Allison James E, Sakoda Lori C, Levin Theodore R, Tucker Jo P, Tekawa Irene S, Cuff Thomas, Pauly Mary Pat, Shlager Lyle, Palitz Albert M, Zhao Wei K, Schwartz J Sanford, Ransohoff David F, Selby Joseph V
Division of Research, Kaiser Permanente Northern California Region, 2000 Broadway, Oakland, CA 94612-2304, USA.
J Natl Cancer Inst. 2007 Oct 3;99(19):1462-70. doi: 10.1093/jnci/djm150. Epub 2007 Sep 25.
One type of fecal occult blood test (FOBT), the unrehydrated guaiac fecal occult blood test (GT), is recommended by the United States Preventive Services Task Force and the Institute of Medicine for use in screening programs, but it has relatively low sensitivity as a single test for detecting advanced colonic neoplasms (cancer and adenomatous polyps > or = 1 cm in diameter). Thus, improving the sensitivity of FOBT should make colon cancer screening programs that use these tests more effective.
We assessed prospectively the performance characteristics of two newer FOBTs in 5841 subjects at average risk for colorectal cancer in a large group-model managed care organization. The tests evaluated included a sensitive GT, a fecal immunochemical test (FIT), and the combination of both tests. Patients with positive and negative test results were advised to have colonoscopy and sigmoidoscopy, respectively. Sensitivity and specificity for detecting advanced neoplasms in the left colon within 2 years after the FOBT screening were evaluated for the two tests administered separately and in combination.
A total of 139 patients were diagnosed with advanced colorectal neoplasms (n = 14 cancers, n = 128 adenomas) within the 2 years following their initial FOBT screening. Sensitivity for detecting cancer was 81.8% (95% confidence interval [CI] = 47.8% to 96.8%) for the FIT alone and 64.3% (95% CI = 35.6% to 86.0%) for the sensitive GT and the combination test. Sensitivity for detecting advanced colorectal adenomas was 41.3% (95% CI = 32.7% to 50.4%) for the sensitive GT, 29.5% (95% CI = 21.4% to 38.9%) for the FIT, and 22.8% (95% CI =16.1% to 31.3%) for the combination test. Specificity for detecting cancer and adenomas was 98.1% (95% CI = 97.7% to 98.4%) and 98.4% (95% CI = 98.0% to 98.7%), respectively, for the combination test; 96.9% (95% CI = 96.4% to 97.4%) and 97.3% (95% CI = 96.8% to 97.7%), respectively, for the FIT; and 90.1% (95% CI = 89.3% to 90.8%) and 90.6% (95% CI = 89.8% to 91.4%), respectively, for the sensitive GT.
The FIT has high sensitivity and specificity for detecting left-sided colorectal cancer, and it may be a useful replacement for the GT.
美国预防服务工作组和医学研究所推荐一种粪便潜血试验（FOBT），即未水化愈创木脂粪便潜血试验（GT）用于筛查项目，但作为检测晚期结肠肿瘤（癌症和直径≥1 cm的腺瘤性息肉）的单一检测方法，其灵敏度相对较低。因此，提高FOBT的灵敏度应能使采用这些检测方法的结肠癌筛查项目更有效。
在一个大型团体模式管理的医疗保健机构中，我们前瞻性地评估了5841名患结直肠癌平均风险受试者中两种新型FOBT的性能特征。所评估的检测方法包括一种灵敏的GT、一种粪便免疫化学检测（FIT）以及两种检测方法的联合。检测结果呈阳性和阴性的患者分别被建议进行结肠镜检查和乙状结肠镜检查。分别对单独使用和联合使用的两种检测方法评估FOBT筛查后2年内检测左半结肠晚期肿瘤的灵敏度和特异性。
在首次FOBT筛查后的2年内，共有139例患者被诊断为晚期结直肠肿瘤（14例癌症，128例腺瘤）。单独使用FIT检测癌症的灵敏度为81.8%（95%置信区间[CI]=47.8%至96.8%），灵敏的GT和联合检测的灵敏度为64.3%（95%CI=35.6%至86.0%）。灵敏的GT检测晚期结直肠腺瘤的灵敏度为41.3%（95%CI=32.7%至50.4%），FIT为29.5%（95%CI=21.4%至38.9%），联合检测为22.8%（95%CI=16.1%至31.3%）。联合检测检测癌症和腺瘤的特异性分别为98.1%（95%CI=97.7%至98.4%）和98.4%（95%CI=98.0%至98.7%）；FIT分别为96.9%（95%CI=96.4%至97.4%）和97.3%（95%CI=96.8%至97.7%）；灵敏的GT分别为90.1%（95%CI=89.3%至90.8%）和90.6%（95%CI=89.8%至91.4%）。
FIT检测左半结肠癌具有高灵敏度和特异性，可能是GT的一种有效替代方法。
