Three new serum markers for prostate cancer detection within a percent free PSA-based artificial neural network

BACKGROUND: We aimed to evaluate the value of macrophage inhibitory cytokine 1 (MIC-1), human kallikrein 11 (hK11) migration inhibitor factor (MIF) in comparison to prostate-specific antigen (PSA) and % fPSA and also to develop a % fPSA-based ANN with the new input factors to determine whether these additional markers can further eliminate unnecessary prostate biopsies. METHODS: Serum samples from 371 patients with prostate cancer (PCa, n=135) or benign prostate hyperplasia (BPH, n=236) within the PSA range 0.5-20 microg/L were analyzed for total PSA, free PSA, MIC-1, hK11, and MIF. 'Leave one out' ANN models with these variables and prostate volume were constructed and compared to logistic regression (LR) and all single parameters. RESULTS: The discriminatory power of MIC-1, hK11, and MIF was less than that for PSA despite significant differences in BPH compared to PCa patients. At 90% and 95% sensitivity, the artificial neural networks (ANNs) were only significantly better than % fPSA if prostate volume was included. CONCLUSIONS: ANNs with the novel input factors of MIC-1, MIF, and/or hK11 and additional use of prostate volume demonstrated significant advantage compared with % fPSA and tPSA and may lead to a reduction in unnecessary prostate biopsies.     

A multicenter clinical trial on the use of alpha1-antichymotrypsin-prostate-specific antigen in prostate cancer diagnosis

BACKGROUND: The aim was to evaluate the clinical performance of alpha(1)-antichymotrypsin prostate-specific antigen (PSA-ACT) for early diagnosis of prostate cancer (PCa) in a multicenter trial. METHODS: Three hundred sixty-seven white men with PCa and 290 with benign prostatic hyperplasia (BPH) with tPSA concentrations between 2 and 20 microg/L were analyzed. The Elecsys system 2010 (Roche Diagnostics, Germany) was used for determination of total PSA (tPSA) and free PSA (fPSA). The PSA-ACT test was a prototype assay used on the ES system (Roche Diagnostics). RESULTS: The median concentrations of tPSA (PCa: 8.43 microg/L vs. BPH: 6.60 microg/L) and PSA-ACT (8.30 microg/L vs. 6.46 microg/L) were significantly different, respectively. The median ratios of fPSA/tPSA (PCa: 12% vs. BPH: 16%) and PSA-ACT/tPSA (98% vs. 95%) were significantly different. Receiver operating characteristics (ROC) analysis for discrimination between PCa and BPH (tPSA between 2 and 20 microg/L) was performed with 252 matched pairs and showed that the area under the curve (AUC) of the ratio fPSA/tPSA (0.66) was significantly different from tPSA (0.50) and PSA-ACT (0.52). PSA-ACT alone or the ratio PSA-ACT/tPSA (0.56) were not significantly different from tPSA. For tPSA between 4 and 10 microg/L (n = 145 pairs), the AUC of the ratio fPSA/tPSA (0.65) was significantly higher than tPSA (0.50) and PSA-ACT (0.54). Significant differences between tPSA and PSA-ACT or PSA-ACT/tPSA (0.56) were not found. CONCLUSIONS: The determination of PSA-ACT as well as the PSA-ACT/tPSA ratio did not improve the diagnostic impact in patients undergoing evaluation for PCa compared to fPSA/tPSA ratio.     

Comparison of the clinical validity of free prostate-specific antigen, alpha-1 antichymotrypsin-bound prostate-specific antigen and complexed prostate-specific antigen in prostate cancer diagnosis

