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

National Institute on Aging at middle age--its past, present, and future

The National Institute on Aging (NIA) at the National Institutes of Health (NIH) leads the federal effort conducting and supporting research on aging. It is also designated as the lead within NIH for research on Alzheimer's disease. Since NIA's establishment in 1974, it has grown to a billion dollar enterprise featuring a balanced program of basic, clinical, and behavioral and social science. Investigator-initiated research and strategic investments have been critical to the NIA's success in bringing new insights and understandings to aging processes and diseases and conditions associated with advancing age. In recent years, constraints in the growth of resources have posed new challenges as the NIA and NIH leadership seek to maintain a robust and productive program. This article will review the history of the NIA, discuss current programs and priorities, and point to new directions in research, looking ahead.

A Review on the Clinical Utility of PSA in Cancer Prostate

Prostate cancer has come to share the oncological centrestage among male cancers. The availability of Serum Prostate Specific Antigen, PSA, as a marker has encouraged it's use to diagnose both cancer and cancer recurrence. Some clarity is required about its precise role in clinical practice. The available literature on Prostate Specific Antigen was reviewed; Articles were reviewed for content, applicability to the problem at hand, availability of data about sensitivity and specificity of values, refinements in measurements and finally for impact of screening programmes using these values on survival and quality of life. The data in the literature was critically re-evaluated and analysed to draw reasonable conclusions. Serum PSA measurements show variable reliability when it comes to diagnosis of Prostate cancer, given the dynamics of PSA physiology. Surrogate measures like PSA density, PSA velocity, free-to-complexed PSA ratio, percentage Pro-PSA, etc., have been used to improve the predictive utility of this assay for Prostate cancer. The ability of PSA to detect those cancers that will cost life, and thereby permit early curative treatment, is as yet unclear. It's most definitive role appears to be in diagnosing recurrences after adequate surgical treatment, and in evaluating response to treatment.

Longitudinal changes of benign prostate-specific antigen and [-2]proprostate-specific antigen in seven years in a community-based sample of men

OBJECTIVE

To determine the longitudinal changes of benign prostate-specific antigen (BPSA) and [-2]proPSA and how these changes relate to the outcomes. These markers have been shown to be predictive of prostate cancer (CaP) and benign prostatic hyperplasia treatment; however, little is known about longitudinal changes in these markers.

METHODS

In 1990, a 25% subsample from a cohort of white men aged 40-79 years, who were randomly selected from Olmsted County, Minnesota residents, completed a detailed clinical examination. BPSA and [-2]proPSA were measured from frozen sera. The men were evaluated biennially (median follow-up 7 years; range 0-8.8). Mixed-effects regression models were used to estimate the longitudinal changes in the BPSA and [-2]proPSA levels overall and by outcomes. Spearman correlations were used to compare these changes with the baseline levels and the annualized changes in urologic measures.

RESULTS

The median and 25th and 75th percentiles annualized percent change for [-2]proPSA and BPSA was 3.7%, 2.5% and 5.2% and 7.3%, 6.8%, and 7.7%, respectively. The annualized percent change for both markers correlated with the baseline and annualized changes in PSA and prostate volume. The annualized percent change increased with increasing age decade for [-2]proPSA but not for BPSA. The rate of increase in [-2]proPSA was significantly greater for men who developed enlarged prostates (median 3.5%, 25th and 75th percentile 2.6% and 4.4%, respectively) or CaP (median 8.1%, 25th and 75th percentile 6.6% and 9.8%, respectively) compared with those who did not develop enlarged prostates (median 1.9%, 25th and 75th percentile 0.9% and 3.0%, respectively) or CaP (median 3.5%, 25th and 75th percentile 2.3% and 4.8%, respectively).

CONCLUSION

BPSA and [-2]proPSA levels increase over time. The annualized percent change in [-2]proPSA increases with age and might be a useful predictor of CaP development.

The current role of circulating tumor cells in the diagnosis and management of bone metastases in advanced prostate cancer

Prostate-specific antigen (PSA) has been used for over two decades as a serum marker for adenocarcinoma of the prostate. Although PSA screening remains an important part of disease screening and monitoring in early prostate cancer (PC), its utility in monitoring disease progression in advanced PC is undetermined. Furthermore, the role of PSA monitoring in the management of patients with PC and bone metastases appears limited. The purpose of this review is to evaluate the role of circulating tumor cells (CTCs) as potential novel biomarkers in advanced PC. We present a review of CTC testing and the clinical data supporting the prognostic potential of CTCs in this setting. We propose that combination of CTCs and PSA velocity or doubling-time assessments may offer insights into the prognosis and management of advanced PC.

Differentiation of lethal and non lethal prostate cancer: PSA and PSA isoforms and kinetics

Prostate-specific antigen (PSA) testing for the early diagnosis of prostate cancer has led to a decrease in cancer mortality. However, the high prevalence of low-grade prostate cancer and its long natural history, competing causes of death in older men and treatment patterns of prostate cancer, have led to dramatic overtreatment of the disease. Improved markers of prostate cancer lethality are needed to reduce the overtreatment of prostate cancer that leads to a reduced quality of life without extending life for a high proportion of men. The PSA level prior to treatment is routinely used in multivariable models to predict prostate cancer aggressiveness. PSA isoforms and PSA kinetics have been associated with more aggressive phenotypes, but are not routinely employed as part of prediction tools prior to treatment. PSA kinetics is a valuable marker of lethality post treatment and routinely used in determining the need for salvage therapy.

