Esophageal Cancer in Iran: A Review

Esophageal cancer is the second and third most common malignancy in Iranian males and females, respectively; killing approximately 5800 Iranians each year. Squamous cell carcinoma (SCC) is presently the most common type 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 of esophageal SCC in the city of Gonabad (Golestan Province, northeast Iran) and further to the east, was found to be one of the highest rates for any single cancer that had been reported worldwide (age-adjusted rates > 100/105/year). Recent studies have shown that the incidence of SCC in Gonabad has declined to less than half of what it was in the past. This decline in the incidence of esophageal SCC parallels an improvement in the socioeconomic situation of people living in this region. According to recent cancer registry data in Iran there is still an obvious intracountry variability between the incidence of esophageal cancer in the south with an age standardizied rate (ASR) of 3 for males and 2 for females in Kerman and 43 and 36 in the northeastern province of Golestan, respectively for males and females. The reasons for the very high rate of SCC in northeastern Iran have been the subject of several studies during the past 35 years. According to results of these studies the suspected risk factors are: low intake of fruits and vegetables, drinking hot tea, consumption of opium products and tobacco, H.pylori infection in the stomach, using unhealthy drinking water from cisterns and genetic susceptabilty. 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 underway in northeastern Iran. The Golestan esophageal cancer cohort study with an enrollment of 50,000 subjects is now in its follow-up phase. We expect both simple and feasible evidence based preventive strategies to be implemented in the future from the results of these studies.