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‘Chemo brain’ frustrating for cancer patients


I was recently speaking with a patient who had completed her treatment for breast cancer several months ago.

Her treatment included a course of adjuvant chemotherapy—preventive chemotherapy, given after surgery to decrease the chances that the cancer will return—followed by radiation.

She had then returned to her work, a high-pressure managerial job overseeing a large team of workers. And she was having trouble coping. Where previously she had been confident and in charge, she now felt unsure, forgetful and confused by simple problems.

While many patients do not experience such difficulties, this was not the first time that I had heard such  a story. More and more patients like her today are survivors, and a growing number are experiencing cognitive problems. Their memory might not seem as sharp as it had been, or they are more easily overwhelmed when trying to multitask.

One of the ironies of medicine is that as we are more successful, and as patients live longer, they begin to show more side effects from our treatments. Over the past 10 or 15 years, patients have been using the term “chemo brain” to describe their problems with memory, concentration and attention, believing their symptoms were a result of the chemotherapy used to treat their cancer.

Early on, doctors weren’t sure what to make of this and tended not to take their complaints that seriously. There were so many other factors that could cause the same symptoms and confuse the situation.

In addition, most chemotherapy drugs do not penetrate easily into the brain, so it seemed unlikely that it was the  chemotherapy that was responsible. Some doctors tended to dismiss their patients’ symptoms as emotional.

One of the most important lessons I learned as a medical student was simply to listen carefully to my patients. The patients’ own stories will tell you most of what you need to know to make a diagnosis. I was also taught by a very wise professor that if I ever made a diagnosis of hysteria, I had probably overlooked something. I think these lessons helped me better understand my patients.

A lot a factors can contribute to cognitive impairment. The awareness of the diagnosis of cancer generates anxiety, which can easily affect how clearly we think. The biological effect of the cancer may also be a factor. Illness and chemotherapy treatments can change levels of hormones such as estrogen, which in turn will change mental functioning.

It is difficult to sort all this out and determine how important each of these factors is.


From the patient’s point of view, none of this seems to matter. It has been suggested that the term “chemo brain” be replaced by “cancer brain,” because whether it is the chemotherapy, the cancer or the stress, patients are still left in the same place, trying to deal with their lives with cognitive and coping skills that seem diminished.

Study of these patients is difficult because we do not have a pre-illness baseline for each patient. Without knowing what a patient’s level of mental function was before the diagnosis, it is difficult to determine how much it has been changed by the experience.

When given a psychological test after diagnosis or treatment, a given patient might test as normal—when in fact she had been above normal before her treatment. Such a test cannot tell us how much her performance has changed.

There have, however, been a number of recent studies that have demonstrated measurable impairment in psychological tests, combined with changes on MRI brain scans.

One done at Stanford University studied three groups of women: women with breast cancer who received chemotherapy; women with breast cancer who did not receive chemotherapy; and women without cancer.

Women with breast cancer, regardless of chemotherapy, showed changes on the MRI that correlated with poor test performance. However, the women who had received chemotherapy showed the most impairment.

A similar study was reported in the Journal of Clinical Oncology earlier this year. Again, three groups were studied. These results were a bit different, in that the control group and non-chemotherapy cancer patients did not show any changes, while the chemotherapy group showed measurable changes on test performance and on MRI.

Such research supports the conclusion that breast cancer patients receiving chemotherapy can have objective evidence of brain injury and cognitive impairment.

While cognitive impairment is a potential side effect of chemotherapy, it should not discourage patients from getting the treatment they need. This is another case in which the benefits of chemotherapy far outweigh the risks.

Adjuvant chemotherapy for breast cancer is largely responsible for the continuing decline in breast cancer deaths over the past 20 years.


Identifying and acknowledging cognitive impairment is important, but more important to patients is the development of interventions that will help them cope more effectively with the consequences of their treatment.

Over time, we may be better able to identify patients who are at increased risk. We may be able to identify which drugs are more likely to cause cognitive problems and avoid them whenever possible.

Training strategies are being developed—mental gymnastics, if you will—to help patients keep their memory and concentration “in shape” during treatment. Patients are taught coping strategies to minimize stress and better organize their days to avoid becoming overwhelmed.

Early studies indicate that these interventions improve both test results and patients’ self-perception of their mental functioning and well-being.

As more patients are being cured, and as more are living longer, we have to make every effort to keep the collateral damage of our treatments, including cognitive impairment, to a minimum.

Dr. Frederick C. Tucker Jr. of Fredericksburg Oncology is board-certified in oncology, psychiatry and internal medicine. You can send him questions or comments about his column to