Research Unit and Section of General Practice, Institute of Public Health, University of Copenhagen, Copenhagen, Denmark.
J Eval Clin Pract. 2013 Apr;19(2):311-6. doi: 10.1111/j.1365-2753.2012.01824.x. Epub 2012 Feb 14.
Colorectal cancer (CRC) is one of the most common types of cancer in European countries and associated with a high mortality rate. A 16% relative risk reduction (RRR) of mortality was found in a meta-analysis based on four randomized controlled trials (RCT) on CRC screening. The aim of this paper was to scrutinize these trials for potential biases and assess their influence on the screening trials.
The four RCTs were reviewed based on the principles of 'Critical Appraisal of the Medical Literature'. Principal investigators of the four RCTs were contacted to clarify uncertainties in their study. Data were collected from The Danish Data Archives. Authors of the Cochrane review were contacted.
Six biases were identified, of which five favour screening. Three of the biases identified were specific to CRC screening: type of diagnostic method, place of surgery and diagnostic delay.
The 16% RRR in CRC mortality found in the updated Cochrane review's meta-analysis is overestimated.
结直肠癌（CRC）是欧洲国家最常见的癌症类型之一，死亡率较高。四项随机对照试验（RCT）的荟萃分析发现，CRC 筛查可使死亡率降低 16%。本文旨在仔细审查这些试验，以发现潜在的偏倚，并评估其对筛查试验的影响。
根据“医学文献批判性评估”的原则对四项 RCT 进行了审查。联系了四项 RCT 的主要研究者，以澄清他们研究中的不确定性。数据来自丹麦数据档案。联系了 Cochrane 综述的作者。
确定了六个偏倚，其中五个有利于筛查。确定的三个偏倚是 CRC 筛查特有的：诊断方法的类型、手术地点和诊断延迟。
在更新的 Cochrane 综述荟萃分析中发现的 CRC 死亡率 16%的降低率被高估了。
