当t-PSA处于低水平时游离PSA百分比在前列腺癌鉴别诊断中的价值探讨

目的探讨游离前列腺特异性抗原百分比在前列腺癌(PCa)诊断中的价值。方法检测50例正常人、46例良性前列腺增生(BPH)患者和32例PCa患者的血清t-PSA和f-PSA,其中BPH和PCa患者t-PSA均在4.0~10.0μg/L,并求得f-PSA百分比,然后进行统计分析。结果疾病组t-PSA水平((6.47±1.66,7.05±2.61)μg/L)明显高于正常对照组((1.02±0.91)μg/L)(P<0.01),而PCa组((7.05±2.61)μg/L)与BPH组((6.47±1.66)μg/L)无显著性差异(P>0.05);BPH组f-PSA百分比((21±11)%)明显高于PCa组((12±9)%),两者有非常显著性差异(P<0.01)。把f-PSA百分比值划分成8个区间,分别为≤8%、≤10%、≤12%、≤14%、≤16%、≤18%、≤20%、≤22%。当f-PSA百分比12%作为诊断PCa的临界值时,诊断的敏感性、特异性、阳性预测值、阴性预测值及正确诊断指数分别为75.0%,73.9%,66.7%,81.0%和48.9%。总的来说,12%的诊断标准最合适。结论f-PSA百分比结合临床表现和影像学检查及其他诊断指标,可显著提高PSA对PCa诊断的特异性,为低水平血清t-PSA的PCa的鉴别诊断提供新的思路。

Value discuss of free PSA percent for differential diagnosis of prostate cancer when t- PSA low

Objective It is to discuss the value of free prostate specific antigen percent in diagnosis of prostate cancer(PCa).Methods The levels of serum t-PSA and f-PSA from 50 cases of normal people,46 cases of benign prostatic hyperplasia(BPH) and 32 cases of PCa were detected.The t-PSA levels of the two disease groups were 4.0 μg/L to 10.0 μg/L.The f-PSA percent was calculated,then the statistical analysis was performed.Results The t-PSA level in disease group((6.47±1.66,7.05±2.61) μg/L) was significantly higher than that in normal group((1.02±0.91) μg/L)(P<0.01),however there was no significant difference on t-PSA between PCa group((7.05±2.61) μg/L) and BPH group((6.47±1.66) μg/L)(P>0.05).The f-PSA percent in BPH group((21±11)%) was significantly higher than that in PCa group((12±9)%),and there was very significant difference(P<0.01).The value of f-PSA percent was plotted into eight parts which were ≤8%,≤10%,≤12%,≤14%,≤16%,≤18%,≤20% and ≤22%.When the f-PSA percent value was 12% that was as the critical value for the diagnosis of PCa,the sensitivity,specificity,positive predictive value,negative predictive value and correct diagnosis index were respectively 75.0%,73.9%,66.7%,81.0% and 48.9%.In general the criterion 12% was optimal.Conclusion The f-PSA Percent combined with clinical manifestation,imageology examination and other diadynamic criterias can significantly enhance the specificity of PSA for the diagnosis of PCa,and that can provide a new train of thought for the differential diagnosis of PCa when PSA level is low.