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Pathways to Discovery: Fall 2011

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Cancer Patients Urged to Tell Their Physicians about Herbal Medicine Use

Patients are enthusiastic about the use of herbal supplements even though we don’t know how effective or dangerous they are.
Chun-Su Yuan, MD, PhD

One in three American adults uses some form of complementary and alternative medicine (CAM)––according to the 2007 National Health Interview Survey—yet most fail to mention this during conversations with their doctor.

While healthy people may look to CAM to improve their health, others, including cancer patients, sometimes choose CAM to treat an illness or to help cope with the side effects of treatment.

Herbal medicine is one of the most commonly used forms of CAM, with many patients regularly taking supplements such as ginseng, St. John’s wort, gingko, echinacea, valerian root, and grape seed extract.

“Patients are enthusiastic about the use of herbal supplements even though we don’t know how effective or dangerous they are,” said Chun-Su Yuan, MD, PhD, Cyrus Tang Professor of Anesthesia & Critical Care. He added that despite their widespread use, herbal supplements do not need FDA approval before they are marketed, and most have not undergone rigorous scientific research to determine their benefits and risks.

The Tang Center for Herbal Medicine Research at The University of Chicago was established in 2000 to study the efficacy and safety of herbs that have long been used in East Asia and are now becoming more popular in the United States as remedies for various illnesses or as enhancements to general health.

Dr. Yuan, who directs the Tang Center, said some herbs with antioxidant properties, such as ginseng and green tea, are being investigated for their potential use in the treatment of side effects from chemotherapy and radiation therapy, as well as for their anticancer properties. He has been working with Tong-Chuan He, MD, PhD, associate professor of surgery, and Wei Du, PhD, professor in The Ben May Department for Cancer Research, to study anti-colon cancer effects of American ginseng and notoginseng, which are widely used but little studied herbal therapies for a variety of ailments.

While many herbs show promise for medicinal benefit, Dr. Yuan cautioned that evidence-based research about herbal medicine is still in its infancy.

Natural vs. Safe
A prevailing misconception is that any product that is natural is harmless; however,
herbs are made of complex chemical compounds and work like drugs to produce changes in the body that are not yet fully understood. Herbal supplements may also trigger harmful interactions with other medications. For example, Dr. Yuan and colleagues published research in 2004 in the Annals of Internal Medicine that showed American ginseng reduces the anticoagulant effect of warfarin, a drug commonly used to prevent blood clots.

Dr. Yuan was a co-author of another study, published in 2001 in The Journal of the American Medical Association, that found several common herbs––such as echinacea, ephedra, garlic, gingko, ginseng, kava, St. John’s wort, and valerian––may have a negative impact on patients before, during, and after surgery. The complications included heart attack, excessive bleeding, and problems with anesthesia.

The increasing popularity of herbal medicine and its potential to interfere with other medications or surgery make it essential for doctors to include herbal supplement use as part of the conversation with their patients.

“Oncology patients are taking herbal medicine whether they tell their physicians or not,” Dr. Yuan said. “Now, more than ever, it is important for physicians to have a working knowledge of herbal medicine and a familiarity with the potential benefits and adverse effects.”

gingko biloba seeds herbal medicine