The inability of prostate specific antigen index to enhance the predictive the value of prostate specific antigen in the diagnosis of prostatic carcinoma

Identification of a serum biomarker signature associated with metastatic prostate cancer

PURPOSE

Improved early diagnosis and determination of aggressiveness of prostate cancer (PC) is important to select suitable treatment options and to decrease over-treatment. The conventional marker is total prostate specific antigen (PSA) levels in blood, but lacks specificity and ability to accurately discriminate indolent from aggressive disease.

EXPERIMENTAL DESIGN

In this study, we sought to identify a serum biomarker signature associated with metastatic PC. We measured 157 analytes in 363 serum samples from healthy subjects, patients with non-metastatic PC and patients with metastatic PC, using a recombinant antibody microarray.

RESULTS

A signature consisting of 69 proteins differentiating metastatic PC patients from healthy controls was identified.

CONCLUSIONS AND CLINICAL RELEVANCE

The clinical value of this biomarker signature requires validation in larger independent patient cohorts before providing a new prospect for detection of metastatic PC.

A discussion on controversies and ethical dilemmas in prostate cancer screening

Prostate cancer (PCa) is one of the the most common cancers in men. A blood test called prostate-specific antigen (PSA) has a potential to pick up this cancer very early and is used for screening of this disease. However, screening for prostate cancer is a matter of debate. Level 1 evidence from randomised controlled trials suggests a reduction in cancer-specific mortality from PCa screening. However, there could be an associated impact on quality of life due to a high proportion of overdiagnosis and overtreatment as part of the screening. The US Preventive Services Task Force (USPSTF) in 2012 recommended that PSA-based PCa screening should not to be offered at any age. However, considering the current evidence, USPSTF recently revised its recommendation to offer the PSA test to men aged 55-69 years with shared decision-making, in line with earlier guidelines from the American Cancer Society and the American Urological Association. A shared decision making is necessary since the PSA test could potentially harm an individual. However, the literature suggests that clinicians often neglect a discussion on this issue before ordering the test. This narrative discusses the main controversies regarding PCa screening including the PSA threshold for biopsy, the concept of overdiagnosis and overtreatment, the practical difficulties of active surveillance, the current level 1 evidence on the mortality benefit of screening, and the associated pitfalls. It offers a detailed discussion on the ethics involved in the PSA test and highlights the barriers to shared decision-making and possible solutions.

RNAs as Candidate Diagnostic and Prognostic Markers of Prostate Cancer-From Cell Line Models to Liquid Biopsies

The treatment landscape of prostate cancer has evolved rapidly over the past five years. The explosion in treatment advances has been witnessed in parallel with significant progress in the field of molecular biomarkers. The advent of next-generation sequencing has enabled the molecular profiling of the genomic and transcriptomic architecture of prostate and other cancers. Coupled with this, is a renewed interest in the role of non-coding RNA (ncRNA) in prostate cancer biology. ncRNA consists of several different classes including small non-coding RNA (sncRNA), long non-coding RNA (lncRNA), and circular RNA (circRNA). These families are under active investigation, given their essential roles in cancer initiation, development and progression. This review focuses on the evidence for the role of RNAs in prostate cancer, and their use as diagnostic and prognostic markers, and targets for treatment in this disease.

Impact of PSA density of transition zone as a potential parameter in reducing the number of unnecessary prostate biopsies in patients with psa levels between 2.6 and 10.0 ng/mL

Purpose:

To assess the accuracy of prostate-specific antigen (PSA) adjusted for the transition zone volume (PSATZ) in predicting prostate cancer by comparing the ability of several PSA parameters in predicting prostate cancer in men with intermediate PSA levels of 2.6 – 10.0 ng/mL and its ability to reduce unnecessary biopsies.

Materials and Methods:

This study included 656 patients referred for prostate biopsy who had a serum PSA of 2.6 – 10.0 ng/mL. Total prostate and transition zone volumes were measured by transrectal ultrasound using the prolate ellipsoid method. The clinical values of PSA, free-to-total (F/T) ratio, PSA density (PSAD) and PSATZ for the detection of prostate cancer were calculated and statistical comparisons between biopsy-positive (cancer) and biopsy-negative (benign) were conducted.

Results:

Cancer was detected in 172 patients (26.2%). Mean PSA, PSATZ, PSAD and F/T ratio were 7.5 ng/mL, 0.68 ng/mL/cc. 0.25 ng/mL/cc and 0.14 in patients with prostate cancer and 6.29 ng/mL, 0.30 ng/mL/cc, 0.16 ng/mL/cc and 0.22 in patients with benign biopsies, respectively. ROC curves analysis demonstrated that PSATZ had a higher area under curve (0,838) than F/T ratio (0.806) (P<0.001) and PSAD (0.806) (P<0.001). With a cut-off value of 0.22 ng/mL/cc, PSATZ had 100% of sensitivity and could have prevented 24% of unnecessary biopsies.

Conclusions:

PSATZ may be useful in enhancing the specificity of serum PSA. Compared to other PSA related parameters, it was better in differentiating between prostate cancer and benign prostatic enlargement. Also, PSATZ could reduce a significant number of unnecessary biopsies.

