Prevalence of Helicobacter pylori infection and intestinal metaplasia in subjects who had undergone surgery for gastric adenocarcinoma in Northwest Italy

Aim: To investigate the seroprevalence of Helicobacter pylori (H pylori) infection and its more virulent strains as well as the correlation with the histologic features among patients who had undergone surgery for gastric cancer (GC). Methods: Samples from 317 (184 males, 133 females, mean age 69±3.4 years) consecutive patients who had undergone surgery for gastric non-cardia adenocarcinoma were included in the study. Five hundred and fifty-five (294 males, 261 females, mean age 57.3±4.1 years) patients consecutively admitted to the Emergency Care Unit served as control. Histological examination of tumor, lymph nodes and other tissues obtained at the time of surgery represented the diagnostic "gold standard". An enzyme immunosorbent assay was used to detect serum anti-H pylori (IgG) antibodies and Western blotting technique was utilized to search for anti-CagA protein (IgG). Results: Two hundred and sixty-one of three hundred and seventeen (82.3%) GC patients and 314/555 (56.5%) controls were seropositive for anti-H pylori (P<0.0001; OR, 3.58; 95%CI, 2.53-5.07). Out of the 317 cases, 267 (84.2%) were seropositive for anti-CagA antibody vs 100 out of 555 (18%) controls (P<0.0001; OR, 24.30; 95%CI, 16.5-35.9). There was no difference between the frequency of H pylori in intestinal type carcinoma (76.2%) and diffuse type cancer (78.8%). Intestinal metaplasia (IM) was more frequent but not significant in the intestinal type cancer (83.4% vs 75.2% in diffuse type and 72.5% in mixed type). Among the patients examined for IM, 39.8% had IM type I, 8.3% type II and 51.9% type III (type III vs others, P = 0.4). Conclusion: This study confirms a high seroprevalence of H pylori infection in patients suffering from gastric adenocarcinoma and provides further evidence that searching for CagA status over H pylori infection might confer additional benefit in identifying populations at greater risk for this tumor.