Longitudinal Evaluation of Prostate-Specific Antigen Levels in Men With and Without Prostate Disease

Perception of abnormal serum prostate-specific antigen (PSA) test results amongst family practitioners

INTRODUCTION

With increased use of serum prostate-specific antigen (PSA) testing, prostate cancers are diagnosed at an earlier stage in younger men, when radical curative treatments are appropriate. Modifications of the PSA test such as PSA velocity and age-adjusted values are available to aid in the selection of patients for biopsy. However, it is not clear whether these data are used in general practice.

PATIENTS AND METHODS

A self-administered questionnaire was mailed to all primary care practices within one region in the UK. A series of visual analogue questions designed to identify referral thresholds for age-adjusted PSA levels and PSA velocity were used to identify patterns in referral behaviour.

RESULTS

Individual family practitioners see only small numbers of patients requesting PSA tests or with newly diagnosed prostate cancer each year. The median (range) thresholds considered for referral at ages 45, 55, 65, 75 and 85 years were 4.5 ng/ml (2.5-15.5 ng/ml), 5.5 ng/ml (3.0-15.5 ng/ml), 6.5 ng/ml (3.5-15.5 ng/ml), 6.5 ng/ml (3.5-25.5 ng/ml), and 7.5 ng/ml (3.5-25.5 ng/ml), respectively. Only 5% of practitioners correctly identified the age-specific PSA threshold for referral of a 45-year-old man.

CONCLUSIONS

It is important to remember that younger men (even those in their forties and fifties) may be at risk of prostate cancer even if asymptomatic. It is important in a climate of increasing demand for PSA testing that those who initiate the process understand the implications and limitations of testing, including appropriate triggers for referral to secondary care. The exact approach required for the successful dissemination of this information to primary care is not clear, but our data suggest that a better understanding is required.

PSA doubling time versus PSA velocity to predict high-risk prostate cancer: data from the Baltimore Longitudinal Study of Aging

BACKGROUND

Our group has previously shown that prostate-specific antigen (PSA) velocity (PSAV) is associated with the presence of life-threatening prostate cancer. Less is known about the relative utility of pretreatment PSA doubling time (PSA DT) to predict tumor aggressiveness.

OBJECTIVE

To compare the utility of PSAV and PSA DT for the prediction of life-threatening prostate cancer.

DESIGN, SETTING, AND PARTICIPANTS

From the Baltimore Longitudinal Study of Aging, we identified 681 men with serial PSA measurements.

MEASUREMENTS

Receiver operating characteristic analysis was used to evaluate the relationship between PSAV, PSA DT, and the presence of high-risk disease.

RESULTS AND LIMITATIONS

Within the period of 5 yr prior to diagnosis, PSAV was significantly higher among men with high-risk or fatal prostate cancer than men without it. By contrast, PSA DT was not significantly associated with high-risk or fatal disease. On multivariate analysis, including age, date of diagnosis, and PSA, the addition of PSAV significantly improved the concordance index from 0.85 to 0.88 (p<0.001), whereas PSA DT did not.

CONCLUSIONS

These data suggest that PSAV is more useful than PSA DT in the pretreatment setting to help identify those men with life-threatening disease.

Hierarchical changepoint models for biochemical markers illustrated by tracking postradiotherapy prostate-specific antigen series in men with prostate cancer

PURPOSE

Biomarkers provide valuable information when detecting disease onset or monitoring disease progression; examples include bone mineral density (for osteoporosis), cholesterol (for coronary artery diseases), or prostate-specific antigens (PSA, for prostate cancer). Characteristics of markers series can then be used as prognostic factors of disease progression, such as the postradiotherapy PSA doubling time in men treated for prostate cancer. The statistical analysis of such data has to incorporate the within and between-series variabilities, the complex patterns of the series over time, the unbalanced format of the data, and the possibly nonconstant precision of the measurements.

METHODS

We base our analysis on a population-based cohort of 470 men treated with radiotherapy for prostate cancer; after treatment, the log(2)PSA concentrations follow a piecewise-linear pattern. We illustrate the flexibility of Bayesian hierarchical changepoint models by estimating the individual and population postradiotherapy log(2)PSA profiles; parameters such as the PSA nadir and the PSA doubling time were estimated, and their associations with baseline patient characteristics were investigated. The residual PSA variability was modeled as a function of the PSA concentration. For comparison purposes, two alternative models were briefly considered.

RESULTS

Precise estimates of all parameters of the PSA trajectory are provided at both the individual and population levels. Estimates suggest greater PSA variability at lower PSA concentrations, as well as an association between shorter PSAdts and greater baseline PSA levels, higher Gleason scores, and older age.

CONCLUSIONS

The use of Bayesian hierarchical changepoint models accommodates multiple complex features of longitudinal data, permits realistic modeling of the variability as a function of the marker concentration, and provides precise estimates of all clinically important parameters. This type of model should be applicable to the study of marker series in other diseases.

Screening and management of prostate cancer in elderly men: the Iowa Prostate Cancer Consensus

OBJECTIVES

The issue of prostate cancer screening and management is likely to assume greater importance with progressive aging of the population. Because there are no currently established guidelines for screening and management of prostate cancer in elderly men (older than 75 years), a multidisciplinary panel was convened to develop consensus recommendations.

METHODS

The panel consisted of experts in urology, internal medicine/geriatrics, medical oncology, radiation oncology, family practice, law, patient advocacy and physician assistants. Four internationally known experts on prostate cancer served as external advisors. Relevant literature was reviewed and consensus was developed based on expert opinion, given the lack of level I evidence regarding most aspects of prostate cancer diagnosis and management in men older than 75 years of age.

RESULTS

On the basis of the opinions of the expert panel, recommendations for screening and management of prostate cancer in elderly men older than 75 years of age was developed. In general, there was support for using greater discretion in screening for prostate cancer in elderly men. The lack of adequate patient education tools to facilitate discussion with patients was recognized. There was also agreement on the need for greater and renewed patient counseling regarding benefits and risks of prostate cancer screening beyond age 75.