Detection of prostate cancer in an ethnically diverse, disadvantaged population with multiple prostate specific antigen measurements before biopsy

PURPOSE

We assessed the predictive effect of prostate specific antigen velocity for men with a minimum of 3 pre-biopsy prostate specific antigen measurements in a racially diverse population.

MATERIALS AND METHODS

We identified 795 patients who underwent 3 or more prostate specific antigen tests before prostate biopsy. Prostate specific antigen velocity was calculated by linear regression and used to assess associations with the risk of prostate cancer overall and of high grade prostate cancer (Gleason score 7-10). We created ROC curves and determined the AUC for several models, including only prostate specific antigen velocity or the last prostate specific antigen measurement before biopsy, to predict prostate cancer and high grade prostate cancer.

RESULTS

The risk of prostate cancer and high grade prostate cancer increased linearly with increasing prostate specific antigen velocity quartiles (each p trend<0.001). Older patients were more likely to be diagnosed with prostate cancer, given the same prostate specific antigen velocity. In black and Hispanic patients there were strong linear associations between increasing prostate specific antigen velocity and the risk of prostate cancer overall and high grade prostate cancer. ROC curves incorporating prostate specific antigen velocity to predict prostate cancer and high grade prostate cancer varied significantly by race. The AUC of models in black and Hispanic patients was significantly higher than in white patients (0.62 and 0.64, respectively, vs 0.47, p=0.03).

CONCLUSIONS

Prostate specific antigen velocity is a significant predictor of prostate cancer and high grade prostate cancer in men with 3 or more prostate specific antigen tests before prostate biopsy. Black and Hispanic patients appear to be at increased risk for prostate cancer at higher prostate specific antigen velocity, as are men older than 60 years. Further studies should confirm these results and create age and race specific guidelines to assess prostate specific antigen velocity.

Sauver JL, Klee GG, Girman CJ, Lieber MM. Sixteen-year longitudinal changes in serum prostate-specific antigen levels: the olmsted county study

OBJECTIVE

To determine the distribution of longitudinal changes in serum prostate-specific antigen (PSA) levels from a population-based sample of men.

PATIENTS AND METHODS

In this prospective cohort study, a random sample of Olmsted County, Minnesota, men aged 40 to 79 years in 1990 were followed up biennially from January 1, 1990, through August 29, 2007. Serum PSA levels were determined at each examination, and men were censored for follow-up with a diagnosis of prostate cancer or treatment for benign prostatic hyperplasia. The empirical distributions of annual percent change and annual absolute change in serum PSA level were calculated and tabulated, including the median and 75th and 95th percentiles.

RESULTS

For men with PSA measurements 2 years apart, the median annual percent change in serum PSA level was 4.83% and the 95th percentile was about 49.76%. The variability in estimated annual change decreased with increasing time between assessments, with a 95th percentile of 21.82% after 8 or more years between assessments. Although the median absolute change per year increased with increasing age, the median percent change per year was fairly consistent across age groups.

CONCLUSION

These data demonstrate that, with shorter intervals between assessments, greater variability should be expected. These distributions should prove helpful to patients and clinicians in interpreting changes in serum PSA levels observed in typical clinical practices.

Predictive effect of serial serum alanine aminotransferase levels on spontaneous HBeAg seroconversion in chronic genotype B and C HBV-infected children

OBJECTIVE

The present study aimed to investigate the association between serial serum alanine aminotransferase (ALT) and spontaneous hepatitis B e antigen (HBeAg) seroconversion age in chronic hepatitis B virus (HBV)-infected children.

PATIENTS AND METHODS

One hundred four HBeAg-positive chronic genotype B or C HBV-infected patients were included in this long-term prospective cohort study (mean initial age 7.20 years). Serial serum ALT levels and HBV serology markers were measured every 6 to 12 months. The 104 subjects made a total of 2525 visits during the study period, and the majority (93.6%) of visits were within a 1-year interval apart from previous visits. Cox proportional hazards model with time-dependent covariates was used in the survival analysis of HBeAg in these subjects.

RESULTS

During the chronic course of HBV infection, the median remaining times to spontaneous HBeAg seroconversion were 8.35, 5.14, 4.25, 3.95, and 2.80 years after the ALT levels crossed 20, 30, 40, 60, and 150 IU/L, respectively. The incidence rate of spontaneous HBeAg seroconversion within 6 months when a subject entered the phase of ALT between 60 and 150 IU/L was 5.57 times that of the phase with ALT < 60 IU/L. The incidence rate of HBeAg seroconversion once ALT levels were above 150 IU/L was 9.87 times that of the phase of ALT < 60 IU/L.

CONCLUSIONS

The ALT levels above 30 IU/L served as a cutoff of the inflammatory phase in chronic genotype B and C HBV-infected patients. Serial ALT levels in chronic HBV-infected subjects offer a predicted effect on the occurrence of spontaneous HBeAg seroconversion.

Alternative splicing of mRNA in the molecular pathology of neurodegenerative diseases

Alternative splicing (AS) is a post-transcriptional process that occurs in multiexon genes, and errors in this process have been implicated in many human diseases. Until recently, technological limitations prevented AS from being examined at the genome-wide scale. With the advent of new technologies, including exon arrays and next-generation sequencing (NGS) techniques (e.g., RNA-Seq), a higher resolution view of the human transcriptome is now available. This is particularly applicable in the study of neurodegenerative brain diseases (NBDs), such as Alzheimer's disease and Parkinson's disease, because the brain has the greatest amount of alternative splicing of all human tissues. Although many of the AS events associated with these disorders were initially identified using low-throughput methodologies, genome-wide analysis allows for more in-depth studies, marking a new chapter in transcript exploration. In this review, the latest technologies used to study the transcriptome and the AS genes that have been associated with a number of neurodegenerative brain diseases are discussed.