Can Prostate-Specific Antigen Kinetics before Prostate Biopsy Predict the Malignant Potential of Prostate Cancer?

PURPOSE

To predict the malignant potential of prostate cancer (PCa) according to prostate-specific antigen velocity (PSAV), PSA density (PSAD), free/total PSA ratio (%fPSA), and digital rectal examination (DRE).

MATERIALS AND METHODS

From January 2009 to December 2012, 548 adult male patients were diagnosed with PCa by prostate biopsy at four hospitals in Korea. We retrospectively analyzed 155 adult male patients with an initial PSA level≤10 ng/mL and whose PSA levels had been checked more than two times at least 6 months before they had been diagnosed with PCa, with test intervals of more than 3 months. Patients with a urinary tract infection, and patients who had previously undergone cystoscopy or surgery of the prostate were excluded. We separated patients into two groups according to Gleason sum [Gleason sum≤7 (n=134) or Gleason sum≥8 (n=21)] and the presence of extracapsular invasion [organ confined (n=129) or extracapsular invasion (n=26)]. Differences between the groups were compared.

RESULTS

The group with a Gleason sum≥8 or extracapsular invasion of PCa showed high PSAV and significantly lower %fPSA. There were no significant differences in PSAD and the presence of an abnormality on DRE between two groups.

CONCLUSION

In PCa patients treated with other therapies besides prostatectomy, a high PSA velocity and a low %fPSA may predict high grade PCa with a Gleason sum≥8 or the presence of extracapsular invasion.

Contribuição da densidade do PSA para predizer o câncer da próstata em pacientes com valores de PSA entre 2,6 e 10,0 ng/ml

OBJETIVO: Estudar o perfil dos pacientes submetidos a biópsia prostática, determinando possíveis padrões que, associados aos níveis de PSA entre 2,6 e 10,0 ng/ml, possam levar a uma diminuição de biópsias desnecessárias. MATERIAIS E MÉTODOS: De 2007 a 2009, foi realizado um estudo transversal com 1.282 indivíduos submetidos a biópsia prostática e que apresentavam níveis de PSA entre 2,6 e 10,0 ng/ml. RESULTADOS: A prevalência de câncer foi de 28,6%. Pacientes com câncer eram, em média, mais idosos, com valores de PSA e densidade de PSA mais altos e menor volume da próstata. Na análise da densidade de PSA, os pacientes com câncer tiveram média de 0,31 ng/ml/cc, enquanto nos pacientes com resultado negativo a média foi de 0,10 ng/ml/cc. Utilizando como critério de positividade para câncer o ponto de corte de densidade de PSA de 0,15 ng/ml/cc, obtivemos especificidade de 74% e sensibilidade de 70%. Para aumentar a sensibilidade é preciso reduzir o ponto de corte. Com o valor 0,09 ng/ml/cc, obtivemos sensibilidade de 84% (IC 95%: 80-87%) e especificidade de 75% (IC 95%: 72-78%). CONCLUSÃO: O uso sistemático da densidade de PSA na indicação de prosseguimento da investigação do paciente com biópsia poderia reduzir a quantidade de procedimentos desnecessários.

[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.

The potential role of prebiopsy magnetic resonance imaging combined with prostate-specific antigen density in the detection of prostate cancer

AIM

Two-thirds of patients with a gray-zone prostate-specific antigen (PSA) level undergo unnecessary biopsy. Sensitivity is not yet sufficient to permit the use of modified PSA parameters or magnetic resonance (MR) imaging alone for prostate cancer screening. Thus, we evaluated the combination of MR imaging and PSA density (PSAD) for specificity and sensitivity.

METHODS

During the period April 2004 through March 2006, 185 patients with a PSA level of 4.0-10.0 ng/mL underwent MR imaging and transrectal ultrasonography-guided 8-core biopsy (systemic sextant biopsy of the peripheral zone plus two cores of transition zone). All MR images were interpreted prospectively by two radiologists. An image was considered positive for prostate cancer if any feature indicated a cancerous lesion. Receiver operating characteristic (ROC) curves were used to compare the usefulness of the PSA level, PSAD and PSA transitional zone density (PSATZ) for the detection of prostate cancer.

RESULTS

Of the 185 patients, 62 had prostate cancer. Sensitivity and specificity of the axial T2-weighted MR imaging findings for cancer detection were 79.0% and 59.4%, respectively. The area under the ROC curve was 0.590 for the PSA level, 0.718 for PSAD and 0.695 for PSATZ. MR imaging findings and PSAD were shown by multivariate analysis to be statistically significant independent predictors of prostate cancer (P < 0.001). With a PSAD cut-off value of 0.111, sensitivity was 96.8%, but specificity was 19.5%. Combining MR imaging findings with PSAD increased the specificity to 40% and retained 95% sensitivity.

CONCLUSION

MR imaging findings combined with PSAD provide high sensitivity and improve the specificity for the early detection of prostate cancer.