CONCLUSIONS

It is possible to build consensus around a standardized approach to prostate cancer screening and management in older men. Promulgation of such consensus recommendations and their widespread adoption may help engender a tailored approach to managing prostate cancer in older men, thereby decreasing health care costs and morbidity while limiting unnecessary therapy.

Total and free PSA kinetics in patients without prostate cancer undergoing radical cystoprostatectomy

BACKGROUND

Radical cystoprostatectomy and radical prostatectomy are the two major operations where prostate is totally and radically removed. Radical cystoprostatectomy is usually performed in patients with invasive bladder cancer. The aim of the study was to examine Total PSA, Free PSA, and Free/Total Ratio elimination kinetics after radical cystoprostatectomy.

METHODS

Serum PSA, Free PSA, and Free/Total Ratio were determined preoperatively, at the time of cystoprostatectomy specimen removal and then at 3, 6, 12, 24, 48, 72, and 168 hr, from seven patients with muscle invasive bladder cancer, who underwent radical cystoprostatectomy. Free and Total PSA concentrations were measured with non-competitive immunological procedures. The elimination rates and half-lives of Total, Free PSA and Free/Total Ratio were studied using a nonlinear regression analysis.

RESULTS

Surgical manipulations caused about 1.5-fold increase of PSA, 5-fold increase in Free PSA and 3-fold increase in Free/Total Ratio. PSA and Free PSA followed a biphasic elimination pattern of a rapid exponential (a) phase with a half-life of 4.27 and 2.14 hr and a terminal, nonexponential (b) phase with a half-life of 63 and 173.2 hr, respectively. Free/Total PSA Ratio followed, also, a biphasic kinetic pattern of a rapid exponential decline with a half-life of 3.34 and a terminal non-exponential increase with a doubling time of 43 hr.

CONCLUSIONS

Comparing PSA kinetics after radical cystoprostatectomy with those of radical prostatectomy, it appears that PSA follows the same elimination pattern in both models. In contrast, Free PSA and Free/Total Ratio elimination kinetics' patterns differ between the two surgical models.

The use of prostate specific antigen (PSA) density in detecting prostate cancer in Chinese men with PSA levels of 4-10 ng/mL

AIM

To investigate the utility of prostate specific antigen density for detecting prostate cancer in men with serum PSA levels of 4-10 ng/mL.

METHODS

Between January 2003 and November 2007, 237 men (aged 48-84 years, median 71) with total PSA levels of 4-10 ng/mL participated in a protocol for prostate cancer screening. Eligible patients were recommended for transrectal ultrasonography (TRUS)-guided prostate biopsies after measuring prostate volumes transrectally. The diagnostic value of PSA levels and the free-to-total PSA ratio (f/tPSA), PSA densities (PSAD) were compared using receiver operating characteristic analysis.

RESULTS

Prostate cancer was diagnosed in 44 (18.6%) of the 237 men who had biopsies. There were significant differences between the groups in the prostate volumes determined by TRUS, PSAD, PSA levels and f/tPSA, whereas there was no significant difference in patient age. The area under the curve (AUC) of PSA (0.6786) and PSAD (0.717) was similar and significantly greater than that of f/tPSA (AUC 0.329). PSAD was a significantly better indicator of prostate cancer than f/tPSA. The sensitivity and specificity of PSA density at a cutoff of 0.134 ng/mL(2) was 90 and 33.7%, respectively.

CONCLUSION

PSAD was a better predictor of prostate cancer in Chinese men with PSA levels of 4-10 ng/mL, especially those who have had prior ultrasound-determined measurements of prostate volume. Our data suggest that different PSAD cutoffs may need to be defined for Chinese.

Prostate-specific antigen and prostate cancer: prediction, detection and monitoring

Testing for prostate-specific antigen (PSA) has profoundly affected the diagnosis and treatment of prostate cancer. PSA testing has enabled physicians to detect prostate tumours while they are still small, low-grade and localized. This very ability has, however, created controversy over whether we are now diagnosing and treating insignificant cancers. PSA testing has also transformed the monitoring of treatment response and detection of disease recurrence. Much current research is directed at establishing the most appropriate uses of PSA testing and at developing methods to improve on the conventional PSA test.

[Correct use of prostate-specific antigen in office practice]

OBJECTIVE

To standardize interpretation and comments of prostate-specific antigen (PSA) assay results by clinical pathology laboratories in office practice.

MATERIAL

From September 2004 to May 2006, interpretation and comments of PSA assay results performed by 100 different laboratories were analysed retrospectively.

RESULTS

Nineteen different PSA assay kits were used. The so-called "normal" value for total PSA was less than 4 ng/ml for two-thirds of kits. Determination of the free PSA/total PSA ratio (91 cases) was based on a cut-off value ranging from 10 to 25% and the frequent laboratory comments (89 cases) more often referred to benign prostatic hyperplasia (51 case) than prostate cancer (nine cases).

CONCLUSION

The marked diversity of PSA assay techniques currently used and the divergent interpretations by various laboratories lead to problems of interpretation for both practitioners and patients.

Is prostate-specific antigen velocity selective for clinically significant prostate cancer in screening? European Randomized Study of Screening for Prostate Cancer (Rotterdam)

BACKGROUND

The value of prostate-specific antigen velocity (PSAV) in screening for prostate cancer (PCa) and especially for clinically significant PCa is unclear.

OBJECTIVE

To assess the value of PSAV in screening for PCa. Specifically, the role of PSAV in lowering the number of unnecessary biopsies and reducing the detection rate of indolent PCa was evaluated.

DESIGN, SETTING, AND PARTICIPANTS

All men included in the study cohort were participants in the European Randomized Study of Screening for Prostate Cancer (ERSPC), Rotterdam section.

INTERVENTION

During the first and second screening round, a PSA test was performed on 2217 men, and all underwent a biopsy during the second screening round 4 yr later.

MEASUREMENTS

PSAV was calculated and biopsy outcome was classified as benign, possibly indolent PCa, or clinically significant PCa.

