“Chemo Brain”: Fact or Fiction?

Over the years patients have been informing their doctors that they experience “chemo brain”.  We now have scientific proof that this is a real entity and hopefully this study will encourage further research into prevention and or treatment of this very real phenomenon. This was a difficult area to address as there are so many other conditions that affect cognition during the cancer experience.  Many of the drugs that are prescribed for nausea, pain control and depression can also impact on short term memory. Narcotics affect many cognitive functions and sometimes an adjustment or change to a different class of drug is warranted.  Depression as a single entity impacts on memory and ability to focus which also mimics this condition we know as “chemo brain”. It remains important to discuss with your medical team any changes associated with brain function and do not “chalk it up to chemo brain”.

The following is an article about it published by the National Cancer Institute (NCI):

Chemotherapy Affects Brain Structure of Breast Cancer Patients

A new study has provided some of the strongest direct evidence to date that chemotherapy has physical effects on areas of the brain that, when altered, could result in the array of cognitive symptoms that is often called “chemo brain.” The study was published online August 6 in Breast Cancer Research and Treatment.

In a small study of women with breast cancer, researchers from the Indiana University School of Medicine used MRI scans to show that chemotherapy was associated with a decrease in the density of brain gray matter. The affected areas include those involved in memory and in the ability to process information. Although several other studies have shown similar changes in these areas of the brain, this was the first study to follow women prospectively and to compare scans before and after chemotherapy.

“The alterations in gray matter density observed in the [chemotherapy] group are… consistent with the pattern of cognitive complaints and impairment found in neurocognitive studies,” wrote Dr. Andrew J. Saykin and colleagues.

The study included 17 women with breast cancer who underwent chemotherapy after surgery, 12 women with breast cancer who did not receive chemotherapy after surgery, and a control group of 18 healthy women. The initial MRI scans, performed shortly after surgery in the participants with cancer, showed no notable differences in gray matter density among the three groups. One month after completion of chemotherapy, however, MRI scans revealed notable decreases in gray matter density in women with breast cancer, as well as changes in gray matter density in women who received surgery only, although the changes for these women were not as great. No changes were seen in women in the control group. After 1 year, women treated with chemotherapy had recovered gray matter losses in some regions, but other deficits persisted.

Exactly how chemotherapy may be causing these changes is unclear, said study co-author Dr. Brenna McDonald. “However, the finding that the changes appear to resolve naturally to some degree in the first year after chemotherapy is completed is a very positive one,” she wrote in an e-mail message. Because of the limited follow-up in the study, she continued, it’s unclear how much further recovery may occur naturally. A number of studies have shown that such cognitive effects can persist for many years, she added. Additional studies are investigating whether other therapies, such as tamoxifen, may have similar effects on brain structure.