Immunotherapy Facts

October 24, 2024

This page was reviewed under our medical and editorial policy by Alexis Boling, MSN-RN, CNML, director, nursing, Immune Effector Cell & Gene Therapy Program, City of Hope^® Cancer Center Duarte

Immunotherapy is a treatment option for many cancer types. It uses biological substances — those made from living organisms, such as cell proteins — to help the body’s own immune system fight cancer cells. An oncologist (a doctor who specializes in diagnosing and treating cancer) may recommend immunotherapy as part of a comprehensive cancer treatment plan.

What Is Immunotherapy for Cancer?

Immunotherapy is a biological therapy that works with a person’s own immune system to boost its natural defenses. The biological substances in immunotherapy medicines may come from a person’s own body or a laboratory. Once in the body, these medicines help to train the immune system to do a better job at destroying cancer.

Immunotherapy for cancer may be used alone or with other cancer treatments, depending on the type of cancer. The different types of immunotherapies include:

• Monoclonal antibodies
• Immune checkpoint inhibitors
• Oncolytic virus therapy
• T cell transfer therapy, such as CAR T cell therapy and TIL therapy
• Cancer vaccines
• Other immunotherapies

Not all cancers respond to immunotherapy. The patient’s care team identifies which types of immunotherapy treatments may help to fight each patient’s cancer.

Chemotherapy Versus Immunotherapy

Cancer cells tend to grow and divide quickly. Standard chemotherapy uses cytotoxic drugs to destroy cancer cells. These drugs slow or stop the growth of cancer cells and may shrink the size of tumors. Chemotherapy drugs also harm healthy cells, causing side effects such as hair loss, mouth sores and nausea. The side effects usually improve after chemotherapy is finished.

Immunotherapy does not use toxic drugs. It relies on substances made from living cells to boost the immune system, helping it work more successfully to fight cancer. But like chemotherapy, immunotherapy may damage healthy cells. Side effects from immunotherapy often are due to the ramping up of the immune system to fight the cancer. Some common side effects are flu-like symptoms, skin reactions and inflammation, but more serious side effects may occur, so always consult the care team about potential side effects.

How Does Immunotherapy Work?

The immune system is a collection of organs, proteins, chemicals and special cells that fight infections and disease. It does this by tracking germs and other abnormal substances found in the body. When an abnormal or foreign substance, such as a virus, bacteria or cancer cell, is identified, the immune system’s job is to attack it.

However, cancer cells are harder for the immune system to target than other foreign substances. Part of the problem is that cancer cells start out as normal cells, so the immune system may not recognize them as foreign. Cancer cells may also give off substances that hide them from the immune system. To counter this, immunotherapy works by:

• Stimulating the immune system to better detect and target cancer cells (helping stop or slow cancer growth)
• Activating proteins or antibodies that attack and destroy cancer cells or keep them from spreading
• Easing side effects of other cancer treatments

How Is Immunotherapy Given?

Treatment with immunotherapy comes in different forms.

Intravenous (IV): The immunotherapy goes directly into the bloodstream through a needle or a tube inserted into the vein.

Oral: Immunotherapy is given in a tablet or capsule form that is swallowed. 

Topical: Immunotherapy may be in the form of a cream or lotion that is rubbed into the skin.

Intravesical: Immunotherapy is placed directly into the bladder through a small tube inserted into the urethra (the tube from the bladder to the outside of the body).

Injection: Some immunotherapy types, such as CAR T cell therapy and TIL therapy, are injected directly into the tumor.

The length of treatment with immunotherapy varies. Some treatments are given in cycles with a rest period between cycles for the body to recover. Other treatments are given daily, weekly or monthly. The length and type of treatment are based on multiple factors:

• The type and severity of the cancer
• The type of immunotherapy used for treatment
• How well a person tolerates the immunotherapy

Immunotherapy at City of Hope

City of Hope experts are at the forefront of immunotherapy research and innovation. Our researchers are constantly evaluating new options and improving the efficacy of existing immunotherapy options to develop more powerful cancer treatments.

Learn more about our immunotherapy research