Prostate Specific Antigen Density Correlates With Features of Prostate Cancer Aggressiveness

PURPOSE

An increased prostate specific antigen density (serum prostate specific antigen divided by prostate volume) is an established parameter to help determine the need to perform prostate biopsies. A man with a high prostate specific antigen and a normal size prostate gland is more likely to have cancer than a man with the same prostate specific antigen and a large gland. Prostate specific antigen in relation to prostate size should also reflect the volume of cancer in the gland. One group defined clinically unimportant prostate cancer as tumor volume less than 0.5 cc, organ confined disease and Gleason less than 7. Another group noted that at the time of biopsy, a prostate specific antigen density less than 0.15 ng/ml/cc combined with low risk clinical tumor features predicted insignificant cancer. There are limited published validating data on the association of prostate specific antigen density with the criteria for prostate cancer aggressiveness. We tested the association of prostate specific antigen density with features of tumor aggressiveness in a screened and in a nonscreened cohort of patients with clinically localized prostate cancer treated with radical prostatectomy.

MATERIALS AND METHODS

The screened patient cohort included 1,280 patients with screen detected prostate cancer treated from 1990 to 2002 at Washington University, and the nonscreened cohort included 382 patients treated from 2003 to 2004 at Northwestern University. We recorded the clinical and pathological tumor parameters in a prospective database. Parameters evaluated were pathological tumor stage, Gleason sum, tumor volume, biochemical progression and the previously mentioned 2 criteria for clinically unimportant cancers. We grouped patients into 4 prostate specific antigen density categories of less than 0.1, 0.1 to 0.14, 0.15 to 0.19 and greater than 0.19 ng/ml/cc.

RESULTS

There was a significant trend for worsening clinicopathological prognostic features as prostate specific antigen density increased. There were 357 (82%), 283 (75%), 171 (75%) and 192 (55%) men with organ confined disease with clear surgical margins if prostate specific antigen density was less than 0.1, 0.1 to 0.14, 0.15 to 0.19 and greater than 0.19 ng/ml/cc, respectively (p <0.001). There were 86 (20%), 102 (27%), 64 (28%) and 157 (45%) men with a Gleason sum greater than 7 when grouped into each increasing PSA density category, respectively (p <0.001). There were 91 (21%), 91 (25%), 74 (33%) and 157 (46%) men with a total cancer volume greater than 0.5 cc when grouped into each increasing PSA density category, respectively (p <0.001). Prostate specific antigen velocity was greater than 2 ng/ml per year in 11%, 30%, 27% and 46% of men if prostate specific antigen density was less than 0.1, 0.1 to 0.14, 0.15 to 0.19 and greater than 0.19 ng/ml/cc, respectively (p <0.001).

CONCLUSIONS

Prostate specific antigen density measurements are useful in helping to determine the aggressiveness of clinically localized prostate cancer, and can be used as an adjunct in predicting insignificant cancer and outcomes after local therapy.

Molecular markers of prostate cancer

Although prostate-specific antigen (PSA) has evolved as a very useful tool for detection of prostate cancer, there remains an urgent need for more accurate biomarkers to diagnose prostate cancer and predict cancer-related outcomes. Recent advances in the study of proteomics and high throughput techniques have led to the discovery of many potential biomarkers for prostate cancer. This article briefly reviews the current status of PSA testing and discusses several candidate protein biomarkers for prostate cancer, as well as highlighting some recent proteomic discoveries with the potential to supplement or even replace PSA for the diagnosis and prognosis of prostate cancer.

Controversies in Transrectal Ultrasonography and Prostate Biopsy

Transrectal ultrasound-guided biopsy of the prostate is the gold standard for the detection of prostate cancer. In its current form, transrectal gray-scale ultrasound is unable to differentiate malignant prostate tissue from benign tissue. The general indications for performing a sonographic guided biopsy of the prostate are an abnormal digital rectal examination or an abnormal prostate-specific antigen (PSA). Several controversial areas remain: the ideal number of biopsy cores, the use of PSA velocity, free PSA, PSA density, age- and race-adjusted PSA, the use of local anesthetics, and the overall best patient preparation methods, including such topics as routine antibiotic prophylaxis or bowel enemas, remain unsettled. There are also unanswered questions regarding repeat biopsy and protocols for managing patients with a diagnosis of high-grade intraepithelial neoplasia. This article will explore some of the current controversies and review the pertinent literature.

[Validity of digital rectal examination in the era of prostate specific antigen]

OBJECTIVE

To determine the presence of a possible correlation between prostate specific antigen (PSA) and the findings from digital rectal examination (DRE) in patients with prostate cancer or benign prostatic hyperplasia.

DESIGN

Retrospective, longitudinal, and observational study of diagnostic tests.

SETTING

Gregorio Marañón Hospital, Madrid, Spain.

PARTICIPANTS

It included 706 patients with a PSA in the range 4.1-20 ng/mL, studied owing to suspected prostate cancer localised using DRE and transrectal ultrasound, in whom randomised prostate biopsies were performed.

MAIN MEASUREMENTS

Total PSA and free/total PSA ratio and DRE normal or suspicious were studied as main variables. The outcome variable was the diagnosis of prostatic cancer by biopsy.

RESULTS

With a detection of cancer of 28.2%, there were no statistically significant differences in the PSA or free/total PSA ratio mean values between patients with or without suspicious DRE. The analysis using ROC curves (with a 95% confidence interval) between both groups of patients found the same sensitivity of 95% with a similar specificity of 6% and 10%, respectively, for a PSA of 4.8 ng/mL.