Predicting prostate cancer many years before diagnosis: how and why?

Evidence of reduced prostate cancer mortality from randomized trials in Europe supports early detection of prostate cancer with prostate-specific antigen (PSA). Yet PSA screening has generated considerable controversy: it is far from clear that the benefits outweigh risks, in terms of overdiagnosis and overtreatment. One way to shift the ratio of benefits to harm is to focus on men at highest risk, who have more to benefit than average. Neither family history nor any of the currently identified genomic markers offer sufficient risk stratification for practical use. However, there is considerable evidence that the levels of PSA in blood are strongly prognostic of the long-term risk of aggressive prostate cancer. Specifically, it is difficult to justify continuing to screen men aged 60 or older if they have a PSA less than 1 or 2 ng/ml; for men 45-60, intervals between PSA tests can be based on PSA levels, with 2-4-year retesting interval for men with PSA of 1 ng/ml or higher, and tests every 6-8 years for men with PSA <1 ng/ml. Men with the top 10% of PSAs at a young age (PSA ~1.5 ng/ml or higher below 50) are at particularly high risk and should be subject to intensive monitoring.

The relationship between prostate volume and prostate-specific antigen variability: data from the Baltimore Longitudinal Study of Aging and the Johns Hopkins Active Surveillance Program

Study Type--Prognostic (cohort). Level of Evidence 2b. What's known on the subject? And what does the study add? Previous studies have attempted to characterize the normal biological variability in PSA among men without prostate cancer. These reports suggest that PSA variability is unrelated to age, but there are conflicting data on its association with the baseline PSA level. There are limited published data regarding the effects of prostate volume on PSA variability. A prior study assessing whether prostate volume changes would confound the use of PSA velocity in clinical practice reported that prostate volume changes were not significantly related to PSA changes. This study did not directly address the effect of baseline prostate volume on serial PSA variability. The objective of the current study was to further examine the relationship between prostate volume and PSA variability. Our hypothesis was that larger baseline prostate volume would be associated with increased PSA variability in men without known prostate cancer and in those with suspected small-volume disease. The results of the study suggest that baseline PSA, not prostate volume, is the primary driver of PSA variability in these populations.

OBJECTIVE

• To clarify the relationship between serial prostate-specific antigen (PSA) variability and prostate volume in both cancer-free participants from the Baltimore Longitudinal Study of Aging (BLSA) and patients with low-risk prostate cancer from the Johns Hopkins Active Surveillance Program (AS).

MATERIALS AND METHODS

• In all, 287 men from the BLSA and 131 patients from the AS were included in the analysis, all with at least two PSA measurements and concurrent prostate volume measurements. • PSA variability was calculated in ng/mL per year, and a linear mixed-effects model was used to determine the relative effects of prostate volume, baseline PSA and age on PSA change over time.

RESULTS

• In a model with prostate volume, age and baseline PSA, there was no significant relationship between prostate volume and PSA variability (BLSA, P= 0.57; AS, P= 0.49). • Only baseline PSA showed a significant relationship to PSA yearly variability (PSAYV) (P < 0.001). Specifically, a one unit higher baseline PSA (ng/mL) corresponded on average to 0.09 and 0.06 ng/mL per year higher PSAYV in the BLSA and AS populations, respectively.

CONCLUSIONS

• The results of the present study suggest that the primary driver of PSA variability is the baseline PSA level, rather than prostate volume. • Clinicians might consider the baseline PSA level to help predict the expected variability in serial PSA measurements.

[How to select the best candidates for prostate biopsies? The role of traditional tools and contribution of new biomarkers in prostate cancer]

In 2010, early detection of prostate cancer continues to rely on digital rectal examination and serum total PSA. However, selecting patients for prostate biopsy requires taking into account the prostate volume and the evolution of PSA over time. PSA derivatives such as PSA density, PSA velocity and the ratio free PSA / total PSA are useful supplements. However, the choice of the threshold value is not well defined and depends on the relative sensitivity and specificity desired. The real innovations come from basic research that has found potential markers of aggressiveness of prostate cancer and molecular biology tools used routinely as the PCA-3 score and the pro-PSA. The role of these new markers for diagnosis and prognosis of prostate cancer remains unclear.

Tumor markers in prostate cancer I: blood-based markers

The introduction of total prostate specific antigen (total PSA) testing in blood has revolutionized the detection and management of men with prostate cancer (PCa). The objective of this review was to discuss the challenges of PCa biomarker research, definition of the type of PCa biomarkers, the statistical considerations for biomarker discovery and validation, and to review the literature regarding total PSA velocity and novel blood-based biomarkers.

METHODS

An English-language literature review of the Medline database (1990 to August 2010) of published data on blood-based biomarkers and PCa was undertaken.

RESULTS

The inherent biological variability of total PSA levels affects the interpretation of any single result. Men who will eventually develop PCa have increased total PSA levels years or decades before the cancer is diagnosed. Total PSA velocity improves predictiveness of total PSA only marginally, limiting its value for PCa screening and prognostication. The combination of PSA molecular forms and other biomarkers improve PCa detection substantially. Several novel blood-based biomarkers such as human glandular kallikrein 2 (hK2), urokinase plasminogen activator (uPA) and its receptor (uPAR), transforming growth factor-beta 1 (TGF-β1); interleukin-6 (IL-6) and its receptor (IL-6R) may help PCa diagnosis, staging, prognostication, and monitoring. Panels of biomarkers that capture the biologic potential of PCa are in the process of being validated for PCa prognostication.

