血清PSA、PSAD和PSAT在前列腺穿刺活检中的意义

目的探讨血清前列腺特异性抗原(PSA)、前列腺特异性抗原密度(PSAD)和前列腺移行带特异性抗原密度(PSAT)在前列腺穿刺活检中的意义。方法对192例患者行前列腺穿刺活检,其中PSA≥4ng/ml者184例,PSA<4ng/ml且直肠指诊及经直肠B超有阳性发现者8例。对PSA、PSAD和PSAT与前列腺穿刺活检的关系进行分析。结果192例患者中经前列腺穿刺诊断为前列腺癌(PCa)100例,活检阳性率52.1%,其中8例PSA<4ng/ml者中,活检结果为前列腺横纹肌肉瘤1例,良性前列腺增生7例;93例PSA>20ng/ml者中80例为PCa,活检阳性率86.0%;91例PSA4~20ng/ml者中19例为PCa,活检阳性率20.9%。血清PSA4~20ng/ml患者,PSAD>0.10或PSAT>0.10时,敏感性均为100%,特异性为11.1%或4.2%,阳性预测值为22.9%或21.6%,可避免8.8%(8/91)或3.3%(3/91)阴性穿刺结果。血清PSA4~20ng/ml时,前列腺穿刺阳性组和阴性组PSA分别为(13.2±4.7)和(11.4±4.6)ng/ml(P>0.05);PSAD分别为0.36±0.18和0.19±0.09(P=0.001);PSAT分别为0.67±0.36和0.32±0.18(P=0.000)。血清PSA、PSAD和PSAT的ROC曲线下面积分别为0.613、0.810和0.833,PSAD和PSAT的ROC曲线下面积与PSA比较,差异均有统计学意义(P<0.05)。结论PSA>20ng/ml时应做前列腺穿刺活检;PSA4~20ng/ml时,PSAD和PSAT对预测患者是否行前列腺穿刺活检有较大帮助。     

2 223例安徽地区男性年龄相关前列腺特异性抗原参考值范围

目的对2223例安徽地区参与体检的健康男性血清前列腺特异性抗原(prostate-specificantigen,PSA)水平进行分析,探讨建立安徽地区男性血清PSA的参考值范围。方法收集2010年2月至2011年5月在安徽医科大学第一附属医院进行健康体检的标本2223例,均来自无下尿路症状的健康男性,用罗氏cobas614全自动电化学分析仪及相应配套试剂进行血清PSA检测。结果 2223例健康男性的PSA均数为1.12μg/L,标准差为1.16μg/L,第一四分位数为0.59μg/L,中位数为0.90μg/L,第三四分位数为1.20μg/L,四分位间距为0.61μg/L。PSA95%可信区间为2.78μg/L;2223例中≤3.00μg/L的有2124例,占95.54%,其年龄组成≤65岁的男性为92.84%;>3.00～10.00μg/L的有91例,占4.09%;如以4.00μg/L为参考值,≤4.00μg/L的有2178例,占97.98%;>4.00～10.00μg/L的有36例,占1.61%;>10.00μg/L的有9例,占0.40%,并且各年龄组间均数差异有统计学意义。结论各个年龄组PSA水平与Oesterling标准存在差异,65岁以下人群PSA水平低于欧美及亚洲其他地区人群,65岁以上人群PSA水平高于欧美及亚洲其他地区人群,该现象提示65岁以下人群参考值设在3.00μg/L为宜,65岁以上人群可继续以4.00μg/L作为参考值。     

双抗体夹心一步法检测前列腺特异抗原及应用的评价

用聚乙二醇、葡聚糖凝胶（ＰＥＧ、Ｓｅｐｈａｄｅｘ）两步法提取精浆前列腺特异抗原（ＰＳＡ），建立了一步检测血清ＰＳＡ的ＥＬＩＳＡ法及正常参考值范围。经５８例临床标本及９５例正常男性血清ＰＳＡ测定，对前列腺癌诊断的敏感性和特异性分别为１００％和９４．２％；６０岁以下和６０岁以上的男性血清ＰＳＡ临界值分别为３．４μｇ／Ｌ和４．６μｇ／Ｌ。表明年龄因素对ＰＳＡ测定有较大影响，在判断测定结果时必须加以考虑。     