OBJECTIVE: To evaluate the diagnostic utility of free prostate specific antigen (fPSA), alpha-1- antichymotrypsin-bound PSA (PSA-ACT), complexed PSA (cPSA), and including their associated ratios to total PSA (tPSA) in serum for discrimination between prostate cancer (PCa) and benign prostatic hyperplasia (BPH). METHODS: A total of 166 white men (age: 65-88 years) with a tPSA between 2 and 20 microg/l were retrospectively analysed. Serum concentrations of tPSA, fPSA, PSA-ACT and cPSA were measured in 118 untreated PCa patients and 48 patients with BPH. The tPSA and cPSA concentrations were measured with the Bayer Immuno 1 system (Bayer Diagnostics, Tarrytown, USA). The Elecsys system 2010 (Roche Diagnostics, Mannheim, Germany) was used for determination of tPSA and fPSA. The PSA-ACT assay is a newly, developed prototype assay on the ES system (Roche Diagnostics, Mannheim, Germany). RESULTS: For statistical analysis only patients with tPSA between 2 and 20 microg/l were enrolled. The median concentrations of tPSA (Bayer: PCa 7.36 microg/l, BPH 4.03 microg/l; Roche: PCa 7.75, BPH 4.13), PSA-ACT (PCa 6.98, BPH 3.18) and cPSA (PCa 6.46, BPH 3.20) were significantly different. The median ratios of fPSA/tPSA (PCa 12.8 vs. BPH 22.4%), PSA-ACT/tPSA (PCa 89.8 vs. BPH 76.1%) and cPSA/tPSA (PCa 90.5 vs. BPH 81.7%) were significantly different between PCa and BPH patients. Using the areas under the curves, receiver operating characteristics analysis (tPSA: 2-20 microg/l) for discrimination between PCa and BPH showed that the ratios fPSA/tPSA (area under the curve: 0.77), PSA-ACT/tPSA (0.72) and cPSA/tPSA (0.78) were significantly different from tPSA (Bayer: 0.53; Roche: 0.55). PSA-ACT (0.64) and cPSA (0.59) alone were not significantly different from tPSA. The calculated ratios fPSA/tPSA, PSA-ACT/tPSA and cPSA/tPSA were not significantly different. CONCLUSION: The determination of PSA-ACT or cPSA and the associated ratios do not improve the diagnostic impact to discriminate between PCa and BPH compared to fPSA/tPSA ratio. The ratios PSA-ACT/tPSA or cPSA/tPSA can be considered to be alternative tools of fPSA/tPSA.     

单纯前列腺上皮内瘤回顾性分析(附142例病例分析)

目的通过对前列腺上皮内瘤(PIN)临床资料分析,探讨PIN的生物特性及应对策略。方法对31例无前列腺癌PIN(NPCaPIN)改变患者(其中1级23例,2、3级8例)的临床资料(包括患者血清PSA、fPSA/tPSA、PSA密度等区域计数资料以及穿刺标本免疫组织化学染色结果)进行回顾性分析,以同期确诊为前列腺癌(PCa)、良性前列腺增生(BPH)患者资料作为对照,分析低级别PIN(LGPIN)和高级别PIN(HGPIN)改变之间及NPCaPIN临床特征与PCa、BPH患者临床特征的差异。结果LGPIN和HGPIN改变的患者之间血清PSA水平和年龄存在差异(P<0.05);LGPIN和PCa患者之间血清PSA水平、前列腺体积、fPSA存在显著差异(P<0.01),PSA密度、fPSA/tPSA比值存在差异(P<0.05),和BPH患者之间各项均无明显差异;HGPIN改变和PCa患者之间前列腺体积、fPSA水平和年龄存在差异(P<0.05),和BPH患者之间血清PSA水平差异显著(P<0.01),fPSA/tPSA比值和年龄(P<0.05)存在差异;NPCaPIN和PCa患者之间血清前列腺体积、fPSA水平和年龄、血清PSA水平、PSA密度存在显著差异(P<0.01),和BPH患者之间fPSA/tPSA比值(P<0.05)存在差异。P63、AE1、AE3、P504S、PSA免疫组织化学结果NPCaPIN组类似于BPH而完全异于PCa。结论LGPIN的临床和病理特征与BPH相似,而HGPIN的临床和病理方面具有一定的前列腺恶性肿瘤特征,需要积极的临床追踪观察。     

睾酮5-α还原酶Ⅱ基因V89L多态性与前列腺癌预后关系的研究

目的:探讨睾酮5-α还原酶Ⅱ(SRD5A2)基因V89L多态性与影响前列腺癌预后因素的关系。方法:对V89L多态性位点用Rsa-1限制性内切酶进行酶切鉴定,观察112例前列腺癌患者和89例BPH患者的V89L(VV、VL、LL)多态性分布情况的差异及其多态性与前列腺癌患者年龄、前列腺特异性抗原(PSA)、游离PSA/总PSA值(tPSA/fPSA,F/T)、Gleason评分、临床分期的关系。结果:前列腺癌组112例与BPH组89例的V89L基因频度风险无显著性差异(χ2=3.606,df=2,P=0.165)。前列腺癌组VV和VL+LL基因型与fPSA、tPSA、F/T、T分期、Gleason评分差异无显著性(P>0.05)。VV和VL+LL各评价预后指标差异无显著性(P>0.05)。分段评价PSA水平、Gleason评分、临床分期、年龄,均与两种基因型无相关性(P>0.05)。结论:V89L多态性与预后无明显关系,但是可能与前列腺癌的风险存在间接的关系。     

