Tumor Dormancy Therapy Against Gastroenterological Cancer by Immunochemotherapy

Yasuyuki Sugiyama, Shigetoyo Saji, Kunihiko Yasuda, Shigeru Mori, Atsushi Matsuo and Atushi Watanabe

Second Department of Surgery, Gifu University School of Medicine

We conducted experimental and clinical studies to establish tumor dormancy therapy against gastroenterological cancer by immunochemotherapy. Immunopotentiators, such as OK-432, protein-bound polysaccharide (PSK) and lentinan, induced apoptosis in gastric cancer cell lines in vitro. Fluorouracil (FUra) in combination with cisplatinum (CDDP) also induced apoptosis in cancer cells, even though dosages did not alter the cancer growth curve. In some cases, lentinan augmented the induction of apoptosis caused by such che-motherapeutic agents. Ten of 25 gastroenterological cancer patients were diagnosed as sensitive to low-dose CDDP-FUra by collagen gel droplet embedded culture drug sensitivity test (CD-DST) testing. Nine patients with measurable advanced gastric cancer lesions in the peritoneal cavity underwent low-dose chemotherapy in combination with immunotherapy using lentinan, with the following clinical therapeutic effects; partial response in 2, minor response in 1, no change in 5, and disease progression in 1. Little toxicity was observed throughout treatment. In conclusion, low-dose chemotherapy combined with immunotherapy efficiently induces cancer cell apoptosis, suggesting this tumor dormancy therapy is a promising strategy in treating gastroenterological cancer.

Key words
tumor dormancy therapy, apoptosis of cancer cells, immunochemotherapy against gastroenterological cancer

Reprint requests
Yasuyuki Sugiyama Second Department of Surgery, Gifu University School of Medicine 40 Tsukasa-Machi, Gifu-City, 500-8705 JAPAN

Accepted
December 19, 2000

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