Your Brain After Chemo

Questions to ask your doctor about post-chemo brain.

By Dan Silverman, MD, PhD, and Idelle Davidson

You’re halfway through what will be six rounds of chemotherapy, and you begin to feel as though a fog has enveloped your mind. You grow forgetful. Making even the smallest decision seems overwhelming. Multitasking has become impossible—you’re lucky if you can complete any task at all. Getting behind the wheel has become anxiety producing. You’re disoriented, no longer sure which direction is home. You lose your keys, your glasses, your cell phone, and you realize with a panic that the kids are waiting for you at school. You haven’t a clue where you parked your car. You leave water running in the sink and food burning on the stove. You may have trouble retrieving words or adding numbers. You no longer read books because you can’t retain even a paragraph of information. You avoid social situations because you can’t follow the thread of a conversation. And you wonder, What is happening to me?

If any of these situations are familiar to you, it might provide some small comfort to know that what you’re experiencing is not a figment of your imagination. In fact, among lymphoma and breast cancer survivors, from whom researchers have gathered the most data, up to 80 percent of people who undergo chemotherapy report some amount of cognitive impairment.1 For some the condition that has come to be known as “post-chemo brain” is temporary, lifting upon completion of treatment. For others it may linger for a few months or even years.

Undoubtedly, you’re concerned. So talk to your oncologist and gather as much information as you can. Here are some questions and related background information you can use to get the conversation going.

Q. Is chemotherapy really responsible for my symptoms?
It’s not clear how much of the fog is due to chemotherapy and how much might be the result of other factors, such as depression, anesthesia, other medications, hormonal therapies or steroids, or even a genetic predisposition. Cytokines (regulatory molecules in the body that help the cells of our immune system talk to each other) may also play a role. Still, there’s enough scientific evidence on the topic now that it’s pretty clear that chemotherapy, with or without hormonal therapy, is at least partially responsible for what’s going on.

Q. Can tamoxifen (Nolvadex®) or other hormonal therapies (such as those called aromatase inhibitors) affect my brain even more?
In studies at UCLA and elsewhere, the breast cancer survivors found to be most cognitively impaired were those who had received a combination of chemotherapy plus tamoxifen.2,3 Many breast cancers are promoted by estrogens; tamoxifen works by blocking the uptake of hormones in breast cancer cells that contain estrogen receptors, thereby stopping cancer cell growth. But estrogen is also important to cognitive function, and without it we may experience fuzzy thinking. As for aromatase inhibitors, they prevent the body from creating estrogen in the first place, which explains why they may exacerbate cognitive problems.

Q. But this is my life—do I have choice in my treatment if it might affect my cognitive function?
One choice lies in knowing that all combination hormonal therapy/chemotherapy regimens may not be as effective as once thought. In 2005 the Lancet (one of the top medical journals in the world) reported an only 3 percent increase in survival for breast cancer patients who received chemotherapy plus tamoxifen compared with those who received only chemotherapy.4 With these statistics in mind, don’t hesitate to ask your oncologist about the risks versus the benefits for your particular treatment. Specifically, ask if, in addition to all the other possible side effects of tamoxifen (such as early menopause, blood clots, cancer of the uterine lining, stroke, and hair thinning), tamoxifen could result in cognitive impairment that might lead you to no longer be able to perform your job or care for your family or home.

Q. Will I know right away if I am experiencing post-chemo brain?
Maybe, but maybe not, depending on your lifestyle. Cognitive changes are generally subtle. It’s not as though your IQ suddenly drops from 120 to 80. If you are a high achiever who relies on your wits professionally or at home to take charge and multitask, you may notice substantial impairment. On the other hand, if you have few responsibilities in your daily life, you may notice very little change.

