Immunotherapy: understanding the basics

Immunotherapy is a type of treatment that harnesses the power of your own immune system to control and eliminate disease. As a treatment for cancer, it has dramatically changed oncology care. It’s been particularly effective for certain difficult-to-treat cancers. 

Immunotherapy tends to be more tolerable than chemotherapy and radiation. It may extend the lives of patients for months or even years. 

What is immunotherapy?

The treatment works in two main ways. It can boost the immune system so it can better fight cancer. Or, it can make the immune system smarter so that it can find and attack cancer cells. 

Immunotherapy may be administered in many different ways, including:

• Through a vein (intravenously)
• Orally with pills
• Topically with creams
• By being directed to a specific body part (such as in the case of bladder cancer)

Unlike the one-size-fits-all, blunt-force approach of chemotherapy and radiation, immunotherapy treatments tend to hone in on cancer in novel ways. They are more individualized to both the condition and the patient.

There are several types of immunotherapy that can be used to treat cancer. They include the following.

T-cell transfer therapy 

With this treatment (also known as adoptive cell therapy), immune cells called T-cells are taken from the patient’s blood. They’re then modified in a lab so they can better attach to tumor cells and kill them. Finally, they’re injected back into the patient. Specific forms include chimeric antigen receptor (CAR) T-cell therapy and tumor-infiltrating lymphocyte (TIL) therapy. 

Checkpoint inhibitors

These are drugs that alter parts of the immune system called checkpoints, which ordinarily help prevent immune responses from being too strong and harming healthy cells. Once the drugs block checkpoints, the immune system may have a stronger response to cancer cells. 

Cytokines

Cytokines are small proteins that help cells communicate. In this kind of immunotherapy, they stimulate immune cells to attack cancer. Interleukins and interferons are types of cytokines used in cancer treatment.

Monoclonal antibodies

These are immune system proteins developed in a lab. They attach to certain parts of a tumor cell to help the immune system better identify and respond to cancer cells. 

Immunomodulators

These are drugs that boost various aspects of the immune system to help it target certain cancers.

Vaccines

Unlike conventional vaccines that help prevent disease, when used in cancer therapy, these enhance the body’s immune response to cancer cells.

Oncolytic viruses

This form of treatment uses viruses that are often specially modified in a lab to infect tumor cells, causing them to self-destruct. Once the tumor cells have been targeted by the virus, the immune system can then continue working to eliminate the tumor.

What types of cancer can immunotherapy treat?

Immunotherapy has been successful as an approach to treating a variety of cancers, including those of the lungs and uterus. Other cancers that may be addressed with immunotherapy include: 

Lymphoma

CAR T-cell treatment is used as a second-line therapy for patients with some non-Hodgkin lymphomas that haven’t responded to other treatments. The therapy shrinks tumors in many patients. A cytokine treatment called interferon-alfa (IFN-alfa) may also be used for some forms of non-Hodgkin lymphoma. 

Bladder cancer

Checkpoint inhibitors such as PD-1 and PD-L1 inhibitors help the immune system attack cancer cells to shrink or slow their growth. These are given intravenously. They can be used for people with bladder cancer when tumors regrow after chemotherapy. They can also be used for people who have invasive cancer removed with surgery, but have a high risk of regrowth afterward. Some cytokine treatments can be used for bladder cancer, as well. They are put into the bladder itself as part of a liquid.

Esophageal cancer

PD-1 inhibitors can be used to treat esophageal cancers that can’t be removed surgically or that return after other treatments. This immunotherapy increases survival rates for patients with these persistent cancers.

Kidney cancer

Patients who had kidney cancer removed by surgery but are at a higher risk of recurrence may benefit from immunotherapy, such as PD-1 and PD-L1 inhibitors. Cytokine treatments such as interleukin-2 (IL-2) may be used for some advanced kidney cancers.

Prostate cancer

Vaccines can be used to activate the body’s immune response and fight advanced prostate tumor cells. The therapy can extend patients’ lives.

Advantages and drawbacks

Most immunotherapy treatments are tolerated better than traditional treatments such as chemotherapy and radiation, which kill cancer cells but can also harm healthy cells. This leads to side effects such as loss of appetite, increased bleeding and bruising, severe nausea, vomiting, diarrhea, fatigue, and hair loss. 

Some immunotherapy patients experience no side effects. But since this treatment does alter the immune system, it may cause the immune system to attack healthy cells during and after treatment, potentially leading to serious side effects. These may include:

• Rashes
• Nausea and vomiting
• Muscle and joint pain
• Fever 
• Headaches
• Cough or problems breathing

Some other less common—though potentially dangerous—side effects include kidney failure, problems with fertility, and issues with the endocrine and immune systems. For example, both the thyroid and adrenal glands are organs that produce several important hormones. Certain checkpoint inhibitors impair the thyroid gland or cause it to become overactive. They may similarly hamper the function of the adrenal glands. In rare cases, checkpoint inhibitors may also cause a form of diabetes to develop. 

Immunotherapy is a constantly changing treatment that has been shown to save lives and expand opportunities for treating cancer. This therapy has enabled healthcare providers to treat a range of complicated, aggressive cancers and help people live longer.