Table of ContentsView AllTable of ContentsTreatment’s Immune System EffectsPost-TreatmentSupporting Your Immune SystemWhen to See a DoctorFrequently Asked Questions
Table of ContentsView All
View All
Table of Contents
Treatment’s Immune System Effects
Post-Treatment
Supporting Your Immune System
When to See a Doctor
Frequently Asked Questions
Chemotherapyandradiationare two of the most common and effective treatments for cancer, but they can weaken your immune system for months after treatment. That makes you vulnerable to illness and infection.
This article will go over changes to the immune system after chemo and radiation, the risks of these treatments, what to do about treatment effects, and when to seek medical help.
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How Does Cancer Treatment Affect the Immune System?
Chemotherapy (chemo) and radiation therapy (also called radiotherapy) kill cancer cells. The problem is, they also kill rapidly dividing healthy cells.
Each treatment has its own effects. When the two treatments are combined, which is common, you can end up with side effects of both.
Chemotherapy
Cancer cells grow and divide quickly. Chemo is designed to go after fast-growing cells like cancer.
However, it can’t tell one fast-growing cell from another. That means it kills many types of cells in your body.
That includesbone marrowcells. One of their jobs is to produce white blood cells for the immune system. White blood cells are responsible for attacking and killing viruses, bacteria, and other pathogens. But when chemo kills off bone marrow cells, your immune system doesn’t have enough white blood cells to fight off infections.
The most common chemo-related problem isneutropenia. This is a decrease inneutrophils(white blood cells), which are important for immunity.
What Happens During Chemo?
RecapChemotherapy kills fast-growing cells, including cancer and bone marrow cells. Damage to bone marrow means it can’t produce disease-fighting immune-system cells. Low white blood cell counts (neutropenia) can result.
Recap
Chemotherapy kills fast-growing cells, including cancer and bone marrow cells. Damage to bone marrow means it can’t produce disease-fighting immune-system cells. Low white blood cell counts (neutropenia) can result.
Radiation
Radiation works differently than chemo. It exposes your cells to high doses of radiation (high-energy beams) that damage their DNA (genetic material).
This means cells either die or become unable to divide, which is how cells reproduce. This shrinks tumors or slows their growth.
Metastatic DiseaseWhen cancer spreads, called metastasis ormetastatic disease, the whole body may need radiation. This causes a reduction in the immune system’s ability to fight off infection, called immunosuppression, much more like that of chemotherapy.
Metastatic Disease
When cancer spreads, called metastasis ormetastatic disease, the whole body may need radiation. This causes a reduction in the immune system’s ability to fight off infection, called immunosuppression, much more like that of chemotherapy.
Depending on where the tumor being treated is located in the body, radiation may directly damage your immune system. It may also cause other conditions that harm the immune system.
For example, radiation near the underarm can damagelymph nodes, which are part of the immune system. The damage can lead to an increased risk of infection in the arm.
Radiation can deal a lot of damage when it’s aimed at bones. The effect on bone marrow is similar to that of chemo. Neutropenia is common.
Drug Treatment for Low Neutrophils
How Strong Is Your Immune System After Cancer Treatment?
After chemo and radiation, your immune system can stay suppressed for several months.
A study of people who had chemo forbreast cancerfound the immune system often took nine months or more to fully recover. Several types of immune-system cells were depleted.
In people who smoked, some immune cells were only at 50% of normal levels after nine months. That’s compared to an 80% rate in nonsmokers.
Researchers say the immune-system damage could leave you vulnerable to some illnesses even if you’ve been vaccinated. These includetetanus(a bacterial infection) andpneumonia(inflection causing inflammation of the air sacs of the lungs).
While newer research has been illuminating, much remains to be learned about the specific immune-system effects of cancer treatments.
RecapIt can take months for the immune system to rebound after chemo and radiation. The specific drug(s) can make a difference in recovery time. Smokers tend to recover more slowly.
It can take months for the immune system to rebound after chemo and radiation. The specific drug(s) can make a difference in recovery time. Smokers tend to recover more slowly.
Ways to Support Your Immune System After Chemo and Radiotherapy
Also, ask your care team if you’d benefit from medicine to increase your white blood cell count.
Managing ComorbiditiesIf you have other medical conditions (comorbidities), make sure you manage them well during and after cancer treatment.
Managing Comorbidities
If you have other medical conditions (comorbidities), make sure you manage them well during and after cancer treatment.
When to Seek Professional Treatment
It’s important to get treatment for illness or infection right away.Symptomsto watch for include:
If you go to urgent care or the emergency room for treatment, be sure to tell the staff you’ve had cancer and what kind of treatments you have had. This will help them understand the seriousness of the situation.
Lasting Side Effect
What If You Get a Cold During Chemo?
Summary
Chemotherapy kills fast-growing cells, which includes many healthy cells, along with cancer cells. Bone marrow cells are frequently damaged and unable to produce white blood cells. This hampers your immune system.
Radiation damages the genetic material of cells. This kills both cancer and immune-system cells. Effects tend to be less than with chemo. Radiation may directly damage the immune system or may cause other conditions that impair your immunity. Much of this depends on where the cancer is.
Your immune system may take months to rebound after chemo and radiation. Be sure to take steps to protect yourself from infection. If you notice symptoms of infection, get medical attention right away.