Q. Can chemotherapy—and post-chemo brain—lead to Alzheimer’s disease?
There is no evidence of a connection between chemotherapy and Alzheimer’s disease at this time. Chemotherapy does not appear to cause the same biochemical changes in the brain that are found in Alzheimer’s patients. On the other hand, for those who are in the early stages of Alzheimer’s and may not know it because they’ve had no symptoms, they may become symptomatic after undergoing chemotherapy. That’s because the front part of the brain—often affected after chemotherapy—loses its ability to compensate for damage to the back part of the brain, where we see the most pronounced loss of function in the early stages of Alzheimer’s disease. As a result, the symptoms of post-chemo brain can unmask the symptoms of Alzheimer’s disease.

Q. Is it possible to have my memory monitored throughout treatment?
Yes. If you are concerned about post-chemo brain, particularly if you are already experiencing cognitive difficulties, consider asking your doctor to refer you to a neuropsychologist for a baseline evaluation—a test of your current cognitive health—before starting treatment. Then request follow-up evaluations during and after treatment to check your thinking abilities across time. Neuropsychologists can provide valuable feedback and suggest coping strategies—or they can provide a referral to someone who may prescribe medication or brain imaging and other medical tests, if it appears you might benefit from them.

Q. What type of medications might be prescribed?
There are several medications that might be appropriate. Provigil® (modafinil) is a drug approved for narcolepsy that has been shown to be effective in clinical trials in improving alertness and concentration in people with post-chemo brain. Focalin® XR (dexmethylphenidate hydrochloride) and its close relative Ritalin® (methylphenidate), both commonly prescribed to treat attention-deficit/hyperactivity disorder, might also be recommended. Like Provigil, these drugs work by stimulating the central nervous system.

Q. Are there non-pharmaceutical strategies for improving cognitive function?
Yes. Strategies that include eating healthy “brain foods,” such as those rich in amino acids and omega-3 fatty acids, and engaging in activities that naturally combat fatigue and stress or those that stimulate attention and concentration—all are good options.

What’s in a Name?
While we often hear and read the terms chemo brain and chemo fog, especially in the news, in reality, these terms are simply not precise enough to reflect our current understanding of what is happening in the brain. Some medical experts conceptualize what’s happening as something like “cancer- and/or cancer-therapy-associated cognitive change.” We don’t expect to see this or similar phrases ingrained in the popular culture, or even in the professional jargon of doctors, anytime soon. In our own work, we use the term post-chemo brain (that is, after-chemo brain) because we just don’t know to what degree chemotherapy is the direct culprit behind these cognitive problems. In other words, this term enables us to focus our attention where it best belongs: understanding, preventing, and treating cognitive problems that become present after chemo—without requiring us to get sucked into the controversy of to what extent chemo caused those problems.

1. Silverman DHS, Castellon SA, Ganz PA. Cognitive dysfunction associated with chemotherapy for breast cancer. Future Neurology. 2007;2(3):271-77.
2. Silverman DH, Dy CJ, Castellon SA, et al. Altered frontocortical, cerebellar, and basal ganglia activity in adjuvant-treated breast cancer survivors 5-10 years after chemotherapy. Breast Cancer Research and Treatment. 2007;103(3):303-11.
3. van Dam FS, Schagen SB, Muller MJ, et al. Impairment of cognitive function in women receiving adjuvant treatment for high-risk breast cancer: high-dose versus standard-dose chemotherapy. Journal of the National Cancer Institute. 1998;90(3):210-18.
4. Early Breast Cancer Trialists’ Collaborative Group (EBCTCG). Effects of chemotherapy and hormonal therapy for early breast cancer on recurrence and 15-year survival: an overview of the randomised trials. Lancet. 2005;365(9472):1687-717.

Prescribed Reading
For more information about post-chemo brain and the proactive steps you can take to improve your cognitive function, check out Dr. Silverman’s and Idelle Davidson’s book, Your Brain After Chemo: A Practical Guide to Lifting the Fog and Getting Back Your Focus (Da Capo Lifelong Books, 2009; $25), available online at