One of the primary concerns of veterinarians is how to control cancer without weakening the host; herbal therapy offers a very practical and effective solution to this dilemma. In the authors’ opinion, when conventional therapy offers a very good chance of curing or sending a cancer into remission, then conventional therapy is warranted, with herbal adjunctive therapy of paramount importance. However, when the outcomes are likely to be palliative, or when they are unknown, then herbal “chemotherapy” is a viable alternative to conventional chemotherapy after risks and benefits of treatment have been weighed. Even with grave prognoses, many cases have demonstrated that improvement in health and longevity is possible, despite the presence of cancer.
The known mechanisms of herbal actions can be integrated in a holistic approach to cancer care through a strategy that incorporates tradition and science. By using a variety of herbs with different anticancer activities, veterinarians are using, in effect, a form of “polyvalent herbal chemotherapy.” At the same time, traditional herbal medicine treatment is aimed at treating the patient, rather than the disease. As has been discussed, the number of herbs that have demonstrated some form of anticancer activity is immense and may at first seem overwhelming, but this fact can be used to take advantage of both approaches.
The individual animal’s diagnosis, stage of disease, history, presentation, vitality or debility, and system functioning will affect treatment strategy and herb selection. Traditional Chinese herbalists and Western herbalists have always used several herbs in combination and will change formulas over time as the needs of the patient change.
The author proposes that several herbs that treat the individual patient should be combined to obtain the following outcomes:
• Alleviation of signs and symptoms of the patient.
• Relief of possible pain, anemia, poor appetite, cachexia, depression, diarrhea, adverse effects of chemotherapy, bleeding, edema, leukopenia and so forth.
• Appropriate herbs that treat specific areas of the body should be selected, for example, renal herbs or liver herbs for renal or liver cancer.
Cancer is a very diverse disease that is considered by herbalists to be an expression of physiologic imbalance. Treatment seeks to improve physiologic functioning and waste removal through “detoxifying” with the use of gentle aperatives and laxatives, lymphatics, and “blood-cleansing” herbs (i.e., alteratives). Particular attention should be paid to herbs of the gastrointestinal system with concurrent actions, such as cholagogues, liver tonics, bitters, diuretics, and carminatives.
Herbs that support the patient should be selected in the first instance, particularly if infection is present (previous high-dose prednisolone therapy is common with occult infections that have often been untreated). Antimicrobials and antiseptics should be considered, if necessary. Herbs that modify or stimulate immunity help the patient’s own body to resist the effects of cancer.
The practitioner seeks to reduce the physical effects of stress and assist “adaptive energy,” particularly when the patient is debilitated, but also in an attempt to prevent debilitation. Most adaptogens have multiple actions, and selection must be made according to which is the best one for the patient. For example, a hyperactive young dog with lymphosarcoma would be better treated with Withania rather than Panax; however, an old, debilitated, sleepy dog might be better suited to Panax.
Tumor biology and tumor type
When possible, the practitioner should incorporate herbs that have known antineoplastic activity; often, these are the same herbs that fall into the other categories discussed earlier. When possible, and when the information is available, one should select herbs that have known activity against particular tumor types.
Patients with cancer or that are on chemotherapy or radiation therapy will benefit from antioxidants. Reviews of the many in vitro, animal, and human studies have demonstrated the beneficial effects of antioxidants on oxidative damage reduction. Many herbs with antioxidant activities have antineoplastic activity, and similarly, many antineoplastic herbs have antioxidant activity.
In summary, a simple approach involves considering the effects or potential effects of the cancer on an individual patient with goals toward strengthening bodily resistance and overall health by improving immunity and physiology, alleviating symptoms, and using antioxidant and adaptogen herbs. If this is done, anticancer activity is usually inherent in the prescription. As well, specific herbs can be used for known activity against particular types of cancers. Many herbs exhibit overlapping actions that fulfill more than one action category.
Strategy for prescribing using key mechanisms of action focused on the patient
Example: An old dog with hepatic adenocarcinoma that is cold, arthritic, and overweight. Chemotherapy has been declined. (Note: This formula could be used concurrently with chemotherapy.)
• Burdock 25% (cold): Differentiation inducer, depurative (alterative), diuretic, mild laxative, mild antiseptic. Traditional use in arthritis, cancer.
