Background The English national bowel cancer screening programme(NHSBCSP) offering a guaiac faecal occult blood test (gFOBT) began in July 2006. In randomised controlled trials of gFOBT screening, reductions in mortality were accompanied by reductions in advanced stage colorectal cancer (CRC). We aimed to evaluate the effect of participation in the NHSBCSP on stage-specific CRC incidence, as a likely precursor of a mortality effect. Methods Population based case-control study. Cases were individuals diagnosed with CRC aged 60–79 between 1 January 2012 and 31 December 2013. Two controls per case were matched on geographic region, sex, date of birth and year of first screening invitation. Screening histories were extracted from the screening database. Conditional logistic regression with correction for self-selection bias was used to estimate odds ratios (cOR) and 95% confidence intervals by Dukes’ stage, sex and age. Results 14,636 individuals with CRC and 29,036 without were eligible for analysis. The odds of CRC (any stage) were increased within 30 days of a screening test and decreased thereafter. No reduction in CRC (any stage) among screened individuals compared to those not screened was observed (cOR 1.00, 95%CI: 0.89–1.15). However, screened individuals had lower odds of Dukes’ stage D CRC (cOR 0.68, 95%CI: 0.50–0.93). We estimate 435 fewer Dukes’ D CRC by age 80 in 100,000 people screened biennially between ages 60–74 compared with an unscreened cohort. Conclusion The impact of colorectal screening on advanced CRC incidence suggests that the programme will meet its aim of reducing mortality.

中文翻译：

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两年一次粪便隐血筛查对英国结直肠癌的益处：一项基于人群的病例对照研究

背景 英国国家肠癌筛查计划 (NHSBCSP) 于 2006 年 7 月开始提供愈创木粪便隐血试验 (gFOBT)。在 gFOBT 筛查的随机对照试验中，死亡率的降低伴随着晚期结直肠癌 (CRC) 的降低。我们旨在评估参与 NHSBCSP 对特定阶段 CRC 发病率的影响，作为死亡率影响的可能前兆。方法基于人群的病例对照研究。病例是 2012 年 1 月 1 日至 2013 年 12 月 31 日期间被诊断为 60-79 岁的 CRC 个体。每个病例的两个对照在地理区域、性别、出生日期和首次筛查邀请年份上匹配。从筛选数据库中提取筛选历史。使用具有自我选择偏差校正的条件逻辑回归来估计杜克斯分期、性别和年龄的优势比 (cOR) 和 95% 置信区间。结果 14,636 名 CRC 患者和 29,036 名非 CRC 患者符合分析条件。CRC（任何阶段）的几率在筛查测试后 30 天内增加，此后降低。与未筛查的个体相比，筛查个体的 CRC（任何阶段）均未降低（cOR 1.00，95%CI：0.89-1.15）。然而，接受筛查的个体患 Dukes D 期 CRC 的几率较低（cOR 0.68，95%CI：0.50-0.93）。我们估计，在 60-74 岁之间每两年进行一次筛查的 100,000 人中，到 80 岁时，与未筛查的队列相比，杜克氏 D CRC 减少了 435 人。