In the past few years, there have been conflicting studies about whether or not particular types of chemotherapy drugs cause “chemo brain” — a condition in which patients experience a mental fog or memory fuzziness during and after treatment.
The following two studies assessed the cognitive effects of anthracycline-based chemo treatment versus nonanthracycline treatments.
Anthracyclines are a class of antibiotic drugs that come from strains of certain Strep bacteria, according to the National Cancer Institute. These types of drugs treat cancer by damaging DNA in cancer cells and eventually causing these cells to die. Anthracycline-based drugs include daunorubicin, doxorubicin and epirubicin.
Let’s take a look at what these studies found.
February 2016 Study
Researchers examined how the brains of breast cancer survivors functioned after treatments with anthracycline drugs, nonanthracycline chemotherapy and no chemotherapy whatsoever.
Researchers noted brain functions in 62 breast cancer survivors. They had an average age of 55 and all stopped undergoing treatments at least 2 years before their participation in the study. Of the 62 women, 20 had anthracycline-based chemotherapy as a primary treatment, 19 received nonanthracycline regimens of chemotherapy and 23 had no chemo whatsoever, according to Medical Xpress. Doctors then found ways to measure the cognitive abilities of these former breast cancer patients.
Participants enrolled in classes at Stanford University from 2008 to 2014, and researchers conducted the analysis during this period. These breast cancer survivors underwent a battery of tests, including standard psychological tests that measure brain function and MRI scans to look at the brain’s signalling network, notes JAMA Oncology. The results of these tests led to some alarming conclusions.
What They Found
Women treated with anthracycline chemotherapy drugs had lower verbal memory skills compared to other forms of chemotherapy or no chemotherapy at all. This includes the ability to immediately remember facts. MRIs indicated that connections in the brain were lower in patients treated with chemotherapy compared to those who received no chemo during treatment for breast cancer, which means the brain processes information less efficiently after undergoing chemo. Patients self-reported greater psychological distress due to chemo treatments versus nonchemotherapy regimens.
This research suggests that anthracyclines may incur greater negative effects on the brain than chemotherapy without anthracyclines. Doctors at Stanford University and the University of Texas conclude more studies should follow up these conclusions due to this very small sample size (just 62 women), and so the doctors can get a better idea of how chemotherapy alters the brain.
April 2013/July 2016 Study
The Mind Body Study [MBS] published in April of 2013 showed no association between anthracycline use and impaired cognition. The MBS “is a large prospective cohort study of recently diagnosed, early-stage breast cancer patients enrolled after completion of adjuvant therapy and prior to initiation of endocrine therapy,” according to the Journal of the National Cancer Institute.
However, after the February 2016 study detailed above was released, the MBS researchers went back and performed a secondary analysis of the April 2013 study results.
Researchers examined brain function of breast cancer survivors after treatment with anthracycline drugs, nonanthracycline chemotherapy and no chemotherapy whatsoever. They looked at 190 breast cancer survivors’ brain function at 4 different points post-treatment: 3 months, 6 months, 1 year, and up to 6.9 years. The patients were between 21–65 years old.
What They Found
Their findings were the same as the first time around:
“Our findings indicate that cognitive functioning following cancer treatment in the areas of memory, processing speed, and executive functioning was comparable among those who received chemotherapy with or without anthracycline and those who did not receive chemotherapy. Furthermore, cognitive functioning over time (i.e., during and after recovery) was also comparable between groups up to 7 years after treatment. We did not find an association between anthracycline exposure and neuropsychological performance on any measure examined.”
The MBS researchers also posited that their research was more rigorous than their counterparts and included more challenging memory measures. They also stated that other factors may play a role in causing chemo brain.
These conflicting results indicate one thing for certain: more research needs to be done.
Chemo brain doesn’t have to control you. Discuss your treatment options with your doctor and then see if he can recommend ways to help your brain and your body reduce the effects of treatment.
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