Immunotherapy

Immunotherapy is treatment that uses the body’s immune system, usually your own, to attack cancer. Learning about how it works and what to expect can often help you prepare for treatment and make informed decisions about your care.

What is immunotherapy?

Immunotherapy is a type of cancer treatment that helps the immune system find and attack cancer cells. It uses substances made by the body or in a lab to:

• Stimulate or boost the immune system so it works better against cancer.
• Add lab-made substances that act like natural parts of the immune system.

There are many different types of immunotherapy, and they work in different ways. The type used depends on the cancer. Immunotherapy is often used for advanced cancers, especially when other treatments haven’t worked.

How the immune system works against cancer

Your immune system is made up of organs, cells, and substances that help protect you from infections and some diseases by finding and destroying germs like bacteria and viruses. It keeps track of what normally belongs in the body. When it finds something that it either doesn’t recognize, or recognizes as “foreign,” the immune system raises an alarm and attacks it. This is called the immune response.

The immune system can also respond to cancer if it sees the cancer cells as foreign. This works best when there are only a few cancer cells. But there are limits on the immune system’s ability to destroy cancer on its own:

• The immune system might not see cancer cells as foreign if they are too similar to normal cells.
• The immune response might not be strong enough to destroy the cancer.
• Cancer cells can give off signals that help them hide from the immune system.

Immunotherapy helps overcome these challenges by helping your immune system recognize cancer cells and strengthening your immune response.

Types of cancer immunotherapy

Several types of immunotherapy used to treat cancer, and many are being studied.

• Monoclonal antibodies (mAbs or MoAbs) are lab-made proteins designed to target specific parts of cancer cells.
• Chimeric antigen receptor (CAR) T-cell therapy modifies the T cells in your blood to make them better able to target cancer cells.
• Tumor infiltrating lymphocytes (TILs) are special white blood cells taken from a tumor, multiplied in a lab, and returned to the body to target and destroy the cancer.
• Immune checkpoint inhibitors remove the immune system’s “brakes, allowing it to recognize and attack cancer.
• Cancer vaccines are used to start an immune response against certain types of cancer.
• Cytokines are small proteins that send signals to immune cells to attack cancer.
• Oncolytic virus therapy uses lab-modified viruses to infect and kill certain tumor cells.
• Immunomodulators (non-specific immunotherapies) boost parts of the immune system to treat certain types of cancer.

What is the goal of immunotherapy?

If your doctor has recommended immunotherapy, it’s important to understand the goal of treatment. This can depend on your type of cancer, its stage (size and location), and how far it has spread. Immunotherapy can have 3 possible treatment goals:

How is immunotherapy different from chemotherapy?

Chemotherapy and immunotherapy are both treatments for cancer, but they are different types of drugs. Immunotherapy works with your body’s immune system to kill cancer cells or limit their growth, while traditional chemo works against cancer cells (and some healthy cells) directly.

Like chemo, immunotherapy is most often a systemic treatment. It travels through the bloodstream and can help your immune system target and kill cancer cells that have spread (metastasized) throughout the body.

Which cancers can be treated with immunotherapy?

Immunotherapies are not yet available for all cancers. While all cancers start because of gene changes (mutation), the specific mutations or protein changes can vary. These are called biomarkers. Even people with the same type of cancer (like melanoma or lung cancer) can have different biomarkers that affect which treatments might work best.

Most often, immunotherapy targets cancers with certain biomarkers. Some immunotherapy, like tumor infiltrating lymphocyte (TIL) therapy, targets many different changes in cancer cells rather than a single change. Common gene or protein changes that immunotherapy can be used for include:

• PD-1 (programmed cell death-1) protein
• PD-L1 (programmed death-ligand 1) protein
• CTLA-4 (cytotoxic T-lymphocyte-associated protein 4)
• TMB (tumor mutational burden)
• MSI (microsatellite instability)
• CD19 (cluster of differentiation 19) protein
• CD20 (cluster of differentiation 20) protein
• BCMA (B cell maturation antigen)
• GPRC5D (G protein-coupled receptor family C group 5 member D)
• CD38 (cluster of differentiation 38) protein
• SLAMF7 (signaling lymphocyte activation molecule family member 7) protein

Biomarker testing is done before treatment to check for these or other changes to help show if immunotherapy may be an option. It may also be done if treatment fails or the cancer grows, to see if new changes have occurred.

What are the most common side effects of immunotherapy?

Immunotherapy can cause different side effects than those from other cancer treatments because of how immunotherapy uses the body’s immune system to destroy cancer.

The side effects may be different for each person. They depend on the type and dose of immunotherapy you receive, as well as your type of cancer, location, and your general health.

Most side effects are mild, however some can be severe. Some general side effects of immunotherapy include:

• Skin changes (such as rash)
• Fatigue
• Nausea, vomiting, or diarrhea
• Endocrine changes (such as thyroid changes)
• Flu-like symptoms (such as fever, chills, and muscle aches)
• Cytokine release syndrome (CRS)
• Neurologic toxicity
• Colitis

Immunotherapy may also cause the immune system to attack healthy cells. This can cause immune-related adverse effects. These may happen at any time during treatment or sometimes even after stopping immunotherapy.

It’s important to be aware of possible side effects from immunotherapy so you know what to watch for and can talk with your cancer care team about preventing and relieving them.

Immunotherapy safety

Because immunotherapy is a newer type of cancer treatment, there isn’t as much information about its long-term effects of exposure. To be safe, many experts recommend treating it as hazardous and taking the same precautions used when handing chemo or other hazardous drugs .

How successful is immunotherapy?

Immunotherapy can be successful at stimulating the immune system to kill cancer cells. However, the success rates are often lower as compared with other types of cancer treatment. This may be because:

• Immunotherapy is often used in advanced stages of cancer where other treatments have been unsuccessful.
• The cancer cells can sometimes outsmart the immune system by making substances to turn off or help them hide from the body’s immune response.
• Drug resistance can cause immunotherapy to stop working. These can include genetic changes in cancer cells that cause the immune system to not be able to recognize or attack them, or changes in the internal and external cell environment that interfere with immune function.
• People can respond differently to immunotherapy. Any variation from person to person affects how well the immunotherapy works against their cancer.

When treatment plans change

It’s important, whenever possible, to get the full course of immunotherapy, the full dose, and keep the cycles on schedule. This gives you the best chance of getting the maximum benefit from treatment.

There may be times, though, when serious side effects require adjusting the plan (dose and/or schedule) to allow your body more time to recover. Sometimes, you might be given supportive medicines to help you recover more quickly. Or sometimes, cancer cells develop resistance to a certain immunotherapy and a different treatment might be tried.

Still, there may be other times when treatment no longer works and there are no good treatment options available to control the cancer. Learn more about things to consider if cancer treatments stop working.