Aniwan Satimai, Ratanachu-Ek Thawee, Pongprasobchai Supot, Limsrivilai Julajak, Praisontarangkul Ong-Ard, Pisespongsa Pises, Mairiang Pisaln, Sangchan Apichat, Sottisuporn Jaksin, Wisedopas Naruemon, Kullavanijaya Pinit, Rerknimitr Rungsun
Division of Gastroenterology, Department of Internal Medicine, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, The Thai Red Cross Society, Bangkok, Thailand.
Department of Surgery, Rajavithi Hospital, Bangkok, Thailand.
Clin Transl Gastroenterol. 2017 Aug 10;8(8):e113. doi: 10.1038/ctg.2017.40.
The Asia-Pacific Colorectal Screening (APCS) scoring system was developed to identify high-risk subjects for advanced neoplasia. However, the appropriate fecal immunochemical test (FIT) cutoff for high-risk population may be different from that of average-risk population. We aimed to evaluate the FIT performance at different cutoffs in high-risk subjects undergoing colorectal cancer (CRC) screening.
We prospectively enrolled asymptomatic subjects aged 50-75 years. Using the APCS score, subjects were stratified into either the average-risk or high-risk groups. All subjects were tested with one-time quantitative FIT and underwent colonoscopy. We compared the FIT performance for advanced neoplasia between two groups using different cutoffs (5 (FIT5), 10 (FIT10), 20 (FIT20), 30 (FIT30), and 40 (FIT40) μg Hb/g feces).
Overall, 1,713 subjects were recruited, and 1,222 (71.3%) and 491 (28.7%) were classified as average-risk and high-risk, respectively. Advanced neoplasia was detected in 90 (7.4%) of the average-risk subjects and 65 (13.2%) of the high-risk subjects. In the high-risk group, by decreasing the cutoff from FIT40 to FIT5, the sensitivity increased by 33.8 percentage points with decreased specificity by 11 percentage points. In the average-risk group, the sensitivity increased by 20 percentage points with decreased specificity by 9.6 percentage points. At the lowest cutoff (FIT5), the number of needed colonoscopies to find one advanced neoplasia was 2.8 and 6.1 for the high-risk and average-risk groups, respectively.
Using an appropriate FIT cutoff for CRC screening in high-risk subjects could improve CRC screening performance and reduce the unnecessary colonoscopies. To maintain high sensitivity and specificity for advanced neoplasia, the optimal cutoff FIT in the high-risk subjects should be lower than that in the average-risk subjects.
亚太地区结直肠癌筛查（APCS）评分系统旨在识别晚期瘤变的高危人群。然而，高危人群合适的粪便免疫化学检测（FIT）临界值可能与平均风险人群不同。我们旨在评估不同临界值下FIT在接受结直肠癌（CRC）筛查的高危人群中的表现。
我们前瞻性纳入了年龄在50 - 75岁的无症状受试者。根据APCS评分，将受试者分为平均风险组或高危组。所有受试者均接受一次性定量FIT检测并接受结肠镜检查。我们比较了两组在不同临界值（5（FIT5）、10（FIT10）、20（FIT20）、30（FIT30）和40（FIT40）μg血红蛋白/克粪便）下晚期瘤变的FIT表现。
总体而言，共招募了1713名受试者，其中1222名（71.3%）和491名（28.7%）分别被归类为平均风险组和高危组。平均风险组中有90名（7.4%）检测到晚期瘤变，高危组中有65名（13.2%）检测到晚期瘤变。在高危组中，将临界值从FIT40降至FIT5时，敏感性增加了33.8个百分点，特异性降低了11个百分点。在平均风险组中，敏感性增加了20个百分点，特异性降低了9.6个百分点。在最低临界值（FIT5）时，高危组和平均风险组发现一例晚期瘤变所需的结肠镜检查次数分别为2.8次和6.1次。
在高危人群的CRC筛查中使用合适的FIT临界值可以提高CRC筛查性能并减少不必要的结肠镜检查。为了对晚期瘤变保持高敏感性和特异性，高危人群中FIT的最佳临界值应低于平均风险人群。
