The first step in evaluating the effectiveness of cervical screening is defining exposure to screening. Our aim was to describe the spectrum of screening exposure definitions used in studies of the effectiveness of cervical screening. This systematic review included case-control studies in a population-based screening setting. Outcome was incidence of cervical cancer. Three electronic databases were searched from January 1, 2012 to December 6, 2018. Articles prior to 2012 were identified from a previous review. The qualitative synthesis focused on describing screening exposure definitions reported in the literature and the methodologic differences that could have an impact on the association between screening and cervical cancer. Forty-one case–control studies were included. Six screening exposure definitions were identified. Cervical cancer risk on average decreased by 66% when screening exposure was defined as ever tested, by 77% by time since last negative test, and by 79% after two or more previous tests. Methodologic differences included composition of the reference group and whether diagnostic and/or symptomatic tests were excluded from the analysis. Consensus guidelines to standardize exposure definitions are needed to ensure evaluations of cervical cancer screening can accurately measure the impact of transitioning from cytology to human papillomavirus–based screening and to allow comparisons between programs.

中文翻译：

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宫颈癌筛查病例对照研究中的暴露定义：系统文献综述

评估宫颈筛查有效性的第一步是确定筛查暴露。我们的目的是描述宫颈筛查有效性研究中使用的筛查暴露定义范围。该系统评价包括在基于人群的筛查环境中进行的病例对照研究。结果是宫颈癌的发病率。从 2012 年 1 月 1 日到 2018 年 12 月 6 日检索了三个电子数据库。2012 年之前的文章从之前的综述中识别出来。定性综合侧重于描述文献中报道的筛查暴露定义以及可能影响筛查与宫颈癌之间关联的方法学差异。包括 41 个病例对照研究。确定了六个筛查暴露定义。当筛选暴露被定义为曾经测试时，宫颈癌风险平均下降 66%，自上次阴性测试后按时间下降 77%，在两次或更多次先前测试后下降 79%。方法学差异包括参考组的组成以及诊断和/或症状测试是否被排除在分析之外。需要标准化暴露定义的共识指南，以确保宫颈癌筛查的评估能够准确衡量从细胞学筛查过渡到基于人乳头瘤病毒的筛查的影响，并允许在计划之间进行比较。方法学差异包括参考组的组成以及诊断和/或症状测试是否被排除在分析之外。需要标准化暴露定义的共识指南，以确保宫颈癌筛查的评估能够准确衡量从细胞学筛查过渡到基于人乳头瘤病毒的筛查的影响，并允许在计划之间进行比较。方法学差异包括参考组的组成以及诊断和/或症状测试是否被排除在分析之外。需要标准化暴露定义的共识指南，以确保宫颈癌筛查的评估能够准确衡量从细胞学筛查过渡到基于人乳头瘤病毒的筛查的影响，并允许在计划之间进行比较。