esophageal cancer in iran a review

esophageal cancer is the second most common malignancy in iranian men; it is the third in women. it is killing about 5800 iranians each year. squamous cell carcinoma (scc) is presently the most common type of esophageal cancer accounting for about 90% of all esophageal cancers in iran. recent studies in iran have shown that there is a gradual increase in the incidence of adenocarcinoma of the distal esophagus along with gastric cardia adenocarcinoma. thirty-five years ago, the age-adjusted incidence rate (asr) of scc of esophagus in gonbad city, golestan province, northeast of iran (›100 per 105 people per year), was found to be one of the highest rates for any single cancer ever reported in the world. recent studies have shown that the incidence of scc in gonbad has declined to less than half of what it was in the past. this decline in the incidence of esophageal scc is in parallel with improvement in socioeconomic status of people living in this region. according to the recent cancer registry data in iran, there is still an obvious intra-country variability between the incidence of esophageal cancer in south with an asr of 3 for men and 2 for women in kerman and 43 and 36, respectively, in northeastern province of golestan. the reasons for this very high rate of scc in northeastern iran has been the subject of several studies during the last 35 years. according to the results of these studies, the suspected risk factors include low intake of fruits and vegetables, drinking hot tea, consumption of opium products and tobacco, h.pylori infection in stomach, using unhealthy drinking water from cistern and genetic susceptibility. the main suspected mutagens are polycyclic aromatic hydrocarbons (pah) and n-nitroso compounds. in order to embark on a primary and secondary prevention of this fatal cancer further prospective studies are presently going on in the northeastern iran. golestan cohort study of esophageal cancer with enrollment of 50,000 subjects is now in its follow-up phase. we expect simple and feasible evidence based preventive strategies to be implemented in future from the results of these studies.