Skip to Main Content

Welcome to

Together is a new resource for anyone affected by pediatric cancer - patients and their parents, family members, and friends.

Learn More

Cognitive Effects of Childhood Cancer and Stem Cell Transplant

What are cognitive effects?

Some treatments for childhood cancer increase the risk for problems in how a person thinks, learns, plans, and solves problems. These problems can last for many years. These are known as cognitive late effects.

Cognitive effects may appear months or years after treatment.

What does cognitive mean?

Cognitive refers to all forms of knowing and awareness such as remembering, reasoning, judging, imagining, and problem solving.

Source: American Pyschological Association

Childhood cancer survivor participates in a neuropsychological assessment with a psychologist. He is leaning over a table trying to balance a wooden block onto a dowel.

Assessments help the care team gather information about how children use their brains. This is called cognitive function.

These effects in childhood cancer survivors often relate to problems in memory or executive function. This set of skills includes self-control, working memory, and mental flexibility. Executive function refers to the ability to plan, remember, pay attention, and do several things at once.

Someone with cognitive effects may have a harder time:

  • Remembering or memorizing things
  • Learning (including spelling, reading, vocabulary, handwriting, and/or math)
  • Thinking (including concentrating, completing work on time, and doing work that involves multiple steps)
  • Problem solving
  • Planning and organizing
  • Focusing and paying attention
  • Responding or thinking quickly

For most childhood cancer survivors, cognitive problems are not due to a loss of skills. Problems are more often caused by a slower rate of new skill development. Children still learn and develop new skills. But they may do so at a slower rate than their peers.


Cognitive effects may be mild to severe. They may be temporary or permanent.

Risk factors for cognitive late effects

Cognitive effects are more likely to happen in children who have had brain tumors, head and neck cancers, and some types of leukemia, including acute lymphoblastic leukemia.

Risk factors for cognitive effects include:

  • Radiation to the head, neck, or upper spine, or total body. Total body radiation therapy (TBI) is sometimes used to prepare patients for stem cell (bone marrow) transplant.
  • Certain chemotherapy medicines, especially high-dose intravenous (IV) methotrexate, cytarabine, and/or intrathecal chemotherapy
  • Brain surgery
  • Corticosteroid medicines

Chemo brain and cognitive side effects

Some childhood cancer patients have changes in thinking, attention, or memory during treatment. This is called chemo brain fog. It is also known as chemo brain or chemo fog.

Read more about chemo brain fog.

Other risk factors include:

  • Younger age at treatment
  • Amount and length of treatment
  • Complications such as stroke, hydrocephalus, infection, or seizures
  • Chronic health conditions including heart, lung, or endocrine disease

Females who have cranial radiation (radiation to the skull) are at higher risk for cognitive effects than males when treated at a younger age.

Some treatments can interfere with the development of the brain’s frontal lobe. The frontal lobe controls motor and higher-order thinking skills.

Cancer treatments may also:

  • Affect brain regions such as the hippocampus. The hippocampus is where memories form.
  • Cause swelling and damage to cells and blood vessels. These things can lead to conditions such as bleeding and strokes.
  • Cause problems with hearing and/or vision.
  • Lead to missed school and emotional or social issues.

Heart disease and lung problems can contribute to cognitive problems.

Assessment of brain function

Your child may have a neuropsychological assessment to look at brain functions and skills such as:

  • Reading and math
  • Attention and concentration
  • Processing speed
  • Learning and memory
  • Organization, planning, and problem solving
  • Language
  • Visual-spatial skills
  • Motor skills
  • Behavioral, emotional, and social function

Tests of intelligence and academic achievement are also important. Parent and teacher observations help find strengths and weaknesses.

How cognitive problems affect school and daily life

Cognitive problems may result in:

  • Lower function than expected for age and developmental stage
  • Behavioral or social problems, particularly in group settings where quick response or decision making is needed

Children with cognitive problems are more likely to have problems in school. As adults they may also have challenges with employment, independent living, and social skills.

Problems may become more obvious during school transitions. As children mature, they are expected to become more independent. For children with cognitive problems, the demands are harder to manage. Peers may progress at a faster rate.

Cognitive problems can have a negative effect on social and emotional skills as well as overall quality of life.

What you can do to manage cognitive problems

Education programs and supportive care are available. Ask your health care provider about resources.

Early intervention and paying close attention to symptoms can help.

Healthy habits can also help improve and protect brain health.

Taking control of brain health

Patients and families can take steps to promote brain health.

  • Know your risk. Talk to your care provider about the risk of cognitive late effects.
  • Watch for signs of cognitive problems. Problems may develop at any time. Some of the early signs are slow thinking and responses.
  • Have regular checkups. Regular assessments can help catch problems early. 
  • Ask for help. Psychologists and education specialists can offer strategies to deal with cognitive late effects. Job and life skills training may help. Marriage and family counseling can help with relationship challenges.
  • Practice good health habits. Many habits that are good for physical health are good for brain health. Be active, get enough sleep, stay connected, control stress, and eat healthy meals.

Questions to ask about cognitive effects

  • Am I at risk for cognitive effects?
  • Whom do I call if I have symptoms?
  • What long-term health issues can I expect as a result of my cancer and treatment?
  • What can I do to stay healthy?
  • Which providers should I see for follow-up care?
  • What records do I need to keep about my treatment?

Key points about cognitive effects

  • Some treatments for childhood cancer increase the risk for cognitive effects, or problems in how you think, learn, plan, and problem-solve.
  • Risk factors for cognitive effects include radiation to the head and spine, certain medicines, and brain surgery.
  • Treatments include medicines, cognitive-behavioral therapy, mental exercises, social engagement, and healthy habits.
  • Cognitive effects may or may not be permanent. They may be mild to severe.
  • There are resources to help you deal with cognitive problems.

For more information

Reviewed: August 2023