Effect of NIH-IV prostatitis on free and free-to-total PSA

OBJECTIVE: To examine the effect of asymptomatic prostatic inflammation (NIH category IV prostatitis) on total PSA (tPSA), free serum PSA (fPSA) and the ratio of free-to-total prostate specific antigen (%fPSA). The role of free and %fPSA as a diagnostic tool for distinguishing between cancer and non-malignant diseases of the prostate was also investigated. MATERIAL AND METHODS: In a retrospective study 1090 prostate biopsies performed between January 2000 and September 2003 were evaluated and the levels of serum total and free PSA as well as the f/tPSA ratio were determined in samples obtained immediately before biopsy. 404 patients with full clinical and histological records were included in the study. All patients underwent 6 or 8 core primary prostate needle biopsies. RESULTS: A total of 404 patients were included in the analysis. 100 prostate cancer (PCa) (24.8%), 137 NIH-IV prostatitis (33.9%) and 143 patients with benign prostatic hyperplasias (BPH) (35.4%) were identified. 24 (5.9%) patients presented with both PCa and prostatitis on histology and were excluded from further analysis. The mean (median) levels of tPSA, fPSA and %fPSA were 11.94 ng/ml (8.0), 1.31 ng/ml (1.07) and 0.15 (0.14) for NIH-IV prostatitis; 11.94 ng/ml (8.35), 1.54 ng/ml and 0.13 (0.11) for prostate cancer; and 8.19 ng/ml (7.0), 1.48 ng/ml (1.03) and 0.18 (0.15) for BPH. No significant difference was found in tPSA levels between PCa and prostatitis (p = 0.32), while the difference in tPSA levels between PCa and BPH was significant (p = 0.007). Free PSA alone had no diagnostic power in distinguishing PCa from prostatitis (p = 0. 37) and BPH (p = 0. 61). By contrast, the f/tPSA ratio showed significant between-group differences (PCa versus prostatitis (p = 0. 011), PCa versus BPH (p = 0.0001). CONCLUSIONS: Chronic asymptomatic prostatitis NIH category IV has similar effects on total PSA and free PSA levels in serum as PCa. fPSA alone cannot distinguish prostate cancer from non-malignant inflammatory disease of the prostate. The ratio of free-to-total PSA is significantly different in PCa and NIH category IV prostatitis.     

Total and Gleason Grade 4/5 Cancer Volumes are Major Contributors of Human Kallikrein 2, Whereas Free Prostate Specific Antigen is Largely Contributed by Benign Gland Volume in Serum From Patients With Prostate Cancer or Benign Prostatic Biopsies

PurposeWe measured concentrations of human glandular kallikrein 2 (hK2), total prostate specific antigen (tPSA), free PSA (fPSA) and percent fPSA to evaluate their relationship to total prostate gland volume, benign prostatic hyperplasia (BPH) volume, total prostate cancer (PCa) volume (CaVol) and the volume of Gleason grades 4/5 cancer (CaVolGl4) in the serum of 256 patients with PCa undergoing radical retropubic prostatectomy and 185 with negative systematic sextant biopsies.Materials and MethodsFree and total PSA was measured using the Delfia Prostatus (Perkin-Elmer, Turku, Finland) total/free PSA assay and hK2 was measured using a research immunofluorometric assay. Transrectal ultrasound was used to determine total prostate and BPH volume. Total CaVol and CaVolGl4/5 were calculated using a volumetric program in specimens from 158 men with pT2a/b and 98 with pT3a or greater PCa. The Pearson correlation was performed after logarithmic conversion of PSA and hK2 levels. Benign gland, and pT2a/b and pT3a or greater PCa cases were subdivided into small vs large prostate gland volumes (42 cc or less vs greater than 42 cc).ResultsTotal prostate and BPH volumes correlated closely with free PSA (r = 0.64 to 0.65, p <0.0001) in 143 patients with negative biopsy and a prostate of greater than 42 cc. Correlations of hK2 and tPSA with total prostate and BPH volumes were weaker (r = 0.35 to 0.36 and 0.45 to 0.46, respectively). In pT2a/b and pT3a or greater PCa cases hK2 most closely correlated with CaVol (range 0.31 to 0.62, p = 0.0072 and <0.0001) and with CaVolGl4/5 (range 0.26 to 0.56, p = 0.021 and <0.0001, respectively). The tPSA level correlated significantly with CaVol and CaVolGl4/5 except in glands 42 cc or greater harboring pT2a/b PCa (p = 0.08). Free PSA correlated significantly with CaVolGl4/5 only in pT3a or greater PCa (p <0.05), and with CaVol in pT3a or greater PCa and in small prostates harboring pT2a/b PCa.ConclusionsLarge benign prostate gland volume affects fPSA more than tPSA in serum. In PCa hK2 more closely correlates with total cancer volume and high grade PCa volume compared with tPSA or fPSA.     

