Infection is one of the most common complications of cancer and cancer treatment. This is because cancer and cancer treatments can weaken the immune system for a period of time. The immune system is a group of organs, tissues, and cells that work together to resist and fight infections. Some infections can spread to other parts of the body and might become life-threatening if not found early. Infections are caused by germs that enter the body, multiply, and cause harm or illness. The main types of germs that can cause infections are:
Certain types of cancer itself can increase your risk of getting an infection. So can certain types of cancer treatment. Once the cancer cells are treated and treatment is over, the risk of infection usually goes back down. For most people with cancer, the greatest risk of getting a serious infection only lasts for a limited time. But every patient is different and the side effects of treatments can be very different. So, your risk of infection depends on the type of cancer you have and the treatment you get. For example, surgery and radiation therapy do not weaken a person’s resistance to infection nearly as much as a bone marrow transplant that uses high doses of chemotherapy (chemo). And some drugs used to treat cancer are less likely than others to affect a person’s ability to resist infection.
Infections that develop in people who have cancer or who are getting cancer treatment can be more serious than those in people who are otherwise healthy. They can also be harder to treat. If you have cancer, it’s important to find and treat infections early, before they get worse and spread. Talk to your cancer care team about your risk for infection.
Common sites of infection in people with cancer include :
It’s important to weigh the risk of infection and other side effects against the benefits of cancer treatment. Each patient's situation is different because people with cancer might have other health problems that can affect how they respond to cancer treatment. Talk with your doctor before and during cancer treatment about your risk for infection. Here are some questions you can ask your doctor or cancer care team about infection:
It’s important to watch for early signs of infection and tell your health care team about them right away. This way treatment can be started as early as possible to prevent the infection from spreading to other parts of the body. This is even more important for people who have a low white blood cell count (neutropenia).
Signs and symptoms of an infection might include:
Fever is especially important because it’s often the first sign of an infection in people with cancer. Sometimes, fever is the only sign of an infection. Patients with neutropenia may not have other signs or symptoms of an infection, except for fever. You should have a thermometer to check your temperature – you can’t rely on how you feel to know when you have a fever. Patients may be told to call their doctor or nurse if they have a fever, or if they have other signs and symptoms of infection. Don’t take medicines to reduce your fever without checking with your doctor first. Ask your doctor what you should do and when you should call. Be sure you know how to reach your health care team after hours, including nights and weekends.
It’s important for people with cancer and their families and friends to know these things:
Review these points with your cancer care team before and during treatment to get the information you need. Double check with them on how you should handle these things and find out if there are any special steps you should take during cancer treatment.
The American Cancer Society medical and editorial content team
Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.
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Last Revised: February 1, 2020
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