Cancer treatments such as chemotherapy, radiation and immunotherapy can result in a weakened immune system.
Chemotherapy
Chemotherapy acts by killing cancer cells but it also kills normal cells which over time can repair and recover. During chemotherapy, bone marrow which produces white blood cells that are essential in the body’s immune response, are damaged. As a result, your immune system may be weakened.
For more information read Cancer Council’s Understanding Chemotherapy booklet.
Radiation Therapy
Radiation therapy uses X-rays to destroy or injure cancer cells so they cannot multiply. In this process, white blood cells, used to fight infections, may also be damaged, which can lower your immune system. New techniques are reducing the impact on the immune system by delivering targeted radiation but you should still be aware that your immune system may be lower than it would usually be if you are healthy and well.
For more information read Cancer Council’s Understanding Radiotherapy booklet.
Hormone Treatments
Hormone treatments slow or stop the growth of cancer that use hormones to grow. Hormone treatments can be broadly categorised into those that block the body’s ability to produce hormones and those that interfere with how hormones behave in the body.
Hormone treatment used on its own is unlikely to affect the immune system, however if it is used in combination with chemotherapy then the immune system may be weakened.
For more information read Cancer Council’s webpage on hormone therapy.
Immunotherapy
Immunotherapy is a relatively new and emerging treatment that assists the body’s immune system to fight cancer. Immunotherapy can boost the immune system to work better against cancer or remove barriers to the immune system attacking the cancer.
Immunotherapy sometimes results in the immune system attacking healthy cells. This can make cancer patients on immunotherapy more susceptable to contracting an infection or virus.
For more information read Cancer Council’s Understanding Immunotherapy factsheet.
Surgery
Surgery for cancer can often be used in combination with other treatments such as chemotherapy and radiation therapy, which may lower your immune system. It is also possible that surgery alone may lower your immune system. Surgery to remove lymph nodes and bone marrow transplants are examples of surgery that may weaken your immune system and make you more susceptible to infections.
For more information read Cancer Council’s Understanding Surgery booklet.
If you are undergoing cancer treatment, you should take extra steps to avoid getting COVID-19 as your body may not be able to as effectively fight the virus if your immune system is compromised.
