Complementary & Alternative Medicine, Department of Veterinary Clinical Sciences, Veterinary Medical Center, College of Veterinary Medicine, University of Minnesota, MN, USA
Introduction
Medicinal herbs have been used for more than 3000 years, and Shen Nong Ben Cao (106 BC–220 AD)9 is the first compiled book of herbs. Herb therapy has been accepted as a fundamental therapeutic modality for cancer treatment in Oriental Medicine in the past. Today, medicinal herb therapy is widely applied as an integrative medical modality that accompanies conventional therapies. Selected medicinal herbs have demonstrated anti-tumor activity, anti-inflammatory effect or analgesic effect for cancer pain.3,5,10 However, medicinal herbs for cancer therapy still remain a controversial medical modality to conventional oncologists due to the lack of knowledge of Oriental Medicine as well as the lack of scientific evidence for medicinal herbs used for cancer treatment as a CAM modality.11 For the last 50 years, Oriental Medicine has embraced conventional medicine continuously in cancer therapy. The integration of Oriental Medicine and conventional medicine will provide the more promising cancer therapy for the future.8 However, the lack of knowledge and profound scientific evidence about medicinal herbs have hampered their application for cancer therapy.
In this presentation, the basic theory and the application of medicinal herbs for cancer therapy will be discussed.
I. Fundamental Principle of Medicinal Herb for Cancer Therapy
The application of medicinal herbs should follow the theory of Oriental Medicine and should be based on the theory of herbology. The prescription of herbs is based on the patient's pattern differentiation.
The general five primary principles using medicinal herbs for cancer therapy are (1) tonification of Qi and blood, (2) elimination of toxic heat, (3) relieving stagnation of Qi, blood and phlegm, (4) nourishing Yin and (5) nourishing Yang.
1. Tonification of Qi and Blood
Since the fundamental etiopathogenic factor for cancer is Qi deficiency, tonification of Zheng Qi is inevitable for treating cancer.7 The herbs for tonification of Qi have an immune surveillance function that stimulates NK cell activity, balances Th/Tc cell ratio, synthesizes cytokines to restrict tumor cell growth, and regulates the cancer cell growth cycle.6 Medicinal herbs to tonify Zheng Qi include Huang Qi, Ren Shen, Dang Shen, Bai Zhu, Fu ling, Shan Yao, Yi Yi Ren, Bian Dou, Chang Zhu, and Chen Pi.1,2,12
2. Elimination of Toxic Heat
Toxic Heat is a leading cause of cancer; therefore, the elimination of toxic Heat is the primary approach in treating cancer. The herbs that eliminate toxic Heat can regulate the cAMP level, DNA/RNA synthesis of tumor cells, and suppress the mutation and growth of cancer. Many herbs in this group can stimulate not only immune functions but also have antibiotic, antitoxic, and anti-inflammatory properties.1,4 The herbs used for elimination of toxic Heat include Bai Mao Gen, Bai Hua Se Se Cao, Yu Xin Cao, Ban Zhi Lian, Qing Dai, Da Huang, Bai Yin, Bai Tou Weng, and Qi Ye Yi Zhi Hua.1
3. Relieve Accumulation of Qi, Blood, and Phlegm
Accumulation of Qi, Blood, or Phlegm leads to the generation of a hard mass, tumor or bleeding. Herbs in this group mainly shrink and dissolve the tumor. These herbs can also alleviate tumor-related pain, control metastasis, invigorate blood circulation, and boost immune functions. Common herbs for this group are San Lung, E Zhu, San Qi, Dang Gui, Dan Shen, Chuan Xiong, Ji Xue Teng, Ru Xiang, Mu Yao, Mu Dan Pi, and Chi Shao.1
4. Nourish Yin
Yin deficiency is a common phenomenon in many late stage cancer patients. Most cancer patients who receive chemotherapy, radiation therapy or surgery may develop Yin deficiency eventually. The reduction of the cooling function by Yin deficiency may increase empty Heat in the body resulting in deficiency of body fluid. Nourishing Yin can regenerate Body Fluid, restore organ function, and support yin, especially Kidney Yin. It can be used as a complementary therapy to regulate the growth of a tumor cell and to maintain a homeostatic stage of the body. The herbs for nourishing Yin include Sha Shen, Tian Dong, Mai Dong, Sheng Di, Shu Di, Huang Jing, Yuan Shen, Gu Qi Zi, Tian Hua Fen, Nu Zen Zi, and Bai He.1
5. Nourish Yang
The major role of Yang is to support the immune and endocrine systems and nourish bone and marrow. Nourishing Yang can be used in late stage lung, stomach, liver, breast, or prostate cancer where hormonal dysfunctions may be the primary concern. Nourishing Yang can also combine with nourishing Yin therapy to alleviate side effects from chemotherapy or radiation therapy. The herbs that Nourish Yang can increase antibody production, regulate macrophage, increase T-cell function, suppress the mutation of tumor cells, promote the proliferation of bone marrow, and regulate the neuro-endocrine system. Nourishing Yang herbs are Dong Chong Xia Cao, Yin Yang Huo (Xian Lin Bi), Xian Mao, Suo yang, Rou Cong Rong, Ba Ji Tian, Bu Gu Zi, Gou Ji, and Tu Si Zi.1
II. The Effect of Herbal Treatment to Manage Side Effects from Conventional Therapy
Three major conventional therapies for treating animal cancer are surgery, radiation therapy, and chemotherapy. Since conventional therapies have been known to be too invasive and often generate therapy-related adverse effects from mild to severe range, medicinal herbs have been applied to treat or alleviate the adverse effects from conventional therapy.
