Jacklyn Gemma, Glasziou Paul, Macaskill Petra, Barratt Alexandra
Sydney School of Public Health, The University of Sydney, Edward Ford Building (A27), Sydney, NSW 2006, Australia.
Centre for Research in Evidence Based Practice, Faculty of Health Sciences and Medicine, Bond University, Gold Coast, QLD 4229, Australia.
Br J Cancer. 2016 May 24;114(11):1269-76. doi: 10.1038/bjc.2016.90. Epub 2016 Apr 28.
Women require information about the impact of regularly attending screening mammography on breast cancer mortality and overdiagnosis to make informed decisions. To provide this information we aimed to meta-analyse randomised controlled trials adjusted for adherence to the trial protocol.
Nine screening mammography trials used in the Independent UK Breast Screening Report were selected. Extending an existing approach to adjust intention-to-treat (ITT) estimates for less than 100% adherence rates, we conducted a random-effects meta-analysis. This produced a combined deattenuated prevented fraction and a combined deattenuated percentage risk of overdiagnosis.
In women aged 39-75 years invited to screen, the prevented fraction of breast cancer mortality at 13-year follow-up was 0.22 (95% CI 0.15-0.28) and it increased to 0.30 (95% CI 0.18-0.42) with deattenuation. In women aged 40-69 years invited to screen, the ITT percentage risk of overdiagnosis during the screening period was 19.0% (95% CI 15.2-22.7%), deattenuation increased this to 29.7% (95% CI 17.8-41.5%).
Adjustment for nonadherence increased the size of the mortality benefit and risk of overdiagnosis by up to 50%. These estimates are more appropriate when developing quantitative information to support individual decisions about attending screening mammography.
女性需要了解定期参加乳腺钼靶筛查对乳腺癌死亡率和过度诊断的影响，以便做出明智的决策。为了提供这些信息，我们旨在对针对试验方案依从性进行调整的随机对照试验进行荟萃分析。
选取了英国独立乳腺筛查报告中使用的9项乳腺钼靶筛查试验。我们扩展了一种现有方法，用于调整意向性分析（ITT）估计值以处理低于100%的依从率，进行了随机效应荟萃分析。这得出了一个综合的去衰减预防率和一个综合的去衰减过度诊断百分比风险。
在受邀进行筛查的39 - 75岁女性中，13年随访时乳腺癌死亡率的预防率为0.22（95%可信区间0.15 - 0.28），去衰减后增至0.30（95%可信区间0.18 - 0.42）。在受邀进行筛查的40 - 69岁女性中，筛查期间ITT过度诊断百分比风险为19.0%（95%可信区间15.2 - 22.7%），去衰减后增至29.7%（95%可信区间17.8 - 41.5%）。
对不依从进行调整使死亡率获益幅度和过度诊断风险增加了高达50%。在制定定量信息以支持关于参加乳腺钼靶筛查的个人决策时，这些估计更为合适。