CONCLUSIONS

In the PSA range of 4.1-20 ng/mL, the findings of DRE appeared as a variable unrelated to the increase in PSA or the free/total PSA ratio and, therefore are not indicative of a lesser or greater volume of a tumour producing PSA. The performing of this examination could be considered as optional.

Value of prostate volume measurement using transabdominal ultrasonography for the improvement of prostate-speci fi c antigen-based cancer detection

PURPOSE

To examine value of prostate-speci fi c antigen (PSA) adjusted by prostate volume measured using transabdominal ultrasonography in prostate cancer detection among men with elevated PSA.

METHODS

238 men aged 79 years or younger with serum PSA levels of 2.0-20.0 ng/mL and normal digital rectal examination fi ndings were studied in terms of total and free PSA, prostate volumes with transrectal (TRUS) and transabdominal (TAUS) ultrasonography and transition zone volumes with TRUS prior to transrectal 10-core biopsy. In addition to sole PSA values and the free-to-total PSA ratio, volume-adjusted PSA values, PSA densities determined by TRUS (PSAD(TRUS)), and TAUS (PSAD(TAUS)), and PSA transition zone densities (PSATzD) were compared using receiver operating characteristic (ROC) analysis.

RESULTS

Prostate cancer was diagnosed in 58 (24.4%) of the 238 men who underwent prostate biopsies. Of the areas under ROC curves (AUC) of studied parameters, PSATzD (AUC 0.751) was the best and signi fi cantly superior to PSAD(TAUS) (AUC 0.664, P = 0.007). However, PSAD(TAUS) exceeded PSA (AUC 0.559, P = 0.004) and showed potential capability of a one-fourth reduction in unnecessary biopsies without spoiling sensitivity (90%). Cancer detection rate was only 4.2% in the 48 patients whose prostate volume in TAUS was > 50 mL and PSAD(TAUS) was < 0.075.

CONCLUSIONS

Since PSAD(TRUS) and PSATzD were signi fi cantly superior to PSAD(TAUS), TRUS is feasible as the standard fashion to determine prostate volume in the diagnosis of prostate cancers. However, TAUS is also worthwhile as it can improve the prostate cancer detection using sole PSA, and primary use of TAUS has the potential to reduce the substantial number of unnecessary biopsy safely.

Screening for Prostate Cancer: Opportunities and Challenges

Prostate cancer screening with PSA and with digital rectal examination isa reality in the United States. Regardless of recent observations regarding the complexities of PSA interpretation, millions of U.S. men expect an annual PSA test and physicians have come to rely on the test, in combination with digital rectal examination, to assess for prostate cancer risk. What has become evident is that PSA can no longer be interpreted dichotomously as a simple yes or no. The test reflects a range of risk and PSA value must be merged with other risk factors of an individual man including ethnicity, family history, as well as the individual's risk aversion to complications from prostate cancer. The future of prostate cancer screening will be built upon incorporation of new biomarkers to the prediction of risk of disease. As these markers move forward in testing, it will no longer be acceptable to move these into clinical usage without formal validation studies and, because of the high frequency of prostate cancer in the general male population, these validation studies will almost certainly have to include measures of prognosis. It is the holy grail of cancer biomarker development to acquire a test that is positive in the man with clinically-aggressive prostate cancer but is negative in both the patient without disease and in the man with disease that will be of no clinical consequence over his lifetime.

Volume-adjusted prostate-specific antigen (PSA) variables in detecting impalpable prostate cancer in men with PSA levels of 2-4 ng/mL: transabdominal measurement makes a significant contribution

OBJECTIVE

To examine whether prostate-specific antigen (PSA) levels adjusted according to prostate volume improve prostate cancer detection using transrected biopsies in men with PSA levels of 2-4 ng/mL, and benign findings on a digital rectal examination (DRE).

PATIENTS AND METHODS

Men aged < or = 79 years and with serum PSA levels of 2-4 ng/mL and normal DRE findings were prospectively enrolled. Eligible patients were recommended for transrectal prostate biopsies after measuring prostate volumes with transrectal (TRUS) and transabdominal (TAUS) ultrasonography, and transition zone volumes with TRUS. In addition to PSA levels and the free-to-total PSA ratio, volume-adjusted PSA levels, PSA densities determined by TRUS (PSAD(TRUS)), and TAUS (PSAD(TAUS)), and PSA transition zone densities (PSATzD) were compared using receiver operating characteristic analysis.

RESULTS

Prostate cancer was diagnosed in 31 (22%) of the 139 men who had prostate biopsies. The area under the curve (AUC) of PSAD(TRUS) (0.796) and PSATzD (0.792) was similar and significantly greater than that of PSA (AUC 0.588) and the free-to-total PSA ratio (AUC 0.658). PSAD(TAUS) was a significantly better indicator of prostate cancer than PSA levels alone (P = 0.043).

CONCLUSION

As predictors of prostate cancer, there were no significant differences between PSAD(TRUS) and PSATzD. Although PSAD(TAUS) was worse than PSA variables adjusted by total and transition zone prostate volumes determined by TRUS, it was a better predictor than the PSA value alone in men with a low PSA level. These results indicate that TAUS is worthwhile where the routine use of TRUS before biopsy is difficult.