1. Surgery
Surgical therapy is often used for localized and encapsulated tumors. Side effects of surgery include gastrointestinal dysfunction, dehydration, weakening of body function. These side effects are due to the deficiency of Qi and blood in the Spleen, Kidney and Lung that lead to Wei Qi deficiency. Therefore, tonification of Wei Qi by nourishing Spleen, Lung and Kidney is the primary approach. Medicinal herbs have been used for alleviating pre- and post- surgery side effects for cancer patients such as pain, Wei Qi deficiency, and delayed duration of healing.
2. Radiation
Radiation therapy can be used for localized cancer, or it can be combined with chemotherapy. Because radiation therapy provides extreme heat, it can induce dryness, thirst, loss of appetite, heat sensations and radiation burns. Radiation therapy can generate deficiency of Qi and Blood, Yin deficiency, and toxic Heat in the radiated area and Blood level. Several herbs have been applied to tonify Qi and Blood, nourish Yin, and eliminate toxic Heat and alleviate pain and burns.1
3. Chemotherapy
Chemotherapy can be applied when metastasis of the tumor to the blood stream or other organs is suspected or confirmed. Side effects due to chemotherapy are gastrointestinal discomfort, hair loss, lowered white blood cell count and red blood cell count, weakened immune system, extreme lethargy, emotional depression, sores/rashes, and peripheral neuropathy. Based on Oriental Medicine theory, the etiopathogenesis of side effects due to chemotherapy is the deficiency of Qi and Blood in Spleen, Kidney, or Lung, Liver Blood deficiency, Kidney Yin deficiency, Stomach Yin deficiency, toxic Heat accumulation, Blood Stasis and Liver Qi stagnation. Herbal medicine can alleviate or prevent gastrointestinal discomfort, tonify and balance Zang Fu-organs, relieve blood stasis, and nourish Yin. In Oriental Medicine oncology, the side effects caused by chemotherapy may be categorized into Qi deficiency, Yin deficiency, and toxic Heat. Therefore, the medicinal herbs for treating chemotherapy-related side effects would be a combination of the herbs for boosting Qi, nourishing Yin, clearing toxic Heat, and eliminating toxins.
III. The Application of Medicinal Herbs For Treating Small Animal Cancer Patients
Cancer in dogs and humans is similar in regards to types, clinical manifestation, and etiopathogenesis. Since the treatment principle in Oriental Medicine oncology is based on pattern differentiation, we have been applying basic principles of human Oriental Medicine for animal cancer treatment.
Herbal formulas have been provided as complementary medical options for dogs undergoing conventional therapy to alleviate the adverse effects from these treatments or to increase the effects of conventional treatment. In addition, herb therapy can also be used as an alternative medical option for cancer dogs or cats that are not able to receive any conventional treatment. In any situation, the pattern differentiation of each patient should be completed.
Discussion
Cancer in dogs and cats shows high mortality and is still regarded as an incurable disease. Most studies on the effect of OM in cancer treatment have focused on human patients. Since the etiology and pathogenesis of small animal cancer in OM are similar to the human ones, Oriental Medicine oncology in small animals will be an essential research area for cancer treatment as well as a spontaneous animal model for cancer research.
In conclusion, the integration of Oriental Medicine and conventional therapies could provide better prognosis for small animal cancer patients. For expansion of the application of medicinal herbs for cancer therapy, further research should be implemented to provide stronger scientific evidences.
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