Chemo Brain, Is It Real or Is It Myth?

 Joanne P. Shelby-Klein BSN RN

Fuzzy-headed, forgetful, mental fogginess, cancer patients who have received chemotherapy have talked and joked about this weird feeling for many years. Cancer Related Cognitive Dysfunction (CRCD) is the official name given to this collection of symptoms that is more commonly known as Chemo Brain.

How common of a problem is Chemo Brain for cancer patients?

According to an article in Neurology now, chemo brain affects up to 75% of cancer patients at some point in their cancer journey. However doctors have only recently begun to recognize it as an actual medical complication from cancer treatments and have started to study chemo brain, its causes and effects. Why has it taken so long for doctors to begin research in this area of cancer? One primary reason is the fact that it is very difficult to study and very difficult to separate from other symptoms such as anxiety and depression. Another reason is patients and doctors are often reluctant to talk about the memory and thinking changes that have occurred.

How often does chemo brain occur?

We're here to help you deal with Chemo brain
We’re here to help you deal with Chemo brain

The National Health and Nutritional Exam Survey (NHANES) examined 1300 patients with cancer and 8500 without. There were an equal number of men and women involved in the study. They found that 14% of people with a history of cancer reported memory problems, while only 8% of patients without a history of cancer reported memory issues. This is considered a 40% for patients with history of cancer according to this study. Further studies conducted on breast cancer patients showed that memory issue risk ranged from 17 to 75%. NHANES and the breast cancer studies also showed that people age 55 and older also have a greater risk for cognitive issues. These studies do indicate that the risk of Cognitive dysfunction or chemo brain associated with a history of cancer is increased and is a national problem.

Now that we know it is a real problem, what exactly is chemo brain?

Chemo brain has been described as a mental fog that includes a series of symptoms that doesn’t go away or last a long time including:

  • Memory lapses or forgetting things they would normally remember.
  • Lack of focus on tasks, lose track of what they are doing
  • Short attention span and become easily distracted. Sometimes spacing out.
  • Trouble remembering dates, names and important large details
  • Unable to do more than one thing at a time. Example, can’t talk on the phone and prepare a meal at the same time.
  • Disorganized, can’t find things or process steps
  • Trouble finding right words to use or unable to finish a sentence.

Chemo brain affects patients in different ways.

For some patients it is a very minor inconvenience in their life, hardly noticeable to others and goes away after a short period of time. For others, it is a long term issue that is very noticeable and affects their lives in many ways. It can be very scary to not remember to turn off lights or forget appointments and to realize that your brain is not working like it used to. It becomes more frustrating when the members of the treatment team do not take the memory problems seriously and discuss what is going on.

What causes chemo brain?

What causes Chemo brain? What can I do?
What causes Chemo brain? What can I do?

Figuring out what causes chemo brain is difficult. There have been a few small animal, laboratory and human studies done that looks at the brain for changes on imaging scans. Brain imaging studies such as MRI’s, PET scans and CT scans have shown evidence that changes in select sections of the brain do occur with chemotherapy, possibly causing chemo brain. These changes occur in the white matter regions of the brain, the regions that work with learning, functioning, processing and cognition. For example; a study at West Virginia University used PET/CT testing to show the brain using energy. The regions of the brain that were affected by chemotherapy, such as the section that controls long-term memory, appeared to use less energy than the areas that were not affected by chemotherapy. Other areas of the brain impacted included mental agility, decision making, problem solving and prioritizing tasks. The changes seen on the PET/CT correlated to the symptoms the patients reported.

How long do the symptoms and changes persist?

That is very difficult to say. One study looked at 42 women with breast cancer. 65% of these women had a decrease in memory and thinking either while on chemotherapy or just after. At a follow up 8 months after their last chemotherapy treatment 61% continued to have a decline in thinking and memory. In fact nearly 1/3 of the patients followed reported new issues with the thinking process. Even 20 years after chemotherapy was completed, some patients still had issues and decreased brain volumes on imaging. In still other patients, their brain volumes and thinking abilities returned to normal after one year. This may be because the brain may have the ability to rewire itself even as it ages, although scientists don’t really know at this point.

Can clinicians predict who will get chemo brain?

It is very difficult question to answer. Researchers can predict the changes in thinking and memory with brain tumors and their treatments; however for all other cancers there is no reliable way to predict chemo brain. One theory is that certain chemotherapy agents can cross from the blood stream into the brain through what is called the blood brain barrier and destroy brain cells. This is plausible, especially with older therapeutic agents. Keep in mind that studies need to be conducted in all these areas.  Other theories include:

  • Hormonal changes, especially in breast cancer patients.
  • Menopause in women
  • Immune system malfunction
  • Mini- strokes
  • Genetic stamp in people who are at risk for Alzheimer’s.
  • Past medical history of head injuries or traumatic brain injuries
  • Depression and anxiety as well as stress
  • Fatigue
  • Side effects from medications used to treat other cancer related symptoms
  • Learning disabilities.
  • Other medical problems that are present in addition to cancer
  • An impact from surgeries and anesthesia.
  • Low blood counts
  • Nutritional deficiencies

Can chemo brain have an impact on a patients life?

