Welcome to Weekly Health Update

“A critical weekly review of important new research findings for health-conscious readers” 

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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Welcome to Weekly Health Update

“A critical weekly review of important new research findings for health-conscious readers”

GINKGO BILOBA, MEMORY & COGNITIVE HEALTH

Regular readers of this column know that I have a strong interest in lifestyle- and diet-based approaches to disease prevention, but that I insist on rigorous, high-quality research-based data before I can recommend a particular lifestyle or dietary modification to my readers (or to myself).  Many past columns have reviewed the findings of research studies with favorable results associated with specific nutritional or other lifestyle approaches to disease prevention.  However, this week’s column will report on a newly published prospective clinical research trial that calls into question the supposed clinical value of the traditional Chinese medicine herb Ginkgo biloba in reducing the cognitive decline associated with aging and Alzheimer’s disease.

Previously published public health research data, based upon low-powered research methods, have suggested that dietary supplementation with Ginkgo biloba might be able to improve memory and cognition, particularly in older adults.  However, more recent data, based upon more robust types of clinical research, have called this assumption into question (as well as previous claims that Gingko biloba can delay or reverse the cognitive decline associated with Alzheimer’s disease).  Now, a newly published prospective, randomized, double-blind, placebo-controlled clinical trial of Gingko biloba supplementation in older adults in the United States appears to have definitively resolved the controversy about the value of Gingko biloba in maintaining memory, and other high level cognitive functions, in older adults. 

Ginkgo biloba trees are often referred to as living fossils, as they are known to survive for 1,500 years or more, and their presence has been documented within fossil-bearing rocks more than 270 million years old.  Although ancient fossils containing the distinctive bilobed leaves of Ginkgo biloba trees have been found on multiple continents, modern day Gingko trees now grow naturally only in China (although they have been widely cultivated, over a period of centuries, throughout Asia, and particularly in Japan and Korea).    

A new highly-powered prospective clinical research trial evaluating Ginkgo biloba supplementation appears in this week’s issue of the Journal of the American Medical Association.  More than 3,000 adults between the ages of 72 and 96 years participated in this placebo-controlled research trial, with an impressive average patient follow-up duration of more than 6 years.  These patient volunteers were secretly randomized to one of two groups.  The patients in the “experimental group” received 120 mg of Ginkgo biloba extract twice daily during the course of this study, while the “control group” of patients received an identical-appearing placebo (“sugar pills) twice daily.  (As this was a double-blind study, neither the patient volunteers nor the researchers knew which patients were receiving Gingko pills and which were receiving the placebo pills until after the research study was completed.) 

Multiple validated cognitive screening exams were given to all of these older patient volunteers during each year of the study, and the rate of annual decline in cognitive function was then compared between the two groups of patient volunteers.  Areas of cognitive function that were specifically tested for in this high-powered prospective clinical research trial included memory, attention, visual-spatial abilities, language function, and overall executive brain function.  (Note: these same cognitive function tests are also routinely utilized to assess cognitive function in patients with Alzheimer’s disease.)

Unfortunately, there was absolutely no difference observed or measured in the rate of decline in cognitive function between the two groups of older patient volunteers, indicating the lack of any clinically detectable benefit in age-related cognitive decline associated with high-dose supplementation with Ginkgo biloba.

(As an editorial aside, the Journal of the American Medical Association (JAMA) is to be commended for publishing this rigorously performed clinical research trial and its Level One research findings, as there is a well-known bias against publishing clinical research studies with “negative findings,” such as this study, among prestigious medical journals.)

Although this is the second recent high-level prospective clinical research trial that has found absolutely no clinical benefit in preserving or improving cognitive function in older adults associated with Ginkgo biloba supplements, there may still be potential clinical applications for this ancient herbal remedy in view of its known ability to improve blood flow through networks of small blood vessels in the body.  There is also some research evidence available suggesting that Ginkgo biloba may have potentially important anti-inflammatory properties, and that these properties might be clinically useful in some chronic inflammatory diseases, such as ulcerative colitis (Ginkgo biloba, ulcerative colitis & colorectal cancer).  For now, however, the overwhelming available clinical research evidence indicates that Ginkgo biloba appears to offer no benefit to older patients in terms of either preserving or improving memory, or in improving other areas of higher cognitive function.

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