Saint Luke’s Cancer Specialists provide early detection, expert diagnosis, personalized treatment options, and survivorship support to every patient.

What Is Stomach Cancer?

What Is Stomach (Gastric) Cancer?

Cancer starts when cells in the body change (mutate) and grow out of control. These cells can form lumps called tumors. Cancer that starts in the cells of the stomach is called stomach or gastric cancer.

Understanding the stomach

The stomach is the sac that holds and helps digest food. The wall of the stomach is made of many layers of tissue.

When food is swallowed, it goes down a tube called the esophagus. The esophagus carries it to the stomach. The stomach adds chemicals and fluids to food that help start the process of digestion. There's a strong muscle layer of the stomach wall. It squeezes and mixes the contents to make it soft. Food then leaves the stomach and goes into the small intestine.

Outline of woman showing mouth, esophagus, and stomach.

When stomach cancer forms

Stomach cancer almost always starts in the stomach’s innermost layer or lining, called the mucosa. This type of stomach cancer is called adenocarcinoma.

Cancer cells can then spread deeper into the other four layers of the stomach. If cancer cells reach the stomach’s outer layer, they can spread into nearby organs.

Stomach cancer can also spread to other parts of the body. This spread is called metastasis. The more cancer spreads, the harder it is to treat.

Treatment choices for stomach cancer

Treatment depends on several things. They include the type and stage of stomach cancer, possible side effects, your overall health, and your preferences. You and your healthcare provider will decide on the treatment plan that’s best for you. It's common to get more than one type of treatment. Your treatment choices may include:

  • Surgery to remove the tumor or the part of the stomach with cancer along with some nearby tissue. Sometimes the whole stomach must be removed (called gastrectomy).

  • Chemotherapy (chemo) uses strong medicines that kill cancer cells. Many times, a combination of medicines is used. Chemo is often given before and after surgery. It can also be given along with radiation. If chemo is given before surgery, it is called neoadjuvant chemotherapy. If given after surgery, it is called adjuvant chemotherapy. When chemotherapy is combined with radiation therapy, it is called chemoradiation.

  • Targeted therapy uses medicines that focus on specific features or changes in the cancer cells. This helps save normal cells while targeting and killing cancer cells. It may be used for advanced stomach cancer.
  • Immunotherapy may also be used for advanced stomach cancers alone or with other treatments. These medicines boost the natural immune system so it can better find and kill cancer cells.
  • Radiation therapy uses focused beams of energy from X-rays or other radiation sources, to kill cancer cells. It may be used before or after surgery.

  • Clinical trials is medical research used to test new ways to treat cancer. Ask your healthcare provider if there are clinical trials you should consider as a treatment choice.


Stomach Cancer: Symptoms

What are the symptoms of stomach cancer?

The symptoms of stomach cancer vary from person to person. Cancer in early stages may have mild or no symptoms. The symptoms may also be like those of other diseases or conditions.

The most common symptoms of stomach cancer include:

  • Indigestion or heartburn

  • Feeling like food gets stuck in your throat when eating

  • Stomach pain or discomfort above the level of your navel

  • Feeling of fullness or bloating after eating even small amounts of food

  • Nausea and vomiting (this often happens soon after eating)

  • Vomiting blood

  • Diarrhea or constipation

  • Blood in your stool

  • Loss of appetite

  • Unexplained weight loss

  • Weakness and tiredness

Stomach cancer that’s more advanced can block your stomach or intestines. This can cause vomiting that doesn’t go away. Stomach cancer can also spread to your liver. If this happens, it can cause yellowing of your skin and the white part of your eyes (jaundice). Or it can cause fluid buildup in your belly (ascites).

When to see your healthcare provider

Many of these symptoms may be caused by other health problems. So it's important to see your healthcare provider if you have these symptoms. Your healthcare provider will examine you and order tests to find out if you have stomach cancer.


Stomach Cancer: Diagnosis

How is stomach cancer diagnosed?

If your healthcare provider thinks you might have stomach cancer, you’ll need certain exams and tests to be sure. Diagnosing stomach cancer starts with your healthcare provider asking you questions. You'll be asked about your health history, your symptoms, risk factors, and family history of disease. Your healthcare provider will also do a physical exam.