Surgical management of prostate cancer: Advances based on a rational approach to the data

The management of localised prostate cancer has undergone important changes in the past two decades, with major improvements in surgical technique, a greater emphasis on structured assessment of quality of life, and a greater attempt to tailor treatment to biological risk. Disease diagnosis is predicated on identification of demographic risk factors, serum levels of prostate-specific antigen and its derivatives, and extended biopsy techniques. Surgical removal of the prostate may be accomplished by open or minimally invasive techniques and in experienced hands results in good functional outcomes a high rate of cure for those with organ confined disease. Radical prostatectomy is also appropriate in selected patients with locally advanced disease and after failed radiation therapy.

[Prostate cancer: Diagnosis and staging]

The discovery and the use of serum prostate specific antigen (PSA) has considerably improved the diagnosis of prostate cancer during the past 20 years. Before PSA era, early diagnosis was only based on the digital rectal examination (DRE) of which the Limitations have been evidenced; over half of the tumours diagnosed by such means had already spread out of the prostate and were incurable. Assessment of serum PSA has allowed the diagnosis to be made at an earlier stage of the disease, curable by current treatments. Whichever the diagnostic tools, transrectal ultrasound (TRUS) prostatic biopsies remain necessary for diagnosis ascertainment, taking into account the low specificity of PSA assessment. The feasibility of a diagnosis at an early and curable stage of the disease has logically resulted in screening procedures aimed at reducing the high mortality related to prostate cancer. The numerous publications on prostate cancer screening provide precise information on the accuracy of available diagnostic means (PSA, DRE, TRUS, combined PSA and DRE), on the characteristics of screened tumours (stage and differentiation), and also on the population of men likely to benefit from the screening (age at beginning and end of the screening, frequency of PSA testing, identification of the men with ethnic and/or genetic predisposition). In those early diagnosed prostate cancers, the assessment of loco-regional cancer extension (extracapsular and/or, microscopic nodal involvement), remains unsatisfactory because no imaging technique (ultrasonography, CT scan, MRI,...) allows visualising the tumour itself or microscopic metastases. Nevertheless, the combination of multiple parameters such as DRE data, PSA level, biopsy data and tumour differentiation helps approaching with an increasing precision (nomograms) the true pathologic stage of the disease. Such advances allow distinguishing, among the very heterogeneous group of prostate cancers, tumours that differ from one to another in terms of disease stage, progression and prognosis, which is helpful for the determination of an adapted therapeutic strategy.

Comparison of prostate-specific antigen adjusted for transition zone volume versus prostate-specific antigen density in predicting prostate cancer by transrectal ultrasonography

OBJECTIVE

Prostate-specific antigen is an excellent tumor marker, but it is not specific for prostate cancer. We evaluated the efficacy of prostate-specific antigen adjusted for transition zone volume calculated by transrectal ultrasonography in predicting prostate cancer in men with intermediate prostate-specific antigen levels of 4.1 to 10.0 ng/mL compared with prostate-specific antigen density.

METHODS

Between June 1998 and December 2001, prostate-specific antigen adjusted for transition zone volume was obtained from 131 patients who underwent ultrasonographically guided biopsies and had prostate-specific antigen of 4.1 to 10.0 ng/mL. Prostate-specific antigen density was calculated by dividing total serum prostate-specific antigen by total prostate volume, and total serum prostate-specific antigen was divided by transition zone volume to yield prostate-specific antigen adjusted for transition zone volume. This was compared with prostate-specific antigen density via receiver operating characteristic curves.

RESULTS

Of 131 patients, 34 (26%) had prostate cancer, and 97 (74%) had benign prostatic hyperplasia on pathologic examination. Total prostate volume was correlated with transition zone volume (P < .001). Mean prostate-specific antigen adjusted for transition zone volume and prostate-specific antigen density were 0.71 +/- 0.25 and 0.27 +/- 0.09 ng x mL(-1) x mL(-1) in patients with prostate cancer and 0.32 +/- 0.09 and 0.16 +/- 0.05 ng x ml(-1) x mL(-1) in patients with benign prostatic hyperplasia. With a cutoff value of 0.35 ng mL(-1) x mL(-1), prostate-specific antigen adjusted for transition zone volume had sensitivity of 82% and specificity of 84%. Receiver operating characteristic curve analysis showed that prostate-specific antigen adjusted for transition zone volume predicted biopsy outcome significantly better than prostate-specific antigen density (P < .05).

CONCLUSIONS

Prostate-specific antigen adjusted for transition zone volume is more accurate than prostate-specific antigen density in distinguishing prostate cancer from benign prostatic hyperplasia in men with intermediate serum prostate-specific antigen of 4.1 to 10.0 ng/mL. Determination of transition zone volume by transrectal ultrasonography may be helpful for predicting the probability of positive biopsy results.

