Arecent meta-analysis of 3 clinical trials in Japan with 1,094 patients showed clear benefit from PSK supplementation (3.0g/day) in improving both survival and disease-free survival in cases of curatively resected colorectal cancer1,2. Chihara et al. also report excellent results from a 4 year follow-up of Lentinan in phase III patients with colorectal cancer3.
In a study on patients with advanced colorectal cancer, a polysaccharide extract from Ganoderma lucidum (5.4g/day) produced improvements in immune parameters with increases in mitogenic reactivity to phytohemagglutinin, counts of CD3, CD4, CD8 and CD56 lymphocytes, plasma concentrations of interleukin (IL)-2, IL-6 and IFN-γ, and NKcell activity, and decreases in plasma concentrations of IL-1 and tumour necrosis factor-alpha4.
It is also likely that dietary consumption of mushrooms might be beneficial in reducing incidences of colon cancer due to their high dietary fibre content and immune modulating activity, with Pleurotus ostreatus given at 5% of feed showing a protective effect on the development of dimethylhydrazine-induced colon cancer in rats5,6. Extracts from G. lucidum and Lentinula edodes also show protective effects against colon cancer development7,8.
1. Efficacy of adjuvant immunochemotherapy with polysaccharide K for patients with curatively resected colorectal cancer: a meta-analysis of centrally randomized controlled clinical trials. Sakamoto J, Morita S, Oba K, Matsui T, Kobayashi M, Nakazato H, Ohashi Y. Cancer Immunol Immunother. 2006;55(4):404–411.
2. Monitoring of immune responses to a herbal immunomodulator in patients with advanced colorectal cancer. Chen X, Hu ZP, Yang XX, Huang M, Gao Y, Tang W, Chan SY, Dai X, Ye J, Ho PC, Duan W, Yang HY, Zhu YZ, Zhou SF. Int Immunopharmacol. 2006;6(3):499–508.
3. Antitumour and metastasis-inhibitory activities of lentinan as an immunomodulator: an overview. Chihara G, Hamuro J, Maeda Y.Y, Shiio T, Suga T, Takasuka N, Sasaki T. Cancer Detect Prev Suppl. 1987;1:423–443.
4. Immune responses to water-soluble ling zhi mushroom Ganoderma lucidum (W.Curt.:Fr.) P. Karst. Polysaccharides in patients with advanced colorectal cancer. Huang M; Gao YH; Tang W; Dai X; Gao H; Chen GL, Ye JX, Chan EL, Zhou SF. Int J Med Mushrooms. 2006;7(4):525–538.
5. Effect of oyster mushroom (Pleurotus ostreatus) on pathological changes in dimethylhydrazine-induced rat colon cancer. Bobek P, Galbavy S, Ozdin L. Oncol Rep. 1998;5(3):727–730.
6. An aqueous polysaccharide extract from the edible mushroom Pleurotus ostreatus induces anti-proliferative and pro-apoptotic effects on HT-29 colon cancer cells. Lavi I, Friesem D, Geresh S, Hadar Y, Schwartz B. Cancer Lett. 2006;244(1):61–70.
7. A water-soluble extract from cultured medium of Ganoderma lucidum (Rei-shi) mycelia suppresses azoxymethane-induction of colon cancers in male F344 rats. Lu H, Kyo E, Uesaka T, Katoh O, Watanabe H. Oncol Rep. 2003;10(2):375–379.
8. Inhibition of human colon carcinoma development by lentinan from shiitake mushrooms (Lentinus edodes). Ng ML, Yap AT. J Altern Complement Med. 2002;8(5):581–589.