CONCLUSIONS

PSA is a strong prognostic marker for long-term risk of clinically relevant cancer. However, there is a need for novel biomarkers that aid clinical decision making about biopsy and initial treatment. There is no doubt that progress will continue based on the integrated collaboration of researchers, clinicians and biomedical firms.

Efficacy of eradicative radiotherapy for limited nodal metastases detected with choline PET scan in prostate cancer patients

AIMS AND BACKGROUND

In patients with recurrent prostate cancer, discriminating local or systemic recurrence is critical to decide second-line treatment. We investigated the capability of stereotactic body radiotherapy to treat limited nodal recurrences, detected using choline PET scan.

METHODS AND STUDY DESIGN

Seventy-one patients with biochemical failure were studied after prostate cancer treatment: prostatectomy (28), radiotherapy (15) or both (28). Following computed tomography and choline PET imaging, stereotactic body radiotherapy was delivered on pathological lymphatic areas by 6 MV Linac, using dynamic micromultileaf collimation and intensity-modulated arc therapy optimization. Sixty days post-treatment, choline PET/CT imaging was carried out.

RESULTS

Median follow-up was 29 months (range, 14.4-48). Choline PET detected recurrences in 39 of 71 patients. Median PSA velocity was 0.40 ng/ml/year in PET-negative patients and 2.88 ng/ml/year in PET-positive subjects (P < 0.05). Twenty-five patients with limited nodal recurrences, out of the 71 submitted to choline PET, received eradicative radiotherapy. Persistent regression was recorded in 13; early spread to bone was found in 2 cases; lymph node recurrences in 8, all in sites outside the irradiated areas; 2 patients were lost to follow-up. At the 3-year follow-up, overall survival, disease-free survival and local control rates were 92%, 17% and 90%, respectively. In patients with a complete regression, PSA fell from 5.65 to 1.40 ng/ml (median). PSA nadir value (median 1.06 ng/ml) was maintained for 5.6 months (median).

CONCLUSIONS

Stereotactic body radiotherapy was effective in disease eradication of limited nodal recurrences from prostate cancer, saving patients from, or at least postponing, systemic treatments.

Development of a real-time clinical decision support system upon the Web MVC-based architecture for prostate cancer treatment

BACKGROUND

A real-time clinical decision support system (RTCDSS) with interactive diagrams enables clinicians to instantly and efficiently track patients' clinical records (PCRs) and improve their quality of clinical care. We propose a RTCDSS to process online clinical informatics from multiple databases for clinical decision making in the treatment of prostate cancer based on Web Model-View-Controller (MVC) architecture, by which the system can easily be adapted to different diseases and applications.

METHODS

We designed a framework upon the Web MVC-based architecture in which the reusable and extractable models can be conveniently adapted to other hospital information systems and which allows for efficient database integration. Then, we determined the clinical variables of the prostate cancer treatment based on participating clinicians' opinions and developed a computational model to determine the pretreatment parameters. Furthermore, the components of the RTCDSS integrated PCRs and decision factors for real-time analysis to provide evidence-based diagrams upon the clinician-oriented interface for visualization of treatment guidance and health risk assessment.

RESULTS

The resulting system can improve quality of clinical treatment by allowing clinicians to concurrently analyze and evaluate the clinical markers of prostate cancer patients with instantaneous clinical data and evidence-based diagrams which can automatically identify pretreatment parameters. Moreover, the proposed RTCDSS can aid interactions between patients and clinicians.

CONCLUSIONS

Our proposed framework supports online clinical informatics, evaluates treatment risks, offers interactive guidance, and provides real-time reference for decision making in the treatment of prostate cancer. The developed clinician-oriented interface can assist clinicians in conveniently presenting evidence-based information to patients and can be readily adapted to an existing hospital information system and be easily applied in other chronic diseases.

Translating research to promote healthy aging: the complementary role of longitudinal studies and clinical trials

An important challenge in epidemiology is the difficulty in inferring causality from observational studies. Even the best longitudinal studies have limitations in this regard, and when clinical trials are feasible, they will provide more-definite evidence of causality, but even when clinical trials are feasible, a large amount can be learned about the disease process, assessment techniques, subject selection criteria, and the effect of potential interventions from longitudinal studies. This review covers the theoretical issues supporting the value and limitations of longitudinal studies, the practical utilization in clinical trials of different aspects of knowledge that can be gained from longitudinal studies, critical issues in the translation of longitudinal observational studies into clinical trials, and the value of observational studies in broadening the applicability of specific trials. Relevant issues are illustrated with examples of unsuccessful and successful trials, with a major emphasis on clinical trials of physical activity in older persons.

Interpretation of the prostate-specific antigen history in assessing life-threatening prostate cancer

OBJECTIVE

To present an effective approach to the early detection of lethal prostate cancer using longitudinal data on prostate-specific antigen (PSA) and its rate of change, i.e. PSA velocity (PSAV). This longitudinal approach might also be extendible to other biomarkers.

SUBJECTS AND METHODS

PSAV was calculated using five techniques for 634 subjects with at least three PSA measurements in a longitudinal ageing study, censoring PSA levels of > 10 ng/mL. The efficacy for predicting death from prostate cancer was assessed with concordance indices and by using net reclassification improvement (NRI), which indicated the net increase in sensitivity and specificity when adding a biomarker to a base Cox proportional hazards model. The PSAV techniques were compared for the 5-10 years before the clinical diagnosis of prostate cancer. The most effective technique was then applied at the transition point when each man's PSA history curve transformed from linear to exponentially increasing, and its predictive value was compared to that of concurrent PSA level.