RESULTS AND LIMITATIONS

A total of 441 cases of PCa were detected, 333 were classified as clinically significant and 108 as possibly indolent. The use of PSAV cut-offs reduced the number of biopsies but led to important numbers of missed (indolent and significant) PCa. PSAV was predictive for PCa (OR: 1.28, p<0.001) and specifically for significant PCa (OR: 1.46, p<0.001) in univariate analyses. However, multivariate analyses using age, PSA, prostate volume, digital rectal examination and transrectal ultrasonography outcome, and previous biopsy (yes/no) showed that PSAV was not an independent predictor of PCa (OR: 1.01, p=0.91) or significant PCa (OR: 0.87, p=0.30).

CONCLUSIONS

The use of PSAV as a biopsy indicator would miss a large number of clinically significant PCa cases with increasing PSAV cut-offs. In this study, PSAV was not an independent predictor of a positive biopsy in general or significant PCa on biopsy. Therefore, PSAV does not improve the ERSPC screening algorithm.

Long-term prediction of prostate cancer: prostate-specific antigen (PSA) velocity is predictive but does not improve the predictive accuracy of a single PSA measurement 15 years or more before cancer diagnosis in a large, representative, unscreened population

PURPOSE

We tested whether total prostate-specific antigen velocity (tPSAv) improves accuracy of a model using PSA level to predict long-term risk of prostate cancer diagnosis.

METHODS

During 1974 to 1986 in a preventive medicine study in Sweden, 5,722 men aged <or= 50 gave two blood samples about 6 years apart. We measured free (fPSA) and total PSA (tPSA) in archived plasma samples from 4,907 participants. Prostate cancer was subsequently diagnosed in 443 (9%) men. Cox proportional hazards regression was used to evaluate tPSA and tPSAv as predictors of prostate cancer. Predictive accuracy was assessed by the concordance index.

RESULTS

The median time from second blood draw to cancer diagnosis was 16 years; median follow-up for men without prostate cancer was 21 years. In univariate models, tPSA level at second assessment and tPSAv between first and second assessments were associated with prostate cancer (both P < .001). tPSAv was highly correlated with tPSA level (r = 0.93). Twenty-year probabilities of cancer for men at 50th, 90th, and 95th percentile of tPSA and tPSAv were 10.6%, 17.1%, and 21.2% for tPSA, and 9.1%, 11.8%, and 14.1% for tPSAv, respectively. The concordance index for tPSA level was 0.771. Adding tPSAv, fPSA, %fPSA or velocities of fPSA and %fPSA did not importantly increase accuracy of tPSA to predict prostate cancer. Results were unchanged if the analysis was restricted to patients with advanced cancer at diagnosis.

CONCLUSION

Although PSA velocity is significantly increased in men with prostate cancer up to two decades before diagnosis, it does not aid long-term prediction of prostate cancer.

The Clinical Impact of who Standardization of PSA Assays

The determination of serum level of the prostate specific antigen (PSA) is widely used for detection and management of prostate cancer. Analytical variability between the various PSA assays on the market has been reported. This discrepancy in the PSA results was shown to be related to non-equimolar detection of total PSA (tPSA) but also to a lack of assay standardization and could have serious clinical repercussions on the diagnostic performance of PSA testing. The recalibration of equimolar assays to common reference preparations (tPSA WHO 96/670 and fPSA 96/668) was thought to promote standardization of PSA assays and limit the clinical implication of assay variability. Comparison studies have demonstrated that PSA assay calibration to the WHO standard certainly improves the harmonisation of PSA testing, but differences between assays remain. Recent evaluations of the clinical impact of analytical variations induced by a calibration to the WHO standard reported that 15% to 30% of prostate cancer could be missed if the historical tPSA cut-off was used. In order to avoid unacceptable erosion of the clinical diagnostic performance of PSA determination for the detection of prostate cancer with WHO calibrated assays, it is critical to define new specific clinical decision points.

Detection of prostate-specific antigen coupled to immunoglobulin M in prostate cancer patients

BACKGROUND

Several reports indicate that the main biomarkers for liver and colorectal cancer circulating in the blood stream associate with immunoglobulin M (IgM) to form stable complexes that show increased diagnostic relevance compared to circulating free biomarkers.

METHODS

To further investigate the association between cancer biomarkers and IgM, we assessed the presence of prostate-specific antigen (PSA) as IgM complexes in sera of patients with prostate cancer (PC) or benign prostatic hyperplasia (BPH) in comparison with PSA measurements.

RESULTS

PSA-IgM levels were significantly elevated in 40% (20/50) and 12% (6/51) of PC and BPH patients, respectively, compared to 22% (11/50) and 29% (15/51) of PSA positive patients in the same groups. Detection of cancer markedly increased from 22 to 60% by co-determination of both markers (30/50 patients). Significantly elevated levels of PSA-IgM were found in 13 out of 30 patients affected by PC with a PSA value between 4 and 10 ng/mL and only in 4 out of 34 BPH patients in the same PSA range.

CONCLUSIONS

The results are the first evidence of the occurrence of PSA-IgM complexes in patients with prostate cancer. The gain achieved in cancer detection by using the combination of PSA and PSA-IgM suggests that PSA-IgM could be a complementary serological marker of prostate cancer.

New circulating biomarkers for prostate cancer

The introduction of prostate-specific antigen (PSA) revolutionized prostate cancer (PCa) screening and ushered the PSA era. However, its use as a screening tool remains controversial and changes in the epidemiology of PCa have strongly limited its prognostic role. Therefore, we need novel approaches to improve our ability to detect PCa and foretell the course of the disease. To improve the specificity of total PSA, several approaches based on PSA derivatives have been investigated such as age-specific values, PSA density (PSAD), PSAD of the transition zone, PSA velocity and assessment of various isoforms of PSA. With recent advances in biotechnology such as high-throughput molecular analyses, many potential blood biomarkers have been identified and are currently under investigation. Given the plethora of candidate PCa biomarkers, we have chosen to discuss a select group of candidate blood-based biomarkers including human glandular kallikrein, early prostate cancer antigens, insulin-like growth factor-I (IGF-I) and its binding proteins (IGFBP-2 and IGFBP-3), urokinase plasminogen activation system, transforming growth factor-beta1, interleukin-6, chromogranin A, prostate secretory protein, prostate-specific membrane antigen, PCa-specific autoantibodies and alpha-methylacyl-CoA racemase. While these and other markers have shown promise in early phase studies, no single biomarker is likely to have the appropriate degree of certainty to dictate treatment decisions. Consequently, the future of cancer prognosis may rely on small panels of markers that can accurately predict PCa presence, stage, metastasis, and serve as prognosticators, targets and/or surrogate end points of disease progression and response to therapy.

