Integrative Cancer Therapy

Patient safety with herbal drug interactions and symptom management are two key areas of integrative cancer therapy where researchers and clinicians are putting in a great deal of effort. K. Simon Yeung, PharmD, is a pharmacist in the Department of Integrative Medicine Service at Memorial Sloan-Kettering Cancer Center, where he and his team evaluate different types of vitamins, dietary supplements, and anti-cancer treatments to determine whether there are genuine benefits and if there are drug interactions that health care professionals and their patients should be aware of when using these therapies in conjunction with chemotherapy or radiation. “We as a hospital have a policy in medication reconciliation that when we admit a patient or when a patient comes in for chemotherapy in an outpatient setting that we always ask them what kind of medication the patient is using. This would include all the dietary supplements and herbs as well,” Dr. Yeung said in an interview. Still, as is now well known, he noted, a significant percentage of patients do not inform their physicians about use of supplemental medications, often for fear of being rejected for chemotherapy treatment. “Mainstream physicians and nurses may or may not have training using dietary supplements so usually by default they will tell the patients not to use these agents because they may interact with the drug they are using,” Dr. Yeung continued. “But patients often continue using the supplements—again, without telling their doctors. That's a problem with communication.” To combat this problem, Dr. Yeung said rather than simply telling patients not to use a certain supplement, he will explain the reasons for his concern. Ginseng, for example, a common dietary supplement used by cancer patients, can have anticoagulating effects, so if a patient who is going into surgery tells him that he or she is using the herb, Dr. Yeung explains that it may cause excessive bleeding, and usually the patient will then comply. Similarly, St. John's wort, another common supplement used by patients, can have negative effects on standard cancer treatment. “Many patients use it for depression, to elevate their mood, and it's not uncommon for cancer patients to be depressed,” Dr. Yeung said. “But if they use St. John's wort together with certain chemo drugs such as irinotecan or imatinib, St. John's wort can induce the cytochrome P450, resulting in, for example, a 40 percent decrease in the serum level of irinotecan or imatinib—so this is a significant interaction.” MSKCC's ‘About Herbs’ Site Sloan-Kettering began addressing integrative medicine in 1999, which is when the “About Herbs” Web site (www.mskcc.org/aboutherbs) was launched. The site, under the direction of the Integrative Medicine Service (led by Barrie R. Cassileth, PhD, Chief of the Service and the Laurance S. Rockefeller Chair in Integrative Medicine), has an A-to-Z listing of common herbal medications. There are two portals on the site, one for health care professionals, and the other for patients. Individuals can search the origin of various herbs, their purported uses, and possible side effects and interactions, and there is also a listing of any clinical studies that have been done on the supplement. Dr. Yeung called the site an excellent source of information for physicians and patients, but emphasized the need for clinical studies in this area of medicine. “Very few herbs and drugs have been studied together in clinical settings so most of the other interactions that we know about or see in the literature are actually extrapolated from other studies or other clinical evidence and are theoretical interactions,” he said. Symptom Management Over the past 20 years researchers at the Mayo Clinic have been involved in 27 studies on symptom management with integrative cancer therapies, noted Charles L. Loprinzi, MD, Professor of Oncology there. Nineteen of those studies have been completed and published in peer-reviewed journals, and two additional manuscripts are currently in press. There are a number of symptoms related to cancer and cancer therapies, but physicians and patients often have trouble addressing these issues, he said. “Sometimes the information that patients are having symptoms does not get to the doctor. That may be because the patient downplays them, it may be because the doctor doesn't listen quite as closely, or it may be because they are both focusing so much on the treatment aspects that they don't spend as much time on the related symptoms.” Despite uncertainty as to whether integrative cancer therapies can be studied efficiently in traditional clinical settings, Mayo researchers have been able to take in-depth looks at 13 particular symptoms related to cancer or cancer therapy: mucosal toxicity, anorexia/cachexia, pain, hot flashes, skin toxicity, sexual symptoms, neuropathy, lymphedema, anemia, cognitive dysfunction, osteoporosis, insomnia, and fatigue.Figure: Memorial Sloan-Kettering Cancer Center's “About Herbs” Web siteThe researchers published a 20-year review of their work earlier this year in the Journal of Supportive Oncology (2007;5:119–125, 128) and concluded that the publication of both positive and negative results is important in order to separate what works from what doesn't.Figure: K. Simon Yeung, PharmD: “Very few herbs and drugs have been studied together in clinical settings, so most of the other interactions that we know about or see in the literature are actually extrapolated from other studies or other clinical evidence and are theoretical interactions.”The team currently has several studies under way, Dr. Loprinzi noted. For example: ▪ Use of ginkgo biloba versus placebo in the prevention of cognitive dysfunction in patients with breast cancer who are receiving adjuvant chemotherapy. ▪ Use of American ginseng to alleviate cancer fatigue. ▪ The herb valeriana officinalis as a treatment for insomnia. ▪ Sunscreen as a treatment of epidermal growth factor receptor-induced dermatitis. ▪ Use of vitamin B to alleviate hand-foot syndrome, after earlier trials showed that aloe vera gel did not improve radiation-induced chest wall toxicity. The group also published a study last year in the Journal of the Society of Integrative Oncol (2006; 4[4]:143–152) looking specifically at the issue of integrative medicine research. That study, led by Debra Barton, RN, PhD, AOCN, concluded that complementary/alternative medicine research can indeed be done in a scientifically sound manner. “Well-designed and adequately powered studies can be implemented and large numbers of patients can be accrued,” the researchers wrote. “The resulting research evaluations can be published in peer-reviewed medical journals.”

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