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Chemobrain

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If you’ve been diagnosed with cancer and you’ve had trouble concentrating on a task, remembering words or directions, doing several things at once, or recalling a date or phone number, you may be experiencing cognitive changes after cancer treatment, often called “chemobrain.”

The medical term for chemobrain is “cancer-related cognitive impairment” (or CRCI). This term recognizes that diagnosed individuals who were not treated with chemotherapy may sometimes experience cognitive symptoms.   

Cancer-related cognitive impairment describes problems with thinking. This can include issues with short-term memory or word-finding. It may start after a cancer diagnosis or after cancer treatment. It’s normal to feel frustrated or worried about these symptoms.

Below, we’ll talk about what causes these cognitive issues, and ways to manage them.

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You are not alone

Even though you may have never heard of it, chemobrain, or cancer-related cognitive impairment, is real. Up to 75% of people with breast cancer who have chemotherapy report symptoms of chemobrain during active treatment.

Despite its name, the symptoms of chemobrain may not only be due to chemotherapy. They can be caused by other medicines used for breast cancer treatment (including hormonal therapies) or other experiences related to going through cancer treatment. People treated for other types of cancer may also develop chemobrain.

Chemobrain can be seen in people of all ages. Older people may be at more risk, but young people also have difficulty with symptoms.

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What causes chemobrain?

The reasons for cancer-related cognitive impairment (chemobrain) are under study, but there are several potential contributing factors:

  • Chemotherapy, radiation therapy, and other cancer treatments may set off chemical reactions (such as inflammation) that can affect your cognition, similar to how you may feel when you have the flu.
  • Some chemotherapy medicines may cross the blood-brain barrier. That means some chemotherapy may pass into the brain and affect its functioning.
  • People taking hormonal therapies, such as tamoxifen and aromatase inhibitors, may also report some chemobrain symptoms. This is due to lowered estrogen levels, which can have an impact on brain function.

Besides cancer treatment itself, other factors related to the entire cancer experience may contribute to some chemobrain symptoms. These may include:

  • Poor sleep
  • Fatigue related to treatment
  • Chronic stress or chronic loneliness
  • Under-treatment or over-treatment of pain
  • Depression and anxiety
  • Lack of exercise or activity
  • Poor nutrition
  • Side effects of medicines for other conditions, including some nausea and sleep medicines
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How long does chemobrain last?

Everyone’s experience of cancer-related cognitive impairment is different. Most people stop having these symptoms 6 to 9 months after completing cancer treatment. Still, about 25% of women continue to struggle with chemobrain. Some may have symptoms that last for years.

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How can I manage chemobrain?

There are many practical ways you can address chemobrain. Talk with your doctor and healthcare team. It may help to keep a record of symptoms and when they occur. Bring the information to your next appointment with your care team and let them know what you’re experiencing. They might suggest a change in medicine to avoid side effects, or another approach.

These tips may also help you function better:

  • Get enough sleep. Try to get 7 to 9 hours of sleep at night. If you are having a hard time sleeping, ask your doctor if you would be a good candidate for cognitive behavioral therapy for insomnia (CBT-I). CBT-I helps people develop new habits that support sleep. It has been proven to improve sleep for people diagnosed with cancer
  • Try to get outside in the daytime. Getting some natural light daily can help regulate your natural biological clock.   
  • Increase your activity. Exercise seems to help many people with cognitive symptoms. Aim for moderate exercise, meaning you are still able to talk while exercising. Moderate exercise includes walking, with a goal of 150 minutes per week. Even a short walk around the block with a friend or a pet can help. Other exercises, such as yoga or tai chi, can be especially helpful for managing distress.
  • If you’re feeling stressed, try some stress management strategies. Use music or a calming activity, such as knitting or reading. Consider meditation and other stress-reducing techniques, such as mindfulness-based stress reduction. Cognitive problems are often magnified when we are under severe stress.
  • If you feel depressed or anxious, talk with your doctor. Treating depression often helps with cognition. A referral to an oncology social worker or mental health professional may help.
  • Improve your nutrition. Consider decreasing processed and sugary foods in favor of whole foods that have fruits, vegetables, and healthy fats and protein. Some experts feel that a Mediterranean diet—which includes plant-based foods, whole grains, nuts, fish, and poultrymight be helpful for cognitive health. Ask your care team to refer you to a nutritionist who can recommend supportive dietary changes. You can also read our Tips for healthy eating.
  • Use lists, calendars, and planners to help you focus and remember important details.
  • Organize your living and work spaces. Choose specific places to store items, such as keys or remotes, and always return them to the same spots.
  • Socialize. Feelings of chronic loneliness and isolation may put some at greater risk for cognitive problems. Interact with others in ways you enjoy.

Here are some specific tips to help you improve your focus:

  • Try to do one thing at a time. We often multitask, but sometimes it helps to focus on one issue at a time. Text messages, phone calls, and email alerts may seem like they don’t have much of an impact, but they often interrupt deep thinking.
  • Follow a routine. Having a pattern can help you focus.
  • Choose quiet places with limited distractions to read, study, or have an important conversation.
  • Alternate difficult tasks with easier and enjoyable tasks. Use your best times of day (often the morning) for your most challenging tasks.   

If chemobrain feels very intrusive and your doctor doesn’t offer much help, ask to be referred to a speech therapist or a neuropsychologist, a psychologist with special training in the connections between the brain and behavior.

In some situations, your doctor may recommend certain medicines, such as methylphenidate (Ritalin) or modafinil (Provigil), to help improve your concentration.

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Reviewed and updated: October 21, 2025

Reviewed by: Arash Asher, MD

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Living Beyond Breast Cancer is a national nonprofit organization that seeks to create a world that understands there is more than one way to have breast cancer. To fulfill its mission of providing trusted information and a community of support to those impacted by the disease, Living Beyond Breast Cancer offers on-demand emotional, practical, and evidence-based content. For over 30 years, the organization has remained committed to creating a culture of acceptance — where sharing the diversity of the lived experience of breast cancer fosters self-advocacy and hope. For more information, learn more about our programs and services.