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CHEMOTHERAPY FOR BREAST CANCER & MEMORY LOSS
“Chemo Brain” is a term often used by breast cancer patients to describe the decreased memory, and other cognitive dysfunctions, associated with chemotherapy for this common form of cancer. However, there has been very little prospective, objective clinical research into this phenomenon. Furthermore, what little research that has been done in this area, to date, has primarily focused upon subjective self-assessments, by breast cancer patients, of their own level of cognitive function following chemotherapy. Moreover, until recently, the complaints of breast cancer patients regarding their self-perceived memory loss following chemotherapy were often dismissed by many physicians.
Now, a newly published prospective clinical research study from the M.D. Anderson Cancer Center suggests that physicians may have vastly underestimated the frequency, severity, and duration of cognitive dysfunction following standard breast cancer chemotherapy. This clinical study, which appears in the current issue of the journal Cancer, prospectively enrolled 42 women with newly diagnosed breast cancer. All of these women then underwent standardized neuropsychological evaluation before, during, and after chemotherapy. Importantly, this study not only tested these breast cancer patients in the early period after they completed their chemotherapy, but also one year after their chemotherapy had ended. The findings from this small study strikingly illustrate just how common, and how enduring, memory loss and other forms of cognitive dysfunction are following chemotherapy for breast cancer.
Prior to beginning chemotherapy, 21 percent of these patients had some detectable degree of cognitive dysfunction. By the end of their chemotherapy treatments, a whopping 65 percent of these 42 patients displayed measurable declines in memory function, organizational ability, and cognitive processing speed. One year later, 61 percent of these women continued to display measurable declines in cognitive function. Worse yet, among this group of women with persistent cognitive dysfunction one year after completion of their chemotherapy, 71 percent continued to display progressively worsening of cognitive function when compared to their level of function immediately after finishing chemotherapy. Finally, the remaining 29 percent of this group of women with long-term evidence of cognitive dysfunction actually displayed a delayed-onset of cognitive decline when they were tested one year after chemotherapy (i.e., when compared to the results of their neuropsychological testing immediately after chemotherapy).
Although this clinical research study enrolled a small cohort of patients, its prospective nature, and its use of validated neuropsychological tests, make it a powerful research study for its size. The findings of this study also fit well with previous laboratory research studies that have shown both acute and delayed changes in the actual structure of the brains of animals treated, proportionately, with the same chemotherapy drugs commonly used to treat breast cancer in humans. Whether or not the significant declines in cognitive function that were observed, one year after chemotherapy in the 61 percent of women who participated in this study, will eventually stabilize, improve or worsen is unknown at this time. Longer follow-up of these 42 breast cancer patients will have to be performed to answer this important question. However, this small prospective study clearly indicates that the majority of women who undergo standard chemotherapy for breast cancer appear to experience significant and prolonged declines in their level of cognitive function, including memory loss, decreased organizational skills, and a general slowing of their cognitive processing speed, and that these adverse changes persist for at least a year after completion of chemotherapy.
The findings of this study should spur additional research into the precise cause(s) of this chemotherapy-associated impairment in cognitive function, as well as strategies to reduce the severity and duration of these adverse health effects following chemotherapy for breast cancer. Meanwhile, it is important for me to stress that chemotherapy unquestionably extends survival, and saves lives, among women who are appropriately advised to undergo such treatment for breast cancer. In my opinion, no patient should read this column, and then go on to refuse chemotherapy that has been appropriately recommended because of the findings of this clinical research study.
To learn more about the prevention, screening, diagnosis and treatment of breast cancer, look for the publication of my new landmark evidence-based book, “A Cancer Prevention Guide for the Human Race,” in the summer of this year.
Disclaimer: As always, my advice to readers is to seek the advice of your physician before making any significant changes in medications, diet, or level of physical activity
Dr. Wascher is an oncologic surgeon, a professor of surgery, a cancer researcher, an oncology consultant, and a widely published author
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