Background: To investigate the feasibility of combining several serum markers into a valid serum screening tool for gastric cancer, we performed a study evaluating the association between gastric cancer and precancerous conditions and a blood test for gastric acidity (the blood quininium resin test [QRT]) combined with serum pepsinogen levels.
Methods: We performed immunoradiometric assays of serum pepsinogen I (PG I), II (PG II) levels, and QRT's in 10 endoscopically normal subjects, in 20 patients with chronic atrophic gastritis, and in 13 patients with biopsy-confirmed gastric adenocarcinoma.
Results: Serum PG I, II levels, I/II ratio were significantly different among normal, gastritis, and cancer patients. Serum PG I/II ratios were much lower in cancer patients. Serum quinine levels by QRT were correlated with PG I/II ratio (rs=0.39, p<0.01). Age was negatively correlated both with PG I/II ratio (rs=-0.58, p<0.01) and serum quinine level (rs=-0.45, p<0.01). The screening using serum PG levels was more valid (sensitivity of 69%, specificity of 77%) than that using QRT alone. The combination of serum PG levels and QRT increased specificity for detecting gastric cancer to 87% without altering sensitivity.
Conclusion: Although blood QRT is a useful addition to other serum screening tests for gastric cancer, these tests alone are not sufficiently accurate as screening tools for gastric cancer.