A patient of mine recently brought turkey tail mushrooms to my attention. He reported that a medical preparation of this naturally occurring fungus is routinely used in Japan to support systemic chemotherapy for certain cancers. He specifically said that Japanese medical insurance covers turkey tail mushrooms prescribed to enhance treatment success.

I like it when patients share information I might not have heard about. I learned three things:

1. He’s right about Japan. According to UCLA Health, “A preparation made from the turkey tail mushroom, known as krestin, has been used as a supportive therapy in cancer treatment in Japan for decades.”
2. It appears that two natural compounds in turkey tail mushrooms boost immune system power and thus reinforce pharmaceutical treatments for various metastatic cancers.
3. I found only one published study on PSK and prostate cancer (PCa).

The following amplifies each of these points.

1 – Japanese use of medicinal turkey tail mushrooms

The National Library of Medicine offers this: “For more than 30 years, medicinal mushrooms have been approved as an addition to standard cancer treatments in Japan and China. In these countries, mushrooms have been used safely for a long time, either alone or combined with radiation or chemotherapy.” Information from a pharmaceutical site states that an extract form these mushrooms is indeed approved as a pharmaceutical-grade medicine in Japan as a supplement to chemotherapy in cases of gastric (stomach), colon and colorectal cancer. It is covered by Japan’s national health insurance. It is typically taken by mouth, and reports of side effects are minimal, and include diarrhea, darkened stools, and darker nail color. It is not used as a stand-alone cancer treatment, but may be given before, during and after conventional drugs.

2 – Two natural compounds

There are two different but molecularly related compounds that seem to be the “active ingredients” in turkey tail mushrooms. The first, polysaccharide-K (PSK), has been shown in lab studies to accelerate the development of the immune system’s anti-cancer weapons, cytokines and natural killer cells. It’s worth noting that since chemotherapy can damage the immune system, there is some thinking that PSK not only boosts the immune system but may help protect or repair it during chemotherapy. The second, polysaccharide peptide (PSP), also demonstrates in lab tests that it helps increase the type of white blood cells that fight infection and boost immunity. Clinical studies using one or both of these compounds as an adjunct with conventional treatment in advanced cases of gastric, breast, colorectal and lung cancer have shown promising results.

3 – What about prostate cancer (PCa)?

I was able to find just one published paper by Wenner, et al. (2012) devoted exclusively to PSK and human PCa cells injected in mice.^[i] In this laboratory study, in which tumors could be felt at the injection site after two weeks’ growth, the mice were randomly assigned to one of 4 groups:

1. A control group treated only with saline (saltwater)
2. A group treated only with the chemotherapy drug docetaxel
3. A group treated only with PSK
4. A group treated with docetaxel plus PSK.

Depending on the protocol for each group, treatment continued for 11-13 days before the mice were sacrificed to harvest the tumors for end-point multi-analysis.

The authors report that the combination of docetaxel plus PSK offered “significantly higher tumor suppression than either treatment alone.” This included reduced tumor growth and greater cancer cell death; meanwhile fewer white blood cells occurred than in the docetaxel only group while there were more tumor-infiltrating killer T cells. Other positive effects were also noted, with the authors concluding, “This study is the first to show that PSK enhances docetaxel-induced prostate cancer tumor suppression, apoptosis and antitumor responses.”

In short, despite the lack of additional studies specific to PCa and PSK, this study clearly revealed that PSK offers the ability to boost the success of chemotherapy against particular cancer. Knowing that PSK derived from turkey tail mushrooms has been used in conjunction with chemotherapy in Japan for 30 years, why isn’t this happening in the U.S.? It seems that there’s no simple answer. There are hints that government-funded research in this area has been proposed, perhaps even begun, but reasons for not pursuing it are unclear.

The best advice I can offer is this: If you’re a PCa patient interested in the benefits of turkey tail mushrooms—or any mushroom-based product, for that matter—please discuss this with your own doctor. Do not prescribe any supplement for yourself without first clearing its use with your doctor, and including it in your medical records. Do not use your cancer as a self-experimental laboratory. While Nature undoubtedly offers us a bounty of healing resources, many of which have not even yet been discovered, having a primary care doctor who is familiar with you and your medical history makes sure that your story finds its way into records that not only benefit you, but may anonymously contribute to future statistics that help us all.

NOTE: This content is solely for purposes of information and does not substitute for diagnostic or medical advice. Talk to your doctor if you are experiencing pelvic pain, or have any other health concerns or questions of a personal medical nature.

References

[i] Wenner CA, Martzen MR, Lu H, Verneris MR, Wang H, Slaton JW. Polysaccharide-K augments docetaxel-induced tumor suppression and antitumor immune response in an immunocompetent murine model of human prostate cancer. Int J Oncol. 2012 Apr;40(4):905-13.