Cognitive changes (chemo brain)
Some people notice trouble with memory, focus, or finding words during or after treatment. This is often called chemo brain, and it is real.
Why it happens
Chemotherapy, hormone therapy, radiation to the brain, and CAR T-cell therapy can affect thinking. Fatigue, poor sleep, anemia, stress, and some medicines can make it worse.
What helps
- Use a planner, calendar, or phone reminders.
- Do one thing at a time, and do hard tasks when you feel sharpest.
- Keep things like keys and glasses in the same place.
- Get regular sleep and physical activity.
- Ask for written instructions at visits, or bring someone to take notes.
- Ask about a referral to a speech therapist or neuropsychologist for memory training.
Call your care team right away if you have
- You have sudden confusion, trouble speaking, or trouble staying awake.
- You have new weakness, a bad headache, or seizures.
- Memory problems are making it unsafe for you to manage medicines or drive.
Questions to ask
- Could any of my medicines, sleep, or mood be affecting my thinking?
- Is there a program or therapist who can help with memory and focus?
- Will this get better after treatment ends?
Medicines that can cause this
Sources
Quick answers
- What is cognitive changes during cancer treatment?
- Some people notice trouble with memory, focus, or finding words during or after treatment. This is often called chemo brain, and it is real.
- Why does cognitive changes happen?
- Chemotherapy, hormone therapy, radiation to the brain, and CAR T-cell therapy can affect thinking. Fatigue, poor sleep, anemia, stress, and some medicines can make it worse.
- What helps with cognitive changes?
- Use a planner, calendar, or phone reminders; Do one thing at a time, and do hard tasks when you feel sharpest; Keep things like keys and glasses in the same place; Get regular sleep and physical activity; Ask for written instructions at visits, or bring someone to take notes; Ask about a referral to a speech therapist or neuropsychologist for memory training.
- When should I call my care team about cognitive changes?
- You have sudden confusion, trouble speaking, or trouble staying awake; You have new weakness, a bad headache, or seizures; Memory problems are making it unsafe for you to manage medicines or drive.
Last updated: 2026-10-27. Medically reviewed by Veli Bakalov, MD, medical oncologist (October 2026). General education from Step by Step, the patient portal of HemeOncBuddy.