1 Synchronous cancers are now becoming increasingly relevant and efforts should be made to diagnose them early. The most frequent synchronous cancer in gastric cancer patients is colorectal cancer,2 with a growing incidence,

probably the result of an increasingly older population and “westernization” selleck of lifestyle factors. The association of GN and CRN was first described in the USA, by Cappell and Fiest in 1995,3 although this association has not been confirmed in Western cancer registries.4 The reason for this geographical difference is not clear, but may be related to genetic and environmental factors, which differ between Eastern and Western countries. The association between gastric and colorectal neoplasm that has been described in countries such as Korea and Japan may be due to genetic factors, as showed by the shared genetic alterations such as microsatellite instability and K-ras point mutations.5 It may also be due to environmental factors. The latter include diet, smoking, alcohol, and aspirin medication. These factors have been extensively studied in relationship PF-01367338 to gastric and colorectal cancer, with conflicting results.6,7

Obesity has also been shown by some investigators to be a significant risk factor for colorectal neoplasia8 and for gastric cancer.9 Kim et al. showed that the prevalence of colorectal neoplasia increases with an increase of body mass index in gastric cancer patients, but they did not find statistical significance in their series.10 There has been a growing recognition of the importance of metabolic syndrome (MetS) as an increased risk for cardiovascular disease and other chronic diseases,

including cancer (in many series the commonest cause of death for people with type 2 diabetes). Several investigators have showed that MetS is associated with rectosigmoid adenomas in Chinese, Japanese 上海皓元 and Korean populations.11–14 Waist circumference and waist-to-hip ratio, indicators of abdominal obesity, were also strongly associated with colorectal cancer risk in a prospective European study.15 A meta-analysis has also confirmed the association between obesity and colorectal cancer risk.16 In this issue of the Journal, Park and co-workers17 have studied for the first time how the presence of MetS in patients with GN (gastric adenoma or cancer) relates to the presence of CRN (colorectal adenoma or cancer) and they have tried to propose a model for risk stratification for colorectal screening in patients with GN. The authors retrospectively studied a group of 492 patients with GN who simultaneously underwent colonoscopy and compared them with a 492 age-matched control group.