Background: Faecal immunochemical testing (FIT) is widely used in bowel screening programmes and assessing symptomatic patients for suspected colorectal cancer (CRC). The evidence for single test performance of FIT in both settings is considerable; however, the use of a repeat test to increase sensitivity remains uncertain. We aimed to review what increase in test positivity would be generated by additional FITs, whether a repeated FIT detects previously missed CRC and advanced colorectal neoplasia (ACRN), and to estimate the sensitivity of double-FIT strategies to diagnose CRC and ACRN. Methods: A systematic search of MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials (CENTRAL) was performed using key search terms. Studies reporting the use of more than one FIT in the same screening round or planned assessment of a single symptomatic patient episode were included. Studies were categorised by the reported study population into asymptomatic, mixed (cohorts of combined asymptomatic, symptomatic, or high-risk surveillance), or symptomatic cohorts. Results: A total of 68 studies were included for analysis (39 asymptomatic, 21 mixed, 7 symptomatic, and 1 study with discrete asymptomatic and symptomatic data). At a threshold of 10 µg Hb/g, the two-test positivity ranged between 8.1 and 34.5%, with an increase from the second test of 3–9.2 percentage points. Four out of five studies comparing one versus two tests for diagnosing CRC at 10 µg Hb/g identified additional cases with the second test, with a minimum of 50% reduction in missed CRC. At a threshold of 20 µg Hb/g, the second test increased the positivity by 1.3–6.7 percentage points, with a two-test positivity of between 5.1 and 25.0%. Using a threshold of 20 µg Hb/g, five out of seven studies had a 25% reduction in missed CRC. A meta-analysis estimated the double-FIT sensitivity at 10 µg Hb/g for CRC in mixed-risk and symptomatic cohorts to be 94% and 98%, respectively. Conclusions: Repeated use of FIT helps to diagnose more cases of CRC with a moderate increase in positivity. A double-FIT strategy at 10 µg Hb/g in mixed and symptomatic cohorts has a very high sensitivity for CRC.
背景：粪便免疫化学检测（FIT）广泛应用于肠道筛查项目以及对疑似结直肠癌（CRC）有症状患者的评估。已有大量证据支持FIT在单一检测场景中的性能表现，然而，通过重复检测以提高敏感性的效果仍不明确。本研究旨在评估重复FIT检测对检测阳性率的提升程度，探究重复FIT能否检出先前漏诊的CRC及晚期结直肠肿瘤（ACRN），并估算双次FIT策略诊断CRC和ACRN的敏感性。 方法：通过关键词在MEDLINE、EMBASE和Cochrane对照试验中心注册库（CENTRAL）进行系统性检索。纳入标准为在同一筛查周期内使用多次FIT检测或对单次有症状患者就诊进行计划性评估的研究。根据研究人群特征将纳入研究分为无症状组、混合组（包含无症状、有症状或高风险监测人群）及有症状组。 结果：共纳入68项研究进行分析（39项无症状组，21项混合组，7项有症状组，1项研究同时包含独立的无症状与有症状数据）。在10微克血红蛋白/克粪便的阈值下，双次检测阳性率介于8.1%至34.5%之间，第二次检测使阳性率提升3-9.2个百分点。在10微克血红蛋白/克阈值下比较单次与双次检测诊断CRC的五项研究中，四项研究通过第二次检测发现了额外病例，漏诊率降低至少50%。在20微克血红蛋白/克阈值下，第二次检测使阳性率提升1.3-6.7个百分点，双次检测阳性率介于5.1%至25.0%之间。七项采用20微克血红蛋白/克阈值的研究中，五项研究的CRC漏诊率降低25%。荟萃分析显示，在10微克血红蛋白/克阈值下，双次FIT对混合风险人群和有症状人群诊断CRC的敏感性分别为94%和98%。 结论：重复使用FIT有助于诊断更多CRC病例，同时阳性率仅适度增加。在混合风险人群和有症状人群中采用10微克血红蛋白/克阈值的双次FIT策略对CRC具有极高的敏感性。
肿瘤(癌症)患者之家