Early detection of prostate cancer in 2007. Part 1: PSA and PSA kinetics

OBJECTIVE

This is the first of two review papers attempting to clarify the best way to detect prostate cancer (PCa) in 2007. Screening for PCa has not yet been shown to lower PCa mortality. Still, opportunistic screening is wide spread in Europe and in most other parts of the world.

METHODS

Current literature and data from screening studies are reviewed and discussed. Prostate-specific antigen (PSA) has been and remains one of the corner stones of early detection of PCa. Traditionally used cut-off values cannot be applied in an uncritical fashion after it was shown that a significant amount of overdiagnosis and that large proportions of cancers and poorly differentiated cancers are present in the low PSA ranges. The paper addresses the continued relevance of PSA cut-off values. The diagnostic value of PSA velocity is reviewed in conjunction with PSA cut-off values and as a possible replacement of total PSA. A need for more selective screening in the low PSA ranges is pointed out.

RESULTS AND CONCLUSIONS

The data show that men presenting initially with PSA values below 1 do not have to be rescreened for a period of 8 yr. In the PSA range 1-2.9 ng/ml, new parameters are needed that improve specificity and are selective for screening for aggressive lesions. PSA velocity so far has not been shown to be useful in the early detection of PCa but may be useful in detecting aggressive PCa selectively. For the time being, it seems sensible to continue using PSA cut-off values such as 3.0 or 4.0 ng/ml provided overtreatment is decreased by using available nomograms.

Progensa PCA3 test for prostate cancer detection

Patients with an elevated serum total prostate-specific antigen value or abnormal digital rectal examination results are at risk of having prostate cancer and should undergo prostate needle biopsies. However, approximately 60% of them will have a negative prostate biopsy result. Therefore, further biopsies are recommended for young patients at risk of prostate cancer with a positive rate of 20-40%. Biomarkers are required in order to avoid unnecessary biopsies. The PCA3 gene product is specifically overexpressed in prostate tumor cells, and modern molecular biology techniques allow us to use a specific test for this gene in order to select patients who have a high risk of having prostate cancer. Literature reviews of the gene product, as well as the first clinical results of the Progensa PCA3 test, are presented.

Methods of Calculating Prostate-Specific Antigen Velocity

OBJECTIVES

Numerous methods of calculating PSA velocity (PSAV) are used and have the potential to produce differing PSAV results from the same PSA data. We calculated PSAV using three common methods and compared differences between the methods and their predictive value for prostate cancer diagnosis.

METHODS

From a population-based database of PSA results, men with initial PSA<10.0 ng/ml and a subsequent diagnosis of prostate cancer or benign histology were identified. Those with > or =3 PSA tests before diagnosis carried out over a minimum of 18 mo were included. PSAV was calculated by using three methods: The differences between the methods and test characteristics of each method were compared.

RESULTS

Of the 2204 men included, 716 (32.5%) were diagnosed with prostate cancer and 1488 (67.5%) benign histology. PSAV differed markedly in each method of calculation. The LR and FL methods had similar predictive values, which were higher than the AE method. There was strong agreement for cancer diagnosis between LR and FL (kappa=0.85), with weaker agreement between LR/AE and FL/AE (kappa=0.69 and 0.66, respectively).

CONCLUSIONS

Methods used to calculate PSAV using the same PSA data can produce markedly different results. Linear regression should be the method of choice for calculating PSAV. Using first and last PSA values only may be adequate for everyday clinical use, as long as measurements are separated by a sufficiently long time period.

Prostate specific antigen recurrence after definitive therapy

PURPOSE

We estimate that approximately 70,000 men yearly have prostate specific antigen-only recurrence after failed definitive therapy. The ideal salvage therapy for these men is not clear. Treatment must be individualized based on the patient risk of progression, the likelihood of success and the risks involved with the therapy. However, to do so the risks and benefits of the various options must be known. Therefore, we provide a comprehensive overview of the natural history and treatment options for men with prostate specific antigen-only recurrence.

MATERIALS AND METHODS

A literature review and overview of prostate specific antigen-only recurrence after failed definitive therapy was done.

RESULTS

The natural history after prostate specific antigen-only recurrence is long but variable. Median time from prostate specific antigen-only recurrence after radical prostatectomy to prostate cancer death exceeds 16 years, although some men die within 1 year after PSA recurrence. Rapid prostate specific antigen doubling time is the best prognostic factor for poor outcome. Salvage radiation therapy after radical prostatectomy results in a 45% 4-year prostate specific antigen response rate, although long-term outcomes appear poor. To our knowledge the effect on survival is not known. Salvage radical prostatectomy is rarely performed but in the highly selected patient it may provide some benefit. There are no randomized studies of early vs late hormonal therapy for men with prostate specific antigen-only recurrence. A retrospective study suggested delayed metastasis when therapy was begun early but only in men at high risk. This mirrors other data suggesting that men at high risk may derive significant benefits from early hormonal therapy, whereas men at low risk are unlikely to benefit and may be harmed by hormonal therapy.

CONCLUSIONS

Prostate specific antigen-only recurrence is the most common form of advanced prostate cancer. Optimal salvage treatments and timing of these treatments remain controversial.

