AIM To evaluate the incidence and clinical characteristics of gastric cancer (GC) in peptic ulcer patients with Helicobacter pylori (H. pylori) infection.

METHODS Between January 2003 and December 2013, the medical records of patients diagnosed with GC were retrospectively reviewed. Those with previous gastric ulcer (GU) and H. pylori infection were assigned to the HpGU-GC group (n = 86) and those with previous duodenal ulcer (DU) disease and H. pylori infection were assigned to the HpDU-GC group (n = 35). The incidence rates of GC in the HpGU-GC and HpDU-GC groups were analyzed. Data on demographics (age, gender, peptic ulcer complications and cancer treatment), GC clinical characteristics [location, pathological diagnosis, differentiation, T stage, Lauren's classification, atrophy of surrounding mucosa and intestinal metaplasia (IM)], outcome of eradication therapy for H. pylori infection, esophagogastroduodenoscopy number and the duration until GC onset were reviewed. Univariate and multivariate analyses were performed to identify factors influencing GC development. The relative risk of GC was evaluated using a Cox proportional hazards model.

RESULTS The incidence rates of GC were 3.60% (86/2387) in the HpGU-GC group and 1.66% (35/2098) in the HpDU-GC group. The annual incidence was 0.41% in the HpGU-GC group and 0.11% in the HpDU-GC group. The rates of moderate-to-severe atrophy of the surrounding mucosa and IM were higher in the HpGU-GC group than in the HpDU-GC group (86% vs 34.3%, respectively, and 61.6% vs 14.3%, respectively, P < 0.05). In the univariate analysis, atrophy of surrounding mucosa, IM and eradication therapy for H. pylori infection were significantly associated with the development of GC (P < 0.05). There was no significant difference in the prognosis of GC patients between the HpGU-GC and HpDU-GC groups (P = 0.347). The relative risk of GC development in the HpGU-GC group compared to that of the HpDU-GC group, after correction for age and gender, was 1.71 (95%CI: 1.09-2.70; P = 0.02).

CONCLUSION GU patients with H. pylori infection had higher GC incidence rates and relative risks. Atrophy of surrounding mucosa, IM and eradication therapy were associated with GC.