Serum pepsinogens I and II and stomach cancer.

Prospective epidemiologic studies among Hawaiian Japanese men have shown that a serum pepsinogen I (PG I) level below 20 ng/ml is highly specific for extensive intestinal metaplasia of the stomach and for the intestinal type of stomach cancer. The test, however, shows a low level of sensitivity as a predictor of the intestinal type stomach cancer. Since antralization of the corpus, as encountered in Type A atrophic gastritis and late stage Type B gastritis, results in an increase of PG II relative to PG I, we examined the sensitivity and specificity of the PG I/PG II ratio as a predictor of gastric cancer. Using a cut-off point of 2.0 in the ratio to separate subjects at high and low risk for stomach cancer, we found a modest improvement in the level of sensitivity with a small decrease in specificity. Abnormally low PG I levels and PG I/PG II ratios were associated mainly with advanced stages of the intestinal type of cancer and therefore, are not useful screening tests to identify early cases of gastric cancer. The use of the PG I/PG II ratio resulted in a modest improvement in the level of sensitivity with a small decrease in specificity.