Diagnostic value of 5'-nucleotide phosphodiesterase isozyme-V for detection of liver metastasis in patients with gastro-intestinal cancer.

Serum 5'-nucleotide phosphodiesterase isozyme-V (5'-NPDase-V) in 200 patients with various gastrointestinal disorders including 178 malignant cases and 22 benign cases was measured, and the usefulness and limitations of this test for the detection of liver metastasis were studied. Of the laboratory tests performed in the 44 patients with liver metastasis, 5'-NPDase-V and carcinoembryonic antigen (CEA) (greater than 10.0 ng/ml) were positive in 68.2%. This rate was higher than that for any other laboratory test. Positive 5'-NPDase-V assays were found in 46.2% of the patients with H1 metastasis, 70% with H2 and 81% with H3. This test was considered to be useful diagnostically, when liver metastasis was of more than a certain degree. 5'-NPDase-V was positive in 85.7% of the patients who had liver metastasis and had a serum total bilirubin value of more than 2.5 mg/dl. Particular attention should be paid to the evaluation of this test when jaundice is present. In eight of the patients with liver metastasis, CEA (greater than 10.0 ng/ml) was negative, whereas 5'-NPDase-V was positive. One or both of these two markers were positive in 86.4%. A combination assay of these two markers was considered to be more useful than 5'-NPDase-V alone as a screening test for the detection of liver metastasis. In one patient who underwent hepatic lobectomy for recurrence of cancer in the liver, 5'-NPDase-V and CEA were measured before and after the operation. CEA returned to normal immediately after the operation, whereas 5'-NPDase-V became negative five months after the operation. It is presumed that the changes in 5'-NPDase-V after hepatic lobectomy were related to liver regeneration.