General Information About Fatigue
Fatigue is the most common side effect of cancer treatment.
Cancer treatments such as chemotherapy, radiation therapy, hormone therapy, bone marrow transplantation, and immunotherapy can cause fatigue. Fatigue is also a common symptom of some types of cancer. People with cancer describe fatigue as feeling tired, weak, worn-out, heavy, slow, or that they have no energy or get-up-and-go. Fatigue in people with cancer may be called cancer fatigue, cancer-related fatigue, and cancer treatment-related fatigue.
Cancer fatigue is different from fatigue that healthy people feel.
When a healthy person is tired from day-to-day activities, their fatigue can be relieved with sleep and rest. Cancer fatigue is different. People with cancer get tired after less activity than people who do not have cancer. Also, cancer fatigue is not completely relieved by sleep and rest, interferes with daily activities, and may last for a long time. Fatigue usually decreases after cancer treatment ends, but some people may still feel fatigue for months or years.
Fatigue can decrease your quality of life.
Cancer fatigue can affect all areas of your life by making you too tired to take part in daily activities, relationships, social events, and community activities. You might miss work or school, spend less time with family and friends, or spend more time sleeping. In some cases, physical fatigue leads to mental fatigue and mood changes. This can make it hard for you to pay attention, remember things, and think clearly. If you suffer from cancer fatigue, you may need to take leave from a job or stop working completely. Job loss can lead to money problems and the loss of health insurance. All these things can lessen your quality of life and self-esteem.
Causes of Cancer Fatigue
Fatigue in people with cancer may have more than one cause.
Doctors do not know all the reasons people with cancer have fatigue. Many conditions may cause fatigue at the same time.
Fatigue in people with cancer may be caused by the following:
- Cancer treatment.
- Receiving more than one type of treatment (for example, both chemotherapy and radiation therapy).
- Anemia (a lower than normal number of red blood cells).
- Hormone levels that are too low or too high.
- Trouble breathing or getting enough oxygen.
- Pain and other symptoms.
- Problems getting enough sleep.
- Loss of appetite or not getting enough calories and nutrients.
- Dehydration (loss of too much water from the body, such as from severe diarrhea or vomiting).
- Changes in how well the body uses food for energy.
- Loss of weight, muscle, and/or strength.
- Medicines that cause drowsiness.
- Not being active.
- Being overweight.
- Tumors in certain parts of the body.
- Other medical conditions.
- Having fatigue before cancer treatment begins.
Fatigue is common in people with advanced cancer who are not receiving cancer treatment.
It is not clear how cancer treatments cause fatigue.
It is unclear how cancer treatments such as surgery, chemotherapy, and radiation therapy cause fatigue.
When cancer treatment begins, many patients are already tired from medical tests, surgery, and the emotional stress of coping with the cancer diagnosis. Fatigue may get worse during treatment.
Different cancer treatments have different effects on a patient's energy level. The type and schedule of treatments can affect the amount of fatigue caused by cancer treatment. Some patients have more fatigue after cancer treatments than others do.
Fatigue related to surgery
Fatigue is often a side effect of surgery, but patients usually feel better with time. However, fatigue related to surgery can be worse when the surgery is combined with other cancer treatments.
Fatigue caused by chemotherapy
Patients treated with chemotherapy usually feel the most fatigue in the days right after each treatment. Then the fatigue decreases until the next treatment. Some studies have shown that patients have the most severe fatigue about mid-way through all the cycles of chemotherapy. Fatigue decreases after chemotherapy is finished, but patients may not feel back to normal until a month or more after the last treatment.
Fatigue during chemotherapy may be increased by the following:
- Lack of sleep caused by some anticancer drugs.
Fatigue caused by radiation therapy
Many patients receiving radiation therapy have fatigue that keeps them from being as active as they want to be. After radiation therapy begins, fatigue usually increases until mid-way through the course of treatments and then stays about the same until treatment ends. For many patients, fatigue improves after radiation therapy stops. However, in some patients, fatigue will last months or years after treatment ends.