Diagnostic efficacy of free to total ratio of prostate-specific antigen and prostate-specific antigen velocity, singly and in combination, in detecting prostate cancer in patients with total serum prostate-specific antigen between 4 and 10 ng/ml

To assess the diagnostic efficacy of prostate-specific antigen (PSA)-related parameters, using a total of 226 patients with gray zone PSA who underwent prostate biopsy, various cutoff points of free to total ratio of PSA (f/t PSA) and PSA velocity (PSAV) were evaluated. Higher cutoff points of f/t PSA resulted in high sensitivity and negative predictive value (NPV): at f/t PSA <15%, sensitivity was 82.0% (41/50) and NPV 84.7% (50/59), and at f/t PSA <20%, 96.0% (48/50) and 92.3% (24/26). Lowering cutoff points also resulted in higher sensitivity and NPV: at PSAV >or=0.75 ng/ml per year, sensitivity was 71.4% (15/21) and NPV 82.4% (28/34), and at PSAV >or=0.40 ng/ml per year, 95.2% (20/21) and 95.2% (20/21). Further, among the patients with both of these parameters available, both sensitivity and NPV achieved 100% (10/10 and 7/7) when the indication for biopsy was determined as f/t PSA <15% or PSAV >or=0.40 ng/ml per year. Our results showed that unnecessary prostate biopsies could be more effectively avoided among patients with "gray zone PSA" by combination of f/t PSA and PSAV than single usage of these indexes.

Assessment of Prostate-Specific Antigen Doubling Time in Prediction of Prostate Cancer on Needle Biopsy

OBJECTIVES

Prostate-specific antigen (PSA) kinetics have failed to predict for the presence of prostate cancer in screening populations in which many patients harbor subclinical disease. We hypothesized that the prebiopsy PSA doubling time (PSADT) and PSA velocity (PSAV) could predict for cancer detection in a referral population with a suspicion of prostate cancer.

METHODS

Data were collected from 1699 consecutive veterans with a PSA level of 10 ng/mL or less who underwent prostate biopsy. Logistic regression analysis was performed on the following: age, race, family history, digital rectal examination findings, PSA, PSA density, PSADT, PSAV, prostate volume, and ultrasound lesions. Model building was accomplished with 70% of the data, and validation was done using the remaining 30%. These data were also analyzed using classification and regression tree analysis.

RESULTS

Using logistic regression analysis (P <0.05) on the model building set, prostate cancer was associated with age (older than 70 years), PSA level (greater than 2.9 ng/mL), PSA density (more than 0.12 ng/mL/cm3), digital rectal examination findings, and the presence of a lesion on ultrasonography. A PSADT of 2 to 5 years was marginally associated with prostate cancer detection (odds ratio 1.6, 95% confidence interval 1.1 to 2.3), and a PSADT of less than 2 years or longer than 5 years and PSAV were not predictive. On classification and regression tree analysis, PSADT was not selected as a predictive factor. Furthermore, neither PSADT nor PSAV was predictive of Gleason score 7 or worse cancer.

CONCLUSIONS

In contrast to its prognostic value after the diagnosis of prostate cancer has been established, PSA kinetics offer little to clinical decision making as predictors of cancer or high-grade cancer in men with a PSA level of 10 ng/mL or less.

'Insignificant' prostate cancer on biopsy: pathologic results from subsequent radical prostatectomy

'Insignificant' prostate cancer is defined as disease of virulence insufficient to threaten survival. In this review, which describes nine articles and two abstracts discussing almost 800 cases, we discuss the correlation of such 'insignificant' biopsy findings in the context of subsequent radical prostatectomy data. From our review, minimal disease on biopsy does not reliably predict minimal disease in the subsequent prostatectomy specimen, in terms of the size and grade of tumor, extracapsular extension or positive margins. Thus, reasoned accounting should be made of other data before undertaking a course of radiation therapy as monotherapy, particularly prostate-specific antigen kinetics and potential molecular markers.

Implications of Prostate-Specific Antigen Doubling Time as Indicator of Failure after Surgery or Radiation Therapy for Prostate Cancer

OBJECTIVES

To review the methodology of PSA doubling time (PSA DT) calculations and the implications of PSA DT for the follow-up of prostate cancer patients curatively treated with surgery or radiation therapy.

METHODS

A literature search of the most recent articles on PSA DT (those published after 2000) led to the selection of six studies with the largest and best-documented cohorts of patients treated with surgery or irradiation with curative intent.

RESULTS

PSA kinetics, in the form of PSA DT, is the most effective parameter for identifying patients at significant risk for mortality specific to prostate cancer. Thresholds of 3, 6, and 12 mo have shown prognostic significance both in surgical and radiation series, notwithstanding differences in treatment selection, definition of biochemical recurrence, and methods of DT calculation.

CONCLUSIONS

In retrospective studies, PSA DT is a reliable predictor of prognosis; however, prospective validation studies are needed to determine the cut points of PSA DT. Optimal time intervals for calculation and optimal thresholds are still to be determined.

The value of different screening tests in predicting prostate biopsy outcome in screening for prostate cancer data from a multicenter study (ERSPC)

BACKGROUND

Although serum PSA testing is widely used as a screening test for prostate cancer (PC), it is known that it is not specific for PC. The study described here focuses on the value of screening tests next to PSA in identifying men with an elevated risk of having PC and the differences between three centers of the European Randomised study of Screening for Prostate Cancer (ERSPC).

METHODS

The study population consists of 2,483 men with a PSA > or =4.0 ng/ml, all biopsied. We assessed data on age, serum PSA level at initial and repeat screening, prostate volume, number of positive DRE and TRUS findings, number of previous negative biopsies, and PPV of the three centers and overall. Using logistic regression analysis, predictors for biopsy outcome at repeat screening in men with a PSA value > or =4.0 ng/ml were determined on the complete dataset and per center.

RESULTS

In 2,483 men biopsied, 665 cancers were detected (PPV = 26.8%). Data show that all predictors except prostate volume loose their predictive value in men previously biopsied. In men not previously biopsied, the predictive value of DRE and TRUS vary considerably among the three centers.

CONCLUSIONS

Looking at the differences in the predictive value of screening tests in three "comparable" centers, generasibility is not as straightforward as it seems. Using a nomogram for predictive purposes developed elsewhere will require a thorough knowledge of the patient population of which it is derived, and one should interpret its results with a critical mind.

Prostate-specific antigen 'velocity' as a diagnostic test for prostate cancer

BACKGROUND

Prostate-specific antigen "velocity" (slope) is promoted as a diagnostic test for prostate cancer, but its clinical usefulness is uncertain. Accordingly, we evaluated the sensitivity of prostate-specific antigen (PSA) velocity among men who are diagnosed subsequently with prostate cancer.