RESULTS

A PSA transition point was found in 522 (82%) of the 634 men, including all 11 who died from prostate cancer. At the transition point, the mean PSA level was 1.4 ng/mL, and PSAV but not PSA level was significantly higher among men who died from prostate cancer than among men who did not (P = 0.021 vs P = 0.112; Wilcoxon two-sample test). At the transition point, adding PSAV to a base model consisting of age and date of diagnosis improved the concordance index by 0.05, and significantly improved the overall sensitivity and specificity (NRI, P = 0.028), while adding PSA level to the same base model resulted in little improvement (concordance index increase < 0.01 and NRI P = 0.275).

CONCLUSION

When the shape of a man's PSA history curve changes from linear to exponential, PSAV might help in the early identification of life-threatening prostate cancer at a time when PSA values are still low in most men.

Evaluation of late-onset hypogonadism (andropause) treatment using three different formulations of injectable testosterone

OBJECTIVE

To compare the modalities of treatment for male hypogonadism available in Brazil.

METHODS

Thirty-two men with late-onset hypogonadism ('andropause') were followed-up in the Hospital de Guarnição de Florianópolis, in Florianópolis, south Brazil. Clinical diagnosis was established according to AMS questionnaire (positive if equal to or higher than 27 points), and laboratory diagnosis was made through low values of total testosterone (under 300 ng/dL) and/or free calculated testosterone (under 6.5 ng/dL). Patients were randomized to three non-enteral treatment groups (Deposteron--11 patients; Durateston--11 patients; and Nebido--10 patients).

RESULTS

Clinically, Nebido seemed to be superior when compared to Deposteron (mean value of improvement percentage; p = 0.03) and when compared to Durateston (post-treatment average AMS score; p = 0.03). According to laboratory analysis, Nebido showed higher testosterone levels than Deposteron and Durateston (p < 0.001).

CONCLUSIONS

All non-enteral testosterone formulas available in the Brazilian market are efficient in raising testosterone levels and in clinical improvement of hypogonadal patients. Nebido showed both a better clinical and laboratory effectiveness.

Biomarkers for prostate cancer detection

Since its approval by the US FDA in 1986, prostate-specific antigen (PSA) has been employed to monitor men with a diagnosis of prostate cancer. In 1994, PSA was approved for use in prostate cancer screening and has been employed worldwide. However, due to the limited specificity of PSA for the disease, novel biomarkers are needed for detecting prostate cancer and for determining which cancers need to be treated. This review will discuss the development of new biomarkers for prostate cancer detection and disease prognostication, focusing on recent progress and particular topical issues related to the development and validation of these new markers.

Prostate kallikrein markers in diagnosis, risk stratification and prognosis

The kallikrein, prostate-specific antigen (PSA), is one of the world's most frequently used disease biomarkers. After almost two decades of research and clinical experience, the diagnostic and monitoring limitations of PSA are beginning to be understood. Most physicians are aware of PSA's low specificity for cancer among older men with benign prostatic conditions; fewer are aware of recent data, which show that a prior negative biopsy or a prior PSA value below the threshold for biopsy might compromise the predictive accuracy of PSA even further. Furthermore, a subtle increase in serum PSA level during early middle age is strongly correlated with clinically important prostate cancer. We review current and past reports on the prostate kallikreins PSA and hK2 in relation to pathology and epidemiology.

Prostate cancer detection yield in repeated biopsy is independent of the diagnosis of earlier biopsies

BACKGROUND

We analyzed data gathered from initial and repeated prostate biopsies at the University Hospital in Olomouc, Czech Republic. We evaluated the diagnostic yield of repeated transrectal ultrasound (TRUS) guided biopsies. We also assessed whether the result of the repeated biopsy depended on the benign diagnosis of the previous biopsy.

METHODS

From June 2006 till December 2008, the total of 794 men underwent a TRUS guided biopsy. The following parameters were recorded for each patient: age, total Prostatic Specific Antigen (PSA) level, free PSA level, digital rectal examination record, total prostate volume, and the histo-pathological evaluation. For patients undergoing a repeated biopsy, the histo-pathological result of the previous biopsy was also available, as well as the total number of previous biopsies and the time since the last biopsy. These data were analyzed using standard statistical methods.

RESULTS

Initial biopsy was positive for prostate cancer in 157 out of 566 men (27.7%). The total PSA level was confirmed to be a significant (P < 0.001) predictor of prostate cancer. The ratio of free PSA to total PSA (the so-called PSA index) was found to be significantly lower (P < 0.001) for patients suffering from adenocarcinoma. A total of 191 men underwent a repeated biopsy. The repeated biopsy was positive for adenocarcinoma in 39 cases (20.4%). Although this yield is lower, the significance is at the threshold (P = 0.04700). In the group of re-biopted men, total PSA level and PSA index were again significant (P = 0.0024 and P = 0.0015 respectively) predictive factors for prostate carcinoma. The diagnostic yield of repeated biopsy was assessed with respect to the most common types of the benign findings in the previous biopsy--adenomyomatous hyperplasia, inflammation, high grade prostatic intraepithelial neoplasia, and suspected adenocarcinoma. No significant difference in the diagnostic yield was found (P = 0.38431).

CONCLUSIONS

Total PSA level and PSA index are the most significant precursors of adenocarcinoma in both initial and repeated biopsy. The histo-pathological result of a repeated biopsy was found to be independent of the type of benign diagnosis of the previous biopsy. A substantial number of prostate cancer is diagnosed in repeated biopsies which advocates for the indication of a repeated biopsy in case of a negative result of the initial one.

Bone mineral content and prostate cancer risk: data from the Baltimore Longitudinal Study of Aging

STUDY TYPE

Aetiology (inception cohort) Level of Evidence 2b.

