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

Authors: Motomichi Torisu, Yoshihiko Hayashi, Toshiyuki Ishimitsu, Takeshi Fujimura, Kazunori Iwasaki, Mitsuo Katano, Hiroshi Yamamoto, Yutaka Kimura, Masaharu Takesue, Motoharu Kondo, and Kikuo Nomoto

Journal: Cancer Immunology Immunotherapy

Study Design: Randomized, double-blind, placebo-controlled trial

• Participants: 111 patients with advanced colorectal cancer who underwent curative surgery
• Trial Length: 2 years
• Intervention:
  • PSK group (n = 56): 3g PSK orally daily for 2 months post-surgery, then 2g daily until 24 months, then 1g daily thereafter
  • Placebo group (n = 55): Placebo orally on the same schedule as the PSK group
• Primary Outcomes: Disease-free interval and survival rate

Summary: The study investigated the impact of oral PSK administration on disease-free interval and survival in patients with colorectal cancer following curative surgery. The results demonstrated that PSK significantly prolonged the disease-free interval (P < 0.05) and improved the overall survival rate (P < 0.05) compared to the placebo. The study also explored potential mechanisms behind PSK’s effects, observing enhanced activity of polymorphonuclear leukocytes in PSK-treated patients. The findings suggest that PSK may be a beneficial adjuvant therapy for colorectal cancer patients, potentially by boosting immune function