Can You Fix Your Foggy Brain After Cancer Treatment?

Can You Fix Your Foggy Brain After Cancer Treatment?

How Cognitive Issues Can Affect Cancer Survivors, and What You Can Do About It

by Sean Smith, MD and Nicolette Gabel, PhD, ABPP

Most people know about the infamous physical side effects of cancer treatment – hair loss, nausea, even radiation burns and chemo-induced neuropathy. However, there’s another cancer side effect that isn’t as visible, but is just as distressing. 

As cancer survivors are figuring out a “new normal” after treatment, many begin to experience trouble thinking, short-term memory loss, and lack of focus. This collection of symptoms goes by many names – some call it chemo brain, while physicians and researchers refer to it as cancer-related cognitive impairment. But, no matter what you name it, the result is the same: a lower quality of life for cancer survivors and trouble resuming social activities, work, and other pursuits that were simply easier before cancer. 

While chemotherapy is often blamed, studies have shown that both radiation therapy and endocrine therapy may cause a reduction in cognition.

The impact of cognitive issues following cancer treatment is staggering. About 75 percent of cancer survivors report a decline in their cognitive function during and shortly after cancer treatment. The good news is that for most survivors these problems are temporary and resolve once treatment ends. But for over a third of survivors, these problems may persist for months, and even years, after completing therapy. Fortunately, with growing attention to this critical issue, healthcare providers and cancer survivors are gaining a better understanding of cancer-related cognitive impairment and what can be done to reduce its symptoms.

What is cancer-related cognitive impairment? 

Cancer-related cognitive impairment, or CRCI, is a catchall phrase for the feeling of not being able to think clearly after cancer treatment. While chemotherapy is often blamed, studies have shown that both radiation therapy and endocrine therapy (such as aromatase inhibitors and androgen deprivation therapy) may cause a reduction in cognition. There is even some evidence that cancer itself has a negative impact on brain functioning, as some people show cognitive declines even before starting chemotherapy and other treatments. 

Cognitive deficits faced by cancer survivors may range from mild to severe, and include trouble concentrating, poor memory, impaired executive functioning (which comprises goal-setting, planning, and multitasking), difficulty recalling words, and other mental difficulties. The exact cause of cognitive impairments is not well known, but researchers believe it may be related to inflammation, treatment-induced toxicity to brain cells, and accelerated aging. 

Some people may be predisposed to these issues due to genetic factors. It’s likely that non-cancer factors – like sleep, diet, stress, and exercise – also play a significant role in how much a person is affected. Many survivors with CRCI express concern that the problem will worsen over time, as with dementia. But it is important to know that cancer-related cognitive impairment does not typically get worse over time. For many, it improves. And for others, it remains stable. 

LIKE THIS ARTICLE? CHECK OUT:  It’s NOT ALL in Your Head

How is CRCI diagnosed? 

Diagnosing cancer-related cognitive impairment is difficult. Brain scans, like an MRI, cannot diagnose changes from chemotherapy. Psychological tests can give us some information, but these can be time consuming (sometimes taking up to six hours!) and may not detect issues that are subtle. These tests are often most useful for more severe cognitive issues – think head trauma, stroke, or dementia – or when a person has had previous testing that can be compared with their new scores (which most people haven’t). 

Additionally, CRCI symptoms may fluctuate throughout the day, making them difficult to detect even with exhaustive testing. Fortunately, research is being conducted to improve tests for cancer-related cognitive impairment. Until then, providers typically rely on cancer survivors’ self-reported symptoms to guide treatment planning. 

6 Things You Can Do Today to Improve Your Memory and Focus

1. Take notes in a notebook you can carry with you, or on your smart device.
2. Set alarms on your phone to remind you to do things you need to do later.
3. Reduce distractions and set up a quiet space where you can do paperwork and other activities that require focus.

4. Take regular breaks, at least once per hour, to “recharge” your brain.
5. Do tasks that require a lot of thinking during times of the day when you have the most energy.
6. Treat yourself with kindness, the way you would treat a friend who is struggling. Don’t beat yourself up if you make mistakes.

To further complicate matters, many factors in a cancer survivor’s life can make symptoms of cognitive impairment worse. And, sometimes, these other factors may actually be the main cause of a person’s cognitive problems (not cancer treatment). Often, cancer survivors experience “symptom clusters,” which is a group of symptoms that occur together and can amplify each other. Therefore, it is necessary to thoroughly review your sleep patterns, stress levels, symptoms of depression and anxiety, physical activity levels, and certain laboratory markers to evaluate for anemia and other issues before treating any suspected cancer-related cognitive impairment.

What can you do to improve cognitive function? 

Since each person’s symptoms and cancer treatment history are unique, there is no single method for managing cancer-related cognitive impairment. But there are broad approaches that have been shown to be helpful for most people: 

  • Think about whether your symptoms are worse when you are stressed or anxious. If so, talk to your doctor about ways to manage your stress and anxiety. 
  • Try to get some moderate or vigorous exercise at least three days a week. 
  • Keep a regular sleep schedule. Aim for seven to nine hours per night, and try to go to bed and wake up at the same time every day. If you are having trouble falling asleep or staying asleep, discuss this with your doctor. 
  • Eat a balanced diet. 
  • Try strategies that can help improve attention and memory. (See sidebar “6 Things You Can Do Today to Improve Your Memory and Focus” for tips.) 
LIKE THIS ARTICLE? CHECK OUT:  Wayne Osmond

How to get help 

In addition to working with your primary care physician and your oncologist, you may also want to meet with healthcare providers who specialize in treating cognitive problems. These can include rehabilitation physicians, neuropsychologists, speech-language pathologists, and other specialists. They may be able to offer you more personalized treatment options. 

Depending on your symptoms, a multidisciplinary team may be the key to helping you achieve your goals and improve your cognitive function. While treatment is not always quick, and may not completely relieve your symptoms, being proactive with seeking care and working with a team dedicated to whole-person healthcare can improve your quality of life. 


Dr. Sean Smith is the director of Cancer Rehabilitation and an associate professor in the Department of Physical Medicine & Rehabilitation at the University of Michigan Health System in Ann Arbor, MI.

Dr. Nicolette Gabel is the director of the Division of Rehabilitation Psychology & Neuropsychology and an associate professor in the Department of Physical Medicine & Rehabilitation, also at the University of Michigan Health. 

This article was published in Coping® with Cancer magazine, July/August 2021.

.