OBJECTIVE

To determine whether there might be differences in bone mineral content (BMC) between men who develop life-threatening prostate cancer and those who do not, as bone is a common site of prostate cancer metastases.

SUBJECTS AND METHODS

From 1973 to 1984, BMC was serially measured in 519 participants (778 observations) as part of a longitudinal study of ageing. We examined the association between serial BMC measurements with the development of overall and high-risk prostate cancer over the next one to three decades. For all prostate cancer cases, BMC was censored at the time of diagnosis.

RESULTS

During a median (range) overall follow-up of 21.1 (0.2-35.0) years after the last BMC measurement, 76 (14.6%) men were later diagnosed with prostate cancer (18 high-risk and 58 not high-risk). BMC declined with age to a greater extent in healthy controls than among men diagnosed with prostate cancer (P = 0.018, likelihood ratio test), and tended to decline less in high-risk than non-high-risk cases.

CONCLUSION

The distribution of BMC was significantly different between men who did and did not develop prostate cancer, over an extended follow-up. Specifically, BMC appeared to decline to a greater extent with age among healthy controls than in men with prostate cancer, especially high-risk disease. The biology underlying the lesser decline in BMC among men with prostate cancer remains unclear, but suggests that host factors in the bony milieu might be associated with prostate cancer development and progression.

Image-based clinical decision support for transrectal ultrasound in the diagnosis of prostate cancer: comparison of multiple logistic regression, artificial neural network, and support vector machine

PURPOSE

We developed a multiple logistic regression model, an artificial neural network (ANN), and a support vector machine (SVM) model to predict the outcome of a prostate biopsy, and compared the accuracies of each model.

METHOD

One thousand and seventy-seven consecutive patients who had undergone transrectal ultrasound (TRUS)-guided prostate biopsy were enrolled in the study. Clinical decision models were constructed from the input data of age, digital rectal examination findings, prostate-specific antigen (PSA), PSA density (PSAD), PSAD in transitional zone, and TRUS findings. The patients were divided into the training and test groups in a randomized fashion. Areas under the receiver operating characteristic (ROC) curve (AUC, Az) were calculated to summarize the overall performance of each decision model for the task of prostate cancer prediction.

RESULTS

The Az values of the ROC curves for the use of multiple logistic regression analysis, ANN, and the SVM were 0.768, 0.778, and 0.847, respectively. Pairwise comparison of the ROC curves determined that the performance of the SVM was superior to that of the ANN or the multiple logistic regression model.

CONCLUSION

Image-based clinical decision support models allow patients to be informed of the actual probability of having a prostate cancer.

Rational approach to implementation of prostate cancer antigen 3 into clinical care

BACKGROUND

Prostate cancer antigen 3 (PCA3) encodes a prostate-specific messenger ribonucleic acid (mRNA) that serves as the target for a novel urinary molecular assay for prostate cancer detection. The objective of the current study was to evaluate the ability of PCA3, added to measurements of serum prostate-specific antigen (PSA), to predict cancer detection by extended template biopsy.

METHODS

Between September 2006 and December 2007, whole urine samples were collected after attentive digital rectal examinations from 187 men before they underwent ultrasound-guided, 12-core prostate biopsy in a urology outpatient clinic. Urine PCA3/PSA mRNA ratio scores were measured within 1 month, and serum PSA was measured within 6 months prior to biopsy. Those measurements were related to cancer-positive biopsies.

RESULTS

Overall, 87 of 187 biopsies (46.5%) were positive for cancer. The sensitivity and specificity of a PCA3 score > or =35 for positive biopsy were 52.9% and 80%, respectively, and the positive and negative predictive values were 69.7% and 66.1%, respectively. By using receiver operating characteristic curve analysis, PSA alone resulted in an area under the curve (AUC) of 0.63 for prostate cancer detection; whereas a combined PSA and PCA3 score resulted in an AUC of 0.71. The likelihood of prostate cancer detection rose with increasing PCA3 score ranges (P > .0001), providing possible PCA3 score parameters for stratification into groups at low risk, moderate risk, high risk, and very high risk for a positive biopsy.

CONCLUSIONS

Adding PCA3 to serum PSA improved prostate cancer prediction. The use of PCA3 in a clinical setting may help to stratify patients according to their risk for biopsy and cancer detection, although a large-scale validation study will be needed to address assay standardization, optimal cutoff values, and appropriate patient populations.

Early Detection of Cancer: Immunoassays for Plasma Tumor Markers

BACKGROUND: Plasma tumor biomarkers are widely used clinically for monitoring response to therapy and detecting cancer recurrence. However, only a limited number of them have been effectively used for the early detection of cancer. OBJECTIVE: To review plasma tumor markers used clinically for the early detection of cancer and to provide expert opinion about future directions. METHODS: Literature review, as well as our expert opinion, of plasma tumor markers that have been widely accepted for the early detection of cancer. RESULTS: In the United States, only prostate specific antigen (PSA), cancer antigen 125 (CA125), and alpha-fetoprotein (AFP) have been clinically used for the early detection of prostate, ovarian, and liver cancers, respectively. Both analytical and clinical issues related to the use of these three markers were discussed. CONCLUSION: Few plasma tumor markers have been used effectively for the early detection of cancer, mainly due to their limited sensitivity and/or specificity. Multiple approaches have been developed to improve the clinical performance of tumor markers for the early detection of cancer. Metrological traceability and antibody specificity are important issues to ensure comparability of immunoassays for the measurement of plasma tumor markers.

