Study Finds Scientific Basis for ‘Chemo Brain’ in Breast Cancer Patients

By Janice Wood
August 6th, 2022
Medically reviewed by Paul Sietes, MD.

chemo brainWhile breast cancer patients often report difficulties with memory, concentration and other cognitive functions following treatment, there’s been a debate in the medical community as to whether this mental fogginess is psychosomatic or a symptom of changes in brain function.

Now, a new study has shown a correlation between poorer performance on neuropsychological tests and memory complaints in post-treatment, early-stage breast cancer patients, particularly those who have undergone chemotherapy and radiation.

“The study is one of the first to show that such patient-reported cognitive difficulties — often referred to as ‘chemo brain’ in those who have had chemotherapy — can be associated with neuropsychological test performance,” said Dr. Patricia Ganz, director of cancer prevention and control research at the University of California-Los Angeles’s Jonsson Comprehensive Cancer Center.

Ganz and her colleagues looked at 189 breast cancer patients who enrolled in the study about a month after completing their initial breast cancer treatments and before beginning endocrine hormone-replacement therapy. Two-thirds had breast-conserving surgery, more than half had received chemotherapy, and three-quarters had undergone radiation therapy. Average age of the women was 52.

Because cognitive complaints following cancer treatment have often been associated with anxiety and depressive symptoms, the researchers excluded women with serious depressive symptoms. They also took into account the cancer treatments used and whether menopause and hormonal changes could be influencing the cognitive complaints. A group of healthy women of about the same age was used as a control group.

The researchers gave a self-reporting questionnaire to the women and found that those with breast cancer reported more severe complaints than normal — 23.3 percent had higher complaints about their memory, and 19 percent reported higher complaints about higher-level cognition, such as problem-solving and reasoning.

The researchers noted that the breast cancer patients who reported more severe memory and higher-level cognition problems were more likely to have undergone both chemotherapy and radiation.

The UCLA researchers found that even when patients reported subtle changes in their memory and thinking, neuropsychological testing showed detectable differences.

For instance, they discovered that poorer performance on the neuropsychological test was associated with higher levels of cognitive complaints and with combined radiation and chemotherapy treatment, as well as with symptoms related to depression.

“In the past, many researchers said that we can’t rely on patients’ self-reported complaints or that they are just depressed, because previous studies could not find this association between neuropsychological testing and cognitive complaints,” Ganz said. “In this study, we were able to look at specific components of the cognitive complaints and found they were associated with relevant neuropsychological function test abnormalities.”

The findings are part of an ongoing study that seeks to examine the extent to which hormone therapy contributes to memory and thinking problems in breast cancer survivors, she said. This latest study provided a pre-hormone therapy assessment, which was able to separate the effects of initial treatments on these cognitive problems, she said. Earlier post-treatment studies of breast cancer patients were difficult to interpret, as they included women already taking hormone therapy, she noted.

“As we provide additional reports on the follow-up testing in these women, we will track their recovery from treatment, as well as determine whether hormone therapy contributes to worsening complaints over time,” Ganz said.

The study was published in the Journal of the National Cancer Institute.

Source: University of California-Los Angeles

Breast cancer patient photo available from Shutterstock

Janice Wood is a long-time writer and editor who began working at a daily newspaper before graduating from college. She has worked at a variety of newspapers, magazines and websites, covering everything from aviation to finance to healthcare.