A Word From Verywell
More people are surviving and thriving after cancer all the time. Once you beat the disease, though, you can’t let up your guard. Impaired immunity can pose a real threat.
Just being aware of the problem is a start. Adopting good habits, enlisting friends and family to help, and staying in touch with your care team can help you stay healthy until your immune system is strong enough to protect you again.
Cancer Treatment Options
Researchers suspect cancer treatments may mimic the effects of aging.
Most people recover a large amount of immune function within nine months of chemo. It may take longer for smokers.Radiation’s effects are less predictable. Ask your care team what to expect based on the tumor’s location and the type of radiation you had.
Most people recover a large amount of immune function within nine months of chemo. It may take longer for smokers.
Radiation’s effects are less predictable. Ask your care team what to expect based on the tumor’s location and the type of radiation you had.
Will Cancer Ever Be Cured?
9 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.American Cancer Society.Why are people with cancer more likely to get infections?Cancer Treatment Centers of America.How do cancer treatments damage the immune system?National Institutes of Health, National Cancer Institute.Radiation therapy to treat cancer.BreastCancer.org.How radiation therapy affects the immune system.Verma R, Foster RE, Horgan K, et al.Lymphocyte depletion and repopulation after chemotherapy for primary breast cancer.Breast Cancer Res. 2016;18(1):10. Published 2016 Jan 26. doi:10.1186/s13058-015-0669-xVerma R, Foster RE, Horgan K, et al.Lymphocyte depletion and repopulation after chemotherapy for primary breast cancer.Breast Cancer Res. 2016;18(1):10. Published 2016 Jan 26. doi:10.1186/s13058-015-0669-xCenters for Disease Control and Prevention.Know the signs and symptoms of infection.BreastCancer.org.How chemotherapy affects the immune system.Cupit-Link MC, Kirkland JL, Ness KK, et al.Biology of premature ageing in survivors of cancer.ESMO Open. 2017;2(5):e000250. Published 2017 Dec 18. doi:10.1136/esmoopen-2017-000250
9 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.American Cancer Society.Why are people with cancer more likely to get infections?Cancer Treatment Centers of America.How do cancer treatments damage the immune system?National Institutes of Health, National Cancer Institute.Radiation therapy to treat cancer.BreastCancer.org.How radiation therapy affects the immune system.Verma R, Foster RE, Horgan K, et al.Lymphocyte depletion and repopulation after chemotherapy for primary breast cancer.Breast Cancer Res. 2016;18(1):10. Published 2016 Jan 26. doi:10.1186/s13058-015-0669-xVerma R, Foster RE, Horgan K, et al.Lymphocyte depletion and repopulation after chemotherapy for primary breast cancer.Breast Cancer Res. 2016;18(1):10. Published 2016 Jan 26. doi:10.1186/s13058-015-0669-xCenters for Disease Control and Prevention.Know the signs and symptoms of infection.BreastCancer.org.How chemotherapy affects the immune system.Cupit-Link MC, Kirkland JL, Ness KK, et al.Biology of premature ageing in survivors of cancer.ESMO Open. 2017;2(5):e000250. Published 2017 Dec 18. doi:10.1136/esmoopen-2017-000250
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
American Cancer Society.Why are people with cancer more likely to get infections?Cancer Treatment Centers of America.How do cancer treatments damage the immune system?National Institutes of Health, National Cancer Institute.Radiation therapy to treat cancer.BreastCancer.org.How radiation therapy affects the immune system.Verma R, Foster RE, Horgan K, et al.Lymphocyte depletion and repopulation after chemotherapy for primary breast cancer.Breast Cancer Res. 2016;18(1):10. Published 2016 Jan 26. doi:10.1186/s13058-015-0669-xVerma R, Foster RE, Horgan K, et al.Lymphocyte depletion and repopulation after chemotherapy for primary breast cancer.Breast Cancer Res. 2016;18(1):10. Published 2016 Jan 26. doi:10.1186/s13058-015-0669-xCenters for Disease Control and Prevention.Know the signs and symptoms of infection.BreastCancer.org.How chemotherapy affects the immune system.Cupit-Link MC, Kirkland JL, Ness KK, et al.Biology of premature ageing in survivors of cancer.ESMO Open. 2017;2(5):e000250. Published 2017 Dec 18. doi:10.1136/esmoopen-2017-000250
American Cancer Society.Why are people with cancer more likely to get infections?
Cancer Treatment Centers of America.How do cancer treatments damage the immune system?
National Institutes of Health, National Cancer Institute.Radiation therapy to treat cancer.
BreastCancer.org.How radiation therapy affects the immune system.
Verma R, Foster RE, Horgan K, et al.Lymphocyte depletion and repopulation after chemotherapy for primary breast cancer.Breast Cancer Res. 2016;18(1):10. Published 2016 Jan 26. doi:10.1186/s13058-015-0669-x
Centers for Disease Control and Prevention.Know the signs and symptoms of infection.
BreastCancer.org.How chemotherapy affects the immune system.
Cupit-Link MC, Kirkland JL, Ness KK, et al.Biology of premature ageing in survivors of cancer.ESMO Open. 2017;2(5):e000250. Published 2017 Dec 18. doi:10.1136/esmoopen-2017-000250
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