Perioperative Herbal Supplement Use in Cancer Patients: Potential Implications and Recommendations for Presurgical Screening

Nagi B. Kumar, PhD, RD, FADA; Kathy Allen, MA, RD; Heather Bell, MS, RD

Disclosures

Cancer Control. 2005;12(3):149-157. 

In This Article

Background

Herbal supplements are dietary supplements that contain herbs, either singly or in mixtures. An herb (also called a botanical) is a plant or plant part used for its scent, flavor, and/or therapeutic properties. Products made from botanicals that are used to maintain or improve health have been called herbal supplements, botanicals, or phytomedicines.[1] Currently, more than 20,000 herbal products are available as over-the-counter therapeutic agents in the United States.[2]

Many herbs have a long history of use and of claimed health benefits. However, herbal supplements and botanicals have potent pharmacologic activity and, consequently, contribute to potential adverse effects and drug interactions.[1] The 2002 National Health Interview Survey conducted by the Centers for Disease Control and Prevention indicated that 38.2 million American adults (approximately 19%) use nonvitamin, nonmineral natural products -- primarily botanical supplements -- despite a lack of evidence for most of these products regarding their safety and effectiveness. Herbal supplements are regulated by the Dietary Supplement Health and Education Act, which limits their regulation by the US Food and Drug Administration.[1]

The use of herbal supplements by cancer patients in the perioperative period is prevalent and consistent with the substantial increase in the use of alternative medical therapies by cancer patients.[3] Anywhere from 25% to 85% of cancer patients are seeking alternative and complementary nutritional therapies for prevention or during cancer treatment. The use of these therapies is highest among patients with breast cancer (80% to 85%),[4,5] pediatric cancer (46%),[6] prostate cancer (27% to 43%),[7,8,9] and head and neck cancer (25%).[10] In a study of 820 cancer patients receiving chemotherapy or radiation therapy, 29.1% reported using complementary/integrative nutritional therapies that were not prescribed by their physi-cian.[3] Of the 820 patients, 50.8% were men and 49.2% were women. Caucasians and patients over 60 years of age were predominant users of complementary/integra-tive therapies during treatment. Over 63% of the patients had a college degree or higher, and 40% were employed at the time of treatment. Most of the patients (65.3%) had a family history of cancer. Of the 820 patients, 237 (29.1%) reported taking one or more nutritional supplements during treatment. Although 58.6% of this group consumed multivitamin/mineral preparations, several patients reported taking one or more vitamins, minerals, botanicals, and/or biologics in addition to the multivitamin/minerals. The most frequently used complementary/integrative nutritional therapies were modular vitamins (86.9% of the patients), followed by botanicals/biologics (43.8%) and mineral supplements (28.6%). Many biologics and botanical supplements used by these patients have no proven efficacy in cancer treatment and may even interfere in traditional treatment modalities such as chemotherapy and radiation therapy if taken perioperatively.[3]

Recent observations[3] and a growing body of literature have increased our understanding of the composition and function of these herbal supplements. As a result, serious concerns have been raised on the widespread use of herbal supplements among the presurgical population, which may have a negative impact on preoperative patient care. More specifically, several botanicals, based on their chemical structure, may produce adverse effects for perioperative use. These herbal supplements have been demonstrated to have adverse effects, possess antiplatelet activity, adversely interact with corticosteroids and the central nervous system depressant drugs, have gastrointestinal manifestations, produce hepatotoxicity and nephrotoxicity, and produce additive effects when used concomitantly with opioid analgesics. In addition to known consequences based on the biochemical composition of herbal supplements, adulteration and product quality issues are particular concerns. Currently, as there are no legal standards for packaging or processing. The content of the supplements varies significantly from batch to batch as well as from the content statements and claims made on the label.[10] Some of the products tested may have less than half the potency listed on the label.[11] In one analysis, some botanicals tested had unsafe levels of mercury and other toxic metals, and prescription drug compounds were discovered in more than a third of products tested.[12]

Despite the rise in herbal medicine consumption, explicitly eliciting and documenting herbal medicine usage among surgical patients by surgical healthcare staff (eg, anesthesiologists, dentists, and surgeons) is poor.[13,14] Few surgeons question patients regarding their use of herbal medicines, and 70% of patients do not reveal their use of herbal medicines to their physicians, clinical pharmacists, or dietitians. In a recent study of 2,186 survey respondents undergoing elective surgery,[13] 57% admitted to using herbal medicine at some point in their life and 38% within the past 2 years. One in 6 respondents continued the use of herbal medicine during the month of surgery. In a study by Leung et al[14] in the California hospital systems, 39.2% of 2,560 survey respondents admitted to using some form of alternative medicine supplements, the most common type being herbal medicine (67.6%). Of those who admitted to taking alternative medicine supplements, 44.4% did not consult with their primary physicians, and 56.4% did not inform the anesthesiologists before surgery regarding their use of these products. Only 53% of the patients ceased using these products before surgery. Although the use of supplements in cancer patients is well documented,[3] there are no randomized clinical trials that have examined the effects of these supplements in the perioperative period.

The objectives of this report are (1) to review the constituents, safety, pharmacokinetics, and pharmacodynamics of those herbal supplements predominantly used by cancer patients, as observed by our group,[3] that may contribute to potential adverse consequences during and following surgery and (2) to provide recommendations for developing and implementing surgical/clinical practice guidelines for screening and prevention of use of herbal supplements perioperatively. As most of these herbal supplements have multiple constituents with specific properties, we focus on the predominant property of the herbal supplement, with implications specific to its use in the preoperative period. Figure 1 presents several examples of the botanical supplements are pictured in plant form, and their potential adverse effects in cancer therapy are noted in Table 1 . Although we selected the herbal supplements used by cancer patients, these are also the most commonly used herbal supplements in other patient populations. Thus, the recommendations and discussions are applicable to other preoperative patient populations.

Botanical images of garlic (A), ginger (B), ginkgo (C), ginseng (D), echinacea (E), St John's wort (F), valerian (G), and kava (H).

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