以前列腺特异抗原水平分组筛查与前列腺穿刺阳性率的关系

目的探讨不同血清前列腺特异抗原(PSA)水平前列腺癌检出情况以及直肠指诊(DRE)、经直肠超声检查(TRUS)、PSA密度(PSAD)等指标对筛查前列腺穿刺活检病例的意义。方法回顾性分析在1996年4月至2002年12月间行TRUS引导前列腺6点系统穿刺活检的634例患者的诊断资料,对各PSA组(≤4.0,4.1~,10.1~和>20.0μg/L组)中前列腺癌的检出率,以及PSA、DRE、TRUS、PSAD等对前列腺癌的预测作用进行t检验、χ2检验和多因素Logistic回归分析。结果PSA≤4.0,4.1~,10.1~和>20.0μg/L各组的前列腺癌检出率分别为11.6%(17/146),26.8%(38/142),39.8%(68/171)和68.6%(120/175)。PSA的敏感性最高(93.0%),特异性低(33.0%);DRE、TRUS等诊断效率较低。随血清PSA水平升高,前列腺癌检出率以及DRE、TRUS的阳性预测值逐渐升高;在PSA4.1~20.0μg/L者中,PSAD对前列腺癌有较大的预测价值(OR=687.09±646.96,P=0.000)。以PSAD≥0.13μg.L-1.cm-3为截点筛查前列腺穿刺病例,可在不明显降低敏感性的基础上,减少阴性穿刺。结论各PSA组国人与欧美等国前列腺癌检出率有较大差别;DRE、TRUS的筛查作用与血清PSA水平有关;按PSA水平分组筛查穿刺病例,可提高前列腺穿刺的阳性率。     

前列腺特异抗原联合分级对前列腺癌患者分期的预测

目的探讨血清前列腺特异抗原(PSA)联合分级对前列腺癌患者的分期进行预测的方法。方法回顾分析我院泌尿外科187例穿刺活检诊断为前列腺癌患者的临床资料。采用等级相关分析、秩和检验、逐步判别多因素分析方法,分析血清PSA水平、游离PSA百分比(FPSA/TPSA值)与Gleason评分(GS)、分期的关系。结果前列腺癌患者GS越高,血清PSA水平越高(r=0.369,P<0.001)。分期越晚,血清PSA、GS越高(r=0.398,0.530,P均<0.001)。FPSA/TPSA值与分期不相关(P>0.70),但当PSA≤10μg/L时,FPSA/TPSA值与分期呈负相关(r=-0.600,P<0.05)。当PSA>20μg/L时,67%~87%的患者可能为C或D期。用PSA、GS预测分期的公式为x=-3.488+0.041×PSA+0.428×GS。结论血清PSA水平与GS呈正相关。血清PSA水平、GS分别与分期呈正相关。当PSA≤10μg/L时,FPSA/TPSA值与分期呈负相关。运用判别公式x=-3.488+0.041×PSA+0.428×GS可以预测前列腺癌患者的分期。     

Three immunoassays based on monoclonal antibodies specific for prostate specific antigen (PSA), alpha-1-antichymotrypsin (ACT), and the PSA-ACT complex

BACKGROUND: Prostate specific antigen (PSA) has been widely used as a biomarker for the screening and diagnosis of prostate cancer. PSA in serum predominantly exists as a complex with alpha-1-antichymotrypsin (ACT), and measurement of free PSA and the PSA-ACT complex may improve the utility of the serum PSA assay for differential diagnosis of prostate cancer and non-malignant prostate diseases, such as benign prostatic hyperplasia (BPH). METHODS: Monoclonal antibodies (MAbs) against PSA, ACT, and the PSA-ACT complex were produced by immunizing mice with an incubated mixture of PSA and ACT, and characterized by Western blot analyses and several enzyme-linked immunosorbant assay (ELISA) methods. RESULTS: The MAbs produced in this study are capable of distinguishing the PSA-ACT complex from free PSA and ACT. Four MAbs have been selected and utilized to construct three ELISA systems for the separate measurements of free PSA, the PSA-ACT complex, and total PSA. CONCLUSIONS: The three PSA assay systems developed in this study can specifically measure free PSA, total PSA, and the PSA-ACT complex with equal molar sensitivity. It is expected that these PSA assay systems could be useful in the diagnosis of prostate cancer.     