METHODS

Among 64,545 men receiving primary care at any of nine Veterans Affairs Medical Centers during 1989-1990, 1,313 men at least 50 years old had an incident diagnosis of prostate cancer during 1991-1995. PSA velocity values obtained prior to diagnosis ("test") were compared with results from prostate biopsies ("truth").

RESULTS

Among men (n = 493) with at least two tests before diagnosis, the sensitivity of PSA velocity > or = 0.75 ng/mL/yr was 75.5% (95% confidence interval [CI] 71.7-79.3) overall and 48.1% (95% CI 34.8-61.5) among men with normal values of PSA (< 4.0 ng/mL). Based on published data for specificity and prevalence, the estimated positive predictive value of PSA velocity > or = 0.75 ng/mL/yr is as low as 5%.

CONCLUSION

PSA velocity may have limited usefulness as a diagnostic test for prostate cancer.

Long-Term Prediction of Prostate Cancer Up to 25 Years Before Diagnosis of Prostate Cancer Using Prostate Kallikreins Measured at Age 44 to 50 Years

Purpose

We examined whether prostate-specific antigen (PSA) forms and human kallikrein 2 (hK2) measured at age 44 to 50 years predict long-term risk of incident prostate cancer.

Methods

From 1974 to 1986, 21,277 men age ≤ 50 years in Malmö, Sweden, enrolled onto a cardiovascular study (74% participation). The rate of PSA screening in this population is low. According to the Swedish Cancer Registry, 498 were later diagnosed with prostate cancer. We measured hK2, free PSA, and total PSA (tPSA) in archived blood plasma from 462 participants later diagnosed with prostate cancer and from 1,222 matched controls. Conditional logistic regression was used to test for association of prostate cancer with hK2 and PSA forms measured at baseline.

Results

Median delay between venipuncture and prostate cancer diagnosis was 18 years. hK2 and all PSA forms were strongly associated with prostate cancer (all P < .0005). None of the 90 anthropometric, lifestyle, biochemical, and medical history variables measured at baseline was importantly predictive. A tPSA increase of 1 ng/mL was associated with an increase in odds of cancer of 3.69 (95% CI, 2.99 to 4.56); addition of other PSA forms or hK2 did not add to the predictive value of tPSA. tPSA remained predictive for men diagnosed ≥ 20 years after venipuncture, and the predictive value remained unchanged in an analysis restricted to palpable disease.

Conclusion

A single PSA test at age 44 to 50 years predicts subsequent clinically diagnosed prostate cancer. This raises the possibility of risk stratification for prostate cancer screening programs.

Prostate-specific antigen (PSA) and PSA velocity for prostate cancer detection in men aged <50 years

OBJECTIVE

To identify threshold values of prostate-specific antigen (PSA) levels and PSA velocity (PSAV) to optimize the assessment of the risk of prostate cancer in young men, as prostate cancer is detected increasingly in men aged <50 years.

PATIENTS AND METHODS

Data for a group of 12 078 men, including 1622 with prostate cancer, were retrieved from the Duke Prostate Center Database. Based on the latest date for a PSA assay, these men were divided into two age groups of <50 and >/= 50 years, with 904 and 11 174 men in each group, respectively. Receiver operating characteristic curves (ROC) of PSA and PSAV were calculated and the cancer risk was assessed.

RESULTS

The prevalence of prostate cancer was 4.4% (40 men) for men aged <50 years and 14.2% (1582 men) for men aged >/= 50 years. For the group with cancer the median PSA in men aged <50 years was significantly lower than that in men aged >/= 50 (1.3 vs 6.3 ng/mL, P < 0.001). ROC curves of PSA and PSAV showed a breakpoint at a PSA level of 2.3 ng/mL and a PSAV of 0.60 ng/mL/year for men aged <50 years. Both the sensitivity and specificity in the younger group at a PSA level of 2.5 ng/mL were higher than in the older group.

CONCLUSIONS

In men aged <50 years the operating characteristics of PSA are more sensitive and specific than in older men. Diagnostic PSA levels in men aged <50 years are significantly lower than suggested by guidelines. Using a 2.0-2.5 ng/mL PSA level threshold for biopsy in men aged <50 years and a PSAV threshold lower than the traditional 0.75 ng/mL/year is reasonable in contemporary practice. Further studies are warranted to validate these thresholds.

Highly elevated PSA and dietary PhIP intake in a prospective clinic-based study among African Americans

African-American men die from prostate cancer (PC) nearly twice as often as white US men and consume about twice as much of the predominant US dietary heterocyclic amine, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), a genotoxic rat-prostate carcinogen found primarily in well-cooked chicken and beef. To investigate the hypothesis that PhIP exposure increases PC risk, an ongoing prospective clinic-based study compared PC screening outcomes with survey-based estimates of dietary PhIP intake among 40-70-year-old African-American men with no prior PC in Oakland, CA. They completed food-frequency and meat-cooking/consumption questionnaires and had a prostate-specific antigen (PSA) test and digital-rectal exam. Results for 392 men indicated a 17 (+/-17) ng/kg day mean (+/-1 s.d.) daily intake of PhIP, about twice that of white US men of similar age. PhIP intake was attributable mostly to chicken (61%) and positively associated (R(2)=0.32, P<0.0001) with saturated fat intake. An odds ratio (95% confidence interval) of 31 (3.1-690) for highly elevated PSA > or =20 ng/ml was observed in the highest 15% vs lowest 50% of estimated daily PhIP intake (> or =30 vs < or =10 ng/kg day) among men 50+ years old (P=0.0002 for trend) and remained significant after adjustment for self-reported family history of (brother or father) PC, saturated fat intake and total energy intake. PSA measures were higher in African-American men with positive family history (P=0.007 all men, P<0.0001 highest PSA quartile). These preliminary results are consistent with a positive association between PhIP intake and highly elevated PSA, supporting the hypothesis that dietary intervention may help reduce PC risk.

Prostate-specific antigen velocity and the detection of gleason score 7 to 10 prostate cancer

BACKGROUND

An increasing prostate-specific antigen (PSA) velocity is associated with a shorter survival after local therapy for prostate cancer. In this study, the authors evaluated whether PSA velocity was associated with prostate cancer detection and grade at diagnosis after adjusting for established predictors.

