Carter H B, Pearson J D, Waclawiw Z, Metter E J, Chan D W, Guess H A, Walsh P C
Department of Urology, James Buchanan Brady Urological Institute, Johns Hopkins Hospital, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
Urology. 1995 Apr;45(4):591-6. doi: 10.1016/S0090-4295(99)80049-1.
To evaluate short-term and long-term variability between prostate-specific antigen (PSA) measurements to determine the most appropriate PSA sampling interval and rate of PSA change (PSA velocity) to distinguish between men with and without prostate cancer.
Retrospective study of PSA variability and PSA velocity in three groups of men without a diagnosis of prostate cancer and PSA levels less than 10 ng/mL: 56 men with a histologic diagnosis of benign prostatic hyperplasia (BPH; histologic BPH group) and 527 men with no history of cancer (noncancer group) who were part of the Baltimore Longitudinal Study of Aging and had PSA sampled at 2-year intervals (long-term), and 223 men with a clinical diagnosis of BPH (clinical BPH group) who had PSA sampled at 3-month intervals (short-term). PSA variability (deviation between consecutive measurements) and PSA velocity based on both two consecutive measurements and three consecutive measurements (average velocity) were calculated for each study group.
PSA velocity is the deviation in PSA measurements relative to the elapsed time between the measurements. Because the variability in PSA between measurements was similar for the groups, the major factors that influenced PSA velocity were the sampling interval between PSA measurements, and to a lesser extent, the number of repeat PSA measurements. The 99th percentile for PSA velocity was 0.7 (histologic BPH group) and 0.75 ng/mL per year for the noncancer group when three measurements with a 24-month PSA sampling interval were used. However, the 99th percentile for PSA velocity was 5.8 and 2.4 ng/mL per year when three measurements with 3-month and 6-month PSA sampling intervals were used. Using three measurements, the percentage of subjects with a PSA velocity more than 0.75 ng/mL per year was 1% for the groups with a 24-month PSA sampling interval and 28% and 17% for 3-month and 6-month PSA sampling intervals, respectively. The 99th percentile for PSA velocity and the percentage of subjects with a PSA velocity more than 0.75 ng/mL per year was higher using two measurements compared to three measurements regardless of PSA sampling interval.
PSA velocity is inversely related to the interval between PSA measurements. A PSA velocity more than 0.75 ng/mL per year is useful in distinguishing between men with and without prostate cancer when: (1) velocity is based on three consecutive measurements; and (2) PSA is sampled long-term (2 years) but not short-term (3 to 6 months).
评估前列腺特异性抗原（PSA）测量值之间的短期和长期变异性，以确定最合适的PSA采样间隔和PSA变化率（PSA速度），从而区分患有和未患前列腺癌的男性。
对三组未诊断出前列腺癌且PSA水平低于10 ng/mL的男性进行PSA变异性和PSA速度的回顾性研究：56名经组织学诊断为良性前列腺增生（BPH；组织学BPH组）的男性和527名无癌症病史（非癌症组）的男性，他们是巴尔的摩衰老纵向研究的一部分，PSA采样间隔为2年（长期）；以及223名临床诊断为BPH（临床BPH组）的男性，PSA采样间隔为3个月（短期）。计算每个研究组基于连续两次测量和连续三次测量（平均速度）的PSA变异性（连续测量之间的偏差）和PSA速度。
PSA速度是PSA测量值相对于测量之间经过时间的偏差。由于各组之间PSA测量值的变异性相似，影响PSA速度的主要因素是PSA测量之间的采样间隔，其次是重复PSA测量的次数。当使用24个月PSA采样间隔的三次测量时，组织学BPH组的PSA速度第99百分位数为0.7，非癌症组为每年0.75 ng/mL。然而，当使用3个月和6个月PSA采样间隔的三次测量时，PSA速度第99百分位数分别为每年5.8和2.4 ng/mL。使用三次测量时，PSA采样间隔为24个月的组中，每年PSA速度超过0.75 ng/mL的受试者百分比为1%，3个月和6个月PSA采样间隔的组分别为28%和17%。无论PSA采样间隔如何，与三次测量相比，使用两次测量时，PSA速度第99百分位数和每年PSA速度超过0.75 ng/mL的受试者百分比更高。
PSA速度与PSA测量之间的间隔呈负相关。当满足以下条件时，每年PSA速度超过0.75 ng/mL有助于区分患有和未患前列腺癌的男性：（１）速度基于连续三次测量；（２）PSA采样为长期（2年）而非短期（3至6个月）。
