Purpose: To investigate the etiologies of remarkably elevated serum levels of CA 19-9.
Methods: During January 2014 to June 2020 patients with CA 19-9>1000 U/ml were included. The frequencies of distant metastases for malignant patients and serum levels of carbohydrate embryonic antigen (CEA) and carbohydrate antigen 125 (CA 125) were analyzed.
Results: Of the 125 patients included, 113 (90.4%) were diagnosed with malignancy, 100 (80%) with digestive cancer and only 36 (28.8%) with pancreatic cancer (PC). In patients with malignancy, 75 (66.3%) had distant metastasis and 60 (53.1%) had liver metastasis. The median levels of CEA and CA 125 in patients with malignant disease were significantly higher than in patients with benign disease (19.05 ng/ml versus 3.16 ng/ml, p=0.01; 83.32 U/ml versus 18.35 U/ml, p=0.01, respectively).
Conclusion: CA 19-9>1000U/ml indicated a high probability of having malignant disease, especially digestive cancer, but not always PC. Patients with malignant disease had high proportion of distant metastasis, mostly in the liver. Combined tests of CEA and CA 125 had potential role in distinguishing between benign and malignant diseases.