Roslani April Camilla, Abdullah Taufiq, Arumugam Kulenthran
Cancer Research Institute, University of Malaya, Kuala Lumpur, Malaysia.
Asian Pac J Cancer Prev. 2012;13(1):237-41. doi: 10.7314/apjcp.2012.13.1.237.
Screening for colorectal cancer using guaiac-based fecal occult blood tests (gFOBT) is well established in Western populations, but is hampered by poor patient compliance due to the imposed dietary restrictions. Fecal immunochemical tests (FIT) do not require dietary restriction, but are more expensive than gFOBT and therefore restrict its use in developing countries in Asia. However, Asian diets being low in meat content may not require diet restriction for gFOBT to achieve equivalent results. The objective of this study was to evaluate and compare the validity and suitability of gFOBT and FIT or a combination of the two in screening for colorectal neoplasias without prior dietary restriction in an Asian population.
Patients referred to the Endoscopic Unit for colonoscopy were recruited for the study. Stool samples were collected prior to bowel preparation, and tested for occult blood with both gFOBT and FIT. Dietary restriction was not imposed. To assess the validity of either tests or in combination to detect a neoplasm or cancer in the colon, their false positive rates, their sensitivity (true positive rate) and the specificity (true negative rate) were analyzed and compared.
One hundred and three patients were analysed. The sensitivity for picking up any neoplasia was 53% for FIT, 40% for gFOBT and 23.3% for the combination. The sensitivities for picking up only carcinoma were 77.8% , 66.7% and 55.5%, respectively. The specificity for excluding any neoplasia was 91.7% for FIT, 74% for gFOBT and 94.5% for a combination, whereas for excluding only carcinomas they were 84%, 73.4% and 93.6%. Of the 69 with normal colonoscopic findings, FOBT was positive in 4.3%, 23.2 %and 2.9% for FIT, gFOBT, or combination of tests respectively.
FIT is the recommended method if we are to dispense with dietary restriction in our patients because of its relatively low-false positivity and better sensitivity and specificity rates.
在西方人群中，使用基于愈创木脂的粪便潜血试验（gFOBT）筛查结直肠癌已得到广泛应用，但由于饮食限制导致患者依从性较差，影响了该方法的实施。粪便免疫化学试验（FIT）不需要饮食限制，但比gFOBT成本更高，因此限制了其在亚洲发展中国家的使用。然而，亚洲饮食中肉类含量较低，对于gFOBT而言，可能不需要饮食限制就能获得等效结果。本研究的目的是评估和比较gFOBT和FIT或两者联合使用在亚洲人群中不进行预先饮食限制筛查结直肠肿瘤的有效性和适用性。
招募到内镜科接受结肠镜检查的患者参与本研究。在肠道准备前采集粪便样本，同时用gFOBT和FIT检测潜血。不实施饮食限制。为评估单独或联合检测结肠肿瘤或癌症的有效性，分析并比较它们的假阳性率、敏感性（真阳性率）和特异性（真阴性率）。
共分析了103例患者。FIT检测出任何肿瘤的敏感性为53%，gFOBT为40%，联合检测为23.3%。仅检测出癌的敏感性分别为77.8%、66.7%和55.5%。排除任何肿瘤的特异性，FIT为91.7%，gFOBT为74%，联合检测为94.5%；而仅排除癌时，特异性分别为84%、73.4%和93.6%。在结肠镜检查结果正常的69例患者中，FIT、gFOBT或联合检测的潜血阳性率分别为4.3%、23.2%和2.9%。
如果要免除患者的饮食限制，FIT是推荐方法，因为其假阳性率相对较低，敏感性和特异性更高。
