New research to address “chemo brain”

Last Modified: 11/22/2021


This post was written by Joseph W McCollom, DO, Director of Palliative, Integrative and Survivorship Oncology, Parkview Cancer Institute, and Emily Powell, PhD, Research Clinical Operations Manager, Oncology, Parkview Research Center.

The term “chemo brain” refers to cognitive impairments that result from chemotherapy treatment. It’s well known to those who have cancer, but very little is known about what causes chemo brain or how to predict or treat it. Furthermore, there are currently no drugs available to treat the condition. About 75% of breast cancer survivors who have undergone chemotherapy report some sort of cognitive symptoms. These problems can be short- or long-term, lasting up to decades for some.  


Chemo brain cognitive impairment symptoms could include slower-than-normal thought processes and trouble concentrating, as well as using the wrong word to describe something or difficulty with short-term memory. These issues can last from a few months to as long as 20 years after the last dose of chemotherapy, and about half of those people reporting chemo brain felt that the symptoms negatively affected their quality of life.

Currently, there is not a diagnostic test that will determine if a patient has chemo brain. We also don't have a way to predict who will develop chemo brain during treatment. This is a critical area of research focus for our patients. Especially as survival rates from cancer are increasing, patients want to have an excellent quality of life with sharp recall and excellent processing. 

Risk factors

Although most of the research done on chemo brain has been performed for breast cancer patients/survivors (over 60 trials), chemo brain has been observed by patients and their medical teams in every cancer type.  

Although no studies have compared chemotherapeutic agents against one another or which are most associated with chemo brain, we do know that many of these drugs cross through the blood brain barrier to impact healthy brain tissue. Additional treatments, such as brain radiation and intrathecal (in the spinal fluid) treatments can also increase this risk.

Despite the name, changes in memory have been observed in cancer patients prior to starting treatment and chemo brain can still be seen in patients on hormone therapy, targeted therapy and immunotherapy. Other "nonchemotherapeutic" agents, such as bortezomib, bevacizumab and traztuzumab, are antibodies which also can impact chemo brain. Newer antibodies and immunotherapies are emerging as potential causes of chemo brain. 

Due to a lack of ability to properly identify, universally screen and diagnose patients with chemo brain, there is no standard of care for treatment. There are no FDA approved medications that have proven to reverse or slow the process of chemo brain. There have, however, been several studies showing potential benefit of multiple strategies such as a structured exercise program, cognitive rehabilitation and mindful meditation. Certain medications that have shown benefit in other neurodegenerative (brain loss) diseases have been used in some cases, including SSRI, SNRI and acetylcholinesterase inhibitors, among others. 

Although there hasn't been any perfect strategy for preventing chemo brain, some studies support that those who were active prior to and during their chemotherapy have improved cognitive function afterward. Baseline testing could identify patients who are more at risk for chemo brain and give them a greater chance at prevention. 

Current research

Parkview Cancer Institute and Parkview Research Center, with the support of The Parkview Foundations and collaboration with IU Health, just launched a new study to examine chemo brain.

The goals of this research include formulating a blood test that can predict the likelihood of onset of chemo brain in cancer patients throughout treatment and thereafter. If these blood factors, or “biomarkers,” can predict the onset of chemo brain, earlier interventions and symptom management can be initiated to improve quality of life for patients. The ultimate goal is to develop a new treatment for chemo brain.

This study involves a group of patients who have colorectal cancer. The basic steps in the process involve collecting personal biometric data and blood samples from patients before, during and for 5 years after chemotherapy. Patients will self-report their cognitive status, and a “cognitive score” will be calculated. The blood samples will then be analyzed for specific molecular markers. If a decline in the cognitive score correlates with an increase in a particular molecule in the blood, this blood molecule can be used to predict the onset of chemo brain. Changes in this blood biomarker can then be used to explore cognitive therapy to manage or eliminate the symptoms for future patients.

This research study is intended to identify molecular markers that can predict chemo brain and treat it early, thus improving quality of life for cancer patients and survivors. Blood biomarkers identified through this study may even be used to develop a chemo brain drug treatment.

If you are interested in learning more about participating in this or other clinical trials, speak to a member of your Parkview Cancer Institute care team.


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