[Serum pepsinogen I level in patients with stomach cancer--its value and limitation in clinical use].

We measured serum pepsinogen I (PG I) levels in 137 stomach cancer patients by the previously described radioimmunoassay and compared them with those of normal cancer-free subjects by a gastric mass survey in a certain workplace. The value and limitations of the measurement of serum PG I level in the diagnosis of stomach cancer were analyzed statistically according to the histology and stage of the disease. The mean serum PG I level of stomach cancer patients was 21.3 micrograms/l [early stage (N = 53): 24.9 micrograms/l; advanced stage (N = 84): 19.2 micrograms/l; well-differentiated (N = 62): 19.5 micrograms/l poorly-differentiated (N = 75): 22.7 micrograms/l]. It was significantly lower than that of the age-matched cancer-free subjects. As to the stage and histology of the disease, early stage poorly-differentiated adenocarcinoma and the same stage well-differentiated adenocarcinoma took the mean serum PG I level of 30.6 micrograms/l (N = 26, p less than 0.05) and 20.2 micrograms/l (N = 27, p less than 0.001). In the advanced stage, they were 19.3 micrograms/l (N = 49, p less than 0.001) and 18.6 micrograms/l (N = 35, p less than 0.001), respectively. Using a cut off point of 25 micrograms/l to separate subjects with stomach cancer, sensitivity was 61% and specificity, 80%. These results suggest a possibility of serological screening of the subjects with stomach cancer and indicate that the measurement of serum PG I level will probably contribute much to the improvement of the effectiveness of a gastric mass survey.