Use of various combinations of free, complexed and total prostate-specific antigen levels as predictors of the pathologic stage of prostate cancer

BACKGROUND: The efficacy of various combinations of total, free and complexed prostate-specific antigen (PSA) levels were assessed to predict the pathologic stage of prostate cancer. METHODS: Total PSA (tPSA), free PSA (fPSA) and complexed PSA (cPSA) levels were measured preoperatively in 52 patients with clinical localized prostate cancer who had undergone radical prostatectomy. Pathologic stages were classified as: organ-confined (n = 27); capsular penetration (n = 14); seminal vesicle involvement (n = 8); involvement of the surgical margins (n = 10); and lymph node involvement (n = 3). RESULTS: The fPSA/tPSA and fPSA/cPSA ratios significantly differed between patients with organ-confined disease and non-organ-confined disease (P = 0.035, P = 0.033, respectively) and between those with favorable versus unfavorable pathology (P = 0.001, P = 0.014, respectively), but tPSA, cPSA, fPSA and the cPSA/tPSA ratio did not. Using a fPSA/tPSA cutoff level of 11%, the prediction of organ-confined disease would increase from 52 to 67% and the rate of predicting favorable pathology would increase from 42 to 62%. A fPSA/cPSA cutoff level of 12% would increase the rate of predicting organ-confined disease to 79% and the rate of predicting favorable pathology would increase to 69%. The positive predictive value of the fPSA/cPSA ratio was higher than that of the fPSA/tPSA ratio, although the receiver operating characteristic curve of the fPSA/cPSA ratio was not different from that of the fPSA/tPSA ratio. CONCLUSION: Although there was no predictive difference found between fPSA/tPSA and fPSA/cPSA ratio, both ratios may help predict the pathologic stage of prostate cancer.     

The value of (-7, -5)pro-prostate-specific antigen and human kallikrein-2 as serum markers for grading prostate cancer

OBJECTIVE: To assess the value of the precursor form (-7,5pro) of prostate-specific antigen (PSA) and human kallikrein-2 (hK2) for detecting and grading prostate cancer, as better serum markers with improved specificity are needed in men with lower ranges of total (t)PSA. PATIENTS AND METHODS: tPSA, free PSA (fPSA), the precursor (-7,5)proPSA and hK2 were measured in a subset of participants of the European Randomised Study of Screening of Prostate Cancer. In a pilot study, sera from 143 men biopsied but with no prostate cancer, 142 with BPH, and 146 with prostate cancer were analysed to determine the relative value of serum markers for differentiating between the groups. Then, in 141 men with prostate cancer who had a radical prostatectomy, these serum markers were related to the pathological grading to analyse their value as prognostic variables. RESULTS: Levels of (-7,5)proPSA, hK2 and fPSA could be used to distinguish between BPH and cancer, but proPSA and hK2, alone or combined, did not improve the specificity of fPSA for discriminating BPH and cancer. There was also no correlation between these serum markers and pathological tumour grade. CONCLUSION: The clinical effect of using (-7,5)proPSA or hK2 for detecting and grading prostate cancer remains limited.     

Comparisons of the various combinations of free, complexed, and total prostate-specific antigen for the detection of prostate cancer