Epigenetic alterations in human prostate cancers

Human prostate cancer cells carry a myriad of genome defects, including both genetic and epigenetic alterations. These changes, which can be maintained through mitosis, generate malignant phenotypes capable of selective growth, survival, invasion, and metastasis. During prostatic carcinogenesis, epigenetic changes arise earlier than genetic defects, linking the appearance of epigenetic alterations in some way to disease etiology. The most common genetic defect thus far described, leading to fusion transcripts between the androgen-regulated gene TMPRSS2 and genes from the ETS family of transcription factors, likely endows prostate cancer cells with the ability to co-opt androgen signaling, the major prostate differentiation pathway, to support the malignant phenotype. Whether epigenetic changes promote the appearance of TMPRSS2-ETS family fusion transcripts or collaborate with fusion transcript expression in the pathogenesis of prostate cancer has not been established. However, a growing list of epigenetic alterations has provided new opportunities for clinical tests that might aid in prostate cancer screening, detection, diagnosis, staging, and risk stratification. The epigenetic changes appear to be more attractive than genetic changes as prostate cancer biomarkers because epigenetic alterations are present in a greater fraction of prostate cancer cases than any of the known genetic defects. In addition, an emerging generation of assay strategies for detection of specific DNA sequences carrying (5-me)C, the major epigenetic genome mark, has pushed somatic epigenetic alterations to the forefront of molecular biomarker assay development for cancer. Finally, a growing portfolio of epigenetic drugs, capable of reversing the phenotypic consequences of somatic epigenetic defects, has entered clinical trials for prostate cancer in the search for a new rational therapy for the disease.

[PSA--Quo vadis?]

Prostate cancer is the most frequent cancer in males. Because of the high cure rates, early detection of prostate cancer should identify organ-confined prostate cancers. An early detection examination should be performed annually starting at the age of 50 years and ending when life expectancy is less than 10 years. Digital rectal examination is supplemented by determination of prostate-specific antigen (PSA). Before the first PSA test, the patient must be informed of possible consequences such as biopsy recommendation and treatment options. A threshold of 4 ng/ml is defined as the indication for prostate biopsy. Imaging methods do not play a major role in early detection of prostate cancer today. Early detection identifies many latent prostate cancers, and patients may receive overtreatment. A possible solution is to change the early detection paradigm from detection of all prostate cancers to identification of aggressive ones. In this article, early detection is discussed based on the recent literature.

A new algorithm in patients with elevated and/or rising prostate-specific antigen level, minor lower urinary tract symptoms, and negative multisite prostate biopsies

Patients with elevated and/or rising prostate-specific antigen (PSA), minor lower urinary tract symptoms (LUTS), and no evidence for prostate cancer on (multiple) extended prostate biopsies are a regularly encountered problem in urological practice. Even now, patients are seen with no objective explanation of this persistent elevated and/or rising PSA. So far, many strategic proposals have been elaborated and published to deal with this specific population including the use of different PSA derivates; applying different biopsy schemes—strategies—biopsy target imaging; diagnostic use of prostate cancer genes; and many more. In this review, we propose a new algorithm in which an urodynamic evaluation should be included since bladder outlet obstruction (BOO) can be expected. Once BOO is confirmed, a transurethral resection of the prostate (TURP) can be offered to these patients. This procedure will result in subjective and biochemical improvement and allows extensive histological examination. Current literature was reviewed with regard to this specific population. This research was performed using the commercially available Medline online search tools and applying the following search terms: “diagnostic TURP”; “elevated PSA”; and “prostate biopsy”. Furthermore, subsequent reference search was executed on retrieved articles.

Single nucleotide polymorphisms and the likelihood of prostate cancer at a given prostate specific antigen level

PURPOSE

Prostate specific antigen is used for prostate cancer screening but its specificity is limited. Specificity might be increased by considering genotype associated prostate specific antigen levels.

MATERIALS AND METHODS

We examined associations between single nucleotide polymorphisms on chromosomes 10 and 19 (previously shown to be associated with prostate specific antigen) with prostate specific antigen and prostate cancer in 505 men from the Baltimore Longitudinal Study of Aging.

RESULTS

In a model with age and date the risk ratio for prostate cancer was 1.18 (95% CI 1.13-1.23) per unit increase in prostate specific antigen. Including the interaction between alleles and prostate specific antigen significantly altered the risk ratio for prostate cancer (Cox proportional hazards p <0.001). Specifically prostate cancer risk per unit increase in prostate specific antigen was significantly different in carriers than in noncarriers of a minor allele (1.28 vs 1.10, respectively, Cox proportional hazards p <0.001), whereas men with a minor allele had a significantly higher risk of prostate cancer at prostate specific antigen levels greater than 6 ng/ml.

CONCLUSIONS

Our data suggest that genotype influences the risk of prostate cancer per unit increase in prostate specific antigen. Prostate cancer risk stratification using prostate specific antigen and genotype could improve prostate specific antigen test performance.

A statistical evaluation of rules for biochemical failure after radiotherapy in men treated for prostate cancer

PURPOSE

The "PSA nadir + 2 rule," defined as any rise of 2 ng/ml above the current prostate-specific antigen (PSA) nadir, has replaced the American Society for Therapeutic Radiology and Oncology (ASTRO) rule, defined as three consecutive PSA rises, to indicate biochemical failure (BF) after radiotherapy in patients treated for prostate cancer. We propose an original approach to evaluate BF rules based on the PSAdt as the gold standard rule and on a simulation process allowing us to evaluate the BF rules under multiple settings (different frequency, duration of follow-up, PSA doubling time [PSAdt]).