Fatigue caused by hormone therapy
Women who are being treated with hormone therapy for breast cancer may have fatigue. Fatigue during hormone therapy may also be increased in breast cancer survivors who are younger than 55 years, overweight, or have more pain and insomnia.
Fatigue caused by immunotherapy
Immunotherapy often causes flu-like symptoms, such as fever, chills, headache, and muscle or body aches. Some patients may also have trouble thinking clearly. Fatigue symptoms depend on the type of immunotherapy used.
Anemia is a common cause of fatigue.
Some types of chemotherapy stop the bone marrow from making enough new red blood cells, causing anemia (too few red blood cells to carry oxygen to the body). Anemia affects the patient's energy level and quality of life. Anemia may be caused by the following:
- Cancer treatments.
- A medical condition not related to the cancer.
Nutrition needs change and cause or increase fatigue.
For many patients, the effects of cancer and cancer treatments make it hard to eat well. The body's energy comes from food. Fatigue may occur if the body does not take in enough food to give the body the energy it needs. In people with cancer, three major factors may affect nutrition:
- A change in the way the body uses food. A patient may eat the same amount as before having cancer, but the body may not be able to absorb and use all the nutrients from the food. This is caused by the cancer or its treatment.
- An increase in the amount of energy needed by the body because of a growing tumor, infection, fever, or shortness of breath.
- A decrease in the amount of food eaten because of low appetite, nausea, vomiting, diarrhea, or a blocked bowel.
Anxiety and depression are the most common psychological causes of fatigue in people with cancer.
The emotional stress of cancer can cause physical problems, including fatigue. It's common for you to have changes in moods and attitudes. You may feel anxiety and fear before and after a cancer diagnosis. These feelings may cause fatigue. The effect of the disease on your physical, mental, social, and financial well-being can increase emotional distress.
About 15% to 25% of people with cancer get depressed, which may increase fatigue caused by physical factors. Patients who have depression before starting treatment are more likely to have depression during and after treatment. The following are signs of depression:
- Lack of energy and mental alertness.
- Loss of interest in life.
- Problems thinking.
- Feeling a loss of hope.
Patients who have a history of stressful experiences in childhood, such as abuse and neglect, may have increased fatigue. See the PDQ summaries on Adjustment to Cancer: Anxiety and Distress and Depression for more information.
Fatigue and memory problems may be related.
During and after cancer treatment, you may find that you cannot pay attention for very long and have a hard time trying to think, remember, and understand. This is called attention fatigue. Sleep helps to relieve attention fatigue, but sleep may not be enough when the fatigue is related to cancer. Take part in restful activities and spend time outdoors to help relieve attention fatigue.
Not sleeping well causes fatigue.
Some people with cancer are not able to get enough sleep. The following problems related to sleep may cause fatigue:
- Waking up during the night.
- Going to sleep at different times every night.
- Sleeping during the day and less at night.
- Being inactive during the day.
- The time of day that cancer treatment is given.
Poor sleep affects people in different ways. For example, the time of day that fatigue is worse may be different. Some people with cancer who have trouble sleeping may feel more fatigue in the morning. Others may have severe fatigue in both the morning and the evening. People with cancer who are inactive during the day, have restless sleep, or who have obesity may have higher levels of fatigue.
Even in people with cancer who have poor sleep, fixing sleep problems does not always improve fatigue. A lack of sleep may not be the cause of the fatigue. See the PDQ summary on Sleep Disorders for more information.
Medicines other than chemotherapy may add to fatigue.
Patients may take medicines for pain or conditions other than the cancer that cause drowsiness. Opioids, antidepressants, and antihistamines have this side effect. If these medicines are taken at the same time, fatigue may be worse.
Taking opioids over time may lower the amount of sex hormones made in the testicles and ovaries. This can lead to fatigue as well as sexual problems and depression.
Assessment of Fatigue
A physical exam and health history will be taken to look for causes of fatigue that can be treated.