METHODS

Between January 1989 and December 2003, 914 men who had PSA levels >/=4 ng/mL were identified by using the Center for Prostate Disease Research (CPDR) multicenter national database, including 541 men who were diagnosed with prostate cancer. Multivariable logistic regression analyses were performed that included continuous variables (PSA velocity and level, number of prior negative biopsies, and age) along with categorical variables (ethnicity and family history) were used to identify the factors associated with prostate cancer detection and grade.

RESULTS

An increasing PSA velocity was associated with Gleason scores from 7 to 10 versus Gleason scores form 2 to 6 or no cancer (adjusted odds ratio [OR], 1.04 ng/mL per year; 95% confidence interval [95% CI], 1.003-1.085 ng/mL per year; P = .035). This finding was not evident in patients who had prostate cancers with Gleason scores between 2 and 6 or for any prostate cancer. PSA level was associated with the detection of any prostate cancer (OR, 1.06 ng/mL; 95% CI, 1.03-1.10 ng/mL; P = .004) and Gleason score </=6 prostate cancer (OR, 1.06 ng/mL; 95% CI, 1.02-1.10 ng/mL; P = .0027); however, in the presence of PSA velocity, PSA no longer remained independently predictive for high-grade prostate cancer (OR, 1.01 ng/mL; 95% CI, 0.98-1.04 ng/mL; P = .45) after adjusting for established predictors.

CONCLUSIONS

PSA velocity enhanced the detection of high-grade cancer in men who had PSA levels >4 ng/mL. These findings, in conjunction with life expectancy, may be used when deciding which men should not be recommended for prostate biopsy despite a PSA level >4 ng/mL.

Role of Zn2+ in epigallocatechin gallate affecting the growth of PC-3 cells

Green tea has chemo-preventive effects to human carcinoma including prostate cancer. Epigallocatechin gallate (EGCG) is the major active component in green tea. Zn(2+) is indispensable to our health, and plays an important role in the normal function and pathology of the prostate gland, and might be a good marker for diagnosing prostate cancer. Effects of Zn(2+), EGCG and their interactions on the growth of androgen-insensitive prostate cancer cell (PC-3) were investigated in the present paper. The results show that Zn(2+) and EGCG inhibited the growth of PC-3 cells in a time- and dose-dependent manner, but effects of interactions of EGCG with Zn(2+) were extremely dependent on their concentrations and added orders. Inhibitory effects of Zn(2+) were significantly decreased in the presence of EGCG on PC-3 cell growth. Therefore, we hypothesize that complexation of EGCG with Zn(2+) might be responsible for the observed decrease of the bioactivities of Zn(2+) against PC-3 cells.

The role of prevalence in the diagnosis of prostate cancer

BACKGROUND

The worldwide incidence of prostate cancer has been rising rapidly, likely due to intensified effort in early detection and screening. Intense effort is also directed at novel schemas of chemoprevention and therapy. Incidence data are insufficient to identify the true magnitude of prostate cancer in a given population. The true prevalence of prostate cancer must be identified.

METHODS

We reviewed the latest worldwide epidemiologic data and clinical studies on prostate cancer studying the true prevalence of this disease.

RESULTS

The incidence of prostate cancer is increasing worldwide, with strong variation among regions. Prevalence studies based on autopsy data have confirmed a high frequency of latent prostate cancer in men of all ages. More aggressive screening measures using a lower prostate-specific antigen (PSA) threshold, together with an increasing number of biopsies, have escalated the detection of these latent cancers.

CONCLUSIONS

Recent improvements in prostate cancer detection narrow the gap between the incidence and true prevalence of prostate cancer. This, however, raises concerns about the risk of over detection of latent cancers and thus identifying a need for improvement in screening strategies to better identify clinically significant disease.

Age-specific reference ranges for prostate specific antigen-total and free in patients with prostatitis symptoms and patients at risk

BACKGROUND

Prostate-specific antigen (PSA) is a tumor marker helpful in the diagnosis and follow-up of prostate cancer. However, PSA level may rise due to other causes than prostate cancer such as benign prostatic hyperplasia (BPH), acute prostatitis, chronic bacteria and a bacterial prostatitis. Total serum PSA (TPSA) and free prostate-specific antigen (FPSA) levels of patients with prostatitis symptoms as well as these levels in male population at risk but without clinical prostatic diseases (>40-years-old) with regard to age should be documented in order to increase the sensitivity and specificity of PSA in prostate carcinoma.

METHODS

A comprehensive urological examination was performed on 1150 male patients over the age of 40 with prostatism symptoms from the random-sample community based in with no diagnostic prostate cancer. Men with PSA level 4.1 ng/ml or greater were referred for biopsy and those with positive biopsies or with medical record, cancer registry, or self-reported evidence of prostate cancer were excluded. Data were studied as a function of age to determine the usefulness of measuring TPSA and FPSA as screening tests for risk patient's cancer.

RESULTS

Because of the greater variability at older ages, the 95th percentile increased faster than the median, the following age-specific reference ranges of TPSA and FPSA for patients with prostatism symptoms were as follows: 3.1 and 0.7 ng/ml for the age group 40-49 years, 4.4 and 0.89 ng/ml for the age group 50-59 years, 5.6 and 1.3 ng/ml for the age group 60-69 years, and 6.3 and 1.8 ng/ml for age group 70-79 years. There was a continuous increase in TPSA and FPSA means and medians with significant correlation (P<0.001, P<0.005) and advancing age group. The aim of this study was to find out age-specific values and ranges of TPSA and FPSA in patients with prostatism symptoms to ensure low false-positive biopsy rates.

Prostate cancer : synopsis of the American Urological Association (AUA) 2006

The 2006 annual American Urological Association (AUA) meeting took place in Atlanta from 20-25th of May. Four hundred and seventy nine abstracts (27.8%) were dedicated to the prostate cancer. The aim of this study is to summarise the most debated topics and to highlight the most original research. The main topics this year were obesity, ethnicity, PSA kinetic, surgical margins, robot and adjuvant therapy.