Development of new prostate specific monoclonal antibodies

BACKGROUND: Despite the need for new prostate-specific diagnostic and therapeutic targets, very few unique prostate (cancer) specific antigens have been characterized. Monoclonal antibody (mAb) technology is a powerful tool to identify specific antigenic markers, which could be potential targets for cancer diagnostics or therapy. METHODS: Splenocytes from mice immunized with prostate cancer (PCa) homogenates of different origin were fused using standard techniques. Employing a differential high-throughput screening method followed by immediate screening in immunohistochemistry (IHC) a large number of hybridomas were screened for prostate (cancer) specificity. RESULTS: From 25 successful fusions approximately 300 clones were identified excreting PCa-reactive antibodies. Subsequent immunohistochemical fine-specificity analysis reduced this number to 26. Eventually, after extensive fine-specificity analysis, the number of mAbs appearing to define prostate-specific antigenic structures that might serve as new diagnostic or therapeutic targets was reduced to three. CONCLUSIONS: Using mAb technology combined with a high throughput screening method we have developed three mAbs (1.8, 2.26, and 3.10) directed against prostate associated antigens that might identify potential new therapeutic targets.     

血清PSA密度变化对前列腺癌高危人群的诊断价值

目的:探讨前列腺特异抗原(PSA)、前列腺特异抗原密度(PSAD)变化对前列腺癌高危人群的诊断价值。方法:对初次活检阴性的432例患者进行随访,其中79例重复穿刺活检,确诊前列腺癌27例(34.2%),消化道来源肿瘤1例,BPH25例,前列腺上皮内肿瘤(PIN)13例,慢性前列腺炎13例。对重复活检患者的PSA、PSAD等临床资料进行统计分析。结果:配对t检验显示,良性病变首末次穿刺前PSA、PSAD差异均无统计学意义,而前列腺癌末次穿刺前PSA、PSAD较首次穿刺前升高,差异有统计学意义。以PSA>4ng/ml筛选前列腺癌,其敏感性、特异性、阳性预测值分别为92.5%、17.6%、37.6%,PSA末-PSA首>0筛选前列腺癌的敏感性、特异性、阳性预测值分别为85.2%、41.2%、40.4%;而以PSAD末-PSAD首>0筛选前列腺癌的敏感性、特异性、阳性预测值分别为81.5%、54.9%、48.9%。结论:在前列腺癌高危人群中应该重复穿刺,以减少漏诊;以PSAD动态升高来指导穿刺,可以明显提高阳性率。     

Serum prostate-specific antigen as a predictor of prostate volume in the community: the Krimpen study

OBJECTIVES: Serum prostate-specific antigen (PSA) is considered a proxy for prostate volume (PV). This study investigates which range of PSA values has the best utility in the determination of PV (<30 cc, at 30, 40, and 50 cc), and whether PSA performs better than digital rectal examination (DRE) when estimating PV. METHODS: In a population-based follow-up study of 1688 men in Krimpen aan den IJssel, The Netherlands, at baseline we estimated PV by DRE and by transrectal planimetric ultrasound (TRUS), in addition to measuring PSA. Men who tested positive for prostate cancer (PCa) at baseline and at 2 and 4 yr of follow-up were excluded from the analyses (n=142). Of the men without PCa, PSA and PV data were available in 1524 participants. RESULTS: Of all 1524 men analysed, 76.7% had a PSA of 0-2.0, 15.0% had a PSA of 2.1-4.0, and 8.3% a PSA>4. Low PSA ranges (0-2 and 2.1-4.0) discriminate better for a PV of 30 cc (eg, in men with a PSA range of 2.1-2.5 ng/ml there was a 72% chance of having a PV>30 cc). Higher ranges of PSA (>4.0) discriminate better for a PV>40 or 50 cc. (eg, in men with a PSA in the range of 4.1-7.0 ng/ml there was a 69% chance of having a PV>40 cc and in men with a PSA>10 ng/ml there was a 75% chance of a PV>50 cc). The receiver operating curve (ROC) for the performance of PSA in estimating a PV>30 cc shows an area under the curve (AUC) of 0.79, denoting reasonable discrimination, and AUCs of 0.86 and 0.92, denoting good discrimination of PVs>40 cc and >50 cc, respectively. PSA performed significantly better than DRE at estimating PV. Multiple regression analysis shows that both DRE and an interaction term for age and PSA provided minimal additional information beyond PSA in the prediction of PV; however, their contribution is numerically minimal/not clinically meaningful. CONCLUSIONS: In men for whom a diagnosis of PCa has been ruled out, PSA can be used to detect an enlarged prostate (>30 cc and with more accuracy PV>40 or 50 cc). More precision in estimating PV can be obtained when using a formula that contains PSA, age, DRE, and an interaction term between age and PSA; however, the clinical advantage of the formula over PSA alone is only modest as shown by the ROC curves. Thus, for clinicians looking for an easy and fast way to identify patients with an enlarged prostate, PSA is a good approximation for men without PCa.     