[Transrectal ultrasound-guided punch biopsies of the prostate. Indication, technique, results, and complications]

The golden standard for diagnosis of prostate cancer is transrectal ultrasound-guided systematic biopsy (TRUS-Bx). The optimal number of cylinders, sampling design, and indications for repeat biopsy are still in a state of flux. At the beginning of the 1980s, considerable doubts persisted regarding the benefit of ultrasound-guided punch biopsy for the diagnosis of prostate cancer. The examination on a chair with a fixed ultrasound head caused the patient substantial discomfort. Besides, in the pre-PSA era, most prostate carcinomas were detected by palpation and digitally guided biopsies were easily obtained. Indeed, the DRU procedure alone exhibited low sensitivity. Keetch et al. found that in only 25% of patients with abnormal palpatory findings and PSA between 4 and 20 ng/ml was a carcinoma revealed upon biopsy. On the other hand, patients with suspicious palpatory findings and proven malignancy suffered more frequently from locally advanced and systemic metastasizing tumors. As a result of restaging based on PSA, in most series more than half of the detected carcinomas presented normal palpatory findings. Ultrasound examination made precise imaging of zonal structures possible and thus offered the advantage of precision guidance for tissue biopsy despite lower sensitivity and specificity for diagnosis of suspicious lesions. Furthermore, calculation of prostate volume was possible. At the end of the 1980s, Hodge defined the systematic sextant biopsy as the first golden standard for early detection of prostate cancer. This meant the systematic removal of three punch cylinders from both lateral lobes of the prostate in the parasagittal midline at various levels (apex, middle, and base).

Comparison of the predictive accuracy of serum prostate specific antigen levels and prostate specific antigen density in the detection of prostate cancer in Hispanic-American and white men

PURPOSE

The Hispanic-American population is the fastest growing in the United States. Although many studies have looked at the performance of prostate specific antigen (PSA) in the detection of prostate cancer in white and black men, few have looked at it in relation to Hispanic men. The objective of this study was to compare the performance of PSA and PSA density (PSAD) in the detection of prostate cancer in Hispanic and white men.

MATERIALS AND METHODS

A total of 404 consecutive Hispanic and 341 consecutive white men with elevated serum PSA and/or abnormal digital rectal examination underwent transrectal ultrasound with lesion directed and systematic peripheral zone biopsies from 1996 to 2001 at a single institution by 2 investigators (ETG, MCB). Before biopsy all patients underwent volume measurements of the entire prostate. Of these patients 242 Hispanic and 255 white men had a total PSA between 2.5 and 10 ng/ml. Serum PSA and calculated PSAD were compared between the positive and negative biopsy groups, and between Hispanic and white men.

RESULTS

Of the 242 Hispanic and 255 white men 85 (35.1%) and 63 (24.7%) had cancer, respectively (p = 0.0147). There was no significant difference in age among the groups. There was no significant difference in median PSA between Hispanic and white men, or white men with malignant versus benign disease. There was a significant difference in median PSA in Hispanic men with malignant versus benign disease (6.3 vs 5.2 ng/ml, p = 0.0072). For PSAD there was a significant difference between Hispanic men with malignant versus benign disease (0.17 vs 0.12, p <0.0001) and white men with malignant versus benign disease (0.13 vs 0.11, p = 0.0019). Overall there was a difference in PSAD between positive and negative biopsy groups, and there was a significant difference in PSAD between Hispanic and white men (0.13 vs 0.11, p <0.0001).

CONCLUSIONS

This study shows for the first time that at similar levels of total PSA, PSAD is higher in Hispanic than in white men. Furthermore, these data show that while PSA was able to discriminate between malignant versus benign disease in Hispanic men, it was not able to do so in white men. Given the large number of patients in this series perhaps different PSAD cutoffs need to be defined for Hispanic men. Further study in this area is warranted.

[Value of prostate-specific antigen density and transitional-zone prostate-specific antigen density in the diagnosis of prostate cancer]

INTRODUCTION

With serum prostate specific antigen (PSA) levels of 4.1 to 10 ng/ml a significant number of patients are unnecessary subjected to biopsy. We try to determine if the calculation of prostate specific antigen density (PSAD) and prostate specific antigen density of the transition zone (PSADTZ) improve the capacity to discriminate between non-malignant disease and prostate cancer.

METHODS

A prospective study including 314 males with PSA levels between 4.1 and 10 ng/ml is reported. Transrectal ultrasonography and prostatic biopsy were performed in all of them and total prostate and transition-zone volumes were calculated. PSA density and PSA density of the transition zone were calculated for each patient. Receiver operating characteristics (ROC) curves for PSA, PSAD and PSADTZ were constructed for all the patients and for those patients with digital rectal examination unsuspicous of malignancy, determining the sensitivity and specificity for several cutoff values.

RESULTS

The area under the curve for both, PSAD and PSADTZ, were greater than for PSA (p < 0.05), without any significant differences between PSADTZ and PSAD. The cutoff value of greatest diagnostic efficiency for PSAD was 0.17 ng/ml/cc (71.4% sensitivity and 55.7% specificity), while it was 0.41 ng/ml/cc for DPSATZ (70% sensitivity and 61.5% specificity). For those cases of normal digital rectal examination, no differences were observed between PSA and PSAD but they were between PSA and PSADTZ. In any event, the area under ROC curves was always less than 0.7, and, in order to avoid a large number of biopsies (high specificity), a large number of cancers are left without diagnosis (low sensitivity).

CONCLUSIONS

We conclude that PSAD and PSADTZ are not excessively useful for adequately discriminating between patients with prostate cancer and those with non-malignant disease, particularly when digital rectal examination is normal.

