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Fatigue in Children with Cancer

Fatigue is a common side effect of cancer and cancer treatments. Fatigue can make it hard to do normal tasks or activities. It can affect school, work, relationships, and emotional and physical health. For some cancer patients, fatigue continues even after treatment ends.

What is cancer-related fatigue?

Cancer-related fatigue is the feeling of low energy, tiredness, or exhaustion. Fatigue in cancer is different from everyday tiredness. It is usually ongoing and does not go away with sleep or rest.  


Fatigue can be one of the most distressing side effects of cancer and cancer treatments for patients and families. It is important to work closely with your care team to identify possible causes of fatigue and develop a plan to address them.

Child cancer patient sleeping with stuffed animal.

Cancer-related fatigue is the feeling of low energy, tiredness, or exhaustion that is ongoing, not explained by other causes, and not made better by rest.

Symptoms of fatigue in children with cancer

Signs and symptoms of fatigue can vary. Common fatigue symptoms in children include:

  • Feeling tired
  • Weakness
  • Low energy
  • Problems thinking or focusing on a task
  • Boredom, lack of motivation, or loss of interest
  • Irritability, crying, or fussiness
  • Being clingy or wanting attention
  • Increase in illness symptoms
  • Change in sleep or eating patterns

Seek medical care if your child has sudden or extreme changes in energy, mood, or alertness. These could indicate a serious medical problem that needs treatment.

Causes of fatigue in childhood cancer

Many factors can cause fatigue during and after childhood cancer. These include treatments, effects of the cancer itself, and other physical, behavioral, and emotional factors.

Chemotherapy and fatigue

Fatigue during chemotherapy can come and go. Fatigue is usually worst in the days after a chemo treatment when blood counts are lowest. Energy levels may gradually increase until the next treatment. Treatment with targeted therapy and immunotherapy can also cause fatigue.

Radiation therapy and fatigue

Patients who have radiation therapy also report fatigue. Fatigue with radiation often gets worse over time. It usually improves after treatment ends. Radiation to the brain is most likely to cause fatigue.

Other factors that can contribute to fatigue during cancer include:

  • Medications such as corticosteroids, pain medicines, and anti-nausea medicines
  • Low red blood cells (anemia)
  • Infection and illness
  • Heart, lung, or kidney problems
  • Hormone changes
  • Changes in the brain or nervous system
  • Pain
  • Stress, anxiety, or depression
  • Sleep problems
  • Low exposure to natural light
  • Low physical activity or poor physical fitness
  • Dehydration
  • Poor nutrition or not meeting calorie or nutrient needs

Ways to manage cancer-related fatigue

It can help to know that the “no energy” feeling is normal during cancer. It should get better.

Ways to manage cancer fatigue include:

  • Healthy sleep habits: Sleep problems are common during cancer, especially during a hospital stay. A regular sleep schedule, exposure to natural light in the morning, and a comfortable sleep environment can improve sleep and lessen fatigue.
  • Exercise and physical activity: Even small amounts of physical activity can help increase energy and reduce fatigue. Exercise also improves strength and fitness to make it easier to do daily tasks. Fatigue can make it hard to exercise. But even when it feels hard, it is important to try to exercise, a little at a time. An occupational therapist or physical therapist might be able to help.
  • Good nutrition: Weight loss and decreased muscle can lead to fatigue. It can be hard to get enough calories and fluids during cancer. This can affect the body’s ability to meet energy needs. Healthy eating habits and clinical nutrition support can help your child get the nutrients they need.
  • Psychotherapy: Mental health professionals can help with fatigue that is related to depression, anxiety, or stress. Talk therapy or counseling can provide strategies to cope with fatigue. For spiritual support, talk to a chaplain.
  • Light therapy: Exposure to natural light, especially in the morning, can encourage healthy sleep and help your child feel less tired. It is especially hard to get natural light during hospital stays. Bright light therapy uses a controlled light source at certain times to help regulate the body’s internal clock.
  • Complementary and supportive therapies: Therapies such as music therapy, art therapy, relaxation techniques, massage therapy, and aromatherapy may help with fatigue. Your child’s care team can help you find techniques that might be useful.

Cancer-related fatigue: Tips for families

  • Talk to your care team about your child’s fatigue.
  • Keep a record of symptoms. Write down when fatigue occurs, what makes it worse, what makes it better, and related factors such as pain, stress, or sleep problems.
  • Make sure your child keeps a consistent sleep schedule and daily routine.
  • Increase exposure to natural light during the day.
  • Plan physical activity as your child is able. Even a little bit of exercise can help.
  • Make sure your child takes time to rest and avoids getting overtired.
  • Make sure your child eats regular healthy meals and snacks and drinks enough fluids.

When to seek help for cancer-related fatigue

Fatigue with cancer treatment is normal and does not mean that the illness is getting worse or that treatment is not working. Still, you may want to seek help from your child’s care providers.

A first step in treating fatigue is to find out more about the problem and possible causes. This includes sharing details about when the fatigue started, how long it lasts, how it affects daily activities, and what makes it better or worse.

A medical history, physical exam, and lab tests help your care team find out about underlying causes. Information about sleep habits, physical activity, and eating habits can also be helpful.

Assessment of cancer-related fatigue may include:

  • Patient and family interview
  • Review of medicines
  • Medical history and physical exam
  • Blood tests
  • Sleep and activity diary

Questions to ask your care team

  • What factors might be causing my child’s fatigue?
  • What do I need to keep track of and report to the care team?
  • What should my child eat and drink to have more energy?
  • How much sleep and rest should my child get each day?
  • What type of exercise should my child get, and how much?
  • Are there medicines or treatments that can help with my child’s fatigue?

Key points about cancer-related fatigue

  • Cancer-related fatigue is a common side effect of cancer and cancer treatments.
  • Childhood cancer-related fatigue can be caused by many factors.
  • Healthy sleep habits, regular physical activity, good nutrition, and exposure to light can help reduce fatigue.
  • Your care team can help make a plan to cope with fatigue based on your child’s needs.

Find more information on fatigue

Reviewed: September 2023