Population-based assessment of prostate-specific antigen testing for prostate cancer in the elderly

ObjectivesTo perform a population-based analysis to characterize the effect of prostate-specific antigen (PSA) testing on oncologic outcomes in men diagnosed with prostate cancer.Materials and methodsWe used the Surveillance, Epidemiology, and End Results–Medicare–linked data to identify 98,883 men diagnosed with prostate cancer from 1996 to 2007. We stratified frequency of PSA testing as none, 1 to 2, 3 to 5, and≥6 tests in the 5 years before prostate cancer diagnosis. We used propensity scoring methods to assess the effect of frequency of PSA testing on likelihood of (1) metastases at diagnosis and (2) overall mortality and prostate cancer–specific mortality.ResultsIn adjusted analyses, the likelihood of being diagnosed with metastatic prostate cancer decreased with greater frequency of PSA testing (none, 10.6; 1–2, 8.3; 3–5, 3.7; and≥6, 2.5 events per 100 person years, P<0.001). Additionally, greater frequency of PSA testing was associated with improved overall survival and prostate cancer–specific survival (P<0.001 for both).ConclusionsGreater frequency of PSA testing in men 70 years of age or older in the 5 years before prostate cancer diagnosis is associated with lower likelihood of being diagnosed with metastatic prostate cancer and improved overall and prostate cancer–specific survival.     

前列腺特异性膜抗原新型剪接变异体PSM-E对前列腺癌细胞骨转移的作用

目的 探讨前列腺特异性膜抗原(PSMA)新型剪接变异体PSM-E对前列腺癌细胞(RM-1)骨转移的作用及其机制.方法 脂质体将PSM-E、PSMA基因转染RM-1,构建细胞模型(RM-1-PSM-E、RM-1-PSMA),检测羧肽酶活性;黏附及迁移实验测定不同细胞在骨基质胶模型上的黏附及迁移能力;Western blot检测不同细胞中粘着斑激酶(FAK)的表达及磷酸化水平.结果 与转染空质粒的RM-1比较,RM-1-PSM-E、RM-1-PSMA的羧肽酶活性分别升高1.96倍和2.13倍,而黏附能力分别升高12倍和14倍,加入羧肽酶活性抑制剂后,RM-1-PSM-E、RM-1-PSMA的黏附能力分别降低2.6倍和3.5倍;与转染空质粒的RM-1比较,RM-1-PSM-E、RM-1-PSMA的迁移能力降低,且FAK的磷酸化水平分别升高1.47倍和1.66倍.结论 PSM-E对前列癌细胞骨转移具有调控作用,这与PSM-E的酶活性及FAK磷酸化水平有关.     