Prostate biopsy: indications and technique

PURPOSE

The last decade has seen numerous modifications in the way prostate cancer is diagnosed. We review the current indications for and methods of prostate biopsy.

MATERIALS AND METHODS

The English language literature was reviewed regarding major indications for and methods of prostate biopsy. Pertinent peer reviewed articles were collated and analyzed.

RESULTS

The most widely accepted indication for prostate biopsy is a prostate specific antigen (PSA) value of greater than 4.0 ng./ml. However, some investigators advocate prostate biopsy for men with a PSA value in the 2.5 to 4.0 ng./ml. range, believing that use of this parameter results in detection of a greater number of cases of curable disease. Age specific PSA range, percent free PSA and presence of prostatic intraepithelial neoplasia or atypia are all considered to be relative indications for prostate biopsy. The current literature describes a trend toward increasing the number of cores obtained and the sites biopsied beyond those of the standard sextant technique. The additional cores in many series are obtained from more lateral regions of the gland.

CONCLUSIONS

Although several criteria are used as indications for initial prostate biopsy, all are based on PSA level and/or abnormal digital rectal examination. Future improvements in currently used prostate cancer markers may result in better selection of cases to biopsy. There is no universally accepted technique of prostate gland biopsy. The current literature supports use of more extensive biopsy techniques to increase the likelihood of prostate cancer detection.

Prostate specific antigen density. Is there a role for this parameter when screening for prostate cancer?

The objective of this paper is to validate prostate specific antigen (PSA) density (PSAD) routine use to enhance PSA specificity in men with normal digital rectal examination and intermediate PSA values. It is a retrospective study of 235 men from a prostate cancer (PCa) screening program. All of them presented PSA values between 4 and 10 ng/ml, normal digital rectal examination, and a transrectal ultrasound (TRUS) guided biopsy available (PSA>/=4 ng/ml as the sole criterion for biopsy). Multivariate analysis failed to demonstrate higher PSAD values in men with PCa. PSAD cutoff points higher than 0.07 ng/ml per cc were considered as unacceptable, with less than 95% sensitivity. When a cutoff point of 0.15 was considered, as many as 30.6% of the cancers were missed. In conclusion we cannot recommend the use of this parameter for the above mentioned purpose.Prostate Cancer and Prostatic Diseases (2001) 4, 146-149.

Improving the utility of prostate specific antigen (PSA) in the diagnosis of prostate cancer: the use of PSA derivatives and novel markers

Prostate specific antigen (PSA) testing is now a routine part of the investigation of men with suspected prostate cancer. While a very useful test it still has its problems, in particular its lack of specificity means abnormal results are often caused by benign disease. This review describes the current problems with PSA testing in prostate cancer diagnosis and highlights potential ways in which these may be reduced.

Early management of prostate cancer: how to respond to an elevated PSA?

Support for prostate cancer screening efforts is provided by observational studies reporting decreases in prostate cancer-specific mortality in areas where screening is performed with digital rectal exam (DRE) and measurement of serum prostate-specific antigen (PSA) levels. The combination of PSA and DRE is an excellent cancer-screening tool with sensitivity and positive predictive value superior to that of mammography and breast exam. Use of percent free PSA further improves the specificity of PSA testing, particularly in the range of 4-10 ng/ml, at which most false positive PSA tests occur. Men older than 50 with a >10-year life expectancy should be considered for prostate cancer screening. Those with an abnormal DRE or a PSA above 4 ng/ml should be referred to a urologist for further discussion of the risks and benefits of a prostate biopsy. Furthermore, those with a significant change in either DRE or PSA results, or those at higher risk for prostate cancer with a PSA level above 2.5 ng/ml, should also be referred for evaluation.

Prostate specific antigen complexed to alpha-1-antichymotrypsin in patients with intermediate prostate specific antigen levels

BACKGROUND

The authors attempted to evaluate prospectively the usefulness of serum prostate specific antigen (PSA) complexed to alpha-1-antichymotrypsin (PSA-ACT) in the early detection of prostate carcinoma and its ability to discriminate between prostate carcinoma and benign prostatic hyperplasia (BPH), especially among patients with intermediate PSA levels.

METHODS

Between December 1999 and August 2000, systematic sextant biopsies were performed on 281 prospective patients with prostate carcinoma who had serum PSA levels between 4.1 ng/mL and 20.0 ng/mL. The serum samples were assayed by using kits that were designed specifically for measuring serum PSA, PSA-ACT, and free PSA levels. The clinical values of PSA, PSA-ACT, the free PSA to total PSA ratio (F/T ratio), the free PSA to PSA-ACT ratio, PSA density (PSAD), and PSA-ACT density (ACTD) were compared by using receiver operating characteristic (ROC) curve analysis.

RESULTS

Biopsy yielded no evidence of malignancy in 198 patients, and prostate carcinoma was confirmed in 83 patients. ROC analysis demonstrated that the area under the curve (AUC) for PSA-ACT was greater than that for total PSA and was equivalent to that for the F/T ratio in both groups of patients (PSA ranges of 4.1-20.0 ng/mL and 4.1-10.0 ng/mL, respectively). The AUC for the ACTD was greater than the AUC for the PSAD and had the highest value of all parameters.