[Localized prostate cancer. Local treatment and what place for lymphadenectomy]

The pretreatment PSA level, the Gleason score, the presence of lymph-node metastases, the status of surgical positive margins are poor pathological risk factors for patients who have a pathologic stage T3 prostate cancer. The increase in PSA level during the year prior to diagnostic is associated with the risk of death due to prostate cancer following radical prostatectomy or external beam radiation therapy. The assessment of Locoregional extension is indicated for such patients. The extended pelvic lymphadenectomy remains the most accurate procedure for a correct staging of the detection of nodal involvement in these patients with high-risk localized prostate cancer. For such patients with a high-risk of progression and, whose the life expectancy is greater than 10 years, treatment must be a combined modality therapy since radical prostatectomy alone correlates with a poor clinical outcome. Adjuvant hormonal therapy following local curative treatment by prostatectomy (or radiotherapy) needs to be often considered. Collegial decision-making is by far the most appropriate setting for the discussion among medical specialists of these complex clinical cases for patients often having associated medical conditions and whose adjuvant treatment will have a significant impact of their future quality of life.

Prostate-specific antigen and detection of prostate cancer: What have we learned and what should we recommend for screening?

Prostate-specific antigen (PSA) has become one of the most commonly used cancer clinical tests, and routine PSA-based screening has led to a dramatic increase in prostate cancer detection. A significant downward stage migration has resulted, and a decrease in prostate cancer mortality has also been observed. However, PSA screening remains controversial because there is no definitive proof that it decreases prostate cancer death rates, and there is concern that it may detect a significant number of clinically insignificant cancers. Screening age and interval have been recently questioned, and the best threshold to recommend biopsy has been complicated by new data showing that prostate cancer exists at all PSA levels, even those thought to be "normal" in the past. It is hoped that ongoing prospective screening trials will determine the value of PSA screening. However, until these results are available the controversy will continue, and men will continue to be screened.

PSA velocity in conservatively managed BPH: can it predict the need for BPH-related invasive therapy?

OBJECTIVE

To study the value of PSA velocity (PSAV) to predict benign prostatic hyperplasia (BPH) progression in patients managed with alpha(1)-blockers or watchful waiting (WW).

METHODS

Nine hundred and forty two BPH patients treated with alpha(1)-blocker or WW were reviewed. PSAV was defined as: (PSA(t)-PSA(b))/(t/12); where PSA(t) = PSA at time of follow-up (t, in months), PSA(b) = PSA at baseline. PSA(t) was taken from the 1 year follow-up visit or, if not present, from the next available visit with a maximum of 24 months.

RESULTS

Five hundred and ninety five patients (234 alpha(1)-blocker, 361 WW) were included in the analyses. PSAV range was -5.24 to 43.06 ng/ml/year in alpha(1)-blocker patients and -6.11 to 19.55 ng/ml/year in WW patients (median: 0.01 ng/ml/year). PSAV was stratified into tertiles (Stable/Decrease/Increase). There were no significant differences in retreatment-free survival and the risk of BPH-related invasive therapy between the tertiles in both treatment groups.

CONCLUSIONS

PSAV did not predict BPH progression in either alpha(1)-blocker treated patients or WW group.

Utility of volume adjusted prostate specific antigen density in the diagnosis of prostate cancer in Arab men

BACKGROUND

This study was undertaken to assess the utility of prostate specific antigen (PSA) and PSA density (PSAD) in discriminating between benign and malignant prostate disease in the Kuwaiti Arab population.

METHODS

A total of 100 consecutive patients suspected of having prostate cancer because of serum PSA > 4 ng/ml, or detection of a prostatic nodule on rectal examination were further investigated by determination of PSAD, TRUS of prostate, sexant prostatic biopsy and histological analysis to establish the correct diagnosis. Other diagnostic measures included the determination of the area under the receiver operating characteristic (ROC) curve, sensitivity and specificity.

RESULTS

Of the 100 prostate biopsies that were performed, 33 cases were confirmed to be prostate cancer and 67 were described as benign lesions comprising benign prostatic hyperplasia (BPH) with or without prostatitis. The age range for patients with prostate cancer was 42-90 years, and 52-90 years for those without prostate cancer. The mean prostate volume was 58.82 cc (range 9-177 cc) and 62.60 cc (range 15-140 cc), the mean PSA value was 36.65 ng/ml (range 5.8-200 ng/ml) and 16.49 ng/ml (range 1.4-46.0 ng/ml), while the mean PSAD was 0.92 (range 0.046-5.714) and 0.452 (range 0.034-2.294) for patients with prostate cancer and patients without prostate cancer respectively. Patients with PSA less than 4 ng/ml (3 cases) all had benign prostate lesions, and 7 cases with PSA more than 50 ng/ml all had prostate cancer and were excluded because values above 50 ng/ml have close to 100% specificity for prostate cancer. Further analysis was done on the remaining 90 cases which were patients with a PSA between 4 and 50 ng/ml. The discriminating power of serum PSA for detecting prostate cancer as estimated by the area under ROC was 0.686 while that for PSAD was 0.732. The maximum likelihood for a positive PSA was at a PSAD cut-off point of 0.32. For the PSA cut-off point of l0 ng/ml, the sensitivity was 80%, and specificity was 42.2%. For the PSAD cut-off point of 0.32, the sensitivity was 58% and the specificity 76.6%.

CONCLUSIONS

Determination of PSAD is not a useful adjunct to serum PSA values in the range of 10-50 ng/ ml in our population. PSAD value less than 0.32 with PSA less than l0 ng/ml strongly suggests benign disease.

Prostate cancer detection strategies

Prostate cancer is the most common malignancy in men and, as a result, there has been a nationwide emphasis on screening and detection. With the widespread use of the prostate-specific antigen (PSA), prostate cancer screening effectively detects localized prostate cancer. However, recent reports have identified a significant proportion of prostate cancer in men with low PSA levels. Many of these cancers are higher-grade malignancies. Consequently, PSA may function more effectively as a screening tool when applied over a continuum that is associated with degree of risk, rather than a binary measure. Other markers are currently being investigated. Ideally, a marker will identify the malignancy that is a clinical threat, thereby avoiding intervention for indolent disease. Prevention strategies may be employed for higher-risk patients, and these strategies eventually may be tailored to genetic or other risks.