Jansen F H, Roobol M, Bangma C H, van Schaik R H N
Department of Urology, Erasmus MC, Rotterdam, The Netherlands.
Clin Chem. 2008 Dec;54(12):1999-2006. doi: 10.1373/clinchem.2007.102699. Epub 2008 Oct 16.
Clinicians may be unaware that replacement of the historical total prostate-specific antigen (tPSA) standard with the WHO 96/670 international standard leads to difficulties in interpreting tPSA results. Our aim was to investigate the relationship between the Hybritech and WHO calibrations of the Beckman Coulter tPSA assay, and to assess the impact on prostate cancer (PCa) detection.
tPSA concentrations were measured in 106 serum samples with both Hybritech and WHO calibrations. The established relationships were used for an in silico experiment with a cohort of 5865 men. Differences in prostate biopsy rates, PCa detection, and characteristics of missed cancers were calculated at biopsy thresholds of 3.0 and 4.0 microg/L.
A linear relationship was observed between the 2 calibrations, with a 20.3% decrease in tPSA values with the WHO standard compared with the Hybritech calibration. Applying the WHO calibration to the cohort of 5865 men yielded a 20% or 19% decrease in prostate biopsies and a 19% or 20% decrease in detected cancers compared with the Hybritech calibration, at a cutoff for biopsy of 3.0 or 4.0 microg/L, respectively. The decrease in detected cancers declined to 9% or 11% if an abnormal result in a digital rectal examination or a transrectal ultrasound evaluation was used as trigger for prostate biopsy (cutoff of 3.0 or 4.0 microg/L, respectively).
Application of the WHO standard for tPSA assays with commonly used tPSA thresholds leads to a significant decrease in PCa detection. Careful assessment of the relationship between the WHO standard and the thresholds used for prostate biopsy is hence necessary.
临床医生可能未意识到用世界卫生组织96/670国际标准取代历史总前列腺特异性抗原（tPSA）标准会导致tPSA结果解读困难。我们的目的是研究贝克曼库尔特tPSA检测的Hybritech校准与世界卫生组织校准之间的关系，并评估对前列腺癌（PCa）检测的影响。
用Hybritech校准和世界卫生组织校准对106份血清样本测量tPSA浓度。将建立的关系用于对5865名男性队列的计算机模拟实验。在活检阈值为3.0和4.0微克/升时，计算前列腺活检率、PCa检测率及漏诊癌症特征的差异。
观察到两种校准之间呈线性关系，与Hybritech校准相比，世界卫生组织标准下tPSA值降低了20.3%。对5865名男性队列应用世界卫生组织校准，在活检阈值分别为3.0或4.0微克/升时，与Hybritech校准相比，前列腺活检分别减少了20%或19%，检测到的癌症分别减少了19%或20%。如果将直肠指检或经直肠超声检查的异常结果用作前列腺活检的触发因素（活检阈值分别为3.0或4.0微克/升），检测到的癌症减少率分别降至9%或11%。
将世界卫生组织标准应用于常用tPSA阈值的tPSA检测会导致PCa检测率显著降低。因此，有必要仔细评估世界卫生组织标准与前列腺活检所用阈值之间的关系。
