Department of Urology, Erasmus Medical Center, Rotterdam, The Netherlands.
Eur J Cancer. 2012 Aug;48(12):1809-15. doi: 10.1016/j.ejca.2012.02.002. Epub 2012 Mar 7.
Prediction models need validation to assess their value outside the development setting.
To assess the external validity of the European Randomised study of Screening for Prostate Cancer (ERSPC) Risk Calculator (RC) in a contemporary clinical cohort.
The RC calculates the probability of a positive sextant prostate biopsy (P(posb)) using serum prostate-specific antigen (PSA), results of digital rectal examination, transrectal ultrasound (TRUS) and ultrasound assessed prostate volume. We prospectively validated the RC in 320 biopsied men (55-75 years), with no previous prostate biopsy, included in five Dutch hospitals in 2008-2011. If the P(posb) was ≥ 20% a biopsy was recommended. The performance of the RC was tested by comparing the observed outcomes to predicted probabilities, using the area under the curve (AUC) and decision curves analyses.
Compared to the screening cohort, men in the clinical cohort differed. They had higher PSA levels (median 6.8 versus 4.3 ng/ml, p<0.01), less TRUS-lesions (27% versus 34%, p = 0.01) and more prostate cancer (PCa) at biopsy (43% versus 25%, p<0.01). Mainly eight biopsy cores were taken. Despite the differences between these cohorts, the mean observed probability agreed with the mean predicted probability (43% versus 40%). The RC predicted P(posb) better than a model with PSA and digital rectal examination, AUC 0.77 (95% confidence interval (CI) 0.72-0.83) and 0.71 (95%CI 0.65-0.76, p<0.01), respectively. This was confirmed by the decision curves analysis. Under the 20% threshold, 17% (11/63) of the biopsied men were diagnosed with PCa. Two of 11 men had an important cancer (Gleason 3+4).
The ERSPC RC performs well in a Dutch clinical cohort in men with previous PSA tests and contemporary biopsy schemes, and outperforms a PSA and DRE-based approach in the decision to perform a biopsy.
预测模型需要验证，以评估其在开发环境之外的价值。
在当代临床队列中评估欧洲随机前列腺癌筛查研究（ERSPC）风险计算器（RC）的外部有效性。
RC 使用血清前列腺特异性抗原（PSA）、数字直肠检查结果、经直肠超声（TRUS）和超声评估的前列腺体积计算阳性六分区前列腺活检（P（posb））的概率。我们前瞻性地验证了 2008-2011 年期间荷兰五家医院的 320 名接受过前列腺活检的无前列腺活检史的 55-75 岁男性。如果 P（posb）≥20%，则推荐进行活检。使用曲线下面积（AUC）和决策曲线分析比较观察到的结果与预测概率，测试 RC 的性能。
与筛查队列相比，临床队列中的男性存在差异。他们的 PSA 水平较高（中位数 6.8 与 4.3ng/ml，p<0.01），TRUS 病变较少（27%与 34%，p=0.01），活检时前列腺癌（PCa）更多（43%与 25%，p<0.01）。主要取 8 个活检核心。尽管这些队列之间存在差异，但平均观察到的概率与平均预测概率一致（43%与 40%）。RC 预测 P（posb）优于基于 PSA 和数字直肠检查的模型，AUC 为 0.77（95%置信区间（CI）为 0.72-0.83）和 0.71（95%CI 为 0.65-0.76，p<0.01）。这一点通过决策曲线分析得到了证实。在 20%的阈值下，17%（11/63）接受活检的男性被诊断为 PCa。11 名男性中有 2 名患有重要癌症（Gleason 3+4）。
ERSPC RC 在有既往 PSA 检测和当代活检方案的荷兰临床队列中表现良好，在决定进行活检方面优于基于 PSA 和 DRE 的方法。
