We have performed mass screening of stomach cancer by using new double contrast radiographic method with high-density barium (180w/v%, 110ml) since 2000. In this study, we elucidate new radiographic method in comparison with usual method using medium-density barium (130w/v%, 150ml) in point of efficiency of the screening. Rate of individuals required to have further examinations, detection rate of the cancer and positive predictive value by new radiographic method were 10.57%, 0.15% and 1.86% compared with 8.07%, 0.15% and 1.56% by usual method. To clarify a factor reducing rate of individuals required to have further examination, we analyzed rate of individuals diagnosed by findings directly depicted on film, rate of individuals possessed findings without further examination and ratio of the early cancer. All of them were indicated higher on new method. In conclusion, these findings suggested that double contrast radiographic method with high-density barium could advance efficiency of mass screening of the gastric cancer.

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

We evaluated the necessity of undergoing close examination in colorectal cancer screening. The course of detection of infiltrating colorectal cancer within 2 years of screening was classified into:(1) detection in the initial screening,(2) false-negative occult blood-detection of cancer in annual or biennial screening,(3) false-negative results of close examination,(4) not undergoing close examination, and (5) interval cancer. The cumulative survival rate calculated by Kaplan-Meier's method and the death risk ratio obtained using Cox's proportional hazard model were evaluated. The cumulative 5-year survival rate in the group who had not yet undergone close examination was the lowest (39.3%) among the above 5 groups. The death risk ratio in this group was significantly high (3.83, p=0.018) compared with the group in whom cancer was detected in the initial screening. When the follow-up period after screening was 3 years, the death risk ratio in the group who had not yet undergone close examination was 3.91 compared with the group who underwent close examination (p=0.012). Thus, close examination should be recommended to all persons who have not yet undergone close examination. However, considering that 36% have not yet undergone close examination in this country, close examination should be strongly recommended at least in the high-risk group in terms of cancer detection (both positive occult blood twice and a high total occult blood value).

View full abstract

[in Japanese]

View full abstract