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Long-Term Side Effects of Chemotherapy

Although chemotherapy kills or disables cancer cells, it may harm some normal cells in the body and cause side effects.

Common long-term side effects of chemotherapy include early menopause and weight gain. Rare side effects include heart problems and leukemia.

Before you begin chemotherapy, talk with your health care provider about possible side effects and how to manage them.

Learn about short-term effects of chemotherapy

Early menopause

Some chemotherapy drugs can damage the ovaries and stop regular menstrual cycles (amenorrhea).

  • In women under 40, it’s often temporary and periods will likely start again [33].
  • In women over 40, it’s more often permanent (early menopause) [33].

Some women may have periods again months or years after chemotherapy ends. However, even for women whose periods return, menopause may begin at an earlier age than for other women [33].

Early menopause and menopausal symptoms

As with natural menopause, you may have symptoms such as hot flashes and vaginal dryness. Because the onset of menopause is sudden, these symptoms may be worse than with natural menopause.

Early menopause can also affect bone health. Menopause can cause osteopenia or osteoporosis (conditions related to bone density loss).

You may also have muscle or joint aches.

Learn about ways to ease menopausal symptoms.

Early menopause and fertility

If you’re hoping to have a child after breast cancer treatment, there are things you can do. Discuss your options with your health care provider (and if possible, a fertility specialist) before making treatment decisions. Some options are described below.

Storing eggs

The most common way to preserve fertility is to store eggs (fertilized or unfertilized) before chemotherapy begins. Some of your eggs are collected, frozen and stored. The eggs may be fertilized by sperm from a spouse, partner or donor. Or you may store unfertilized eggs, which don’t require a sperm donor.

After treatment, the eggs can be thawed, and if they were frozen unfertilized, they are fertilized. Then the eggs are implanted into the uterus.

Insurance coverage for fertility services varies from state to state. Check with your insurance company to find out what’s covered.

Protecting the ovaries

There are no known treatments guaranteed to protect the ovaries from chemotherapy.

However, drugs that shut down the ovaries during chemotherapy may help women return to regular menstrual periods after treatment ends. This may help preserve fertility.

Learn more about fertility options for women undergoing breast cancer treatment.

Weight gain

Weight gain is a common side effect of chemotherapy [34].

Changes in metabolism caused by chemotherapy and a less active or inactive lifestyle add to weight gain during treatment.

Some studies have found women with breast cancer who got chemotherapy were 40%-65% more likely to gain weight compared to women who didn’t get chemotherapy [35-37].

Women who gain weight usually put on about 5 to 15 pounds [34,37]. The more weight a woman gains, the less likely she is to return to her pre-diagnosis weight [35].

Preventing weight gain

Getting regular physical activity during treatment (if possible) may help prevent weight gain. Being active can also help reduce fatigue and improve quality of life [38].

Seeing a registered dietician may also help. 

Tips to manage your weight

  • Eat regularly (3 small meals per day).
  • Include protein, fiber and healthy fat (found in foods such as olive and canola oils, nuts, natural nut butters and avocados) in meals and snacks to give a feeling of fullness.
  • Avoid meals and snacks that contain mainly refined carbohydrates, such as most pastas, breads and rice as well as cookies, ice cream and other desserts.
  • Fill half of your plate with vegetables.
  • Choose fresh fruits instead of fruit juices.
  • Avoid eating while doing other activities, such as watching TV or reading.
  • Eat slowly.
  • Drink plenty of water.

Susan G. Komen® has a fact sheet with tips on diet and nutrition during treatment.

The National Cancer Institute (NCI) has a booklet with eating hints before and during cancer treatment.

Fred Hutchinson Cancer Center’s Cook for Your Life website offers recipes, cooking videos and nutrition and health information in English and Spanish.

Healthy weight and survival

Maintaining a healthy weight after a breast cancer diagnosis is important for overall health and can improve well-being. Some studies suggest maintaining a healthy weight may also improve survival [39-42].

However, there are no known specific foods to eat (or to avoid) to improve breast cancer survival.

Aim for a well-balanced, healthy diet. Eating unhealthy foods every now and then is OK and doesn’t have any harmful effects on breast cancer survival.

Learn more about body weight and survival after breast cancer.

Learn more about a healthy diet and survival after breast cancer.

Learn more about exercise and survival after breast cancer.


Chemotherapy can cause fatigue (extreme tiredness). Fatigue is mainly a short-term problem, but for some, it can persist [13].

You may feel like you don’t have any energy and may feel tired all the time. Resting may not help.

Regular exercise, even just walking for 20 minutes every day, can help reduce fatigue [13-16]. Getting a good night’s sleep is also important.

Talk with your health care provider if you’re fatigued or have insomnia (problems sleeping).

Learn more about fatigue and insomnia.

