食管癌是一种发病于人体食管部位(包括贲门)的恶性肿瘤,世界各地发病率(与死亡率相近似)有较大差异,且有地区性集中多发的特点,甚至在世界上存在着断续的带状分布现象。对这种地理分布情况或规律的分析,有助于从地理环境方面探索食管癌病因、发病规律以及预防方法等,对研究食管癌具有重要的实践和理论意义。

In this paper,we have analysed the factors of the geographical environments, such asgeology,geomorphy,climate,soil,drinking water,and vegetation.The primary results have been obtained as below: In North China,the areas of high incidence rate are located on top of the layer of Permo-carboniferous period.In the coal bed,there is nitrogen which can form nitrosamines,but in the areas of high incedence rate of Sichuan Province, there is no such layer.This is something still should be studied. In the regions of low mountains and hills,and inclined plains,the mortality rates of esophageal cancer are the highest.As one moves away from these regions, the mortality rate will decrease.This variation in mortality rates seems to have some relation with the geomorphic features. These areas of high incidence rate are mostly located at regions of the subarid and subhumid climate which have relatively arid and warm environments (refer to moisture and heat).Taking the northern areas of esophageal cancer in Sichuan Province for instance,it has been found that the farther away from the central region with a high incidence rate of esophageal cancer,the more rainfall and the less arid it is,and the mortality rate of esophageal cancer decreases. In the drinking water and soil in these regions with a high incidence rate, there are nitrites and nitrates which are the precursor compounds of nitrosamines of carcinogenic substance.This phenomenon coincides with the meteorologic conditions of the subarid and subhumid regions and the contents of the trace elements such as molybdenum,copper,manganese,zinc are correspondingly lower than that for areas of low incidence rate.Among these elements,the low content of molybdenum is most obvious. Under the geomorphic features of low mountain and hill regions and the environments of the subarid and subhumid climate,the local masses of these areas of high incidence rate like pickled vegetables ,a local favorite food,This food has been identified that these pickled vegetables cooperated with the action of fungi produce strong carcinogen,