High prevalence of Helicobacter pylori infection in patients with colonic adenomas and carcinomas.

In some uncontrolled studies, a high prevalence of Helicobacter pylori infection unexpectedly has been found in patients with colorectal cancer. The purpose of the study was to investigate the prevalence of H. pylori infection in patients with colonic polyps or cancer. We reviewed 50 consecutive patients with either colonic adenomas or cancer who entered a preliminary case-control study. For each patient, 2 age- and gender-matched control subjects were selected (72 males; mean age, 63.1 years). A further 44 consecutive patients (30 with polyps and 14 with cancer) subsequently were enrolled. The H. pylori prevalence in patients with either polyps or cancer was compared with that in control subjects. Anti-H. pylori immunoglobulin G antibodies were assayed by an immunoenzymatic method. The prevalence of H. pylori antibodies was 49 (49%) of 100 in control subjects, 40 (71.4%) of 56 in patients with polyps (p < 0.006 vs. control subjects), and 21 (55%) of 38 in patients with cancer (not significant). Among patients with colorectal cancer, H. pylori prevalence was 9 (69.2%) of 13 for patients evaluated at the time of diagnosis and 12 (48%) of 25 for patients evaluated 1 to 9 years after surgery. We conclude that colonic neoplastic lesions, especially adenomas, are associated with an increased prevalence of H. pylori infection. The mechanisms underlying this association need to be elucidated.