• Turmeric 25% (warm): Inhibits metastasis, angiogenesis, local invasion. Is anti-inflammatory, antioxidant, antiplatelet, hepatoprotective, cholagogue. Traditional use in arthritis, cancer, and improved digestion and hepatic function.
• Panaxginseng 25% (neutral to warm, dry): Inhibits local invasion, adaptogenic, stimulant, tonic, hypoglycemic, immune stimulant, hepatoprotective, cardioprotective. Traditional use for cancer, chronic inflammation, improved resistance to infection, and minimization of adverse effects of chemotherapy.
• Astragalus 25% (sweet and slightly warm): Inhibits metastasis. An adaptogen, tonic, cardiotonic, immune enhancer, diuretic. Used for cancer, chronic debility, chronic hepatitis.
This formula provides antineoplastic activity; adaptogen, antioxidant, alterative, and immune-supporting herbs; and alleviates symptoms of chronic inflammation (arthritis). In addition, some hepatoprotective and tonic effects are given for this old dog. This formula could be altered with milk thistle, Schisandra, or Bupleurum over time. In addition, this diet should be supplemented with turmeric or green tea for further antioxidant and antineoplastic actions. Generally, the formula is also warming.
Herbs and Conventional Tumor Therapies: Many oncology drugs induce cellular toxicity and death through free radical generation; some concern exists that antioxidants may negate these cytotoxic properties. In a review of all English articles listed in Index Medicus between the years 1990 and 2000 that were related to antioxidants and interactions with anticancer drugs or radiation, the authors concluded, “There is a rational basis for the continued use of antioxidant agents as a therapeutic adjunct in cancer therapy, with such use also offering potential to abrogate the carcinogenic process and mutation-driven drug resistance, but convincing data and widespread acceptance of such a role [are] dependent on additional, appropriately relevant trials”. Chemotherapeutic drugs that are best known for creating cellular damage by initiating free radical and reactive oxygen species (ROS) damage include the alkylating agents, such as cyclophosphamide, ifosfamide, and melphalan; the tumor antibiotics, such as doxorubicin, bleomycin, and epirubicin; and the platinum compounds, such as cisplatin. Radiation therapy uses ionizing radiation to produce cell kill through free radical generation. Unfortunately, a number of physiologic adverse effects of these therapies (e.g., doxorubicin-induced cardiotoxicity cisplatin-induced nephrotoxity, bleomycin-induced pulmonary fibrosis) are related to oxidative damage. Evidence is accumulating that antioxidants are helpful in attenuating these side effects. Careful selection of herbs that help reduce these adverse effects and protect these organs and systems (see relevant system herbs) can be used. Because antioxidant activity is inherent in many herbs, two options with chemotherapy and radiation therapy are available, if the theoretical concern exists. Herbal treatment should be stopped just before conventional treatment is begun (24-48 hours) and recommenced in approximately 5-7 days depending on the half life of the chemotherapeutic drug (or longer for radiation therapy); or herbal treatment should be continued concurrently. In the authors’ experience, concurrent treatment helps to reduce the adverse effects of treatment and to maintain “wellness.”
Much has been made in the medical literature of drug-herb interactions, and specifically the CYP450 hepatic microsomal system which is responsible for metabolizing many commonly prescribed drugs. While the list of potential interactions is very long, the evidence for real interference, by herbs, in the metabolism of most drugs is lacking. In many cases, medical experts warn that potentially useful herbs should not be administered on the basis of a single in vitro study of a single chemical contained within that plant. Food itself can alter the activities of CYP450 enzymes. Herbs taken orally must pass through the GI tract, be acted upon by digestive enzymes and gut bacteria, pass through portal circulation and get to the liver for whatever processes occur there.
As an example, isolated gingkolic acids from gingko and hyperforin from Saint John’s Wort inhibit CYP2C19 activity in vitro. However, using more complete extracts of the herb of each in humans appears to induce CYP2C19. To date, a small number of herbs have been examined in humans and animals for their influences on metabolism of a small number of drugs. Site provides a listing of potential herb-drug interactions, and should be used by the practitioner as a starting point for an evidence-based approach to the subject.