Strategies combining total and percent free prostate specific antigen for detecting prostate cancer: a prospective evaluation

PURPOSE: Determining total prostate specific antigen (PSA) in plasma can often identify men who are subsequently diagnosed with prostate cancer. However, excess false-positives create large financial and psychological burdens in prostate cancer screening. The percent free PSA is lower when prostate cancer is present, although to our knowledge no large prospective analyses to date have evaluated whether adding testing for free PSA may decrease false-positives, while maintaining or perhaps improving the detection of potentially curable tumors. MATERIALS AND METHODS: We measured total and percent free PSA in banked plasma samples from the Physicians' Health Study in 430 men who were later diagnosed with prostate cancer and 1,642 age matched controls who were not diagnosed with prostate cancer during a 12-year observation period. We calculated the number of cancers detected and the number of false-positives for various strategies of combined free and total PSA levels, and compared them to the use of total PSA alone. RESULTS: Total PSA with a cutoff of 4 ng./ml. detected 149 cases but also yielded 144 false-positives. A strategy that applied percent free PSA to men with total PSA 4 to 10 ng./ml. detected 133 to 140 cancers and decreased false-positives to 83 of 117 depending on the percent free PSA cutoff used. As the percent free PSA cutoff was lowered from 25% to 20%, additional undetected cancers did not occur until year 9 of followup and the 20% cutoff decreased false-positives and, thus, potential negative biopsies, by 42%. Percent free PSA was superior to total PSA for discriminating cases from controls within the total PSA range of 4 to 10 or 3 to 10 ng./ml. (p <0.0001). A percent free PSA cutoff of 20% in men with total PSA 3 to 10 ng./ml. detected 10% more cancers with 12.5% fewer false-positives than the conventional strategy of total PSA greater than 4 ng./ml. Cancers missed by combined total and free PSA testing had longer intervals between blood sampling and diagnosis, and a greater likelihood of later diagnosis at an organ confined stage. CONCLUSIONS: These results demonstrate that in a prospective setting with long-term followup free PSA strategies can be identified that decrease unnecessary biopsies, while preserving or even improving cancer detection. Thus, total and free PSA can be combined without the need to weigh subjectively the trade-offs and relative costs of false-negative and false-positive results.     

Polarity of prostate specific membrane antigen,prostate stem cell antigen,and prostate specific antigen in prostate tissue and in a cultured epithelial cell line

BACKGROUND: Madin-Darby canine kidney (MDCK) cells are immortalized epithelial cells that have been used extensively as a model system to study intracellular molecular trafficking, polarized expression, and secretion of proteins in various epithelia. In order to determine if MDCK cells might serve as a model to study molecular events within prostate epithelial cells, we have evaluated the polarized distribution of three prostate restricted proteins, PSMA, PSCA, and PSA, in situ, and in MDCK cells. METHODS: Using immunofluorescence, confocal microscopy, cell surface biotinylation, antibody internalization, and biochemical assays we evaluated surface expression and secretion of three prostate restricted proteins expressed in MDCK cells. We compared these patterns of expression to results observed within prostatic epithelium. RESULTS: We demonstrate that PSMA is localized primarily to the apical plasma membrane in both the prostatic epithelium and transfected MDCK cells, whereas PSCA is expressed in a non-polarized fashion. We also show that PSA is secreted predominantly from the apical surface of transfected MDCK cells, consistent with in vivo observations. CONCLUSIONS: Similar patterns of localization among MDCK and prostatic epithelial cells suggest that the mechanisms of polarized sorting within these cell types are conserved. Thus, MDCK cells offer a useful model system to study mechanisms of targeting of these proteins within the prostate.     

