胃がんの内視鏡スクリーニングの死亡率減少効果―検診の立場から

The Reduction of the Mortality Rate Brought about by Gastric Cancer Screening Using Endoscopy

要旨　内視鏡による胃がん検診の有効性を評価するには，職域や人間ドックでなく対策型検診として住民に広く実施する必要がある．その精度によって死亡率減少効果を客観的に評価することが可能となる．2003年に政令指定都市の住民に対する胃がん検診に内視鏡検診を導入して5年が経過した．安全と感染防止を第一とし，読影委員会によるダブルチェックにより診断精度の向上に努めている．2006年度の内視鏡検診者数は158施設23,882人で直接撮影者数を超え，4年間における胃がん発見率は0.91％で，直接撮影による0.33％，間接撮影の0.22％を大きく上回る．また内視鏡検診で発見された胃がんのうち早期がんの比率は82.4％であった．ダブルチェックで新たに病変が指摘されたのは6.4％で，第三者に評価されることが実施施設の診断精度の向上に有用であった．内視鏡検診は実施施設や専門医数が限られるが，むしろ都市住民における検診で可能である．2003年度の内視鏡検診群とのコホートによる胃がん，食道がんの死亡率の検討を行ったが，既に死亡率減少効果があるとされているX線検診群と同等であった．さらに追跡調査することによって胃がん死亡率への抑制効果は明らかになることが期待される．

　The Niigata gastric cancer screening program using endoscopic examination is appraised for its effectiveness in bringing about a reduction of the mortality rate.

　It is possible to make an objective appraisal by using data from a wide range of inhabitants.

　Five years have elapsed since gastric cancer screening using endoscopy was introduced in Niigata City in 2003. By double checking with a commission for the interpretation of the endoscopic data, efforts have been made to achieve diagnostic precision and thus enable the prevention of further development of the lesions.

　In 158 facilities, 23,882 subjects received endoscopic examination in 2006. This number exceeded the number of patients who underwent direct X-ray examination.

　In a period of 4 years 0.91％of patients screened endoscopically were found to have stomach cancer. This exceeds the 0.33％of cancers in patients who were examined by direct X-ray and the 0.22％of cancers in patients who were examined by fluorography.

　In 557 cases, early gastric cancer was discovered by endoscopy in 82.4％of the subjects. Carrying out endoscopic examination is limited by the number of endoscopy specialists available. However for city inhabitants it is quite possible. It can be assumed that due to the cooperative effort carried out since 2003, the mortality rate due to stomach cancer has already been reduced, but it is expected that this mortality reduction rate will be made further evident over the long period.