The answer is yes, it can. A study conducted in conjunction with the Mayo Clinic in Minnesota and UCLA looked at 74 white and African American breast cancer survivors whoreported that 70% listed some form of thinking or mental impairment as a debilitating hidden effect from cancer. They described chemo brain as limiting their ability to think, concentrate on tasks and learn new material. These limitations left these women feeling scared, dependent on others physically and emotionally, and most importantly frustrated. When the study patients talked about this with their healthcare team, they felt that there was little to no recognition that these symptoms were real and when they were acknowledged, they were offered no advice on how to cope with the symptoms. Many respondents expressed a need for future research in this area.

Patients who are working may find that chemo brain can affect performance on the job. Many patients reported that it took them longer and was more difficult to perform routine job duties. This decreased efficiency while at work lead to patients having fewer opportunities for promotions and even losing job projects. Patients reported the memory problems lead to increased stress and frustration especially when job hunting and interviewing.

This study also looked at how patients coped with chemo brain and their ideas are listed below.

  • Keeping a journal to write down everything they needed to do for each project.
  • Using a calendar to write down each task needed to complete in a day. Some found that electronic calendars with alarm reminders worked.
  • The most common method reported in the study was Post-it notes placed everywhere, in every room as reminders of what needed to be done.
  • Keeping keys and other important items in specific places.
  • Keeping their minds active by using work books, word search books, Sudoku and other memory games.
  • Cutting back on work and social activities, rather than put themselves in a situation where their memory might be tested.
  • Some patients have just accepted the limitations that chemo brain brings.

The American Cancer Society also has compiled a list of coping strategies some of which are the same as above:

  • Use a detailed planner on a smart phone or electronic device, preferably one that will alarm when a task or appointment is due.
  • Make to do lists every day, even for the simple routine tasks.
  • Make an effort to exercise the brain by doing puzzles, reading, learning something new, even taking a class.
  • Make sure to get enough rest and sleep, preferably 6-8 hours per night.
  • Do some form of regular physical activity or exercise. Make sure the body moves periodically. This helps circulate oxygen through your body, especially the brain, and helps with feelings of fatigue.
  • Make sure to eat a healthy diet, especially one with lots of veggies. Some studies have shown that eating more veggies as you age helps maintain healthy brain power.
  • Establish and follow a daily routine, including a specific place for car keys, portable phones and any important items.
  • Focus on one task or item at a time. Multi-tasking can cause stress and forgetfulness. If something comes up that needs to be done right away, write it down and complete it after finishing the current task.
  • Don’t be afraid to ask for help. Family and friends may be able to help with routine tasks so that you have time to focus on more important items.
  • Don’t be afraid to tell people about the symptoms you are having and how they can help.
  • Talk to your doctor and healthcare team about what you are experiencing. Write down a list of questions for the team. Some patients find it helpful to write a memory log and take it with them to appointments.
  • Carry a list of all medications you take, both prescription and over the counter, rather than rely on your memory to recall the names, especially under times of stress.
  • Take a notepad and pen with you to all doctor visits and write down what is said during the visit. If possible take someone with you to act as a second pair of ears to hear what is being discussed. If you are not sure what has been discussed at the visit, call the office for clarification. When in doubt, ask.

Here are a few expert tested tips from the Cancer and Careers Website:

  • Know your stress level and develop a strategy to keep the stress to a minimum. If you can identify the source of your stress such as loud noises, co-workers chattering, etc, you can work to minimize it.
  • Take a few, slow deep breaths when you begin to feel stressed or tense. Close your eyes and concentrate on breathing and stretch your muscles.
  • Keep your work area cleared except for the task you are working on. Set your emails and voicemail to auto reply and only check it at set times during the day.
  • Rehearse any speeches and presentations. Keep a note card with any routine information you need to give out. Use it as a script to help you stay in focus.

A very important question: can chemo brain be prevented?

Right now there is no known way to prevent chemo brain. However, researchers are continuing to study this important, yet often forgotten issue. They are looking into what chemotherapeutic agents are linked to chemo brain and also into what medications can help protect the brain. Studies are also being planned and conducted to look at the relationship between other cancer side effects including anemia, fatigue and genetics and the mysterious reality known as chemo brain.


  1. Liano, C. Chang, L MD. (2012, November). Chemo brain, real and not Patient Imagined. Retrieved from:
  3. Gordon, D ( 2014, April/May)  Chemo brain: cognitive problems after cancer treatment are not imaginary.  Neurology now. Volume 10 issue 2 p 20-27. Retrieved from:
  4. Susman, EC , Carinci, A MD. Accessed 2015, May). All Cancer Therapies May Impair Memory. Retrieved from:
  5. Boykoff,N , Moeini, M , Subramanien, SK.  (2009, September) Confronting Chemo Brain: An In-depth Look at Survivors Reports of Impact on Work, Social Networks and Healthcare Response.  Journal of Cancer Survivorship Volume 3: Issue 4, pp223-232. Retrieved from: