Evaluation for efficacy of lung cancer screening in Miyagi Prefecture by means of a mathematical model

摘要

Objective. The objective of this study is to confirm the result of a case-controlled study for lung cancer mass screening in Miyagi Prefecture using a deterministic model method. Methods. A mathematical model of cancer screening is used for calculating numbers of lung cancer deaths in the screened population and those of the unscreened population in Miyagi Prefecture. Numerical values for various parameters have been obtained from the results of a screening program of Miyagi Prefecture such as the sensitivity of screening tests, ratio of participation in secondary examinations and fatality in the screen-detected lung cancer group and that in the unscreened lung cancer group. These values were introduced into the model and relative risk (RR) for screened/unscreened was obtained. Finally the calculated RR was compared with the odds ratio (OR) reported in a case-controlled study. Results. Among various numerical values used, the most important one was the fatality in the screen-detected lung cancer which is 39%. Calculated relative risk (RR) is between 0.65 and 0.71 depending upon the different fatality values of the screened population. This RR is worse than the reported OR of 0.54, but was statistically significant. Conclusion. The calculated RR of Miyagi lung cancer screening is 0.65-0.71 which is statistically significant in reducing the mortality of lung cancer.