History of kampo medicine
Kampo medicines are traditional Japanese medicines produced from medicinal plants and herbs. Kampo originates from China and has been adapted to the Japanese culture
. Chinese herbal medicine was imported to Japan in 552 AD, after which it was uniquely developed into Japanese Kampo
. Traditional Chinese Medicine is deeply philosophical and ideological, while Japanese Kampo tends to be more practical and simplified, and relies little on Taoist or other Chinese philosophy
Kampo medicines are currently of great interest to palliative care physicians because of their potential to alleviate the adverse side effects of cancer treatment and improve patients’ quality of life.
Use of Kampo and CAM in Japan
In the past few decades, Kampo has reintegrated into modern medical practice, accompanied by a scientific reevaluation and critical examination of its relevance in conventional medicine
[2, 3]. Kampo has been used in addition or alternatively to conventional medicines
. Currently more than 70% of Japanese physicians prescribe Kampo medicines in daily clinical practices
. Previous survey research has reported that 76% of the general population in Japan and 50% of outpatients in Tokyo have used some form of CAM and that 10% of the general population and 19% of outpatients in Tokyo had used Kampo medicine prescribed by physicians within the last 12 months
[6, 7]. In addition, the prevalence of use of CAM by cancer patients was 44.6% in Japan
. Internationally, the estimates of CAM use are higher in East Asia and highest in Japan compared to the USA and European countries
[9, 10]. CAM is often used in palliative care settings where the goal is not cure but rather improvement in QOL
To date, the Ministry of Health, Labour and Welfare (MHLW) has approved the use of 148 Kampo medicines, and the prescription of Kampo medicines is within the national health insurance system
[3, 11]. Although Kampo can be seen as orthodox from a historical Japanese perspective, it tends to be classified as Complementary and Alternative Medicine (CAM) according to Western conventions. The main reason for this is the lack of scientific evidence of its efficacy and the limited knowledge and spread of this therapy in other regions, especially outside of East Asia.
However, clinical studies of Kampo have been conducted in Japan, and its efficacy has been reported in research papers. For example, a randomized control trial demonstrated that the Kampo medicine Rikkunshito exerted greater effects in alleviating gastrointestinal symptoms than cisapride (a gastroprokinetic agent)
. The efficacy of Rikkunshito against non-ulcer dyspepsia (NUD)
[13, 14], gastrointestinal symptoms after gastrectomy (surgical NUD)
, functional dyspepsia
[16, 17], and nausea and vomiting caused by selective serotonin reuptake inhibitors
 has also been reported. Also, the Japanese Society for Oriental Medicine has compiled comprehensive data on randomized controlled trials of Kampo medicine in Japan, published as “Evidence Reports of Kampo Treatment” (EKAT)
. In addition to clinical trials, the potential mechanisms of action of Kampo medicines are also starting to be reported
As described above, there is increasing evidence of the efficacy of Kampo medicines and increasing attention has been given to their clinical application. However, there has been no comprehensive investigation of the use of Kampo medicines in cancer treatment. Therefore, we conducted a nationwide survey of the current use of Kampo medicines for cancer-related treatment and of physicians’ attitudes toward using Kampo medicines in Japan.