Significant prolongation of disease-free period gained by oral polysaccharide K (PSK) administration after curative surgical operation of colorectal cancer

Cancer Immunol Immunother. 1990;31(5):261-8. doi: 10.1007/BF01740932.


To examine the clinical efficacy and the mechanism of action of polysaccharide K (PSK), a protein-bound polysaccharide extracted from a Basidiomycetes fungus, a randomized double-blind trial was performed by administering PSK to 56 patients and a placebo to another group of 55 patients after surgical operations on their colorectal cancers. The rate of patients in remission (or disease-free) was significantly higher in the PSK group than in the placebo group; the difference between both groups was statistically significant at P less than 0.05 by the log-rank test. The survival rate of patients was also significantly (P less than 0.05) higher in the PSK group than in the control group. The most significant laboratory finding was that polymorphonuclear leukocytes from PSK-treated patients showed remarkable enhancement in their activities, such as random and/or chemotactic locomotion, and phagocytic activity, when compared with those in the control group. In conclusion, PSK was useful as a maintenance therapy for patients after their curative surgical operations for colorectal cancer. The beneficial effects were probably due to the activation of leukocyte functions as one of the many biological-response-modifying (activities induced by PSK).

Publication types

  • Clinical Trial
  • Randomized Controlled Trial

MeSH terms

  • Administration, Oral
  • Adult
  • Aged
  • Aged, 80 and over
  • Antibiotics, Antineoplastic / administration & dosage
  • Antibiotics, Antineoplastic / adverse effects
  • Antibiotics, Antineoplastic / therapeutic use*
  • Blood Proteins / physiology
  • Chemotaxis, Leukocyte / drug effects
  • Colorectal Neoplasms / drug therapy*
  • Colorectal Neoplasms / mortality
  • Colorectal Neoplasms / surgery
  • Complement System Proteins / drug effects
  • Complement System Proteins / physiology
  • Double-Blind Method
  • Humans
  • Leukocytes / drug effects
  • Leukocytes / physiology
  • Luminescent Measurements
  • Middle Aged
  • Proteoglycans / administration & dosage
  • Proteoglycans / adverse effects
  • Proteoglycans / therapeutic use*
  • Randomized Controlled Trials as Topic
  • Skin / drug effects
  • Skin / immunology


  • Antibiotics, Antineoplastic
  • Blood Proteins
  • Proteoglycans
  • phagocytosis-stimulating factor
  • polysaccharide-K
  • Complement System Proteins