早期胃癌のスクリーニング―ペプシノーゲン法と間接X線検査

Gastric Cancer Screening by Serum Pepsinogen Levels－Compared with Radiofluorography

要旨　胃集団検診は間接X線検査による胃検診が定番であった．近年，X線検査の代わりに血液検査であるペプシノーゲン(以下PG)検査を行う市区町村が増えている¹⁾．PGのcut-off値は通常PGⅠが70μg/l以下かつPGⅠ/Ⅱ比が3以下の組み合わせでこの値を基準値としている²⁾．(1)胃集団検診を受診した50歳以上の男性4,151人にPGを測定しかつ内視鏡検査を行ったところ，陽性者は43％の1,785人であり，この中に癌は41例(早期胃癌37例，進行癌4例)含まれ，陽性反応適中度は2.3％であった．また，53％の陰性者2,366人中には早期胃癌の14例が含まれ，癌の含まれる確率は0.6％であった．(2)PG(＋)とPG(－)例を比較すると，部位，大きさ，深達度では統計学的に有意差はみられなかったが，組織型の比較だけ有意差がみられPG(－)例は未分化型に多かった．(3)基準値を用いている施設間で胃癌の発見率を比べると，0.26～1.4％と様々であった¹⁾．これは“内視鏡検査の質”の差を物語っている．

　A notice for primary screening by photofluorography of the stomach is sent out to all residents. Every year, approximately 6 million people go through the screening. Another recent trend for primary screening is to measure the serum pepsinogen level.

　Among people over 50 years of age, the positive rate for standard was 40％, that for moderate positive was 27％ and that for severe positive was 11％. The figures for early cancers, in 37 standard cases out of 51 early cancers (72.5％) were included. For moderate positive 31 out of 51 cases of early cancers (60.8％) were included. For severe positive 19 out of 51 cases of early cancers (37.3％) were included. We were also able to seach the same conclusion for advanced cancers. There is no relation between PG (＋) and PG (－) cases in terms of size, location and depth of invasion, but the undifferentiated type is more common in PG (-) cases. The screening method by photofluorography has been encouraged for many years. The X-ray depiction rate of early and advanced cancers used in this study was 46.3％ of the early cancers and 92.7％ of the advanced cancers. The largest problem remaining in this method is the quality of endoscopic examination.