Colorectal Surgery, Croydon University Hospital, Croydon, UK.
Colorectal Surgery, Basingstoke and North Hampshire Hospital, Basingstoke, UK.
Gut. 2021 Jun;70(6):1130-1138. doi: 10.1136/gutjnl-2020-321956. Epub 2020 Oct 21.
To assess whether a faecal immunochemical test (FIT) could be used to select patients with suspected colorectal cancer (CRC) symptoms for urgent investigation.
Multicentre, double-blinded diagnostic accuracy study in 50 National Health Service (NHS) hospitals across England between October 2017 and December 2019. Patients referred to secondary care with suspected CRC symptoms meeting NHS England criteria for urgent 2 weeks wait referral and triaged to investigation with colonoscopy were invited to perform a quantitative FIT. The sensitivity of FIT for CRC, and effect of relevant variables on its diagnostic accuracy was assessed.
9822 patients were included in the final analysis. The prevalence of CRC at colonoscopy was 3.3%. The FIT positivity decreased from 37.2% to 19.0% and 7.6%, respectively, at cut-offs of 2, 10 and 150 µg haemoglobin/g faeces (µg/g). The positive predictive values of FIT for CRC at these cut-offs were 8.7% (95% CI, 7.8% to 9.7%), 16.1% (95% CI 14.4% to 17.8%) and 31.1% (95% CI 27.8% to 34.6%), respectively, and the negative predictive values were 99.8% (95% CI 99.7% to 99.9%), 99.6% (95% CI 99.5% to 99.7%) and 98.9% (95% CI 98.7% to 99.1%), respectively. The sensitivity of FIT for CRC decreased at the same cut-offs from 97.0% (95% CI 94.5% to 98.5%) to 90.9% (95% CI 87.2% to 93.8%) and 70.8% (95% CI 65.6% to 75.7%), respectively, while the specificity increased from 64.9% (95% CI 63.9% to 65.8%) to 83.5% (95% CI 82.8% to 84.3%) and 94.6% (95% CI 94.1% to 95.0%), respectively. The area under the receiver operating characteristic curve was 0.93 (95% CI 0.92 to 0.95).
FIT sensitivity is maximised to 97.0% at the lowest cut-off (2 µg/g); a negative FIT result at this cut-off can effectively rule out CRC and a positive FIT result is better than symptoms to select patients for urgent investigations.
ISRCTN49676259.
评估粪便免疫化学检测（FIT）是否可用于选择有疑似结直肠癌（CRC）症状的患者进行紧急检查。
2017 年 10 月至 2019 年 12 月，在英格兰 50 家国民保健制度（NHS）医院进行的多中心、双盲诊断准确性研究。符合英格兰国民保健制度（NHS）标准的 2 周内紧急转诊条件、经分诊后拟行结肠镜检查的疑似 CRC 症状患者被邀请进行定量 FIT 检测。评估 FIT 对 CRC 的敏感性，以及相关变量对其诊断准确性的影响。
9822 例患者纳入最终分析。结肠镜检查 CRC 的患病率为 3.3%。FIT 阳性率分别在 2、10 和 150μg 血红蛋白/g 粪便（μg/g）的截止值时从 37.2%降至 19.0%和 7.6%。在这些截止值时，FIT 对 CRC 的阳性预测值分别为 8.7%（95%CI，7.8%至 9.7%）、16.1%（95%CI 14.4%至 17.8%）和 31.1%（95%CI 27.8%至 34.6%），阴性预测值分别为 99.8%（95%CI 99.7%至 99.9%）、99.6%（95%CI 99.5%至 99.7%）和 98.9%（95%CI 98.7%至 99.1%）。在相同的截止值时，FIT 对 CRC 的敏感性从 97.0%（95%CI 94.5%至 98.5%）降至 90.9%（95%CI 87.2%至 93.8%）和 70.8%（95%CI 65.6%至 75.7%），而特异性从 64.9%（95%CI 63.9%至 65.8%）增至 83.5%（95%CI 82.8%至 84.3%）和 94.6%（95%CI 94.1%至 95.0%）。受试者工作特征曲线下面积为 0.93（95%CI 0.92 至 0.95）。
FIT 的敏感性在最低截止值（2μg/g）时最高可达 97.0%；在此截止值时，阴性 FIT 结果可有效排除 CRC，阳性 FIT 结果优于症状，可用于选择患者进行紧急检查。
ISRCTN49676259。
