Page 355 - Withrow and MacEwen's Small Animal Clinical Oncology, 6th Edition

CHAPTER 17 Integrative Oncology 333

more mechanisms. Toxicity from Chinese herbs coadministered Evidence-Based Complementary and Alternative Medicine. This
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with chemotherapy may lead to diagnostic dilemmas when clini- research investigated the ability of an extract of turkey tail mush-
room (Coriolus versicolor) containing standardized amounts of the
cians misattribute problems to the drug rather than the TCHM
VetBooks.ir product, thereby delaying discontinuation of the appropri- bioactive agent polysaccharopeptide (PSP), to affect the survival
ate compound. In fact, Chinese herbalists in Taiwan who work
and quality of life of a small number (n = 15) of dogs with heman-
directly with herbs in the raw form are at increased risk of liver giosarcoma. Results suggested that the median time to developing
and bladder cancer, possibly owing to heavy metal contamination abdominal metastases or finding progression was lengthened in five
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of TCHMs and/or the intrinsic toxicity of some ingredients. dogs taking 100 mg/kg/day of the commercially available prepara-
This heightened risk for urologic cancers, chronic and unspecified tion called “I’m-Yunity” compared with lower doses of I’m-Yunity.
nephritis, renal failure, and renal sclerosis “highlights the urgent No differences were noted in survival times, however. Of note, the
need for safety assessments of Chinese herbs.” 56 survival time of nearly 200 days for five dogs in the highest dose
Public perception holds that TCHMs may protect cancer treatment group was numerically longer than that reported for
patients’ health and well-being during chemotherapy. A double- dogs on doxorubicin-based chemotherapeutic treatment protocols,
blind, randomized, placebo-controlled study questioned this which typically falls between 141 and 179 days. These findings
assumption, showing that TCHMs did not significantly reduce raise important questions. Could this product demonstrate survival
hematologic toxicities (leukopenia, neutropenia, and thrombo- effects similar to or beyond that provided by standard of care che-
cytopenia) associated with adjuvant chemotherapy for breast and motherapy in larger scale studies? Could research such as this lead
colon cancer. Three licensed, experienced TCHM practitioners to changes in standard of care from cytotoxic drugs to botanical
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from China prescribed herbal formulas to patients on an individu- medicine? The answers to these questions are yet unanswered. No
alized basis, as many believe this approach yields superior benefits. direct statistical comparison was made between this very small (n =
Even the myth that individualizing TCHMs produces more sig- 5) group of dogs and dogs receiving standard of care chemotherapy.
nificant improvement could be more folklore than fact. Accord- The “randomization” in this trial was between I’m-Yunity dosing
ing to some critics, “[A]lmost all individualized herbal medicine groups, not between I’m-Yunity and standard of care. Although
is practiced without the support of any rigorous evidence about these results suggest activity, a randomized trial with sufficient sta-
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effectiveness whatsoever.” They continue, tistical power would be necessary to confirm activity either equiva-
lent or superior to standard of care chemotherapy.
The lack of standardisation and use of multiple herbs in a single Human trials have found benefit with turkey tail mushroom as
prescription also greatly multiply the safety risks. There are addi- well. A proprietary, protein-bound polysaccharide extract of Cori-
tional risks associated with variability in the diagnostics skills of olis versicolor reduced serum levels of immunosuppressive acidic
the practitioner, their awareness or lack of awareness of potential protein in stage II and III colorectal cancer patients, increased
interactions, and their ability or inability to identify red flag symp- 5-year disease-free survival, and decreased relative risk of regional
toms indicating serious diseases requiring immediate mainstream metastases. A meta-analysis of three trials involving more than a
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medical treatment. Given the risks and lack of supporting evi- thousand subjects with colorectal cancer confirmed these results.
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dence, the use of individualised herbal medicine cannot be recom- Moreover, a systematic review and meta-analysis of the efficacy of
mended in any indication. Coriolus versicolor on survival in cancer patients revealed that this
mushroom confers survival benefit for patients with breast, stom-
Examples of Herbs Suggested for Patients with Cancer ach, and colorectal carcinoma.
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The botanical agents covered in the text that follows appear
because of their popularity, not as a means of advocacy for their Bloodroot
inclusion in veterinary oncologic care. The responsibility of pre- Bloodroot extract acts as an escharotic when topically applied in a
scribing or recommending herbal products lies with the practitio- salve or destructive agent when injected directly into tumors. 66,67
ner handling each case and should be approached with the same The “black salve” version of bloodroot (Sanguinaria canadensis)
critical mindset and scientific rationale as any chemotherapeutic may come admixed with mineral agents such as zinc chloride,
drug or other conventional intervention. chromium chloride, or arsenic trisulfide and possibly other herbs.
Bloodroot pastes became popular in the midtwentieth century
Asian/Medicinal Mushrooms and have persisted despite risks of serious injury. It causes strong
Medicinal mushrooms and fungi display more than a hundred and rapid apoptotic responses through several modes of cell death,
medicinal functions potentially relevant to the treatment of can- including an early and severe glutathione-depleting effect.
cer. These activities include antitumor, immunomodulatory, Sanguinarine, the active ingredient in bloodroot, supposedly
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antioxidant, radical scavenging, and hepatoprotective effects that targets only cancer cells, according to its enthusiastic supporters.
enhance humoral and cell-mediated immune responses. A vari- Sanguinarine does appear to selectively target cancer cells over
ety of medicinal mushrooms and extracts have proved beneficial, normal cells in vitro, and it may sensitize these cells to chemother-
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improving immune parameters such as natural killer (NK) cell apy-mediated growth inhibition and apoptosis. Sanguinarine
activity and cytokine expression, without significant toxicity. has also been reported to exert dose-dependent differential anti-
Mushroom mixtures and mushroom-derived polysaccharide proliferative and apoptotic effects on cancer and normal cells.
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preparations modify tumor response and improve immune func- How tissue levels in vivo would compare with those tested in vitro
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tion in patients with solid tumors. The active agents in Asian is unknown, although high concentrations of sanguinarine can
mushrooms, polysaccharides, also possess antitumor effects cause normal keratinocytes to necrose.
through inhibition of cellular proliferation and tumor growth, Websites selling black salves for veterinary cancer patients
invasion, and angiogenesis. 61 have, over the years, posted pictures showing tumor elimina-
Enthusiasm for the use of medical mushrooms in dogs with tion for patients that were purportedly deemed untreatable by
cancer followed the publication of a 2012 study in the journal conventional practitioners. Even Dr. Andrew Weil, the author of