A physical exam will be done. This is an exam of the body to check general signs of health or anything that seems unusual. The doctor will check for problems such as trouble breathing or loss of muscle strength. Your walking, posture, and joint movements will be checked.
Blood tests to check for anemia will be done. The most common blood tests to check if the number of red blood cells is normal are:
- Complete blood count (CBC) with differential: A procedure in which a sample of blood is taken and checked for the following:
- The number of red blood cells and platelets.
- The number and type of white blood cells.
- The amount of hemoglobin (the protein that carries oxygen) in the red blood cells.
- The portion of the blood sample made up of red blood cells.
- Peripheral blood smear: A procedure in which a sample of blood is checked for the number and kinds of white blood cells, the number of platelets, and changes in the shape of blood cells.
- Other blood tests may be done to check for other conditions that affect red blood cells. These include a bone marrow aspiration and biopsy or a Coombs' test. Blood tests to check the levels of vitamin B12, iron, and erythropoietin may also be done.
The healthcare team will take a health history by asking about the status of your cancer and cancer treatments. It is important that you and your family tell the healthcare team if fatigue is a problem. You will be asked to describe the fatigue.
Other questions that you will be asked about include:
- The level of fatigue: You will be asked to rate the level of fatigue. The doctor may ask you to rate the fatigue on a scale from 0 to 10.
- When the fatigue started, how long it lasts, and what makes it better or worse.
- Symptoms or side effects, such as hot flashes, that you are having from the cancer or the treatments.
- Medicines being taken.
- Sleeping and resting habits.
- Eating habits and changes in appetite or weight.
- How the fatigue affects daily activities and lifestyle.
- How the fatigue affects being able to work.
- Whether you have depression, anxiety, or pain.
- Health habits and past illnesses and treatments.
Your healthcare team will continue to look for patterns of fatigue.
A fatigue assessment is repeated to see if there is a pattern for when fatigue starts or becomes worse. The same method of measuring fatigue is used at each assessment. This helps show changes in fatigue over time. The healthcare team will check for other causes of fatigue that can be treated. See the Causes of Cancer Fatigue section.
Treatment for Fatigue
Fatigue is often treated by relieving related conditions.
Treatment of fatigue depends on the symptoms and whether the cause of fatigue is known. When the cause of fatigue is not known, treatment is usually given to relieve symptoms and teach you ways to cope with fatigue.
Treatment of anemia
Anemia causes fatigue, so treating anemia when the cause of anemia is known, helps decrease fatigue. When the cause is not known, treatment for anemia is supportive care and may include the following:
Change in diet
Eat more foods rich in iron and vitamins combined with other treatments for anemia.
Transfusions of red blood cells
Transfusions work well to treat anemia. Even though problems from a transfusion are low, there are risks of an allergic reaction, infection, graft-versus-host disease, immune system changes, and too much iron in the blood.
Drugs called erythropoiesis-stimulating agents (ESAs) cause the bone marrow to make more red blood cells and may be used to treat anemia-related fatigue in terminal patients receiving chemotherapy. Since ESAs increase the risk of blood clots, few patients are offered this treatment. The Food and Drug Administration (FDA) has not approved these drugs for the treatment of fatigue. Discuss the risks and benefits of these drugs with your doctor.
Treatment of pain and depression
If pain is making fatigue worse, your pain medicine may need to be changed. If too much pain medicine is making fatigue worse, the dose may be decreased, or the medicine might be changed to a different one. Fatigue in patients who have depression may be treated with antidepressant drugs.
Certain drugs are being studied for cancer fatigue.
The following drugs are being studied for cancer fatigue:
- Psychostimulants are drugs that improve mood and help decrease fatigue and depression. Psychostimulant drugs may help some patients have more energy, a better mood, and help them think and concentrate. The use of psychostimulants for treating fatigue is still being studied. The FDA has not approved psychostimulants for the treatment of fatigue.
- Bupropion is an antidepressant that is being studied to treat fatigue in patients with or without depression.
