Precision in the first stage of the gastric carcinoma mass survey

A new method of estimating false-negative rate (FNR) in gastric carcinoma mass surveys is reported. It is called the "ADC method", since estimation of FNR is based on "Accidentally Detected Carcinoma". ADC is a carcinoma detected by chance upon close examination because of abnormalities falsely pointed out in the first stage of the mass survey (mass screening) in a region other than the one in which carcinoma is located. This method was tested in the gastric carcinoma mass survey program conducted by the Hokkaido Anti-cancer Association. Overall FNR was estimated at 28.3%. The FNRs estimated by the ADC method appear more reasonable and reliable indicators of precision of the mass survey program. The ADC method is discussed in comparison with the previously used "follow-up study" and several advantages of this new method are presented.