Immuno-oncology is the study and development of treatments that take advantage of the body’s immune system to fight cancer.

Our immune system is a network of organs, cells, and molecules which protects us from foreign substances—such as bacteria and viruses—which can cause infection. In addition to finding and destroying foreign substances, the immune system can also locate and attack abnormal cells.

There are two main parts of the immune system:

  • Humoral, also called antibody-mediated, in which B cells (a type of white blood cell called a lymphocyte) make antibodies that identify and destroy foreign substances.
  • Cell-mediated, in which T cells (another type of white blood cell or lymphocyte) identify and destroy abnormal cells, including those that are cancerous.

Both an overactive and an underactive immune system can be harmful. Our growing understanding of the health benefits of a balanced immune system has led to the development of immunotherapies as a treatment approach for many types of cancer.

Types of Immunotherapy

The purpose of immunotherapy in the treatment of cancer is to modify the immune system to recognize the cancer as foreign to the body, and that it needs to be attacked. This can be difficult, because the differences between cancer cells and healthy cells are often quite small.

Additionally, lymphocytes have an “immune checkpoint” molecule that is able to alert the lymphocyte to either “engage and fight” or” ignore and rest” when it recognizes something as being foreign. The checkpoint molecule acts to prevent our immune system from attacking normal cells. The development of new drugs, called checkpoint inhibitors, allows the immune cells to start attacking cancer cells by blocking this “checkpoint.”

One type of immune checkpoint inhibitor works by interfering with a molecular “brake” known as PD-1 that prevents the body’s immune system from attacking tumors. Drugs in this category currently approved by the United States Food and Drug Administration (FDA) are nivolumab (Opdivo), atezolizumab (Tecentriq), and pembrolizumab (Keytruda).

Another type of immune checkpoint inhibitor seeks out and locks onto CTLA-4 (cytotoxic T-lymphocyte associated protein 4), a protein that normally helps keep immune system cells (called T-cells) in check. The drug ipilimumab (Yervoy) is thought to help the immune system destroy cancer cells by blocking the action of CTLA-4.

In addition to checkpoint inhibitors, immunotherapy approaches fall into the following main categories:

  • Monoclonal antibodies are lab-generated molecules that target specific tumor antigens (substances that the immune system sees as being foreign or dangerous).
  • Therapeutic vaccines can boost the immune system and have the potential to treat cancer or prevent it from recurring (coming back) after treatment. The FDA has approved vaccines for certain cancers; additionally, a number of types of vaccines are being studied in clinical trials.
  • Adoptive T cell transfer (also called CAR-T cell therapy) is an approach in which T cells are removed from the patient, genetically modified to create a known cancer molecule to which the T cell can be directed. These cells are re-introduced into the patient with the goal of improving the immune system’s anti-cancer response.

Immunotherapies have been shown to work well in combination with other treatment types, such as surgery, radiation, chemotherapy, and targeted therapy (treatments designed to target the specific cell mechanisms that are important for the growth and survival of cancer cells).

Immunotherapy travels through the bloodstream, helping to prompt what is called an “immune response.” Because immunotherapy can attack healthy cells as well as cancer cells, certain side effects may be experienced, including digestive tract symptoms, loss of appetite, fatigue, and flu-like symptoms.

It’s important that you report any side effects that you experience to your health care team so they can help you manage them. The side effects can range from mild to severe; early reporting to your doctor can minimize their intensity and seriousness. Reporting them right away can also improve your quality of life and allow you to stick with your treatment plan.

It’s important to remember that not all patients experience all side effects, and patients may experience side effects not listed here.

Managing Digestive Tract Symptoms

Nausea and vomiting

  • Avoid food with strong odors, as well as overly sweet, greasy, fried, or highly seasoned food.
  • Eat meals cold or at room temperature, which often makes food more easily tolerated.
  • Nibble on dry crackers or toast. These bland foods are easy on the stomach.
  • Having something in your stomach when you take medication may help ease nausea.


  • Drink plenty of water. Ask your doctor about using drinks such as Gatorade which provide electrolytes as well as liquid. Electrolytes are body salts that must stay in balance for cells to work properly.
  • Over-the-counter medicines such as loperamide (Imodium A-D and others) and prescription drugs are available for diarrhea but should be used only if necessary. If the diarrhea is bad enough that you need medicine, discuss it with your doctor or nurse.
  • Choose foods that contain soluble fiber—for example beans, oat cereals, oranges, and flaxseeds. High-pectin foods such as peaches, apples, oranges, grapefruit, bananas, and apricots can also help to avoid diarrhea.
  • Avoid food high in refined sugar and those sweetened with sugar alcohols such as sorbitol and mannitol. Look for this low-calorie sweetener on food labels; the names of this type of sweetener usually end with the letters “ol.”
  • Low fat food choices are less likely to cause diarrhea than fatty, greasy, or fried foods. The fats you eat should come from healthy sources, such as olive oil, canola oil, avocado, olives, nuts, and seeds.
  • Limit or avoid lactose, especially if you are lactose-intolerant. There are plant-based milk alternatives you can try, such as soy or rice milk. If lactose is an essential part of your diet, there are dairy products with added lactase (which breaks down lactose) and dietary lactase supplements.
  • Any change in bowel habits, including frequency of bowel movements and any change in the quality or quantity of your stool, should be immediately be reported to your doctor or nurse.

