disease. The cancer has grown into the stomach tissue and thin muscle layers and beneath the top layer of cells in the mucosa, but it has not spread to the lymph nodes.
- In stage 1B, the cancer has spread to lymph nodes near the stomach, but it has not yet connected with distant organs or tissues. In some people who have stage IB stomach cancer, the cancer has grown into main muscle layers of the stomach wall.
- By Stage 2A of stomach cancer, the cancer has grown into the top layer of cells of the mucosa and commonly into the thin muscle layers and connective tissues below. Although stage 2A cancer has not yet spread to distant sites, it may affect three to six nearby lymph nodes.
- Stage 2B stomach cancer is diagnosed when cancer grows into the main muscle layer or the top layer of the cells of the mucosa and into connective tissues. The cancer has not yet spread into organs or distant tissues, but up to 15 nearby lymph nodes may be affected by the disease. During this stage, cancer may also affect the subserosa tissue layer of the stomach or grow completely through layers of the stomach wall, thus affecting the outer covering of the stomach.
- Stage 3 stomach cancer is divided into three categories of severity. This stage is diagnosed when cancer affects the main muscle layer, three to 15 lymph nodes or all layers of the stomach wall. Distant tissues or organs are not yet affected.
- Stage 3B occurs when the cancer has grown into the subserosa layer, layers of the stomach wall including the outer covering of the stomach and into nearby organs, such as major blood vessels, the liver, pancreas intestines or spleen. At this stage, the cancer has not spread to distant tissues or organs.
- Stage 3C is the most severe form of stage 3 cancer and occurs when the cancer affects all layers of the stomach and affects nearby organs, structures and lymph nodes.
- Stage 4 is the final stage of stomach cancer. During this stage, the cancer has spread to distant organs of the body, which is known as metastasis.
Causes of and Risk Factors for Stomach Cancer
Stomach cancers occur as a result of a mutation in the DNA of cells located in the stomach. The mutation causes the affected abnormal cells to grow and divide at an increased rate. It also allows those cells to continue living even in conditions when normal cells would die. As the cells continue to multiply, they form cancer, which can ultimately invade the stomach and its surrounding tissues.
Certain risk factors for stomach cancer are related to lifestyle choices, such as:
- Eating a diet high in salty or smoked foods
- Eating a diet low in fruits and vegetables
However, some other risk factors may also play a role. If you have a history of stomach cancer in your family, your own risk of developing this type of cancer increases. In addition, having certain health conditions may lead to an increased risk of stomach cancer. These include stomach polyps, a prior infection with a bacterium called Helicobacter pylori, long-term stomach inflammation and pernicious anemia (a condition that keeps your body from making enough healthy red blood cells).
Diagnosing Stomach Cancer
It may take several visits to your doctor’s office to determine a diagnosis of stomach cancer. The first step involves your primary care physician taking a thorough medical history and performing a physical exam.
Next, your physician may order blood tests to check for a low red blood cell count, also known as anemia. This is a potential side effect of stomach cancer, which may cause bleeding in your stomach or stool. If your primary care physician suspects stomach cancer based on your medical history, physical exam and initial blood test, they will likely refer you to a specialist known as a gastroenterologist.
A gastroenterologist has access to several more specialized forms of testing, including machinery that can not only visualize the inside of your gastrointestinal tract but can also remove a small sample of potentially cancerous tissue (a process known as a biopsy). This sample will then go to a laboratory for testing to determine the presence or absence of cancerous cells and certain proteins that may impact your treatment.
One form of testing for stomach cancer is known as an upper endoscopy, or esophagogastroduodenoscopy (EGD). This involves passing a thin, flexible camera down your throat and esophagus and into your stomach and small intestine. Depending on the stage of cancer, your physician may be able to remove the entire cancerous area during this procedure.
Your physician may also request imaging tests such as an upper gastrointestinal (GI) series, computed tomography (CT) scan, positron emission tomography (PET) scan, magnetic resonance imaging (MRI), X-ray or endoscopic ultrasound to better visualize cancerous areas.
Treatments for Stomach Cancer
There are several treatment options for stomach cancer, including:
- Surgery. There are several types of surgery that can remove stomach tumors. Sometimes the tumor itself can be removed along with a small portion of healthy tissue surrounding the tumor to ensure total removal. However, in more severe cases of stomach cancer, a part of the stomach or even the entire stomach may be removed to fully eliminate the cancer. Risks of this treatment option include infection, bleeding and digestive issues.
- Radiation therapy. Radiation therapy involves aiming high-powered beams of energy at the affected area to kill the cancerous cells. Side effects of this treatment often include diarrhea, indigestion, nausea and vomiting.
- Chemotherapy. Chemotherapy involves using drugs to kill the cancerous cells. These drugs can be administered orally or intravenously. Chemotherapy is often used for the rarer forms of stomach cancer. Side effects of this treatment option vary based on which drugs are used.
Although many risk factors for stomach cancer are lifestyle-related and you can change them to improve your overall health, there's no guaranteed way to ensure you won't develop stomach cancer. However, you can improve your diet choices by avoiding salty and smoked foods and by adding more fruits and vegetables to your daily meals. Additionally, quitting smoking will decrease your risk of developing stomach cancer and many other forms of cancer. Lastly, make sure you see your physician promptly for any stomach-related discomfort or conditions, such as infections, ulcers and polyps.