PSA密度对灰区内前列腺癌的诊断价值

目的:研究前列腺特异性抗原密度(PSA density,PSAD,即血清总PSA与前列腺体积的比值)在F/TPSA位于0.16两侧时对灰区内前列腺癌的预测能力并制定合理的参考界值。方法:收集tPSA位于4～10ng/ml并行前列腺穿刺活检的患者135例,病理证实BPH112例,PCa23例,检测其tPSA、fPSA、F/TPSA及PSAD,分为两组,A组F/TPSA≤0.16,B组F/TPSA>0.16;绘制tPSA、PSAD的ROC曲线,计算并比较曲线下面积,分析PSAD在不同取值时的敏感度和特异度。结果:A组tPSA与PSAD的曲线下面积分别为0.554、0.803(P<0.05);PSAD>0.18时敏感度(75%)和特异度(78.38%)均达到最大。B组tPSA、PSAD的曲线下面积分别为0.549、0.862(P<0.05);PSAD>0.22时,敏感度(72.73%)和特异度(86.67%)均最大。结论:在灰区内tPSA对鉴别前列腺癌无明显价值。联合F/TPSA有助于提高诊断的特异性,当F/TPSA≤0.16时推荐PSAD参考界值为0.18,当F/TPSA>0.16时推荐为0.22。

Value of prostate-specific antigen density in detection of prostate cancer in PSA gray zone

Objective: To study the value of PSAD in the diagnosis of prostate cancer in PSA gray zone cases and make appropriate cut-off values. Methods: TPSA,fPSA,F/TPSA,prostate volume and PSAD were detected in 135 cases with PSA levels of 4.0-10.0 ng/ml who underwent trans-rectal ultrasonography-guided prostate biopsies.Of the 135 patients,23 had prostate cancer and 112 had benign prostatic hyperplasia(BPH) on pathologic examination.All cases were divided into two groups with F/T≤0.16 as cut-off values.The relevant parameters of PSA between BPH and PCa cases were compared and the ROC analysis was used to check the sensitivity and specificity of different cut-off points. Results: In group A,the area under the ROC curve(AUC) for PSAD is larger than tPSA(P<0.05) and better sensitivity and specificity(75% and 78.38% respectively) were obtained when the cut-off point was 0.18.In group B,the AUC for PSAD was ampler than tPSA,and the cutoff point of 0.22 was recommended with sensitivity of 72.73% and specificity of 86.67%. Conclusion: In PSA gray zone cases tPSA has no significant value in diagnosis of prostate cancer.The PSAD with the cutoff points as 0.18 when F/TPSA≤0.16 and 0.22 when F/TPSA >0.16 may be helpful to improve the specificity of diagnosing prostate cancer.