Abstract
Objective: Generally, cancer screening using only tumor markers is considered insufficient because cancer often goes undetected in the early stage, and they sometimes produce false-positive results. The aim of this study was to evaluate the positive predictive value (PPV) of serum CA19-9 and perform analysis on patients with high CA19-9 levels.
Methods: Of the 32,508 patients whose serum CA19-9 was first measured from January 2006 to June 2013 in our center, 790 patients (0.024%) had high levels (> 37.0 U/mL). The subjects of our analysis were 320 patients among them whose serum CA19-9 was measured twice or more after the first measurement.
Results: Among the eight patients diagnosed with cancer, 4 had pancreatic cancer, 2 had duodenal cancer, 1 cystic duct carcinoma and 1 colon cancer. The median serum CA19-9 level of the 8 patients was 198.2 U/mL (Range 46.4 - 2,968 U/mL). The positive predictive value (PPV) was 2.5%.
Conclusion: Since the PPV of CA19-9 was only 2.5%, further examination of all patients with high levels may not be cost-effective. The use of the novel cancer detection method using organ-specific microRNA in combination with conventional tumor markers may be promising.
