Evaluation of a mass screening program for stomach cancer.

To evaluate a mass screening program for stomach cancer, we followed 32,789 subjects for 6.1 years by means of a record linkage to a population-based cancer registry. The results show that the mortality from stomach cancer among those studied decreased by 9% as compared with the expected number calculated on the basis of the sex- and age-specific rates among the general population. When the study subjects were limited to those aged 40-59 years, the decrease in stomach cancer deaths became more marked, i.e., a 26% decrease was observed. Because this study is not a controlled trial, the results must be interpreted with the reservation that some biases were present in the study subjects.