Launoy G, Herbert C, Reaud J M, Thezee Y, Tichet J, Maurel J, Ollivier V, Pegulu L, Caces E, Valla A
Registre des Tumeurs Digestives du Calvados, Caen, France.
Br J Cancer. 1995 Oct;72(4):1043-6. doi: 10.1038/bjc.1995.459.
Despite encouraging results from recent studies, there is still no consensus to undertake mass screening using the Haemoccult test in the general population. The success of mass screening for colorectal cancer depends among other things on Haemoccult test properties. In on-going screening programmes, the Haemoccult test consists of six slides and a test is considered positive if at least one slide is coloured. The aim of this work was to study the influence of the type and number of positive slides on the Haemoccult test's positive predictive value and characteristics of screened lesions. This work focuses on 63,958 first tests in a mass screening programme in Calvados (France) among people aged 45-74 years. There was a linear relation between the positive predictive value for cancer or an adenoma larger than 1 cm and the number of positive slides (P < 10(-4)). The positive predictive value for cancer or large adenoma was significantly higher when 4-6 slides were positive (44.3%) than when only 1-3 were positive (19.1%) (P < 10(-4)). In this latter group, the subjects in whom tumours were detected were younger and had significantly less extensive cancers. Borderline tests (no slides positive and at least one slide with a blue coloration confined to the edges) had a positive predictive value for cancer or an adenoma larger than 1 cm no different to that of tests with 1-3 positive slides. Subjects with borderline results were markedly younger than the others and had less extensive cancers and rectal localisation more often than the others. Our results suggest that (1) increasing the number of positive slides required to declare a test positive leads to an increase in the positive predictive value but is not to be recommended because of the sensitivity of the test and (2) considering borderline Haemoccult tests as positive in on-going and future mass screening campaigns would allow an increase in the sensitivity of the test, especially for rectal cancer and low extensive tumours without any decrease in its positive predictive value.
尽管近期研究取得了令人鼓舞的结果，但对于在普通人群中使用潜血试验进行大规模筛查仍未达成共识。结直肠癌大规模筛查的成功与否在一定程度上取决于潜血试验的特性。在正在进行的筛查项目中，潜血试验由六张载玻片组成，若至少有一张载玻片显色，则该测试被视为阳性。本研究的目的是探讨阳性载玻片的类型和数量对潜血试验阳性预测值及筛查病变特征的影响。本研究聚焦于法国卡尔瓦多斯地区一项针对45 - 74岁人群的大规模筛查项目中的63958例初次检测。癌症或直径大于1厘米腺瘤的阳性预测值与阳性载玻片数量之间存在线性关系（P < 10⁻⁴）。当4 - 6张载玻片呈阳性时，癌症或大腺瘤的阳性预测值显著高于仅有1 - 3张载玻片呈阳性时（分别为44.3%和19.1%）（P < 10⁻⁴）。在后一组中，检测出肿瘤的受试者更年轻，且癌症范围明显更小。临界试验（无载玻片阳性且至少有一张载玻片仅边缘呈蓝色显色）对于癌症或直径大于1厘米腺瘤的阳性预测值与1 - 3张载玻片呈阳性的试验无差异。临界结果的受试者明显比其他受试者年轻，癌症范围更小，且直肠癌定位更为常见。我们的研究结果表明：（1）提高判定测试为阳性所需的阳性载玻片数量会导致阳性预测值增加，但由于该测试的敏感性，不建议这样做；（2）在正在进行的和未来的大规模筛查活动中将临界潜血试验视为阳性，会提高该测试的敏感性，尤其是对于直肠癌和低范围肿瘤，同时不会降低其阳性预测值。
