[A case of peritoneal disseminated sigmoid colon cancer with liver metastasis responding to S-1].

In October 2004, a 73-year-old man underwent loop ileostomy because of unresectable peritoneal disseminated sigmoid colon cancer with liver metastasis. The oral chemotherapy by S-1 was administered(80 mg/day for 4 weeks followed by a 2-week rest period). A half year later, the primary lesion was remarkably diminished on barium enema, and peritoneal dissemination and liver metastasis disappeared on CT. Because he was unwilling to have an ileostomy, we decided to resect the primary lesion and close the ileal stoma in May 2005. There was no obvious peritoneal dissemination, and operation was successful. He died without intestinal stoma one year after second operation. This therapy can be orally administered at home, and is considered to be useful from the viewpoint of QOL as well. S-1 is expected to be an effective agent for the treatment of colon cancer.