Clinical studies in China showed polysaccharide extracts of Polyporus umbellatus to be as effective in preventing post-operative recurrence of bladder cancer as BCG (Bacillus Calmette-Guérin) and greater than Mitomycin C (MMC)1,2. One study of 313 patients after TURBT (transurethral resection of bladder tumour) or partial cystectomy who were followed up for 2 to 15 years (average 7.6 years) reported recurrence rates of 34.9% in the group receiving P. umbellatus polysaccharide extract, compared with 35.1% in the BCG group, 41.7% in the MMC group and 64.7% in the control group3.
In animal experiments P. umbellatus also inhibited the development of bladder cancer in rats exposed to N-butyl-N-(4-hydroxybutyl)nitrosamine with 11 of 18 animals staying cancer free. Polysaccharide extracts of Lentinula edodes, Grifola frondosa and Pleurotus ostreatus showed similar increases in host resistance with 9 of 17, 13 of 20 and 7 of 15 animals staying cancer free4.
In vitro studies with G. frondosa and Phellinus linteus extracts showed synergistic action with vitamin C against bladder cancer cell lines with non-cytotoxic doses of polysaccharide extracts becoming highly cytotoxic in combination with non-toxic levels of vitamin C5.
1. Inhibitory effect of Chinese herb medicine zhuling on urinary bladder cancer. An experimental and clinical study. Yang DA, Li SQ, Shi BY, Wang HW, Liu SG, Li YT, Zhou BM, Wang XX. Zhonghua Waike Zazhi, 1991;29(6):393–395, 399.
2. Prophylactic effects of zhuling and BCG on postoperative recurrence of bladder cancer. Yang DA, Li SQ, Li XT, Liu SG, Wang HW, Gao DJ. Zhonghua Waike Zazhi. 1994;32(7):433–434.
3. Prevention of postoperative recurrence of bladder cancer: a clinical study. Yang DA, Li SQ, Wang HW, Li XT, Liu SG, Han W, Hao JW, Zhang HB. Zhonghua Waike Zazhi. 1999;37(8):464–465.
4. Effects of Lentinus edodes, Grifola frondosa and Pleurotus ostreatus administration on cancer outbreak, and activities of macrophages and lymphocytes in mice treated with a carcinogen, N-butyl-N-butanolnitrosoamine. Kurashige S, Akuzawa Y, Endo F. Immunopharmacol Immunotoxicol. 1997;19(2):175–183.
5. Effect of various natural products on growth of bladder cancer cells: two promising mushroom extracts. Konno S. Altern Med Rev. 2007;12(1):63–68.