[A case of multiple liver metastases of colon cancer with PyNPase-positive successfully treated with 5'-DFUR].

A 75-year-old man was diagnosed with transverse colon cancer. We therefore performed a transverse colectomy. Diagnosis of multiple liver metastases was made by intraoperative palpation, core needle biopsy and postoperative abdominal CT scan. 5'-deoxy-5-fluorouridine (5'-DFUR) 800 mg/day was administered orally after the surgery. After 2 months of administration, an abdominal CT scan showed the metastatic lesions of liver were reduced. After 8 months, an abdominal CT scan showed no evidence of liver metastases. Pyrimidine nucleoside phosphorylase (PyNPase), an enzyme that converts 5'-DFUR to 5-FU, has an important role in the expression of the anti-tumor activity of 5'-DFUR. Primary specimens of this case were regarded as PyNPase-positive. We think that administration of 5'-DFUR may be a useful treatment for advanced colon cancer that is PyNPase-positive.