Ferreira Marcos D, Koff Walter J
Division of Urology, General Hospital of Porto Alegre, Federal University of Rio Grande do Sul, UFRGS, Porto Alegre, Rio Grande do Sul, Brazil.
Int Braz J Urol. 2005 Mar-Apr;31(2):137-45; discussion 146. doi: 10.1590/s1677-55382005000200008.
To determine the clinical usefulness of prostate-specific antigen (PSA) density in the transition zone (PSADTZ) for increasing the specificity in early detection of prostate cancer (PCa) and reducing unnecessary biopsies in males with PSA between 4.0 and 10 ng/mL.
This cross-sectional study obtained PSADTZ measurements in 68 patients with PSA between 4.0 and 10 ng/mL. All patients underwent transrectal ultrasonography (TRUS) with biopsies. PSADTZ was estimated by dividing the PSA value by the volume of the transition zone (TZ) obtained. We compared performance measurements for these parameters with those from the PSA itself, PSA density (PSAD) and free PSA/total PSA ratio (F/T PSA). The ability of the method in increasing PSA specificity was demonstrated and compared in univariate and multivariate analyses, and by Receiver Operating Characteristic Curves (ROC).
Of the 68 patients under study, 17 (25%) were diagnosed with PCa. The TZ volume (p = 0.001) and PSADTZ (p = 0.001) variables presented means that exhibited statistically significant differences. When compared with the area under the curve (AUC), ROC curves obtained by this method revealed that PSADTZ was the strongest predictor for PCa when considering the cut-off point provided by the curve; that is, 0.35 ng/mL/cc. When PSADTZ was employed, the detection failure would be close to 20%, and less than 45% of cases would undergo unnecessary biopsies. On the other hand, when F/T PSA was used, the loss would reach almost 40%; however less than 30% would undergo unnecessary biopsies. Nevertheless, PSADTZ had the only AUC presenting p < 0.05 in significance when compared with 50%, and was consequently discriminative.
PSADTZ increased PSA specificity in early detection of PCa in males with PSA between 4.0 and 10 ng/mL. However, it was shown to have lower predictive value and lower accuracy than the percentage of free PSA since it presents a higher negative predictive value than all other parameters assessed, and it can be considered clinically useful for reducing unnecessary indications for biopsy.
确定前列腺移行区特异性抗原（PSADTZ）在提高前列腺癌（PCa）早期检测特异性及减少前列腺特异性抗原（PSA）水平在4.0至10 ng/mL男性患者不必要活检方面的临床实用性。
这项横断面研究对68例PSA水平在4.0至10 ng/mL的患者进行了PSADTZ测量。所有患者均接受经直肠超声检查（TRUS）及活检。PSADTZ通过将PSA值除以所获得的移行区（TZ）体积来估算。我们将这些参数的性能测量结果与PSA本身、PSA密度（PSAD）及游离PSA/总PSA比值（F/T PSA）的结果进行了比较。通过单因素和多因素分析以及受试者操作特征曲线（ROC），展示并比较了该方法提高PSA特异性的能力。
在68例研究对象中，17例（25%）被诊断为PCa。TZ体积（p = 0.001）和PSADTZ（p = 0.001）变量的均值存在统计学显著差异。与曲线下面积（AUC）相比，该方法获得的ROC曲线显示，考虑曲线提供的截断点（即0.35 ng/mL/cc）时，PSADTZ是PCa最强的预测指标。采用PSADTZ时，漏诊率接近20%，且不到45%的病例会接受不必要的活检。另一方面，使用F/T PSA时，漏诊率将达到近40%；然而，接受不必要活检的病例不到30%。尽管如此，与50%相比，PSADTZ的AUC具有唯一的显著p < 未找到具体数值，因此具有鉴别性。
PSADTZ提高了PSA在PSA水平在4.0至10 ng/mL男性患者PCa早期检测中的特异性。然而，与游离PSA百分比相比，其预测价值和准确性较低，因为它的阴性预测价值高于所有其他评估参数，并且可被认为在临床上有助于减少不必要的活检指征。
