PSK, a Turkey Tail extract used in Japan, was tested in randomized trials alongside older chemotherapy. The survival signal is modest, and mushroom tea is not PSK.
PSK (krestin) has been used in Japan as an add-on to chemotherapy. Randomized trials in gastric and colorectal cancer reported a modest survival signal.
The evidence is low certainty, the chemotherapy regimens tested are outdated, and no trial tested mushroom tea.
Did you know that an extract from the turkey tail mushroom has been tested in thousands of actual cancer patients, including in random controlled human trials with statistically significant benefits? It's called PSK, short for polysaccharide K. It is from the turkey tail mushroom.
I had a patient who survived stage three colorectal cancer and credited her Japanese mushroom regimen for it. I made light of her non-FDA-approved remedies at the time, but now I feel guilty about it, because the National Cancer Institute cites a 2007 meta-analysis involving eight randomized trials and 8,009 patients with gastric cancer. Adding PSK to chemotherapy alone was associated with a 12% reduction in the risk of death compared to chemotherapy alone.
One particularly interesting randomized trial involved 262 patients after surgery for gastric cancer. Everyone received standard of care, but one group also received polysaccharide K, and there was a 28% relative risk reduction of cancer reoccurrence in five years for patients taking PSK. In layman's terms, listen to this, that means for every 100 patients treated, adding PSK resulted in about 11 additional patients being alive.
One randomized colorectal study of 205 patients reported a 43.6% reduction in recurrence when PSK was added to chemotherapy. That is, for every 100 patients treated, adding PSK was associated with about 14 additional patients being alive and cancer-free five years later.
Effective? Safe? Yes and yes. We're the Verity Health Institute. We give you the research. You decide.
Educational research summary, not medical advice. Talk with your oncologist and pharmacist before starting, stopping or changing any treatment or supplement.