Roehrborn C G, Boyle P, Gould A L, Waldstreicher J
Department of Urology, University of Texas Southwestern Medical Center at Dallas 75235-9110, USA.
Urology. 1999 Mar;53(3):581-9. doi: 10.1016/s0090-4295(98)00655-4.
To assess the utility of prostate-specific antigen (PSA) as a predictor of prostate volume by characterizing the relationship between prostate volume and serum PSA in men with symptomatic benign prostatic hyperplasia (BPH) and no evidence of prostate cancer, stratified by decade of life.
Placebo-controlled multicenter trials in patients with BPH and a safety study in normal young men provided baseline measurements of serum PSA and prostate volume. The analyses included patients with a baseline prostate volume measured by either transrectal ultrasound (TRUS) or magnetic resonance imaging and baseline serum PSA. A common central laboratory was used for all but one of the individual studies; both laboratories used the Hybritech method. Patients 80 years of age or older were excluded. Patients with a baseline serum PSA greater than 10 ng/mL were excluded to reduce the likelihood of including occult prostate cancer cases. The patients in the BPH trials were screened at baseline by digital rectal examination (DRE) and serum PSA. Those with suspicious findings underwent TRUS-guided biopsy; only patients with negative biopsies are included in these analyses.
The analyses included 4627 patients, 4448 from the BPH trials and 179 from the safety study. The men in the BPH trials were older (mean age+SE, 63.7+0.10 years) than the men in the safety study (mean age + SE, 30.8+/-0.43), had larger prostates (mean volume+/-SE, 43.7+/-0.38 mL versus 26.3+/-0.49 mL in the safety study), and had higher serum PSA values (mean+/-SE, 2.6+/-0.03 ng/mL versus 0.7+/-0.39 ng/mL in the safety study). The relationship between prostate volume and serum PSA was evaluated using only the BPH trial data. Prostate volume and serum PSA have an age-dependent log-linear relationship (ie, their logarithms are linearly related, and the parameters of the relationship depend on age). Older men tend to have a steeper rate of increase in prostate volume with increasing serum PSA (P < 0.00 for differences between slopes), and there was a slight tendency for PSA density to increase with age. Receiver operating characteristic (ROC) curves were constructed to evaluate the ability of serum PSA to predict threshold prostate sizes in men with BPH. The ROC curve analyses revealed that PSA had good predictive value for assessing prostate volume, with areas under the curve ranging from 0.76 to 0.78 for various prostate volume cutoff points (30, 40, and 50 mL). Conclusions. Prostate volume is strongly related to serum PSA in men with BPH and no evidence of prostate cancer, and the relationship depends on age. Since treatment outcome or risk of long-term complications depend on baseline prostate volume, serum PSA can estimate the degree of prostate enlargement sufficiently accurately to be useful for therapeutic decision making. To achieve a specificity of 70% while maintaining a sensitivity between 65% and 70%, approximate age-specific criteria for detecting men with prostate glands exceeding 40 mL are PSA > 1.6 ng/mL, >2.0 ng/mL, and >2.3 ng/mL for men with BPH in their 50s, 60s, and 70s, respectively.
通过描述有症状的良性前列腺增生（BPH）且无前列腺癌证据的男性患者前列腺体积与血清前列腺特异性抗原（PSA）之间的关系，并按年龄段分层，评估PSA作为前列腺体积预测指标的效用。
BPH患者的安慰剂对照多中心试验以及正常年轻男性的安全性研究提供了血清PSA和前列腺体积的基线测量值。分析纳入了通过经直肠超声（TRUS）或磁共振成像测量基线前列腺体积以及有基线血清PSA的患者。除一项单独研究外，所有研究均使用同一个中央实验室；两个实验室均采用Hybritech方法。排除80岁及以上患者。排除基线血清PSA大于10 ng/mL的患者，以降低纳入隐匿性前列腺癌病例的可能性。BPH试验中的患者在基线时通过直肠指检（DRE）和血清PSA进行筛查。有可疑发现的患者接受TRUS引导下的活检；这些分析仅纳入活检阴性的患者。
分析纳入4627例患者，其中4448例来自BPH试验，179例来自安全性研究。BPH试验中的男性比安全性研究中的男性年龄更大（平均年龄±标准误，63.7±0.10岁 vs 30.8±0.43岁），前列腺更大（平均体积±标准误，43.7±0.38 mL vs 安全性研究中的26.3±0.49 mL），血清PSA值更高（平均±标准误，2.6±0.03 ng/mL vs 安全性研究中的0.7±0.39 ng/mL）。仅使用BPH试验数据评估前列腺体积与血清PSA之间的关系。前列腺体积与血清PSA呈年龄依赖性对数线性关系（即它们的对数呈线性相关，且关系参数取决于年龄）。年龄较大的男性随着血清PSA升高，前列腺体积增加的速率往往更陡（斜率差异P<0.00），且PSA密度有随年龄略有增加的趋势。构建受试者工作特征（ROC）曲线以评估血清PSA预测BPH男性患者前列腺阈值大小的能力。ROC曲线分析显示，PSA对评估前列腺体积具有良好的预测价值，对于不同前列腺体积截断点（30、40和50 mL），曲线下面积范围为0.76至0.78。结论。在无前列腺癌证据的BPH男性患者中，前列腺体积与血清PSA密切相关，且这种关系取决于年龄。由于治疗结果或长期并发症风险取决于基线前列腺体积，血清PSA能够足够准确地估计前列腺增大程度，有助于治疗决策。为达到70%的特异性，同时保持65%至70%的敏感性，对于50多岁、60多岁和70多岁的BPH男性患者，检测前列腺超过40 mL的男性的近似年龄特异性标准分别为PSA>1.6 ng/mL、>2.0 ng/mL和>2.3 ng/mL。
