Dual roles of peptic ulcer in the carcinogenesis or extension of early gastric cancer

Background: Early gastric cancer (EGC) often coexists with peptic ulcer. In this study we investigated the roles of peptic ulcer in the carcinogenesis and extension of gastric cancer. Methods: The clinicopathological characteristics of EGC and peptic ulcer an d their relationship, as well as that of the background intestinal metaplas ia, were compared among the following three groups: patients with peptic ul cer only inside the EGC (Contained group, 53 patients); patients with pepti c ulcer only outside the EGC (Separate group, 26 patients); and patients of EGC with no peptic ulcer (Absent group, 43 patients). Results: In the Separate group, a male preponderance was observed (P = .006 ), and all EGCs developed in the middle or lower third of the stomach (P = .06). Most of the ECCs were an intestinal type of cancer with severe backgr ound intestinal metaplasia. Topographically, 88% of the peptic ulcers in th e Separate group developed proximal to the EGG. On the other hand, in the C ontained group, most EGCs developed in the middle third of the stomach with an intestinal/diffuse type ratio of 1:1. Peptic ulcers inside the EGC were significantly more shallow than those that developed outside the EGC (P = 0.008). Although the incidences of submucosal cancer were nearly the same a mong the three groups, the maximum cancer diameter tended to be increased i n the Contained group compared to that in the Absent group, and the inciden ce of lymph node involvement tended to be higher in the Contained group (8% ) as compared with the other two groups (4%-5%). Conclusions: These results suggest that peptic ulcer outside the EGC contri butes to the development of the intestinal type of EGC, with the background of more severe intestinal metaplasia during the peptic ulcer healing proce sses, whereas peptic ulcer inside the EGC develops secondary to EGC and fav ors cancer extension and metastasis, Peptic ulcer associated with EGC can b e considered to exert different biological roles in the carcinogenesis or e xtension of ECG according to the location of the peptic ulcer.