Cole Eddie, Narayanan Deepa, Tiam Ree Nee, Shepherd John, Hajjawi Mark O R
Blood Sciences Department, York and Scarborough Teaching Hospitals NHS Foundation Trust, York, United Kingdom.
Clinical Biochemistry Department, Hull University Teaching Hospitals NHS Trust, Hull, United Kingdom.
Br J Biomed Sci. 2024 May 29;81:12862. doi: 10.3389/bjbs.2024.12862. eCollection 2024.
Colorectal cancer has a high prevalence and mortality rate in the United Kingdom. Cancerous colorectal lesions often bleed into the gastrointestinal lumen. The faecal immunochemical test (FIT) detects haemoglobin (Hb) in the faeces of patients and is used as a first line test in the diagnosis of colorectal cancer. A retrospective audit of all FIT performed and all colorectal cancers diagnosed in the Hull and East Riding of Yorkshire counties of the United Kingdom (population approximately 609,300) between 2018 and 2022 was conducted. FIT were performed using a HM-JACKarc analyser from Kyowa medical. The predominant symptom suggestive of colorectal cancer which prompted the FIT was recorded. Colorectal cancer was diagnosed using the gold standard of histological biopsy following colonoscopy. Between 2018 and 2022, 56,202 FIT were performed on symptomatic patients. Follow on testing identified 1,511 with colorectal cancer. Of these people, only 450 people with a confirmed colorectal cancer had a FIT within the 12 months preceding their diagnosis. Of these 450 FIT results, 36 had a concentration of <10 μg/g and may be considered to be a false negative. The sensitivity of FIT in the patients identified was 92.00%. The most common reason stated by the clinician for a FIT being performed in patients with colorectal cancer was a change in bowel habits, followed by iron deficient anaemia. The number of patients diagnosed with colorectal cancer decreased in 2020, but increased significantly in 2021. This study shows that 8.00% of people diagnosed with colorectal cancer in the Hull and East Riding of Yorkshire regions had a negative FIT. This study also shows that the SARS-CoV-2 pandemic affected the number of people diagnosed with colorectal cancer, and therefore skews the prevalence and pre-test probability of a positive test. There are many reasons why a FIT could produce a false negative result, the most likely being biological factors affecting the stability of haemoglobin within the gastrointestinal tract, or pre-analytical factors influencing faecal sampling preventing the detection of haemoglobin. Some colorectal lesions do not protrude into the gastrointestinal lumen and are less likely to bleed. This is the first study showing data from outside of a structured clinical trial and provides the largest study to date showing the sensitivity of FIT in a routine clinical setting. This study also provides evidence for the impact COVID-19 had on the rate of colorectal cancer diagnosis.
在英国，结直肠癌的患病率和死亡率都很高。结直肠癌性病变常向胃肠道腔内出血。粪便免疫化学检测（FIT）可检测患者粪便中的血红蛋白（Hb），并用作结直肠癌诊断的一线检测方法。对2018年至2022年期间在英国约克郡的赫尔和东里丁地区（人口约609,300）进行的所有FIT检测以及所有确诊的结直肠癌进行了回顾性审计。FIT检测使用的是协和医疗的HM-JACKarc分析仪。记录了促使进行FIT检测的提示结直肠癌的主要症状。结直肠癌通过结肠镜检查后的组织学活检这一金标准进行诊断。在2018年至2022年期间，对有症状的患者进行了56,202次FIT检测。后续检测发现了1511例结直肠癌患者。在这些患者中，只有450例确诊为结直肠癌的患者在诊断前12个月内进行了FIT检测。在这450份FIT检测结果中，有3份浓度<10μg/g，可能被视为假阴性。在已确诊的患者中，FIT的敏感性为92.00%。临床医生对结直肠癌患者进行FIT检测最常见的原因是排便习惯改变，其次是缺铁性贫血。2020年确诊的结直肠癌患者数量有所下降，但在2021年显著增加。这项研究表明，在约克郡的赫尔和东里丁地区，8.00%被诊断为结直肠癌的患者FIT检测结果为阴性。这项研究还表明，SARS-CoV-2大流行影响了被诊断为结直肠癌的人数，因此扭曲了检测呈阳性的患病率和检测前概率。FIT可能产生假阴性结果的原因有很多，最有可能的是影响胃肠道内血红蛋白稳定性的生物学因素，或影响粪便采样的分析前因素，从而妨碍了血红蛋白的检测。一些结直肠病变不会突入胃肠道腔内，出血的可能性较小。这是第一项展示来自结构化临床试验之外数据的研究，也是迄今为止展示FIT在常规临床环境中敏感性的最大规模研究。这项研究还为COVID-19对结直肠癌诊断率的影响提供了证据。
