Section for Colorectal Cancer Screening, Cancer Registry of Norway, Oslo, Norway.
Center for Cancer Treatment, Sørlandet Hospital, Kristiansand, Norway.
Int J Cancer. 2023 Apr 1;152(7):1414-1424. doi: 10.1002/ijc.34351. Epub 2022 Nov 21.
Repeated rounds of faecal immunochemical testing (FIT) for occult blood is a common method for screening for colorectal cancer (CRC). However, the time interval between FIT rounds is not thoroughly investigated. In a CRC screening trial in South-Eastern Norway, individuals were invited for biennial FIT between 2012 and 2019. The positivity threshold was >15 mcg haemoglobin/g faeces (mcg/g). Due to organizational challenges, the interval between screening rounds randomly varied between 1.5 and 3.5 years, forming a natural experiment. We investigated the detection rate of CRC and advanced neoplasia (AN: CRC or advanced adenoma) at the subsequent round (FIT ), according to the faecal haemoglobin concentration (f-Hb) at the initial screening round (FIT ), and time between the two screening rounds. 18 522 individuals with negative FIT who attended FIT were included in this study. 245 AN were detected at FIT , of which 34 were CRC. The CRC detection rate at FIT for participants with FIT = 0 mcg/g was 0.09% while it was 0.28% for participant with 0 > FIT ≤ 15 mcg/g; odds ratio (OR) 3.22, 95% CI 1.49-6.95. For each 3 months' increment between FITs, the OR for detecting CRC was 1.33 (95% CI 0.98-1.79), while the OR was 1.13 (1.02-1.26) for AN. Individuals with FIT -value of 0 mcg/g, had a lower AN detection rate compared with participants with 0 > FIT ≤ 15 mcg/g, irrespective of time between tests. Although CRC and AN detection rates increase with increasing time interval between FITs, individuals with undetectable f-Hb at first screen have substantially lower risk of CRC at the next screening round compared with individuals with detectable f-Hb.
粪便免疫化学检测（FIT）的重复检测是结直肠癌（CRC）筛查的常用方法。然而，FIT 检测轮次之间的时间间隔尚未得到充分研究。在挪威东南部的一项 CRC 筛查试验中，邀请个体在 2012 年至 2019 年期间每两年进行一次 FIT 检测。阳性阈值为>15mcg 血红蛋白/g 粪便（mcg/g）。由于组织方面的挑战，筛查轮次之间的间隔时间随机在 1.5 年至 3.5 年之间变化，形成了一个自然实验。我们根据初始筛查轮次（FIT）时粪便血红蛋白浓度（f-Hb）以及两次筛查轮次之间的时间，研究了后续轮次（FIT）时 CRC 和高级别瘤变（AN：CRC 或高级别腺瘤）的检出率。本研究共纳入了 18522 名 FIT 检测阴性且参加了 FIT 检测的个体。在 FIT 检测中发现了 245 例 AN，其中 34 例为 CRC。FIT 检测结果为 f-Hb=0 mcg/g 的个体中，CRC 的检出率为 0.09%，而 f-Hb 在 0mcg/g 至 15 mcg/g 之间的个体中，CRC 的检出率为 0.28%；比值比（OR）为 3.22，95%置信区间（CI）为 1.49-6.95。FIT 检测结果之间每增加 3 个月，检测 CRC 的 OR 为 1.33（95%CI 0.98-1.79），而检测 AN 的 OR 为 1.13（1.02-1.26）。与 f-Hb 在 0mcg/g 至 15 mcg/g 之间的个体相比，FIT 检测结果为 0 mcg/g 的个体的 AN 检出率较低，而无论两次检测之间的时间间隔如何。尽管随着 FIT 检测轮次之间时间间隔的增加，CRC 和 AN 的检出率增加，但初次筛查时 f-Hb 未检出的个体在下一次筛查时 CRC 的风险显著低于 f-Hb 可检出的个体。
