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

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

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4．0～10．0pg／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）pg／L）明显高于正常对照组（（1．02±0．91）pg／L）（P＜0．01），而PCa组（（7．05±2．61）pg／L）与BPH组（（6．47±1．66）／zg／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。

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 ttg/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 ） tLg/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 were48%, 410%, 412%, 414%, 416%, 418%, 420% and 422%. 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.