OBJECTIVES: We compared the ability of three prostate-specific antigen (PSA) ratios - free-to- total PSA ratio (fPSA/tPSA), free-to-complexed PSA ratio (fPSA/cPSA), and complexed-to-total PSA ratio (cPSA/tPSA) - to distinguish prostate cancer from benign prostatic hyperplasia (BPH). METHODS: We tested 258 consecutive patients who underwent transrectal ultrasound-guided prostate needle biopsy because of an abnormal digital rectal examination or a Tandem-R PSA of >4.1 ng/ml. Free PSA (fPSA) and total PSA (tPSA) were measured by Tandem-R assay. alpha(1)-Antichymotrypsin-complexed PSA (cPSA) was measured by Markit-M PSA-ACT assay. RESULTS: Of the 258 patients, 204 had BPH, and 54 had prostate cancer. The specificity at 96% sensitivity for fPSA/tPSA, fPSA/cPSA, and cPSA/tPSA was 23, 25, and 33%, respectively. Of 162 patients with tPSA between 4.1 and 10.0 ng/ml, 132 had BPH and 30 had prostate cancer. The specificity at 96% sensitivity for f/tPSA, f/cPSA and c/tPSA was 32, 44, and 41%, respectively. There was no significant difference in the area under the receiver-operating characteristic curves among fPSA/tPSA, fPSA/cPSA, and cPSA/tPSA in the overall PSA range or in tPSA between 4.1 and 10.0 ng/ml. CONCLUSION: fPSA/tPSA, fPSA/cPSA, and cPSA/tPSA did not differ in their ability to distinguish prostate cancer from BPH.     

有下尿路症状的良性前列腺增生患者前列腺特异性抗原检测的临床意义

目的:探讨前列腺特异性抗原(PSA)测定在有下尿路症状的良性前列腺增生(BPH)患者的临床意义。方法:比较520例有症状和196例无症状的BPH患者的总PSA(tPSA),游离PSA(fPSA)和fPSA/tPSA等指标,并进行统计学分析。结果:有症状组和无症状组的tPSA值分别为(5.13±2.49)、(1.73±1.26)μg/L,差异有极显著性(P<0.01);fPSA分别为(1.57±0.80)、(0.54±0.38)μg/L,差异有极显著性(P<0.01);fPSA/tPSA分别为0.31±0.09和0.30±0.11,差异无显著性(P>0.05)。结论:有下尿路症状BPH患者的tPSA、fPSA明显高于无症状,但fPSA/tPSA比值在BPH患者中稳定。     

Determination of alpha1-antichymotrypsin-PSA complex in serum does not improve the differentiation between benign prostatic hyperplasia and prostate cancer compared with total PSA and percent free PSA

Objectives. To evaluate the analytical performance and diagnostic utility of alpha₁-antichymotrypsin (ACT)-prostate-specific antigen (PSA) complex in serum to improve the differentiation between benign prostatic hyperplasia (BPH) and prostate cancer (PCa).Methods. Serum concentrations of total PSA (tPSA), free PSA (fPSA), and ACT-PSA were measured in 112 untreated patients with PCa (median age 65 years), 34 patients with BPH (median age 66 years) with histologic confirmation, and 33 men without prostate disease and with a normal digital rectal examination considered as controls (median age 54 years). Sera were frozen at −80°C within 2 hours after collection and then analyzed during a 12-week period. Determinations were made with the Enzymun-Test for tPSA and fPSA and with a prototype assay for ACT-PSA on the ES system (Roche Diagnostics, Boehringer Mannheim).Results. The new ACT-PSA assay showed reliable data of analytical performance. The lower detection limit amounted to 0.068 μg/L. The assay was linear to 50 μg/L. Spiking experiments showed a mean recovery rate of 98.2%. No interferences of the assay were observed in patients with acute inflammation and highly increased ACT concentrations. The values of intra- and interassay imprecision ranged from 1.51% to 3.48% and 2.1% to 6.3%, respectively. The median value of ACT-PSA concentrations were significantly different (P <0.001) between controls and patients with BPH and PCa (0.40, 3.86, 5.26 μg/L, respectively). The median fPSA/tPSA and fPSA/ACT-PSA ratios were significantly different between BPH and PCa (24.3% versus 12.2%, P <0.001 and 32.9% versus 15.0%, P <0.001, respectively), but no difference of the ACT-PSA/tPSA ratio was observed (78.2% versus 78.7%, P = 0.696). Receiver operating characteristics of ACT-PSA (area under the CURVE = 0.630) and all the derivative ratios of fPSA/ACT-PSA (area = 0.737) and ACT-PSA/tPSA (area = 0.528) were not different from that of tPSA (area = 0.619), but showed a lower discrimination power between BPH and PCa than the fPSA/tPSA ratio (area = 0.790).Conclusions. Using this prototype assay to quantify ACT-PSA in serum, we have demonstrated that ACT-PSA and the calculated derivatives are not superior in the differentiation between BPH and PCa compared with tPSA and the ratio of fPSA to tPSA.     