Managing Loss of Appetite

  • To help maintain your weight, eat small meals throughout the day. That’s an easy way to take in more protein and calories. Try to include protein in every meal.
  • To keep from feeling full early, avoid liquids with meals or take only small sips (unless you need liquids to help swallow). Drink most of your liquids between meals.
  • Be as physically active as you can. Sometimes, taking a short walk an hour or so before meals can help you feel hungry.
  • Keep high-calorie, high-protein snacks on hand such as hard-boiled eggs, peanut butter, cheese, ice cream, granola bars, liquid nutritional supplements, puddings, nuts, canned tuna, or trail mix.
  • Eat your favorite foods any time of the day. For example, if you like breakfast foods, eat them for dinner.
  • If you are struggling to maintain your appetite, talk to your health care team about whether appetite-building medication could be right for you.

Managing Fatigue

Fatigue (extreme tiredness not helped by sleep) is one of the most common side effects of many cancer treatments. If you are taking a medication, your doctor may lower the dose of the drug, as long as it does not make the treatment less effective. If you are experiencing fatigue, talk to your doctor about whether taking a smaller dose is right for you.

There are a number of other tips for reducing fatigue:

  • Take several short naps or breaks.
  • Take short walks or do some light exercise, if possible.
  • Try easier or shorter versions of the activities you enjoy.
  • Ask your family or friends to help you with tasks you find difficult or tiring.
  • Save your energy for things you find most important.

Fatigue can be a symptom of other illnesses, such as anemia, diabetes, thyroid problems, heart disease, rheumatoid arthritis, and depression. So be sure to ask your doctor if he or she thinks any of these conditions may be contributing to your fatigue.

Also, it could be very valuable to talk to an oncology social worker or oncology nurse. These professionals can also help you manage fatigue. They can work with you to manage any emotional or practical concerns that may be causing symptoms and help you find ways to cope.

Managing Flu-Like Symptoms

The fever and aches that may occur with immunotherapy treatments can be managed with a combination of rest and medication. Acetaminophen (such as Tylenol) is often a doctor’s first choice to treat these symptoms. Nonsteroidal anti-inflammatory drugs (NSAIDs) can also help, but should be taken only if recommended by your doctor, as they can cause other side effects. NSAIDs include aspirin, ibuprofen (Motrin and others), and naproxen (Naprelan, Midol, Aleve, and others).

Managing Changes to the Skin

About 20 to 30 percent of people being treated with immunotherapy experience changes to the skin, such as an itchy, measle-like rash. If this occurs, contact your health care team so the appropriate treatment can be prescribed. The rash and itching can be treated with prescription-strength medications that are applied directly to the skin, or taken as tablets. These medications are typically either antihistamines (drugs used to treat allergic reactions) or corticosteroids (drugs that act against inflammation).

It’s especially important to contact your health care team if you have any open skin or painful areas, as this could indicate an infection. Infections can be treated with an oral antibiotic or topical antibiotic cream.

Frequently Asked Questions

Q. I’ve recently been diagnosed with cancer. What questions should I ask my oncologist about immunotherapy as a possible treatment approach?

A. Specific questions to discuss with your oncologist include:

  • Does immunotherapy have a role in treating my type of cancer, alone or in combination with other treatments?
  • Are there FDA-approved immunotherapies for my type of cancer?
  • Are there any immunotherapies currently being studied in clinical trials for my type of cancer?
  • What are the possible side effects of the immunotherapy approaches for my type of cancer?

Q. Will immunotherapy replace other types of cancer treatments?

A. While there is much enthusiasm for immunotherapy as a treatment approach for many types of cancer, other forms of treatment are still considered to be effective, depending on the individual’s specific circumstances. This includes treatments that have been used for many years such as radiation and chemotherapy, and newer approaches such as targeted therapy. It’s also important to note that immunotherapy can often be most effective when used in combination with other forms of treatment.

Q. I have prostate cancer, and am being treated with the vaccine sipuleucel-T. Will this interfere with the other vaccines I usually get?

A. In order to stay as healthy as possible during any type of cancer treatment, it is generally recommended that you continue to receive the vaccines recommended for your specific situation, which can include shots for influenza, pneumonia, and herpes zoster. However, this is an important issue to discuss with your health care team, as there can be exceptions to this general guidance.

Q. How long do I have to stay on my immunotherapy treatment?

A. The duration of immunotherapy treatments depends on a number of factors, including the type of immunotherapy being received. For instance, a vaccine might be given just once, while other drugs may be given at set intervals over a number of weeks. How long to continue certain immunotherapies is an area of ongoing research in clinical studies.

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This activity is supported by an independent educational grant from Merck & Co. Inc and Pfizer.

Last updated June 13, 2017

The information presented in this publication is provided for your general information only. It is not intended as medical advice and should not be relied upon as a substitute for consultations with qualified health professionals who are aware of your specific situation. We encourage you to take information and questions back to your individual health care provider as a way of creating a dialogue and partnership about your cancer and your treatment.

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