Cognitive function (cancer brain, chemo-brain)

Some people have cognitive problems after chemotherapy, including mental “fogginess” and trouble with concentration, memory and multi-tasking [43-48]. This condition is often called “cancer brain” or “chemo-brain.”

Most people have mild symptoms, but some have more troubling cognitive problems that can impact daily life.

Symptoms may last for a short period of time, or they may last 1-2 years after treatment or longer. Most people report they go away over time.

Cognitive function and breast cancer treatment

The link between cognitive problems and chemotherapy remains unclear.

Problems with cognitive function may be related to the breast cancer treatment, regardless of the type of treatment [49]. For example, women treated with hormone therapy (and not chemotherapy) have also reported cognitive problems [44,47-48,50-52].

Stress, anxiety, depression and insomnia (sleeping problems) can affect cognitive function [49,53]. After a breast cancer diagnosis, people may have cognitive problems, even before treatment begins [54-55]. These symptoms may first appear with the stress related to diagnosis and treatment and then become worse after chemotherapy or other treatment begins [49,54-55].

Medications used to treat the side effects of chemotherapy, such as sleeping aids and anti-nausea medications, can also cause cognitive problems.

Age and genetic factors may also play a role. Some studies show older women with breast cancer tend to have more cognitive problems after chemotherapy than younger women [44,56]. Genetic factors may also decrease cognitive function in older women with breast cancer [57].

The true extent of the cognitive effects of chemotherapy is not well understood. More research in this area is needed.

Tips to improve cognitive function

Although no studies show the tips below improve cognitive function, they may help some people with memory problems [58].

Tips to improve cognitive function

  • Plan your day to do the things that need the most thinking when you feel your best.
  • Get extra rest at night, but limit naps during the day to less than one hour.
  • Exercise (ask your health care provider what light exercise may be helpful for you).
  • Write down or record things you want to remember.
  • Use a calendar and write down important dates and information.
  • Use a pill box to keep track of medications.
  • Ask a friend or family member for help when you need it.
  • Ask your nurse, social worker or patient navigator for help keeping track of clinic visits.
  • Ask your health care provider about complementary therapies, such as meditation, that may help.
  • Do puzzles or play games for mental exercise.

Adapted from National Cancer Institute materials [58].

Changes in mood

During and after chemotherapy, some people have emotional distress, such as anxiety or depression. These feelings are normal and should ease with time. Talk with your health care team about how you’re doing emotionally. They can refer you to a support group, counselor or other support resources.

Learn more about support groups and social support

Long-term health risks

For most people with breast cancer, the benefits of chemotherapy outweigh the long-term health risks.

Heart problems

Heart problems are rare but severe side effects of some types of chemotherapy. These risks are related to the dose and type of chemotherapy drug. With the doses given today, the risk of heart problems is low [59-60].

Heart problems, like cardiomyopathy (enlarged, weakened heart) and heart failure, have been linked to the use of certain chemotherapy drugs (such as doxorubicin and epirubicin) and the HER2-targeted therapy drug trastuzumab (Herceptin) [59-63].

When these drugs are used, extra care is taken to avoid heart problems.

For example, before you begin treatment with doxorubicin or trastuzumab, your heart function will be measured to make sure there are no pre-existing heart conditions.

If a heart problem occurs, it can sometimes be reversed if the drugs are stopped at the first sign of heart damage [59].


Leukemia is a rare but severe side effect of some types of chemotherapy. This risk is related to the dose and type of chemotherapy drug. With the doses given today, the risk of leukemia is low [59,64-65].

In very rare cases, the use of some chemotherapy drugs (such as cyclophosphamide, doxorubicin and epirubicin) has been linked to leukemia [59,65-67].

Nerve damage

Chemotherapy drugs including carboplatin and taxanes (such as paclitaxel and docetaxel), can cause nerve damage [68].

If this happens, you may have neuropathy (feel a burning or shooting pain or numbness), usually in your fingers or toes.

This side effect often goes away after chemotherapy ends, though it may take weeks or months. However, some people have lingering nerve issues (numbness and/or pain).

Learn more about managing pain and numbness related to chemotherapy.

Susan G. Komen® Support Resources

  • Do you need help? We’re here for you. The Komen Patient Care Center is your trusted, go-to source for timely, accurate breast health and breast cancer information, services and resources. Our navigators offer free, personalized support to patients, caregivers and family members, including education, emotional support, financial assistance, help accessing care and more. Get connected to a Komen navigator by contacting the Breast Care Helpline at 1-877-465-6636 or email helpline@komen.org to get started. All calls are answered Monday through Thursday, 9 a.m to 7 p.m. ET and Friday, 9 a.m. to 6 p.m. ET. Se habla español.
  • The Komen Breast Cancer and Komen Metastatic (Stage IV) Breast Cancer Facebook groups are places where those with breast cancer and their family and friends can talk with others for friendship and support.
  • Our fact sheets, booklets and other education materials offer additional information.

Updated 04/10/24