Many women who get chemotherapy to treat breast cancer say they have problems remembering, thinking, and concentrating during and after treatment. These problems are commonly called “chemo brain” or “chemo fog” -- doctors call these issues “cognitive impairment” or “cognitive problems.” Some women may have trouble with:
- learning new tasks
- remembering names
- paying attention and concentrating
- finding the right words
- organizing thoughts
- remembering where things are (keys, glasses, etc.)
A small retrospective study suggests that a chemotherapy regimen that includes an anthracycline may increase the risk of thinking and memory problems more than regimens that don’t include an anthracycline.
The study was published in the February 2016 issue of JAMA Oncology. Read the abstract of “Neurotoxic Effects of Anthracycline- vs Nonanthracycline-Based Chemotherapy on Cognition in Breast Cancer Survivors.”
Anthracycline chemotherapy medicines kill cancer cells by damaging their genes and interfering with their reproduction. Adriamycin (chemical name: doxorubicin), Doxil (chemical name: doxorubicin), and Ellence (chemical name: epirubicin) are all anthracyclines.
A retrospective study means the researchers analyzed information that was collected before the study was designed. Some doctors think that the results of retrospective studies aren’t as strong as studies that are designed first and then collect new information specifically for that study.
This study involved 62 women who had been diagnosed with breast cancer who had completed chemotherapy more than 2 years earlier:
- 20 of the women were treated with anthracycline chemotherapy
- 19 women were treated with non-anthracycline chemotherapy
- 23 women weren’t treated with chemotherapy
The women were about 55 years old.
The researchers measured the women’s cognitive functioning with standard tests and also looked at functional MRI test results. A functional MRI uses MRI technology to measure brain activity by detecting changes associated with blood flow caused by brain activity.
The results showed that women who had been treated with an anthracycline had worse short-term and long-term memory compared to the women in the other two groups. These differences were statistically significant, which means they were likely because of the difference in chemotherapy treatment and not just due to chance.
Women treated with an anthracycline also had less left precuneus connectivity. The left precuneus region of the brain is involved in memory, spatial processing, and consciousness. It is part of what’s called the brain’s default mode network, which means it helps perform cognitive activities while the brain is at rest. Changes in connectivity in the left precuneus region could make a person less efficient at processing information.
When the women were asked to report any thinking or memory issues, women who were treated with chemotherapy -- both anthracycline and non-anthracycline -- reported more thinking and memory problems and more psychological distress than women who didn’t get chemotherapy. Women who were treated with chemotherapy also had worse fatigue and executive functioning skills. Executive functioning skills are the mental processes that allow us to plan, focus, remember instructions, and successfully juggle multiple tasks.
The researchers found no link between the number of chemotherapy cycles and cognitive function.
While the results of this study are concerning, it’s important to remember that this study only looked at the women’s cognitive function AFTER they had been treated for breast cancer. We don’t know if some of the women had problems with thinking and remembering before they were diagnosed.
"Larger, prospective studies are needed that include pretreatment and post-treatment assessments so that patients' individual cognitive and neurobiologic trajectories can be evaluated with respect to potential anthracycline-related neurotoxic effects," the researchers said. "Continued research regarding the mechanisms by which anthracyclines disrupt neurocircuitry could help identify interventions that will protect against anthracycline-associated neurotoxic effects without reducing the anticancer efficacy of these regimens."
The good news is that most women who have memory and thinking problems during breast cancer treatment recover and are able to remember and think clearly after treatment is done. Still, a small number of women continue to have problems for a year or more after treatment ends.
If you’ve been diagnosed with breast cancer and are having thinking and memory problems, there are things you can do to help yourself. You might want to check out the Breastcancer.org page on Memory Loss in our side effects section. You’ll find tips on:
- managing memory challenges
- keeping your mind alert
- keeping track of things when you’re forgetful
Stay tuned to Breastcancer.org Research News for the latest information on chemo brain and its causes.