Chemotherapy, targeted therapy, and immunotherapy may help you live longer and have fewer symptoms. Your MSK care team will decide if these treatments are best for you. Treatment will be based on your situation, the stage of cancer, and biomarkers (tumor traits we test for).

Chemotherapy: MSK oncologists (cancer doctors) are experts in chemotherapy (chemo) for stomach cancer. Chemotherapy is a treatment that uses strong drugs to kill cancer cells or stop or slow their growth. Chemotherapy can help people with stomach cancer live longer and keep their quality of life.

Targeted therapy: Our experts can choose a treatment that targets your tumor’s genetic changes. Targeted therapies are systemic treatments, which means they go throughout the body. But they only attack cancer cells that match what the medicine is targeting.

Immunotherapy:  Immunotherapy is a cancer treatment. It uses medicines that make your body’s own immune system recognize and attack the cancer.

When do you have chemotherapy for stomach cancer?

Before surgery: Chemotherapy before surgery is called  neoadjuvant (NEE-oh-A-joo-vant) chemotherapy. It’s recommended for some people with stomach cancer that can be treated with surgery. Chemo can shrink the tumors and make them easier to remove.

After surgery: Chemotherapy after surgery is called adjuvant (A-joo-vant) chemotherapy. Chemo can kill any tiny circulating cancer cells that are still there after surgery.

How is chemotherapy for stomach cancer given?

Chemotherapy is a drug or a combination of drugs. It’s given by vein (intravenously, also called IV) or by mouth (orally).

Side effects of stomach cancer chemotherapy

Chemotherapy drugs have fewer side effects than in the past. There also have been many improvements in supportive care to help with any side effects.

Common side effects of chemotherapy include:

• Fatigue (feeling very tired)
• Thinning hair
• Low blood counts
• Nausea (feeling like throwing up)
• Diarrhea (loose, watery poop)
• Neuropathy (tingling or numbness in the fingers and toes) 

Targeted therapies for stomach cancer

MSK offers the latest tests to get information about a tumor’s characteristics (traits). We can test the tumor tissue, or sometimes blood, using tumor genetic profiling tests and other tests. These tests help us understand exactly what’s making your tumor grow.

Depending on the test results, your treatment may include a targeted therapy. This treatment targets a specific trait your tumor has. Targeted therapy may be given with chemotherapy and immunotherapy.

Targeted therapy and trastuzumab

About 2 out of every 10 people with stomach and esophageal cancers have too much of a protein called HER2. This is called HER2-postive gastric cancer.

For the past 10 years or so, people with HER2-postive gastric cancer have been treated with chemotherapy along with trastuzumab (Herceptin®). Trastuzumab is the first targeted therapy developed to treat HER2-positive cancers, including stomach cancer. Trastuzumab is an antibody that blocks the growth signals sent out by HER2.

Targeted therapy and trastuzumab deruxtecan

Trastuzumab deruxtecan (T-DXd) is an antibody-drug conjugate (ADC). ADCs have powerful chemotherapy drugs attached to antibodies. They recognize tumors and deliver the chemotherapy right to them.

With T-DXd, trastuzumab is attached to a payload of chemotherapy, which it delivers to the site of the stomach tumor. T-DXd is used to treat advanced HER2-positive stomach cancer. Most often, it’s used after trastuzumab was tried first.

Immunotherapy for stomach cancer

Immunotherapy is a type of cancer treatment. Most cancer treatments use drugs or radiation to target cancer cells directly. Immunotherapy instead boosts your immune system’s natural ability to fight cancer. Your immune system attacks cancer cells, much the same way it attacks bacteria or viruses.

When is immunotherapy given for stomach cancer? 

Immunotherapy can help some people after they have surgery. Most often, it’s a treatment for people who have stage 4 or metastatic disease. Immunotherapy is given along with chemotherapy. It’s sometimes also used with targeted therapies.

How is immunotherapy given?

Immunotherapy is given intravenously (IV), which means in the vein.

What are the side effects of immunotherapy? 

Immunotherapy works by stimulating your body’s immune system to attack the cancer. Your body’s immune system can attack normal parts of your own body, similar to an autoimmune disease. This causes side effects, which can be managed safely if treated early.

Common side effects include:

• Skin problems, such as a rash or itching
• Chills, fatigue (feeling very tired), and other flu-like symptoms
• Gastrointestinal problems, such as diarrhea (loose poop)
• Pain from joint inflammation (swelling)
• Low hormone levels