A cell in the human body.
Cancer cells can confuse the immune system, making it unsure of which cells to attack.

How Cancer Affects the Immune System

If you have cancer, you are at a heightened risk of infection due to the effects that cancer has on your immune system. Cancer, as well as certain cancer treatments, can alter your immune system, leaving you more susceptible to infection. For this reason, we uncover how cancer affects the immune system.

The Immune System’s Purpose

Before we dive into the effects of cancer on the immune system, let’s discuss what the immune system does. The immune system is responsible for protecting the body against infection and illness. Various immune system reactions and responses work to help the body deal with damaged cells and invading viruses, bacteria, parasites, or fungi.

So, why is the immune system important to consider if you have cancer? Well, cancer, and cancer treatments can weaken the immune system, and sometimes the immune system helps to fight cancer.

How Cancer Weakens the Immune System

While there are cancers of the immune system – leukemia and lymphoma – any type of cancer can alter the immune system.

Cancer cells develop from your own cells, resulting in immune system confusion because it does not always know that it is supposed to launch an attack against the cancerous cells. In some cases, the immune system knows that the cancerous cells should not be there, but often the cancerous cells go unnoticed. Additionally, cancer cells have the ability to turn off the immune response all together, allowing them to multiply and spread.

In some cases, cancer can cause damage to various parts of your immune system. For example, a cancerous tumor growing on the skin can break down the body’s natural defense barriers, allowing germs to get in and cause an infection. Additionally, larger tumors may interfere with blood flow to tissues because they are pressing on them or their direct blood supply. Lastly, lung tumors can block normal drainage of mucus, resulting in infection.

How Cancer Treatment Weakens the Immune System

Cancer treatments, including chemotherapy, targeted therapy, radiation and high-dose steroids, affect the body’s immune system because they cause decreased white blood cells. The blood cells of the body are made in the bone marrow and when cancer treatment affects the bone marrow it leads to a decreased number of blood cells, leading to a decreased ability of the body to fight off invading infections.

Cancer surgery can also temporarily weaken the immune system. This weakened state can last from about 10 days to several months. Surgery breaks through the skin via an incision, which can lead to mucous membrane and tissue damage, allowing easy access for germs. Often, the surgical incision site is a place of infection.

How Inadequate Nutrition Weakens the Immune System

In order for the immune system to work properly, it needs a variety of vitamins, minerals, proteins and calories. Being malnourished can lead to a weakened immune system. Many times, people with cancer become malnourished because their cancer makes it difficult to eat and/or digest food, their cancer treatment causes side effects such as decreased appetite and nausea, or the cancer cells use up all of the consumed nutrients.

Often, individuals with cancer need extra protein and calories to support their immune system through cancer and cancer treatment. In order to receive adequate nutrition, a dietitian or doctor is often needed to help with dietary supplements, tube feedings, and in some cases, intravenous feedings.

You May Also Like

Cancer Treatments That Utilize the Immune System

In some cases, certain cancer treatments, known as immunotherapy, are used to help the immune system fight cancer. This type of therapy boosts the immune response or helps the immune system to recognize cancer cells and defend against them.

Another type of cancer treatment that works with the body’s immune system, is a stem cell transplant (bone marrow transplant) that replaces the body’s immune cells. Typically, stem cell transplants are utilized for cancers that affect the blood cells, such as lymphoma, leukemia and multiple myeloma, but are occasionally used to treat other types of cancer including neuroblastoma, testicular cancer and retinoblastoma. The ultimate goal of a stem cell transplant is to allow the body to once again be able to make healthy blood cells that are necessary for a strong immune system.

Symptoms of Weakened Immune System

A variety of symptoms may indicate a weakened immune system:

  • Constant infection (commonly pneumonia, bronchitis, and meningitis)
  • Bronchiectasis
  • Gastrointestinal symptoms (loss of appetite, diarrhea, abdominal cramping)

Additionally, individuals with a weakened immune system are more likely to suffer from autoimmune disorders, internal organ inflammation and blood disorders. In infants and children, growth and developmental delays may occur.

Protecting Your Immune System

If you have been diagnosed with cancer, or are going through cancer treatment, you should be proactive and help protect your immune system:

  • Practice good hygiene, especially proper hand washing.
  • Pay attention to your body – if you are feeling sick, speak to your doctor. What you think might be a minor issue, may actually be something more serious.
  • Ensure that you are up-to-date on all of your vaccinations. Additionally, many cancer patients should be receiving the pneumonia and flu vaccines.
  • Eat a healthy, balanced diet and exercise regularly.
  • Quit smoking.
  • Avoid being in contact with friends or family who are sick, even with minor infection such as the common cold.
  • Learn how to manage stress effectively (meditation, yoga, deep breathing, etc.).
  • Get an adequate amount of quality sleep.

In Conclusion

Cancer and cancer treatments, can significantly affect your immune system, leaving you susceptible to infection. Ensure that you are practicing the tips mentioned above to protect your immune system and help your body recover from cancer and associated treatments.