Kim, Sang-Eun;Shong, Young-Kee;Cho, Bo-Youn;Kim, Noe-Kyeong;Koh, Chang-Soon;Lee, Mun-Ho;Hong, Seong-Woon;Hong, Kee-Suk
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To evaluate the performance characteristics of CA 19-9 radioimmunoassay and the clinical significance of serum CA 19-9 assay in patients with malignancy, serum CA 19-9 levels were measured by radioimmunoassay using monoclonal antibody in 135 normal controls, 81 patients with various untreated malignancy, 9 patients of postoperative colon cancer without recurrence and 20 patients with benign gastrointestinal diseases, who visited Seoul National University Hospital from June, 1984 to March, 1985. The results were as follows; 1) The CA 19-9 radioimmunoassay was simple to perform and can be completed in one work day. And the between-assay reproducibility and the assay recovery were both excellent. 2) The mean serum CA 19-9 level in 135 normal controls was $8.4{\pm}4.2U/mL$. Normal upper limit of serum CA 19-9 was defined as 21.0 U/mL. 4 out of 135(3.0%) normal controls showed elevated CA 19-9 levels above the normal upper limit. 3) One out of 20(5.0%) patients with benign gastrointestinal diseases showed elevated serum CA 19-9 level above the normal upper limit. 4) In 81 patients with various' untreated malignancy, 41 patients(50.6%) showed elevated serum CA 19-9 levels. 66.7% of 18 patients with colorectal cancer, 100% of 2 patients with pancreatic cancer, 100% of 3 patients with common bile duct cancer, 47.1% of 17 patients with stomach cancer, 28.6% of 28 patients with hepatoma and 60.0% of 5 other gastrointestinal tract cancers showed elevated serum CA 19-9 levels. 5) The sensitivities of serum CA 19-9 related to resectability in colorectal and stomach cancer were 33.3% in resectable colorectal cancer, 83.3% in unresectable colorectal cancer, 41.7% in resectable stomach cancer, 60.0% in unresectable stomach cancer respectively. 6) The sensitivity of serum CA 19-9 in 9 patients of postoperative colorectal cancer without recurrence were 33.3% and significantly decreased compared with that of untreated colorectal cancer, 66.7% (p<0.05). 7) In patients with colorectal cancer, simultaneous measurement of serum CA 19-9 and serum CEA levels increased sensitivities. From above results, we concluded that serum CA 19-9 radioimmunoassay is simple to perform and reproducible, and is a useful indicator reflecting tumor extent and responses to the treatment in patients with malignancy.