良性前列腺增生病人血清不同类别PSA的检测与分析

目的 :分析前列腺增生 (BPH)病人血清中不同前列腺特异抗原 (PSA)的稳定性 ,探讨其在前列腺疾病诊断中的应用价值。　方法 :将病理诊断证实的 1 0 5例BPH病人按总PSA(tPSA)水平分为 3组 :A组 (tPSA <4μg/L)67例 ,B组 (tPSA值 4～ 1 0 μg/L) 2 6例 ,C组 (tPSA >1 0 μg/L) 1 2例。按年龄分为 3组 :a组 (≤ 55岁 ) 1 8例 ,b组 (56～ 69岁 ) 33例 ,c组 (≥ 70岁 ) 54例。采用Bayer磁微粒化学发光免疫方法 ,测定各组BPH病人血清中的复合PSA(cPSA)、tPSA、游离PSA(fPSA) ,并计算cPSA/tPSA、fPSA/tPSA、fPSA/cPSA比值 ,比较它们在不同年龄和tPSA水平组间的稳定性。　结果 :无论在不同的tPSA水平组 ,还是在不同的年龄组 ,cPSA/tPSA比值和fPSA/tPSA、fP SA/cPSA比值比其它各种PSA更稳定。　结论 :cPSA/tPSA比值和fPSA/tPSA、fPSA/cPSA比值在前列腺疾病的诊断中可能更具有应用价值     

经会阴B型超声引导下前列腺穿刺活检的临床价值研究

目的:探讨经会阴扇型B型超声引导下前列腺6针穿刺活检术诊断前列腺癌的临床价值。方法:对经直肠指检或经腹部B超检查发现前列腺结节、血清总前列腺特异性抗原(tPSA)在4μg/L以上或游离PSA(fPSA)/tP-SA<0.16的可疑前列腺癌104例患者,经会阴扇型B超引导下18G自动穿刺活检针行双侧叶6点法穿刺,对穿刺的阳性率和并发症及影响穿刺阳性率的因素进行分析。结果:经病理诊断,检出前列腺癌24例,检出率23%,前列腺癌分级评分中位数为7分,高分化癌(2~4分)、中分化癌(5~7分)和低分化癌(8~10分)分别为12.5%(3/24)、62.5%(15/24)和25%(6/24);其余80例为良性前列腺增生(BPH)。术后短暂和轻度的肉眼血尿5例(4.8%),均在1~3 d后缓解,4例(3.8%)发热37.2℃~38.0℃,术后会阴部轻度不适5例(4.8%)。术后无1例出现血便、血精、前列腺脓肿、高热、败血症、急性尿潴留等严重并发症。经分析发现tPSA、fPSA、fPSA/tPSA、前列腺抗原密度(PS-AD)和前列腺体积是影响前列腺穿刺阳性率的重要因素(P<0.05),经会阴穿刺优势主要反映在tPSA≥10μg/L、fP-SA≥2μg/L、fPSA/tPSA<0.16、PSAD≥0.2和前列腺体积<40 m l时提示应行会阴穿刺术。结论:经会阴扇型B型超声引导下6针前列腺穿刺活检,是一种安全准确的前列腺癌检出方法。     

Comparative evaluation of various prostate specific antigen ratios for the early detection of prostate cancer

OBJECTIVE: To compare the performance of various ratios using total prostate specific antigen (PSA), complexed PSA (cPSA) and free PSA (fPSA) in the early detection of prostate cancer. PATIENTS AND METHODS: The study included 535 consecutive patients evaluated at a prostate cancer detection clinic between January 1998 and October 1999. Patients had blood samples drawn before transrectal ultrasonography and prostate biopsy to measure PSA, cPSA and fPSA. Receiver operating characteristic (ROC) curves (sensitivity vs 1 - specificity) were used to evaluate the performance of PSA, cPSA, f/tPSA, cPSA/tPSA, fPSA/cPSA, tPSA/prostate volume (PV), fPSA/PV, and cPSA/PV. The areas under the curve (AUC) were calculated for each ratio. The performance of each ratio over all patients or in those with a tPSA of 4-6 or 4-10 ng/mL were evaluated. RESULTS: Of the 535 patients, 204 (38%) had biopsy-confirmed prostate cancer. The AUC obtained with tPSA alone was 0.64; when measured for all patients the cPSA/PV (0.78), PSA/PV (0.77), f/tPSA (0.76) and fPSA/cPSA (0.75) performed better than tPSA alone. Furthermore, in patients with a tPSA of 4-10 ng/mL, tPSA/PV (0.72), cPSA/PV (0.71), f/tPSA (0.69), fPSA/cPSA (0.69) and cPSA/tPSA (0.62) performed better than tPSA alone (0.52). Finally, in patients with a tPSA of 4-6 ng/mL, PSA/PV and cPSA/PV performed better than the other ratios. CONCLUSIONS: The use of PSA ratios gives a higher sensitivity and specificity for detecting prostate cancer than the use of tPSA alone.     