METHODS AND MATERIALS

We relied on a retrospective, population-based cohort of individuals identified by the Connecticut Tumor Registry and treated for localized prostate cancer with radiotherapy. We estimated the 470 underlying true PSA trajectories, including the PSAdt, using a Bayesian hierarchical changepoint model. Next, we simulated realistic, sophisticated data sets that accurately reflect the systematic and random variations observed in PSA series. We estimated the sensitivity and specificity by comparing the simulated PSA series to the underlying true PSAdt.

RESULTS

For follow-up of more than 3 years, the specificity of the PSA nadir + 2 rule was systematically greater than that of the ASTRO criterion. In few settings, the nadir + 2 rule had a lower sensitivity than the ASTRO. The PSA nadir + 2 rule appeared less dependent on the frequency and duration of follow-up than the ASTRO.

CONCLUSIONS

Our results provide some refinements to earlier findings as the BF rules were evaluated according to various parameters. In most settings, the PSA nadir + 2 rule outperforms the ASTRO criterion.

Systematic review of pretreatment prostate-specific antigen velocity and doubling time as predictors for prostate cancer

PURPOSE

Pretreatment prostate-specific antigen (PSA) dynamics (PSA velocity and PSA doubling time) are widely advocated as useful prognostic markers in prostate cancer. We aimed to assess the published evidence for the clinical utility of PSA dynamics in this population.

METHODS

We conducted a systematic review of studies published before March 2007 in which a PSA dynamic (velocity or doubling time) was calculated in patients before definitive treatment, a subsequent event (such as biopsy or recurrence) was ascertained, and the association between the two was analyzed. Our principal end point was the type of analysis reported, particularly whether the predictive accuracy of a statistical model that included both absolute PSA level and a PSA dynamic was compared with that of a model that included only PSA.

RESULTS

Eighty-seven articles were eligible for analysis. The most common end points were biopsy (42 articles), and either recurrence (14 articles) or metastases or death (14 articles) after definitive therapy. Although PSA dynamics were generally found to be associated with outcome, only one article compared predictive accuracy of models with and without a PSA dynamic: this reported that PSA velocity improved prediction slightly (from 0.81 to 0.83), but was subject to verification bias. No article used decision analytic methods to examine the clinical impact of PSA dynamics.

CONCLUSION

There is little evidence that calculation of PSA velocity or doubling time in untreated patients provides predictive information beyond that provided by absolute PSA level alone. We see no justification for the use of PSA dynamics in clinical decision making before treatment in early-stage prostate cancer.

National Academy of Clinical Biochemistry Laboratory Medicine Practice Guidelines for Use of Tumor Markers in Testicular, Prostate, Colorectal, Breast, and Ovarian Cancers

Background: Updated National Academy of Clinical Biochemistry (NACB) Laboratory Medicine Practice Guidelines for the use of tumor markers in the clinic have been developed.

Methods: Published reports relevant to use of tumor markers for 5 cancer sites—testicular, prostate, colorectal, breast, and ovarian—were critically reviewed.

Results: For testicular cancer, α-fetoprotein, human chorionic gonadotropin, and lactate dehydrogenase are recommended for diagnosis/case finding, staging, prognosis determination, recurrence detection, and therapy monitoring. α-Fetoprotein is also recommended for differential diagnosis of nonseminomatous and seminomatous germ cell tumors. Prostate-specific antigen (PSA) is not recommended for prostate cancer screening, but may be used for detecting disease recurrence and monitoring therapy. Free PSA measurement data are useful for distinguishing malignant from benign prostatic disease when total PSA is &lt;10 μg/L. In colorectal cancer, carcinoembryonic antigen is recommended (with some caveats) for prognosis determination, postoperative surveillance, and therapy monitoring in advanced disease. Fecal occult blood testing may be used for screening asymptomatic adults 50 years or older. For breast cancer, estrogen and progesterone receptors are mandatory for predicting response to hormone therapy, human epidermal growth factor receptor-2 measurement is mandatory for predicting response to trastuzumab, and urokinase plasminogen activator/plasminogen activator inhibitor 1 may be used for determining prognosis in lymph node–negative patients. CA15-3/BR27–29 or carcinoembryonic antigen may be used for therapy monitoring in advanced disease. CA125 is recommended (with transvaginal ultrasound) for early detection of ovarian cancer in women at high risk for this disease. CA125 is also recommended for differential diagnosis of suspicious pelvic masses in postmenopausal women, as well as for detection of recurrence, monitoring of therapy, and determination of prognosis in women with ovarian cancer.

Conclusions: Implementation of these recommendations should encourage optimal use of tumor markers.

[PSA and hK2 in the diagnosis of prostate cancer]

Serum markers for prostate carcinoma are widely applied for the purpose of early detection of cancer and the differentiation between benign and malignant disease, for the pre-treatment staging of detected prostatic cancers, and for the monitoring of prostate cancer after curative or palliative therapies. Since its discovery in 1979, serum PSA has been the most powerful marker of prostate cancer, but, when used alone, PSA is not sufficiently sensitive or specific to consider it an ideal tool for the early detection or staging of prostate cancer. To optimize the use of PSA, the concepts of PSA velocity, PSA density, and age-related PSA values were developed. Moreover, the molecular forms of PSA, especially the percentage of free PSA, seem to be useful tools for the detection of prostate cancer in men with slightly elevated total PSA. Human kallikrein 2 (hK2), a serine protease closely related to PSA that also is expressed predominantly in the prostate, is a new complementary marker to PSA for early detection of prostate cancer. In this review, we examine PSA testing and its effectiveness in the diagnosis of prostate cancer. Further, we also evaluate recent literature regarding the use of hk2.