Chinese herbal medicine for pancreatic cancer

Description

Chinese herbal medicine is part of traditional Chinese medicine (TCM), a 3,000-year-old holistic system of medicine combining medicinal herbs, acupuncture, food therapy, massage, and therapeutic exercise for both treatment and prevention of diseases 1.

Components

TCM has its unique theories around concepts of aetiology, systems of diagnosis, and treatment, which are vital to its practice. The theories of TCM include Yin-Yang (e.g. positive and negative), the five elements (fire, earth, metal, water, and wood), Qi (vital energy) and blood, Zhang-Fu (five viscerae and six bowels), as well as channels and collaterals (Meridian doctrine) 2,3. Diseases are considered to result from internal causes as well as external causes, which are defined as disturbances e.g., the imbalance between Yin and Yang. Chinese medicines consist typically of complex prescriptions combining between four and 12 different herbal ingredients, including minerals or animal components. The combinations are based on special Chinese diagnostic patterns that involve inspection, listening, smelling, inquiry, and palpation.

Herbal therapy is the most commonly used part of TCM, and includes around 3,200 herbs. Herbs often used by cancer patients include Ginkgo biloba, Panax ginseng, and Astragalus membranaceus. About 300 mineral and animal extracts and over 400 formulas are used 2.

Application and dosage

TCM herbal therapy is applied in three different ways, including individualised treatment (prescription of herbs on the basis of a TCM differentiation of the symptoms), use of fixed herbal formulae (such as Chinese patented medicines), or the combined use of herbal medicine with conventional therapy. The composition of herbal preparations, dosage, and treatment duration vary.

History/providers

TCM practitioners can either prescribe herbal formulae as decoctions, or prescribe commercially marketed herbal products such as Chinese patented medicines. Chinese patented medicines are manufactured mainly in China, while other neighbouring countries such as Japan, Korea, also produce herbal products.

Claims of efficacy/alleged indications/mechanism of action

According to TCM principles, herbs are used for correcting the imbalance of Yin and Yang in the body and maintaining kinetic balance under the movement of five elements. “Bianzheng Lunzhi” (the differentiation of symptom patterns and the prescription of formula of herbs) is the application of these theories.

In TCM, there is no equivalent diagnosis for pancreatic cancer, but the treatment intends to relieve the symptoms related to pancreatic cancer. Herbal treatment is supposed to inhibit tumour growth and metastasis, stop pain and improve symptoms, reduce the adverse effects of chemotherapy and/or radiotherapy, enhance immunity, prevent relapse, increase survival, and improve quality of life. In line with TCM theory, practitioners prescribe herbal formulae according to the differentiation of symptoms of patients with pancreatic cancer 4. Therefore, the treatment varies from patient to patient and even at different stages of the disease.

Prevalence of use

Traditional Chinese herbal medicine has been used in China to manage the symptoms of patients with pancreatic cancer, such as jaundice, pain, and low appetite. There is no available data for the prevalence of herbal medicine use in pancreatic cancer patients. However, in China, it is not uncommon for patients with advanced pancreatic cancer to use herbal preparations and other TCM therapies.

Legal issues

In most European countries, herbal medicines are strictly regulated as dietary supplements. The European Directive on Traditional Herbal Medicinal Products allows herbal medicines to be registered as drugs if they have been used for 30 years (at least 15 years in EU countries and 15 years in non-EU countries) 5.

Cost

The cost of herbal medicine for patients with advanced pancreatic cancer can vary substantially. For herbal decoction only, it might take around 1,000 RMB (€120 or US$160) per month, and proprietary herbal products cost more, approximately, oral proprietary herbal medicine cost 2,000-3,000 RMB (€240-360 or US$320-480), and intravenous herbal injection costs an extra 4,000-8,000 RMB (€480-960 or US$640-1280) per month.

Chinese herbal medicine has been claimed by TCM practitioners to be able to improve survival and relieve pain and symptoms in pancreatic cancer patients. A total of 53 clinical studies investigate herbal therapy for pancreatic cancer, including 20 RCTs 6-25 and 4 non-randomized studies 26-29. There are no study reports on other TCM modalities such as dietary therapy, acupuncture, qigong, or massage available for this CAM summary.

Controlled clinical trials

Twenty-four clinical trials (Table 1) including 20 RCTs and 4 non-randomized trials are available. The 20 RCTs including 1145 mid/advanced stage pancreatic cancer patients tested different herbal medicines with or without chemotherapy. The 4 non-randomized studies involving 204 mid/advanced stage pancreatic cancer patients compared Chinese herbal products plus chemo/radiotherapy with chemo/radiotherapy alone.

In general, the randomised and non-randomised clinical studies, which were all conducted and published in China, showed significant benefits from the combination of Chinese herbal medicine with chemotherapy in terms of complete and/or partial remission, improvement of immunity function, improved quality of life, pain relief, and survival.

The outcomes reported in the included studies differed substantially. Although the number of clinical studies increased over time and a variety of positive clinical outcomes were reported, there was no solid evidence for a relative benefit of Chinese herbal medicine alone over chemotherapy. Risk of bias in these studies is high due to small sample sizes, and methodological flaws (randomization and blinding, intention-to-treat analysis, and attrition).

According to an empirical study by Vickers et al. 33, almost all Chinese acupuncture trials published in Chinese report positive results, and publication bias might be the major explanation. Since the studies in this summary were conducted and published in Chinese literature, the positive findings need to be interpreted with caution.

Pre-clinical studies

An in vitro study on two Chinese herbal formulations in pancreatic cancer cell lines showed a growth inhibition effect 32.

As the active ingredients of the herbal preparations are largely undefined, the biologic mechanisms of the potential effect have not been clearly elucidated.

Adverse events

The clinical studies reviewed above did not report adverse effects from herbal preparations in patients with pancreatic cancer. A further phase I safety study conducted in the US found PHY906 to be well tolerated 30,31. However, there are reports of liver toxicity and kidney damage associated with using Chinese herbal medicines 34,35. In recent years, Chinese herbal medicines have become the leading cause of hepatotoxicity from herbs.

Contraindications

TCM physicians prescribe different herbs and conventional treatments according to clinical experiences, and little evidence about contraindications has been found currently.

Interactions

Possible interactions between herbs and drugs may also exist 36,37. Studies indicate that taking antioxidants such as flavonoids could decrease or increase the effectiveness of some chemotherapy if used at the same time 36,38.

Warnings

In recent years, more and more manufacturers of herbal medicines in China meet Good Manufacturing Practices. For practitioner-prescribed herbal decoctions, it is, however, more difficult to assure the quality of both herbs and herbal preparations. Therefore, long-term use of herbs should be under close monitoring of liver and kidney functions.