Comparative epidemiology of gastric cancer between Japan and China

AIM:To clarify the similarities and differences in gastric cancer epidemiology between Japan and China.METHODS:A comprehensive literature search of the PubMed database was performed.The relevant literature published in China was also been cited.Data on incidence and mortality rates in 2008 were obtained from the Cancer Mondial database,published by International Agency for Research on Cancer at http://www-dep.iarc.fr/.RESULTS:Gastric cancer remains a significant publichealth burden in both Japan and China.The prevalence of Helicobacter pylori(H.pylori)colonization is high in the adult populations of both countries.Accumulating evidence from intervention studies in both countries has shown the effectiveness of H.pylori eradication in reduc-ing gastric cancer incidence.There are differences,however,in many aspects of gastric cancer,including patterns of incidence and mortality,trends in the prevalence of H.pylori infection,H.pylori strains,the magnitude of risk of gastric cancer related to H.pylori infection,and associations with dietary habits.Compared with China,Japan has seen a more rapid decline in H.pylori infection among adolescents.While Japanese cohort studies have dominated the literature concerning the associations between gastric cancer and dietary habits,numerous case-control studies in China suggest a positive association between a high intake of preserved fish and vegetables and gastric cancer risk.There is a need for a multidisciplinary research approach to understand the interactions between various strains of H.pylori,host factors,and other lifestyle and environmental factors in gastric carcinogenesis in both countries.CONCLUSION:The shared high incidence of gastric cancer and high prevalence of H.pylori,as well as differences in many aspects of gastric cancer,provide an excellent opportunity to establish Sino-Japanese collaborations.

ABO blood type, long-standing diabetes, and the risk of pancreatic cancer

AIM: To retrospectively study pancreatic cancer patients with respect to their ABO blood type and diabetes. METHODS: Our analysis included a cohort of 1017 patients with pancreatic ductal cancer diagnosed at our hospital in Tokyo. They were divided into two groups: 114 patients with long-standing type 2 diabetes (DM group, defined as diabetes lasting for at least three years before the diagnosis of pancreatic cancer) and 903 patients without diabetes (non-DM group). Multivariate analysis was performed to identify factors that are associated with long-standing diabetes. The DM group was further divided into three subgroups according to the duration of diabetes (3-5 years, 5.1-14.9 years, and 15 years or more) and univariate analyses were performed. RESULTS: Of the 883 pancreatic cancer patients with serologically assessed ABO blood type, 217 (24.6%) had blood type O. Compared with the non-DM group, the DM group had a higher frequency of blood type B [odds ratio (OR) = 2.61, 95%CI: 1.24-5.47; reference group: blood type A]. Moreover, male (OR = 3.17, 95%CI: 1.67-6.06), older than 70 years of age (OR = 2.19, 95%CI: 1.20-3.98) and presence of a family history of diabetes (OR = 6.21, 95%CI: 3.38-11.36) were associated with long-standing type 2 diabetes. The mean ages were 64.8 ± 9.2 years, 67.1 ± 9.8 years, and 71.7 ± 7.0 years in the subgroups with the duration of diabetes, 3-5 years, 5.1-14.9 years, and 15 years or more, respectively (P = 0.007). A comparison of ABO blood type distribution among the subgroups also showed a significant difference (P = 0.03). CONCLUSION: The association of pancreatic cancer with blood type and duration of diabetes needs to be further examined in prospective studies.