What Is the True Number Needed to Screen and Treat to Save a Life With Prostate-Specific Antigen Testing?
What Is the True Number Needed to Screen and Treat to Save a Life With Prostate-Specific Antigen Testing?
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DOI：
10.1200/jco.2010.30.6373
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发表时间：
2011-02-01
影响因子：
45.3
通讯作者：
Catalona, William J.
中科院分区：
文献类型：
--
作者：
Loeb, Stacy;Vonesh, Edward F.;Catalona, William J.
目的：欧洲前列腺癌筛查随机研究（ERSPC）报告了前列腺特异性抗原（PSA）筛查可降低20%的死亡率。然而，他们估计，为了防止9年前列腺癌死亡，筛查（NNS）所需的人数为1410人，治疗（NNT）所需的人数为48人。尽管NNS和NNT是评估干预措施利弊的有用统计数据，但在ERSPC等生存研究环境中，NNS和NNT是特定于时间的，在一个时间点报告的值可能导致对结果的误解。我们的目的是从ERSPC报告中推断的数据，重新检查不同随访时间对NNS和NNT的影响。基于已发表的ERSPC数据，我们使用分段指数模型对累积风险函数进行建模，假设试验第1至7年筛选组和对照组的恒定风险为0.0002，第8至12年筛选组和对照组的恒定风险分别为0.00062和0.00102。年化癌症检出率和退出率也根据ERSPC公布的数据中观察到的处于危险中的个体数量进行了近似计算。结果根据我们的模型，9年时的NNS和NNT分别为1254和43。随后，NNS从第10年的837下降到第12年的503，NNT从29下降到18。尽管估计NNT的性质看似简单，但对其缺陷存在广泛的误解。随着ERSPC的进一步随访，如果死亡率差异继续扩大，PSA筛查挽救生命的NNT将减少。[J]中华医学杂志，29:464-467。(C) 2010年由美国临床肿瘤学会出版
Purpose The European Randomized Study of Screening for Prostate Cancer (ERSPC) reported a 20% mortality reduction with prostate-specific antigen (PSA) screening. However, they estimated a number needed to screen (NNS) of 1,410 and a number needed to treat (NNT) of 48 to prevent one prostate cancer death at 9 years. Although NNS and NNT are useful statistics to assess the benefits and harms of an intervention, in a survival study setting such as the ERSPC, NNS and NNT are time specific, and reporting values at one time point may lead to misinterpretation of results. Our objective was to re-examine the effect of varying follow-up times on NNS and NNT using data extrapolated from the ERSPC report.Materials and Methods On the basis of published ERSPC data, we modeled the cumulative hazard function using a piecewise exponential model, assuming a constant hazard of 0.0002 for the screening and control groups for years 1 to 7 of the trial and different constant rates of 0.00062 and 0.00102 for the screening and control groups, respectively, for years 8 to 12. Annualized cancer detection and drop-out rates were also approximated based on the observed number of individuals at risk in published ERSPC data.Results According to our model, the NNS and NNT at 9 years were 1,254 and 43, respectively. Subsequently, NNS decreased from 837 at year 10 to 503 at year 12, and NNT decreased from 29 to 18.Conclusion Despite the seemingly simplistic nature of estimating NNT, there is widespread misunderstanding of its pitfalls. With additional follow-up in the ERSPC, if the mortality difference continues to grow, the NNT to save a life with PSA screening will decrease. J Clin Oncol 29:464-467. (C) 2010 by American Society of Clinical Oncology