Side Effects of Immunotherapy

Approved by the Cancer.Net Editorial Board, 12/2016

Immunotherapy, also called biologic therapy, is a type of cancer treatment that boosts the body's natural defenses to fight cancer. It uses substances made by the body or in a laboratory to improve or restore immune system function.

Your doctor may recommend immunotherapy as the only treatment. Or it may be given after or at the same time as another treatment, such as chemotherapy, radiation or surgery. Read more about the different types of immunotherapy.

Why immunotherapy causes side effects

Certain types of immunotherapy attack cancer or slow its spread to other parts of the body. Others make it easier for the immune system to destroy cancer cells.

Immunotherapy sometimes results in the immune system attacking healthy cells, which can cause side effects.

Managing side effects

Different types of immunotherapy can cause different side effects. Many side effects depend on the type of treatment, the type and location of the cancer, and a person’s overall health.

The treatment of side effects is important to your health care team, so be sure to tell them if you experience any side effects.

The most common side effects of immunotherapy include:

Mouth sores. Immunotherapy can damage the cells inside the mouth and throat. This causes painful sores in these areas, a condition called mucositis. These sores can get infected. Mouth sores usually happen 5 to 14 days after a treatment. Eating a healthy diet and keeping your mouth and teeth clean can lower your risk of mouth sores. They usually go away completely when treatment ends.

Skin reactions. Skin redness, blistering, and dryness are common reactions to immunotherapy. Skin on the fingertips may crack. Skin may also become more sensitive to sunlight. A lot of scratching can break the skin, making it more prone to infections. Inflammation around the nails can make grooming, dressing, and other activities painful or difficult. Read more about managing and treating skin irritations and reactions.

Flu-like symptoms. Fatigue (feeling tired), fever, chills, weakness, nausea (feeling sick to your stomach), vomiting (throwing up), dizziness, and body aches are all common side effects of immunotherapy. They are especially common in non-specific immunotherapies and oncolytic virus therapy. It is very important to stay hydrated when experiencing these symptoms, and seek medical attention if you are unable to keep any liquids down. Talk with your health care provider about how to manage these side effects. Many side effects will go away on their own, but others can be very serious and require immediate attention.

Other potential side effects you may experience include:

  • High or low blood pressure
  • Muscle aches
  • Shortness of breath (trouble breathing)
  • Swelling of legs (edema)
  • Sinus congestion
  • Headaches
  • Weight gain from retaining fluid 
  • Diarrhea
  • Hormone changes
  • Cough

Follow-up Care 

Getting care after treatment ends is important. Many side effects will go away when treatment ends, but some long-term effects may occur months or years later. Your health care team can help you manage long-term side effects.

More Information

Understanding Immunotherapy

Skin Reactions to Targeted Therapy and Immunotherapy

Immunotherapy: The 2016 Clinical Cancer Advance of the Year

Side Effects

Additional Resource

National Cancer Institute: Immunotherapy