Abstract
OBJECTIVE: Using the mathematical model of cancer screening designed by Iinuma et al., I calculated the prolongation of life expectancy by a screening program based on the incidence of stomach cancer, and investigated the benefit of gastric cancer screening in the eligible age range. METHODS: According to the model, net lifesaving due to screening in a 100,000 population was multiplied by average life expectancy or healthy life expectancy to determine the prolonged life expectancy. The prolongation of life expectancy calculated by Iinuma et al. in 1990 was compared with that calculated using 2008 annual data to calculate the reduction of mortality in each age group. RESULTS: In males, the prolongation of life expectancy was twice as long as in females, and it was significant in males (but not females) above 40-44 years. Prolongation of life expectancy peaked at 70-74 years, and declined above 75 years, especially the prolongation of life expectancy determined from healthy life expectancy in females. Compared with data calculated by Iinuma, the prolongation of life expectancy was smaller in each age group. The effect of the reduction of mortality was considered above 50 years in males and above 60 years in females. CONCLUSIONS: There was no elongation of prolonged life expectancy above 80 years and the benefit of gastric cancer screening became smaller in the 40s because of the declining incidence of this cancer.