- Steroids are being studied in patients with advanced cancer. Dexamethasone is a steroid that reduces inflammation, but has unwanted side effects. In one clinical trial, patients who received dexamethasone reported less fatigue than the group that received a placebo.
Talk to your doctor about the risks and benefits of these drugs.
Dietary supplements are being studied for cancer fatigue.
American ginseng in the form of capsules of ground ginger root may be used to treat fatigue. In a clinical trial, people with fatigue who were being treated for cancer or who had finished cancer treatment received either ginseng or a placebo. The group receiving ginseng had less fatigue than the placebo group.
Other dietary supplements, such as coenzyme Q10 and L-carnitine, are also being studied in clinical trials. No positive results have been published. See the PDQ summary on Coenzyme Q10 for more information.
Exercise has a positive effect on fatigue during and after cancer treatment.
Exercise (including walking) may help people with cancer feel better and have more energy during and after treatment. The effect of exercise on fatigue in people with cancer is being studied. One study reported that breast cancer survivors who took part in enjoyable physical activity had less fatigue and pain and were better able to take part in daily activities. In clinical trials, some people with cancer reported the following benefits from exercise:
- More physical energy.
- Better appetite.
- Better memory.
- More able to do the normal activities of daily living.
- Better quality of life.
- More enjoyment with life.
- A greater sense of well-being.
Moderate activity for 3 to 5 hours a week may help cancer fatigue. You are more likely to follow an exercise plan if you choose a type of exercise that you enjoy. Your healthcare team can help you plan the best time and place for exercise and how often to exercise. You may need to start with light activity for short periods of time and build up to more exercise little by little. Studies have shown that exercise can be safely done during and after cancer treatment.
Mind and body exercises such as qigong, tai chi, and yoga may help relieve fatigue. These exercises combine activities like movement, stretching, balance, and controlled breathing with spiritual activity such as meditation.
Cognitive behavior therapy
Cognitive behavior therapy (CBT) helps you change how you think and feel about certain things. Therapists use CBT and talk therapy to treat certain emotional or behavioral disorders. Talk therapy may help decrease your fatigue by working on problems related to cancer that make fatigue worse, such as:
- Stress from coping with cancer.
- Fear that the cancer may come back.
- Feeling hopeless about fatigue.
- Lack of social support.
- A pattern of sleep and activity that changes from day to day.
Studies have shown that talk therapy can help control fatigue over long periods of time. CBT with hypnosis may also help decrease fatigue.
Other ways to manage fatigue
You may feel that reporting fatigue is complaining and wait for your doctor to ask about it. Fatigue is a normal side effect that should be reported and treated.
Working with the healthcare team to learn about the following may help you cope with fatigue:
- Possible medical causes of fatigue such as an electrolyte imbalance, breathing problems, or anemia.
- Maintain a healthy diet.
- Learn how patterns of rest and activity affect fatigue.
- Learn to avoid or change activities that cause fatigue.
- Identify things that help decrease fatigue.
- Schedule important daily activities during times of less fatigue. Give up less important activities.
- Plan activities that help you feel more alert but take less energy, such as watching a sunset, walking in a park, or bird watching.
- Find exercise programs that you like.
- Ask if physical therapy is needed if you have nerve problems or muscle weakness.
- Ask if respiratory therapy is needed if you have trouble breathing.
- Learn to tell if treatments for fatigue are working.
- Become familiar with the difference between fatigue and depression.
These changes will help you cope with fatigue and improve your quality of life.
Current Clinical Trials
Use our clinical trial search to find NCI-supported cancer clinical trials that are accepting patients. You can search for trials based on the type of cancer, the age of the patient, and where the trials are being done. General information about clinical trials is also available.
To Learn More About Fatigue
For more information from the National Cancer Institute about fatigue, see the following:
- Fatigue and Cancer Treatment
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This PDQ cancer information summary has current information about the causes and treatment of fatigue. It is meant to inform and help patients, families, and caregivers. It does not give formal guidelines or recommendations for making decisions about health care.
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Last Revised: 2021-08-20
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