Martínez Jabaloyas J M, García Morata F, Villamón Fort R, Pastor Hernández F, Gil Salom M, García Sisamón F
Servicio de Urología, Hospital Clínico Universitario de Valencia, Valencia.
Actas Urol Esp. 2003 Jun;27(6):442-9. doi: 10.1016/s0210-4806(03)72951-9.
With serum prostate specific antigen (PSA) levels of 4.1 to 10 ng/ml a significant number of patients are unnecessary subjected to biopsy. We try to determine if the calculation of prostate specific antigen density (PSAD) and prostate specific antigen density of the transition zone (PSADTZ) improve the capacity to discriminate between non-malignant disease and prostate cancer.
A prospective study including 314 males with PSA levels between 4.1 and 10 ng/ml is reported. Transrectal ultrasonography and prostatic biopsy were performed in all of them and total prostate and transition-zone volumes were calculated. PSA density and PSA density of the transition zone were calculated for each patient. Receiver operating characteristics (ROC) curves for PSA, PSAD and PSADTZ were constructed for all the patients and for those patients with digital rectal examination unsuspicous of malignancy, determining the sensitivity and specificity for several cutoff values.
The area under the curve for both, PSAD and PSADTZ, were greater than for PSA (p < 0.05), without any significant differences between PSADTZ and PSAD. The cutoff value of greatest diagnostic efficiency for PSAD was 0.17 ng/ml/cc (71.4% sensitivity and 55.7% specificity), while it was 0.41 ng/ml/cc for DPSATZ (70% sensitivity and 61.5% specificity). For those cases of normal digital rectal examination, no differences were observed between PSA and PSAD but they were between PSA and PSADTZ. In any event, the area under ROC curves was always less than 0.7, and, in order to avoid a large number of biopsies (high specificity), a large number of cancers are left without diagnosis (low sensitivity).
We conclude that PSAD and PSADTZ are not excessively useful for adequately discriminating between patients with prostate cancer and those with non-malignant disease, particularly when digital rectal examination is normal.
血清前列腺特异性抗原（PSA）水平在4.1至10 ng/ml时，相当一部分患者会接受不必要的活检。我们试图确定前列腺特异性抗原密度（PSAD）和移行区前列腺特异性抗原密度（PSADTZ）的计算是否能提高区分非恶性疾病和前列腺癌的能力。
报告一项前瞻性研究，纳入314名PSA水平在4.1至10 ng/ml之间的男性。对所有患者进行经直肠超声检查和前列腺活检，并计算前列腺总体积和移行区体积。为每位患者计算PSA密度和移行区PSA密度。为所有患者以及直肠指检未怀疑恶性肿瘤的患者构建PSA、PSAD和PSADTZ的受试者操作特征（ROC）曲线，确定几个临界值的敏感性和特异性。
PSAD和PSADTZ的曲线下面积均大于PSA（p < 0.05），PSADTZ和PSAD之间无显著差异。PSAD的最大诊断效率临界值为0.17 ng/ml/cc（敏感性71.4%，特异性55.7%），而DPSATZ为0.41 ng/ml/cc（敏感性70%，特异性61.5%）。对于直肠指检正常的病例，PSA和PSAD之间未观察到差异，但PSA和PSADTZ之间存在差异。无论如何，ROC曲线下面积始终小于0.7，并且为了避免大量活检（高特异性），会有大量癌症未被诊断出来（低敏感性）。
我们得出结论，PSAD和PSADTZ对于充分区分前列腺癌患者和非恶性疾病患者并非非常有用，尤其是在直肠指检正常时。