Receiver-operating characteristic as a tool for evaluating the diagnostic performance of prostate-specific antigen and its molecular forms--What has to be considered?

BACKGROUND: Receiver-operating characteristic (ROC) analysis is often applied as evaluation tool to compare the diagnostic validity of laboratory tests. The aim of this study was to draw attention to preconditions which should be taken into account when ROC analysis is used to assess the diagnostic performance of total prostate-specific antigen (tPSA) and its molecular forms in differential diagnosis between prostate cancer and benign prostatic hyperplasia (BPH). METHODS: Using a standard software (GraphROC for Windows), ROC analyses were performed and the areas under the curves were calculated for four hypothetical pairs of groups. Every group included 40 patients with prostate cancer and with BPH showing different tPSA concentrations (range of 2-10 microg, but similar free-to-total PSA ratios (fPSA%). RESULTS: The area under the fPSA% ROC curve showed the highest value, whereas the areas under the tPSA ROC curves were dependent on the distributions of tPSA concentrations in the patients. The ability of fPSA% to improve the differential diagnosis between prostate cancer and BPH in comparison to tPSA was not furthermore evident, if the prostate cancer group included more patients with higher tPSA concentrations than the BPH group. CONCLUSIONS: When the diagnostic performance of tPSA and its derivatives like molecular forms in patients with prostate cancer and BPH should be compared by ROC analysis, a matching procedure is recommended prior to ROC analysis to compensate the effect of possible unequal tPSA distributions in both groups. Each BPH (or PCa) patient should be matched with a PCa (or BPH) patient with nearest tPSA concentration so that an optimum of overlapping tPSA concentrations in both groups can be achieved.     

Clinical utility of human glandular kallikrein 2 within a neural network for prostate cancer detection

OBJECTIVE

To assess, using artificial neural networks (ANNs), human glandular kallikrein 2 (hK2), prostate‐specific antigen (PSA), and percentage free/total PSA (f/tPSA), for discriminating between prostate cancer and benign prostatic hyperplasia (BPH).

MATERIAL AND METHODS

Serum samples from 475 patients with prostate cancer (n = 347) or BPH (n = 128) within the PSA range of 1–20 ng/mL were analysed for tPSA, fPSA and hK2 (research assay, Toronto, Canada). Data were analysed in the ranges of 1–4, 2–4, 4–10, and 2–20 ng/mL tPSA. Back‐propagation ANN models with the variables PSA, f/tPSA, and hK2, hK2/fPSA and hK2/(f/tPSA) were constructed. The diagnostic validity was evaluated by receiver‐operating characteristic (ROC) curve analysis.

RESULTS

Whereas the median concentration of hK2 was not significantly different between patients with BPH or prostate cancer in any of the tPSA ranges, the f/tPSA, hK2/fPSA and hK2/(f/tPSA), and the hK2‐based ANN outputs were always significantly different between patients with prostate cancer or BPH. Using ROC curve comparison, all variables were significantly better than hK2 in all ranges. The hK2‐based ANN performed better than f/tPSA except in the 4–10 ng/mL tPSA range. At 90% and 95% sensitivity, the hK2‐based ANN was also significantly better than f/tPSA in the 1–4 ng/mL tPSA range. hK2/(f/tPSA) achieved equal results to the hK2‐based ANN except in the range 2–20 ng/mL tPSA.

CONCLUSIONS

The hK2‐based ANN improves the outcome of f/tPSA but not hK2/(f/tPSA) in almost all analysed subgroups. When comparing the results at 90% and 95% sensitivity the hK2‐based ANN only performed significantly better than f/tPSA in the lowest tPSA range. Only in lower tPSA ranges do hK2‐based ANNs show an advantage for further improving prostate cancer detection.