What tests might I need?

If signs are pointing to stomach cancer, you may have 1 or more of these tests:

  • Fecal occult blood test (FOBT)

  • Blood tests

  • Upper endoscopy

  • Upper GI series

  • Biopsy

Lab tests

Fecal occult blood test (FOBT)

This test is used to check for hidden blood in your stool. A small amount of your stool is put on a plastic slide or a special type of paper. You may do this test at home. Stomach cancer can sometimes cause small amounts of bleeding. This can be hard to see. But other problems that aren’t cancer can also cause it. Even if the test shows blood in your stool, you’ll likely need more tests to find the cause.

Blood tests

Blood tests can check if you have low red blood cell counts. This could be due to bleeding in your stomach. Blood tests can also be used to see how well certain organs are working and to get an idea of what your overall health is like. Tumor marker levels for CA19-9 and CEA may be checked. These markers are occasionally made by stomach cancer. And their levels may be higher at diagnosis.

Endoscopic tests

Upper endoscopy

This test is also called an EGD (esophagogastroduodenoscopy). It's a common procedure used to look for stomach cancer. It’s often the first test done.

This test lets your healthcare provider look at the inside of your stomach. A long, thin, flexible, lighted tube (endoscope) is used to do this. First, you are given medicines to make you sleepy. A numbing medicine is sprayed into your throat to help keep you from gagging. Then the scope is put in through your mouth and is passed down your food pipe (esophagus) and into your stomach. A camera on the end lets your provider look at your stomach lining. The provider also checks the lining of your esophagus and part of the first section of your small intestine (duodenum).

If your provider sees any abnormal changes in the tissue, small pieces (called samples) of the changed tissue can be taken out through the scope. They're then examined under a microscope for cancer cells by a pathologist. This is called an endoscopic biopsy. 

Imaging tests

Upper GI series

This is also called a barium swallow. It uses X-rays to find even small changes in your stomach lining. This test might be useful in some situations. It is used less often than an upper endoscopy since a biopsy can't be done during the test and it may miss some abnormal areas in the stomach. For this test, you’ll drink a thick, chalky fluid with barium in it. The barium lines your stomach. This makes it easier to see on an X-ray.

To look for very small tumors, your healthcare provider may use a double contrast method. For this, a small tube is placed in your stomach after you drink the barium. Air is then pumped through the tube into your stomach. The air makes the barium coating thinner around the inside of your stomach. This helps tiny changes in your stomach lining show up on the X-rays.


A biopsy is when your healthcare provider takes out small pieces of abnormal tissue from your stomach. A pathologist does tests on the tissue samples and looks at them under a microscope. It's the only way to know if a change is stomach cancer. But a biopsy can also show other problems. These can include an H. pylori bacterial infection, other diseases besides cancer, or another type of cancer called a lymphoma.

A biopsy is needed to confirm a diagnosis of stomach cancer.

Endoscopic stomach biopsy

This is the most common type of biopsy used. Before the procedure, you’re given medicine to help you relax and a numbing medicine is sprayed into your throat. It helps prevent gagging. Then your healthcare provider puts a long, thin, flexible tube called an endoscope into your mouth. It's guided down your esophagus and into your stomach. Your provider looks at the lining of your stomach with the scope. Tools can be passed through the scope to take tissue samples for a biopsy from any abnormal areas.

Endoscopic ultrasound-guided needle biopsy 

This procedure may be used if your healthcare provider thinks the cancer is deeper in the wall of your stomach (not just in the stomach lining).

This test also uses an endoscope. You’ll be given medicine to help you relax. A numbing medicine is sprayed into your throat to help prevent gagging. The endoscope is then put into your mouth and guided into your stomach. This scope has a special ultrasound tool at the tip. The ultrasound tip is put against your stomach wall to create images. 

Your healthcare provider looks at your stomach lining with the scope. They can also see images of the deeper layers of your stomach, lymph nodes, and other nearby tissues. If abnormal changes in the tissues are seen, your provider will pass a thin, hollow needle through the scope into the abnormal tissue. This needle is used to take out tiny pieces of tissue to test in the lab.