Prostate-specific antigen as a marker of adenocarcinoma of prostate

Summary Prostate-specific antigen (PSA) and prostatic acid phosphatase (PAP) serum levels were measured in 117 patients with prostatic adenocarcinoma, in 9 patients with prostatic hyperplasia and in 14 patients with other malignancies to compare the clinical usefulness of the PSA and PAP levels. PSA was elevated (PSA⁺) in 14 of 18 untreated patients (78%) with prostatic cancer. PAP was elevated (PAP⁺) only in 3 of these untreated cases (17%). Also in previously treated patients PSA was more often positive than PAP. PSA was positive in 40 of the 99 treated patients (40%), PAP was elevated only in 21 cases (21%). There was a significantly (P<0.001) higher tendency towards elevated PSA in the prostatic cancer patients: 32 (27%) patients with PSA⁺ and PAP^- compared with only 2 cases (2%) with PAP⁺ and PSA^-. The PSA⁺/PAP^- patients were analyzed further. In seven of them the PSA level also returned to its normal level after orchiectomy or/and radiotherapy. In two patients the PSA levels indicated tumor progression earlier than PAP, their PAP levels did not rise until bone metastasizing was evident. There were also progressive disease in some patients evidenced only by increased PSA levels. In addition to cancer patients the PSA level was increased in three (30%) of the prostatic hyperplasia patients. It was also elevated in three patients with other malignancies. However, these three patients also had prostatic hyperplasia and the increase in the PSA level is considered more likely to be due to that. According to these findings it is suggested that PSA is more sensitive than PAP in local and advanced prostatic cancer and may be more useful in monitoring responses and recurrence after therapy.     

Radioimmunotherapy of prostate cancer in human xenografts using monoclonal antibodies specific to prostate specific membrane antigen (PSMA): studies in nude mice

BACKGROUND: Prostate specific membrane antigen (PSMA), expressed by virtually all prostate cancers is an ideal target for targeted therapy of prostate cancer. Radiolabeled J591 monoclonal antibody (MAb) binds with high affinity to an extracellular epitope of PSMA and localizes specifically in PSMA positive LNCaP tumors in vivo. METHODS: Pre-clinical radioimmunotherapy (RIT) studies using (131)I-huJ591 and (90)Y-1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid (DOTA)-huJ591 MAbs were studied in nude mice bearing LNCaP xenografts. RESULTS: A 15-90% reduction in mean tumor volume was observed after a single dose of (131)I-huJ591 (3.7-11.1 MBq) or (90)Y-DOTA-huJ591 (3.7-7.4 MBq). The median survival time increased 2-3 times relative to untreated controls. Multiple administrations of fractionated doses of (90)Y-DOTA-huJ591 were even more effective with minimal toxicity. Radiation dose to blood and tumor was higher with (90)Y than with (131)I. The maximum tolerated dose (MTD) is 5.55 MBq for (90)Y-DOTA-huJ591 and more than 11.1 MBq for (131)I-huJ591. For (90)Y-DOTA-huJ591 at MTD, dose to the tumor was 2,753 cGy. CONCLUSIONS: In nude mice bearing PSMA positive tumors, radiation dose to the tumor with (90)Y-DOTA-J591 is greater for large tumors than with (131)I-J591. The theoretical and practical considerations strongly suggest that (90)Y-DOTA-huJ591 may be a suitable radiopharmaceutical for the treatment of prostate cancer.     

The association between total prostate specific antigen concentration and prostate specific antigen velocity

PURPOSE: It has been previously demonstrated that a prostate specific antigen velocity greater than 2 ng/ml per year is associated with reduced cancer specific survival following radical prostatectomy or external beam radiation. However, men with different initial prostate specific antigen levels may be more or less likely to reach this prostate specific antigen velocity threshold. Because prostate specific antigen and prostate specific antigen velocity contain much of the same predictive information, our objective was to further examine the relationship between them. MATERIALS AND METHODS: From a large prostate cancer screening study, serial prostate specific antigen measurements were available for 13,276 men, including 1,851 with a negative digital rectal examination who underwent biopsy and 894 who were diagnosed with prostate cancer. Prostate specific antigen velocity was calculated using simple linear regression of the prostate specific antigen values from the year before diagnosis. ANOVA and the Kruskal-Wallis test were used to compare the mean and median prostate specific antigen velocity of men in different total prostate specific antigen ranges. In addition, chi-square analysis was used to compare the number of men in each total prostate specific antigen range who presented with high risk prostate specific antigen velocity greater than 2 ng/ml per year. RESULTS: In the total prostate specific antigen ranges of 2.5 ng/ml or less, 2.6 to 4.0, 4.1 to 10.0 and more than 10.0 ng/ml, the proportion of screened men with a prostate specific antigen velocity of more than 2 ng/ml per year was 1%, 14%, 31% and 74%, respectively (p <0.0001). Mean and median prostate specific antigen velocity were also significantly higher as the total prostate specific antigen level increased. CONCLUSIONS: Prostate specific antigen velocity varies directly with total prostate specific antigen. Men with high initial prostate specific antigen levels are significantly more likely to present with a prostate specific antigen velocity of more than 2 ng/ml per year that is more frequently associated with prostate cancer specific mortality.     

