Immunotherapy to Treat Colorectal Cancer

Immunotherapy, also called biological therapy, is a type of treatment that uses the body's own immune system to fight cancer. The therapy mainly consists of stimulating the immune system to help it do its job more effectively. It can also involve adding things to your immune system, such as man-made proteins.  Immunotherapy is a fairly new way to fight colorectal cancer. Many of these treatments are still being evaluated in clinical trials.

Types of Immunotherapy

Biological Response Modifiers -- These substances do not directly destroy the cancer, but they are able to trigger the immune system to indirectly affect tumors. Biological response modifiers include cytokines (chemicals produced by cells to instruct other cells) such as interferons and interleukins. This strategy involves giving larger amounts of these substances by injection or infusion in the hope of stimulating the cells of the immune system to act more effectively.

Tumor Vaccines-- Researchers are developing vaccines that may encourage the immune system to better recognize cancer cells. These would, in theory, work in a similar way as vaccines for measles, mumps, and other infections. The difference in cancer treatment is that vaccines are used after someone has cancer, and not to prevent the disease. The vaccines would be given to prevent the cancer from returning or to get the body to reject tumors. There are also ongoing studies involving possible vaccines to prevent breast and prostate cancers. Using vaccines for tumors is much more difficult than preventing a viral infection.

Monoclonal Antibodies -- These are substances produced in the laboratory that can locate and bind to cancer cells wherever they are in the body. These antibodies can be used to see where the tumor is in the body (detection of cancer) and call in other immune system cells to destroy them, or as therapy to deliver drugs, toxins, or radioactive material directly to a tumor.

Immune Checkpoint Inhibitors – These are drugs that take the “brakes” off of checkpoint proteins in the immune system, which helps these proteins recognize and attack cancer cells.

What are the Side Effects of Immunotherapy?

Like other forms of cancer treatment, immunotherapy can cause a number of side effects. These side effects can vary widely from person to person. Biologic response modifiers may cause flu-like symptoms, including fever, chills, nausea, and loss of appetite. In addition, rashes or swelling may develop at the site where they are injected and blood pressure may drop as a result of treatment. Fatigue is another common side effect of biologic response modifiers.

The side effects of monoclonal antibodies vary, and serious allergic reactions may occur.

Vaccines can cause muscle aches and low-grade fever.

Immune checkpoint inhibitors can have serious side effects. One concern is that they can allow the immune system to attack normal organs in the body. More common side effects include fatigue, cough, loss of appetite, and rash.

Talk to your doctor to learn if immunotherapy is right for you.

WebMD Medical Reference Reviewed by Jennifer Robinson, MD on May 11, 2019



American Cancer Society: "Immune checkpoint inhibitors to treat cancer." "What is cancer immunotherapy?" "Cancer vaccines." "Monoclonal antibodies to treat cancer."

National Cancer Institute: "NCI Dictionary of Cancer Terms."

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