Getting your test results

Your healthcare provider will contact you with your biopsy results. Your provider will talk with you about other tests such as CT scans that you may need if stomach cancer is found. Make sure you understand the results and what follow-up you need.


Stomach Cancer: Treatment Introduction

Learning about your treatment choices

There are different treatment choices for stomach cancer. Which may work best for you? It depends on many things, such as:

  • The tumor's size and location

  • Test results

  • Stage of the disease

  • Your overall health

  • Your age

  • Your personal needs and concerns

  • What side effects you find acceptable

You may also want to know how you’ll feel and function after treatment, including if you’ll have to change your normal activities.

Your healthcare provider is the best person to answer your questions. They can tell you what your treatment choices are, how well they’re expected to work, and what the risks and side effects are. Your provider may advise a certain treatment plan. It may include different types of treatment. Or they may offer more than one, and ask you to decide which one you’d like to use. It can be hard to make this decision. So it's important to take the time you need to make the best decision.

Types of treatment for stomach cancer

Here is an overview of the treatment choices for stomach cancer:


This is the most common treatment for stomach cancer. The goal is to remove the entire tumor and any cancer cells that may have spread to nearby tissue. If the cancer is only in your stomach, surgery may be all that you need. Or you may have surgery before or after another treatment is used to shrink the tumor first.

Radiation therapy

This treatment uses high-energy beams of X-rays or particles to kill cancer cells. The main goal of radiation is to kill cancer cells and reduce the chance the cancer will come back (recurrence). Sometimes it’s used to reduce the symptoms of cancer. These can include pain, blockages, or bleeding.


The goal of chemotherapy (chemo) might be to shrink a tumor, destroy cancer cells, ease symptoms from the cancer, or help prevent cancer recurrence. Chemo is often used for early-stage stomach cancer, which has not spread. It may be the main treatment if the cancer has spread beyond the stomach to other parts of the body. Chemo can be used before surgery (neoadjuvant therapy). Or it may be given after surgery (adjuvant therapy). Chemo may be combined with radiation therapy (chemoradiation).

Targeted therapy

These are medicines that target stomach cancer cells rather than all stomach cells. These medicines work differently from regular chemo medicines. They only work if your cancer cells have particular gene mutations or express a protein that one of the current medicines can target. Your healthcare provider will look for biomarkers in your tumor to see if you are a candidate for targeted therapy.


This treatment uses medicines to help your body's immune system find and kill cancer cells. Immunotherapy may be given alone or with other types of treatment. It may be a choice for more advanced stomach cancer.

Making treatment decisions 

Your healthcare provider may advise that you have more than one of these types of treatment. This is sometimes called combination therapy. Newer types of treatment may be available only through a research study (clinical trial). Talk with your provider about what clinical trials may be a choice for you.

Deciding on the best plan may take some time. Talk with your healthcare provider about how much time you can take to explore your choices. You may want to get another opinion before deciding on your treatment plan. Your provider can help you with this. You may also want to include your family and friends in this process.


Norin Ansari, MD, MPH

Oncology / Hematology

Juliet Gyamfua Appiah, MD

Oncology / Hematology

Dhruv Bansal, MD

Oncology / Hematology

John Russell Davis, MD

Thoracic and Cardiovascular Surgery, Vascular Surgery, Surgery (General)

Sreekanth Donepudi, MD

Oncology / Hematology

Michael Ford Gibson, MD

Thoracic and Cardiovascular Surgery, Surgery (General)

Jessica K Heimes, DO

Heart Transplant, Thoracic and Cardiovascular Surgery, Surgery (General)

Sashidhar Manthravadi, MD

Oncology / Hematology

Megan E McNally, MD

Surgical Oncology, Surgery (General)

Marc T Roth, MD

Oncology / Hematology

Eston James Schwartz, MD

Oncology / Hematology

Addison R Tolentino, MD

Oncology / Hematology

Rachana Yendala, MD

Oncology / Hematology