From Our 2007 Archives
Herbs May Cut Cancer Treatment Effects
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Chinese Herbs May Help Breast Cancer Patients; More Study Needed
Reviewed By Louise Chang, MD
April 18, 2007 -- Chinese herbal medicines may be a new weapon against breast cancer treatment side effects, a new study shows.
The researchers agree, however, that better research is needed to prove the safety and efficacy of these therapies.
Researchers who analyzed the seven Chinese studies concluded the trials provided "limited evidence" that Chinese herbal treatments can reduce some short-term side effects of chemotherapy, such as fatigue, nausea, vomiting, and bone marrow suppression.
But the researchers also acknowledged that the seven studies were of poor quality and that more scientifically rigorous research is needed before recommendations can be made.
"Western physicians not trained in traditional Chinese medicine or the use of Chinese medicinal herbs should not dismiss these approaches as being without theory or clinical basis, and should likewise support further studies in the field," researchers from the Chinese Cochrane Centre wrote in the latest issue of the online journal Cochrane Library.
'Avoid Unproven Treatments'
Memorial Sloan-Kettering Cancer Center statistician Andrew Vickers, PhD, has studied alternative and complementary cancer treatments for many years.
He agrees that higher-quality studies are needed but says breast cancer patients should avoid Chinese herbal treatments until they are proven to be safe.
"The policy at Memorial Sloan-Kettering Cancer Center is to advise patients against using any herbs or other supplement -- even vitamins -- during, and for a few weeks before chemotherapy or radiotherapy," he tells WebMD.
That policy stems from studies linking specific herbals and supplements to poorer outcomes in cancer patients undergoing treatment.
The herbal supplement St. John's wort, for example, has been shown to lower blood levels of certain chemotherapeutic agents. And vitamin E was linked to an increased risk of death in head and neck cancer patients treated with radiation.
Vickers says herbal supplements and vitamins can reduce the effectiveness of chemotherapy in two ways -- by speeding up the metabolism of cancer-killing drugs and by serving as antioxidants.
Faster metabolization of drugs given to kill cancer cells means the drugs don't stay in the body as long doing their job.
And while antioxidants may help protect healthy cells, they may also protect cancer cells, Vickers says.
"There is certainly reason to believe that some herbs and vitamins may actually make cancer treatments work better, but the studies that prove this have not been done," he says. "If there is a reasonable possibility of harm and no proof of benefit, we say stay away."
No Evidence of Harm
The seven studies in the analysis included a total of 542 breast cancer patients who were undergoing or had recently undergone chemotherapy. All the studies compared treatment with chemotherapy alone vs. chemotherapy plus a Chinese herb or herbal regimen.
Researchers found no evidence of harm among patients who got the Chinese herbal treatments, but Vickers questions this finding.
He points out that only two of the studies included important information on how patients were randomized, and none included information on patient follow-up or withdrawals.
"These studies failed to provide crucial details on every single important methodological criterion," he says.
SOURCES: Zhang, M. Cochrane Library, Jin Li, Chinese Cochrane Centre, Chengdu, China. Andrew Vickers, PhD, associate attending research methodologist, Memorial Sloan Kettering Cancer Center, New York City. Mathijssen, R. Journal of the National Cancer Institute, Aug. 21, 2002; vol 94: pp 1247-1249. Bairati, I. International Journal of Cancer, Nov. 1, 2006; vol 119: pp 2221-2224.
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