Department of Gastroenterology and Hepatology, Erasmus University Medical Center, Rotterdam, 's-Gravendijkwal 230, Rotterdam 3015 CE, The Netherlands.
Eur J Gastroenterol Hepatol. 2010 Apr;22(4):437-43. doi: 10.1097/MEG.0b013e328333fc6a.
To assess the prior exposure to colorectal examinations between colorectal cancer (CRC) patients and matched control participants to estimate the effect of these examinations on the development of CRC and to obtain insight into the background incidence of colorectal examinations.
A population-based case-control study was conducted within the Dutch Integrated Primary Care Information database over the period 1996-2005. All incident CRC cases were matched with up to 18 controls (n=7,790) for age, sex, index date (date of CRC diagnosis) and follow-up before diagnosis. All colorectal examinations performed in symptomatic participants in the period 0.5-5 years before index date were considered in the analyses.
Within the source population of 457 024 persons, we identified 594 incident cases of CRC. In the period 0.5-5 years before index date 2.9% (17 of 594) of the CRC cases had undergone colorectal examinations, compared with 4.4% (346 of 7790) in the control population [odds ratio (ORadj): 0.56, 95% confidence interval (CI): 0.33-0.94]. For left-sided CRC, significantly more controls than cases had undergone a colorectal examination (4.7 vs. 2.0%, respectively, ORadj: 0.36, 95% CI: 0.17-0.76), which was not seen for right-sided CRCs (3.3 vs. 3.9%, respectively, ORadj: 0.98, 95% CI: 0.42-2.25).
Patients diagnosed with CRC were less likely than controls to have had a colorectal examination in previous years, being more pronounced in patients diagnosed with left-sided CRCs. If diagnostic examinations have a similar protective effect as screening examinations, this finding supports the concept that colorectal examination can have a major impact on the reduction of CRC risk.
评估结直肠癌（CRC）患者与匹配对照参与者之间之前接受结直肠检查的情况，以估计这些检查对 CRC 发展的影响，并深入了解结直肠检查的背景发病率。
在 1996 年至 2005 年期间，在荷兰综合初级保健信息数据库中进行了一项基于人群的病例对照研究。所有 CRC 病例均与年龄、性别、索引日期（CRC 诊断日期）和诊断前随访时间匹配的最多 18 名对照者（n=7790）进行匹配。在分析中考虑了在索引日期前 0.5-5 年内症状参与者进行的所有结直肠检查。
在 457024 人的基础人群中，我们确定了 594 例 CRC 病例。在索引日期前 0.5-5 年内，594 例 CRC 病例中有 2.9%（17 例）接受了结直肠检查，而对照组中有 4.4%（346 例）[比值比（ORadj）：0.56，95%置信区间（CI）：0.33-0.94]。对于左侧 CRC，接受结直肠检查的对照组明显多于病例组（分别为 4.7%和 2.0%，ORadj：0.36，95%CI：0.17-0.76），但右侧 CRC 未见这种情况（分别为 3.3%和 3.9%，ORadj：0.98，95%CI：0.42-2.25）。
与对照组相比，诊断为 CRC 的患者在过去几年中接受结直肠检查的可能性较小，在诊断为左侧 CRC 的患者中更为明显。如果诊断性检查具有与筛查性检查类似的保护作用，这一发现支持结直肠检查可以对降低 CRC 风险产生重大影响的概念。
