血清游离PSA百分率在前列腺癌诊断盲区的价值评价

Value of free/total PSA ratio in differentiating prostate cancer from BPH during the diagnostic grey zone

目的探讨血清游离前列腺特异性抗原(prostatespecificantigen,PSA)百分率在血清总PSA(totalPSA,t-PSA)介于4.0-20.0ng/mL时对前列腺癌(prostatecancer,Pca)的诊断价值。方法用化学发光法测定94例t-PSA介于4.0-20.0ng/mL的未治前列腺疾病患者血清游离PSA(freePSA,f-PSA),其中良性前列腺增生(benignprostatichyperplasia,BPH)患者77例,Pca患者17例,并计算其f-PSA百分率(f/t-PSA)。结果t-PSA介于4.0-20.0ng/mL时,Pca组f/t-PSA明显低于BPH组(P<0.01)。以f/t-PSA为0.18、0.22为界值时其诊断Pca的敏感度为83.9%、94.1%,特异度为75.2%、63.7%,阳性预测值为42.5%、37.1%,阴性预测值为95.4%、98.3%。结论t-PSA介于4.0-20.0ng/mL诊断盲区时,f/t-PSA对诊断Pca有较好的临床价值,以0.22为界值其敏感度达94.1%,阴性预测值达98.3%。

Objective To evaluate the clinical value of free/total prostate specific antigen （PSA） ratio as a marker to differentiate between benign prostatic hyperplasia（BPH） and prostate carcinomas when the total PSA ranged from 4 to 20 ng/mL. Methods Free PSA and total PSA were measured by chemiluminescent immunoassay of all samples from 77 men with untreated BPH and 17 men with untreated prostate carcinomas. Results The free/total PSA ratio was significantly different between patients with prostate cancer and patients with BPH （P〈0.01） when their total PSA ranged from 4 to 20 ng/mL. The sensitivity of free/total PSA ratio in diagnosing prostate cancer was 83.9% and 94.1% respectively, and the specificity was 75.2% and 63.7% respectively, when the cutoff value was 0.18 and 0.22. Conclusion The free/total PSA ratio has better clinical value for differentiating prostate cancer when the total PSA 94.1% and NPV is 98. 3% when the cutoff value is 0.22, and at the is between 4 and 20 ng/mL. Its sensitivity is as high as same time it can avoid 63.7% unnecessary biopsy.