Based on new experiment and investigation data, this paper studied relationship between incidence and mortality of esophageal cancer (EC) and water improvement in Linzhou City, China. Linzhou City is one of areas with highest incidence and mortality of EC over the world. Up to now, the carcinogenic substances and correct sanitation actions are not clear. This study investigated the corrective relationship between incidence and mortality of EC and improvement of drinking water by carrying out experimental and data analysis. Firstly, the vicia faba micronucleus test was performed to detect genetic toxicity of substances in drinking water. For this purpose, broad beans were oaked, pre-germination fixed, hydrolysised and dyed for different water samples. Micronucleus among 1000 apical meristem cells on buds were counted under microscope. In the mean time, distilled water and dilution of potassium dichromate were also tested for negative and positive control. Micro-pollution index of sample water was detected as rate between micronucleus rates of the sample water and distilled water. Secondly the areas of Linzhou City were divided into two groups according to their conditions of drinking water. One is improved drinking water group in which people drink deep well water, and another is non-improved drinking water group containing the rest part of areas. Finally historical data of farmer population, incidence and mortality of EC was obtained from Linzhou Cancer Research Institute for years 1959-1974, and recollected by our center for years 2001-2003. After performing comparisons between incidence and mortality of EC for different area groups and time periods, it was found that the incidence and mortality of improved drinking water group were not different from that of non-improved drinking water group before applying drinking water improvement. After drinking water improvement, the incidence and mortality of improved drinking water group decreased 29% and 43%, respectively. For the non-improved drinking water group, on the contrast, the incidence increases 6%, and the mortality decreases only 1.7%. It was also found that micro-pollution indexes of drinking water agree well with incidences and mortalities of the areas. Areas with high micro-pollution indexes have high incidences and mortalities. From the obtained results, it was concluded that drinking water in Linzhou City was one of most important carrier of EC carcinogenic substances. Its improvement can significantly decrease incidence and mortality of EC, and was an important sanitation treatment for EC prevention. This study also suggested that the way that carcinogenic substances cause EC is by altering gene of meristem cells.
98th AACR Annual Meeting-- Apr 14-18, 2007; Los Angeles, CA