Gastric cancer in Ardabil, Iran--a review and update on cancer registry data.
The incidence rate of gastric cancer in western countries has shown a remarkable decline in recent years while it is still the most common cancer among men in Iran. Ardabil, a North Western province, was found to have the highest rate of GC in Iran and one of the highest gastric cardia cancer rates in the world. We used the most recent data from Ardabil cancer registry to update on the incidence and mortality of GC and performed an extensive search of the English and Persian literature in Pub Med, Embase and all 5 Persian web-based databases, respectively, to summarize all possible risk factors for GC in Ardabil. The age-standardized incidence rate of gastric cancer was 51.8 (95% CI: 47.8-55.8) in men and 24.9 (95% CI: 21.5-27.2) in women per 100,000. Age-standardized mortality rates for gastric cancer in this population were 32.2 (95% CI: 29.1-35.3) and 16.3 (95% CI: 13.9-18.6). The gastric cardia sub-site was the most common location (32.7%) in Ardabil. According to our review H.pylori infection, gastroesphageal reflux symptoms, tobacco smoking, and high intakes of salt, red meat and dairy products increase the risk of GC while diets with a high content of allium vegetables and fruits, especially citrus fruits, and consumption of fresh fish, were significantly protective against GC. We conclude that Ardabil has the highest rate of GC in Iran and one the highest rates of gastric cardia cancer in the world, with no evidence of decline in incidence since 2000. In addition to H.pylori infection, the epidemic of gastroesphageal reflux disease and several dietary factors may be responsible for the very high incidence of gastric cardia cancer in Ardabil.