Screening for prostate cancer using prostate-specific antigen testing in Japanese men on hemodialysis

Objectives The objectives of this study were to evaluate the usefulness of serum prostate-specific antigen (PSA) screening in detecting prostate cancer in Japanese men on hemodialysis, and to analyze features of prostate cancer detected in these patients. Materials and methods This study included 115 male hemodialysis patients aged >55 years who agreed to the measurement of serum PSA value (group A) and 7529 men aged >55 years participating in a PSA mass screening test in Kobe City (group B) between April 2005 and March 2006. Prostate biopsy was recommended in men with serum PSA > 4.0 ng/ml in both groups. Seventy-eight patients with normal renal function aged >55 years diagnosed as having prostate cancer during the same time period as groups A and B were also included as a comparison group (group C). Results There was no significant difference in the distribution of serum PSA values between groups A and B. Prostate biopsy was performed in 8 and 205 men in groups A and B, respectively, and prostate cancer was detected in 5 and 68 in groups A and B, respectively; that is, there was no significant difference in the rate of positive prostate biopsy between these two groups (group A, 62.5%; group B, 33.2%), while the cancer detection rate in group A (4.3%) was significantly greater than that in group B (0.90%). In addition, there was no evident metastasis in five patients on hemodialysis who were diagnosed as having prostate cancer, and their serum PSA, clinical T stage and biopsy Gleason score were similar to those in group C. However, the percent of positive biopsy cores in these five was significantly greater than that in group C. All five were treated by maximal androgen blockade therapy, and all are currently alive without emergence of hormone-refractory diseases. Conclusions These findings indicate that hemodialysis patients may have an increased risk of prostate cancer, and that prostate cancer detected in such patients tends to be relatively advanced. Therefore, it would be recommended for hemodialysis patients to undergo PSA testing to screen for prostate cancer.     

Comparative analysis of complexed prostate specific antigen, free prostate specific antigen and their ratio in detecting prostate cancer

PURPOSE: We evaluate the diagnostic use of total, free and complexed serum prostate specific antigen (PSA), and their ratios for enhancing the specificity in detecting prostate cancer. MATERIALS AND METHODS: A total of 354 nonconsecutive men undergoing prostate biopsy were eligible for this retrospective and prospective study. Cancer was found in 122 of these 354 men (34%). Receiver operating characteristics curve analyses were used to calculate and compare the performance of total PSA (Hybritech, San Diego California and Bayer, Tarrytown, New York), complexed PSA (Bayer), percent complexed PSA and percent free PSA. In addition, sensitivity and specificity were calculated and compared. RESULTS: The area under the receiver operating characteristics curve was highest for percent free PSA, followed by percent complexed PSA, complexed PSA and the 2 total PSA assays (Hybritech and Bayer). The cutoff value of 3.45 ng./ml. for complexed PSA detected the same number of cancers and resulted in 1 additional false-positive case compared with a Hybritech total PSA threshold of 4.0 ng./ml. At sensitivities of 80% to 95%, there were no significant differences for detection comparing the corresponding specificities between Hybritech total PSA and complexed PSA for all 354 men. Complexed PSA alone did not enhance the overall diagnostic accuracy compared with percent free PSA in the Hybritech total PSA range between 4.01 and 6.00 ng./ml., between 6.01 and 10.00 ng./ml., and between 2.50 and 6.00 ng./ml. At sensitivities of 80% to 95% specificity of percent complexed PSA was almost identical to that of percent free PSA except for the Hybritech total PSA range less than or equal to 4.00 ng./ml. CONCLUSIONS: This study suggests complexed PSA is equivalent to total PSA for the early detection of prostate cancer. Percent free PSA outperforms complexed PSA and percent complexed PSA performed equivalently to percent free PSA in all total PSA ranges analyzed between 2.5 and 10 ng./ml.