     

血清EPCA-2检测在前列腺癌诊断中的临床意义

目的：通过比较血清中早期前列腺癌抗原-2（EPCA-2）与前列腺特异性抗原（PSA）在前列腺癌（PCa）诊断中的特异性与敏感性,研究血清中EPCA-2对诊断PCa的临床意义。方法：收集非前列腺疾病患者20例（作为A组）,BPH患者56例（作为B组）,PCa患者44例（作为C组）,采用酶联免疫吸附实验（ELISA）分别检测三组患者血清中EPCA-2和PSA水平,进行统计学分析。结果：①C组患者血清中EPCA-2和PSA水平分别与A组和B组患者的进行比较,均显著增高,差异有统计学意义（P〈0．01）。②A组血清中EPCA-2水平均≤分界点（30μg／L）。③以30μg／L为分界点,EPCA-2对PCa诊断的特异性为92．1％,敏感性为93．2％;以4μg／L为分界点,PSA对PCa诊断的特异性为55．3％,敏感性为79．5％;PSA结合fPSA／tPSA（以0．15为分界点）,对PCa诊断的特异性为78．9％,敏感性为68．2％。结论：EPCA-2作为新的诊断PCa的肿瘤标志物,较PSA具有更高的特异性和敏感性,对临床PCa的诊断具有重要意义。     

Human glandular kallikrein 2 levels in serum for discrimination of pathologically organ-confined from locally-advanced prostate cancer in total PSA-levels below 10 ng/ml

BACKGROUND: We measured serum levels of human glandular kallikrein 2 (hK2) in patients treated with radical retropubic prostatectomy (rrP) for clinically localized prostate cancer (PCa) with a total PSA (tPSA)-level below 10 ng/ml to investigate whether hK2 can be applied to preoperatively distinguish organ-confined (pT2a/b) from nonorgan-confined (> or = pT3a)-PCa more accurately than total PSA. Further, we evaluated hK2, free- and tPSA-concentrations in all pathologic stages of PCa. METHODS: 161 serum samples from men scheduled for rrP were collected 1 day before surgery prior to any prostatic manipulation. Pathologic work-up revealed > or = pT3a-PCa in 48 and pT2a/b-PCa in 113 patients. HK2-levels in serum were measured using an immunofluorometric assay with an analytical sensitivity of 0.5 pg/ml, a functional sensitivity of 5 pg/ml and insignificant cross-reactivity with PSA (< 0.005%). Total (tPSA) and free PSA (fPSA) levels were measured using a commercially available assay from which we calculated %fPSA and an algorithm that combined hK2 and PSA-levels [hK2] x [tPSA/fPSA]. Means, medians, and ranges were calculated for pT2a/b vs. >/= pT3a-PCa and for all pathologic stages. Statistical significance of differences was calculated using Mann-Whitney-U and Kruskal-Wallis tests. Calculation of receiver-operator-characteristic (ROC) curves were performed for hK2, [hK2] x [tPSA/fPSA] and tPSA to compare diagnostic performance. RESULTS: A mean tPSA level in serum of 6.12 ng/ml in > or = pT3a-PCa was not significantly different (P = 0.366) from 5.78 ng/ml in pT2a/b-PCa. Also, there were no statistically significantly different levels of fPSA (P = 0.947) or %fPSA (0.292) for these two groups. By contrast, mean hK2-level in pT2a/b-PCa of 80 pg/ml was significantly different (P = 0.004) from a mean hK2 level of 120 pg/ml in > or = pT3a-PCa as shown by Mann-Whitney-analysis Moreover, the algorithm of [hK2] x [tPSA/fPSA] was significantly lower (P = 0.0004) in pT2a/b-PCa vs. > or = pT3a-PCa. Calculation of areas under curve (AUC) by receiver-operator-characteristics (ROC) demonstrated that the AUC for hK2 (0.64) was larger and the AUC for [hK2] x [tPSA/fPSA] (=0.68) significantly larger (P = 0.007) compared to the AUC of tPSA (0.55). Furthermore, Kruskal-Wallis Test revealed a highly significant correlation to pathologic stage using hK2 (P = 0.008) and [hK2] x [tPSA/fPSA] (P = 0.0015) compared to no significant differences in serum concentration of tPSA (P = 0.296). Also at tPSA-levels from 10-20 ng/ml, the hK2-levels in pT2a/b-PCa were close to significantly different (P = 0.051) from those in men with >/= pT3a-PCa, while the algorithm of [hK2] x [tPSA/fPSA] in that tPSA-range was significantly lower (P = 0.002) in pT2a/b-PCa compared to > or = pT3a0-PCa. CONCLUSIONS: Highly significant differences in serum concentration enable hK2 to be a powerful predictor of organ-confined disease and pathologic stage of clinically localized prostate cancer, especially in the PSA-range below 10 ng/ml. As such, there are important clinical consequences for the application of hK2 for the adequate treatment of prostate cancer patients, i.e., the option of nerve-sparing surgery. (c) 2001 Wiley-Liss, Inc.