CONCLUSIONS

The measurement of PSA-ACT represents an alternative to the use of total and free PSA. The ACTD value is the most useful for discriminating between BPH and prostate carcinoma.

The procedure of transrectal ultrasound guided biopsy of the prostate: a survey of patient preparation and biopsy technique

PURPOSE

We surveyed urologists in community and academic practice regarding their standard approach to patient preparation and their technique of transrectal ultrasound guided prostate biopsy.

MATERIALS AND METHODS

We mailed 110 surveys to community urologists in Florida and urological oncologists at academic centers across the United States. Responses were calculated per group.

RESULTS

Of the 88 respondents 34% were at academic centers and 66% were community urologists. Overall 79% of respondents prescribe an enema in preparation for biopsy, 81% administer an oral fluoroquinolone before biopsy, 50% give some type of analgesia, usually an oral agent, 63% obtain 8 or more cores per biopsy session, 36% biopsy the lateral and midline locations, and 83% do not use prostate specific antigen density to plan the biopsy strategy.

CONCLUSIONS

The majority of urologists who responded to our survey ask their patients to use an enema in preparation for a transrectal biopsy procedure, prescribe an oral antibiotic and administer some type of analgesia. Few urologists administer a periprostatic nerve block. The majority obtain at least 8 biopsies and only 17% perform sextant biopsy. Some of these practices are not consistent with the literature. This survey provides insight into the practice patterns of urologists in regard to one of the most commonly performed office procedures.

Combined Use of Prostate-Specific Antigen Derivatives Decreases the Number of Unnecessary Biopsies to Detect Prostate Cancer

The authors evaluated the prostate cancer detection rate in Turkish patients with prostate-specific antigen (PSA) levels of 4 ng/ml to 10 ng/ml and who had normal digital rectal examination (DRE) findings. They also aimed to evaluate the value of PSA density and percent free PSA in minimizing unnecessary prostate biopsies for these PSA ranges. This prospective study included 134 consecutive men referred for early prostate cancer detection or lower urinary tract symptoms. All men underwent transrectal ultrasound with systematic sextant needle biopsies. The ability of PSA density and percent free PSA to improve the power of PSA in the detection of prostate cancer was evaluated with statistical analyses as well as receiver operating characteristics curves. Among the 134 men, 124 (92.5%) had a benign histology and 10 (7.5%) had cancer diagnosed on the initial biopsies. Despite the disappointing results in regard to the sensitivity and specificity of PSA derivatives alone, the combination of PSA density and percent free PSA significantly increased the area under the curve compared with the use of each test alone. To increase the specificity of PSA in this patient population, the authors recommend combining two PSA derivatives in deciding whether to perform a biopsy. In a PSA range of 4 ng/ml to 10 ng/ml and with normal DRE, a percent free PSA < 21% and a PSA density > 0.18 yields highest specificity with 90% sensitivity.

Separation methods applicable to prostate cancer diagnosis and monitoring therapy

During the last decade, significant research has been conducted using prostate-specific antigen (PSA) in the basic and clinical sciences and many advances have occurred in the clinical use of PSA for detecting and monitoring prostate cancer (PCa). Separation methods including gel-permeation chromatography, isoelectric focusing, lectin-affinity chromatography, polyacrylamide gel electrophoresis and high-performance liquid chromatography have made significant contributions to the discovery and identification of different molecular forms of PSA. Furthermore, the measurement of free and total PSA has improved the ability of PSA to detect early PCa. However, unnecessary biopsies are still needed for men with slightly elevated PSA values. On the other hand, PSA is not adequate for staging newly diagnosed PCa and prognosticating the course in individual cases. The possible application of separation methods in the basic science of prostate cancer may be associated with identification of more cancer-specific forms of PSA and discoveries of other serum proteins useful not only for detecting, but also for staging and prognosticating PCa. Such novel markers might lead to a better understanding of PCa aggressiveness and to developments in the clinical field of treatment.

Volume-specific cutoffs are necessary for reproducible application of prostate-specific antigen density of the transition zone in prostate cancer detection

OBJECTIVES

To determine the effect of prostate volume on the specificity of prostate-specific antigen density (PSAD) and PSAD of the transition zone (PSA-TZ) in the detection of prostate cancer.

METHODS

Between February 1994 and April 1998, transrectal ultrasound-guided prostate needle biopsies were performed in 235 men with serum prostate-specific antigen (PSA) levels between 4.0 and 10.0 ng/mL. The PSAD and PSA-TZ specificities were calculated at 95% sensitivity cutoff levels generated from the whole group, as well as from cohorts stratified by transition zone index or prostate volume.

RESULTS

Statistical significance was noted between the benign (n = 176) and prostate cancer (n = 59) groups for all tested PSA parameters. At 95% sensitivity, PSA-TZ carried a specificity of 37.5% compared with 29.6% for PSAD. When applying a single 95% sensitivity cutoff derived from the entire group to individual volume-stratified cohorts, the specificity decreased to 0% in glands less than 30 g in size. A 95% sensitivity PSA-TZ cutoff generated individually for volume-stratified cohorts of glands less than 30, 30 to 40, and 40 to 60 g resulted in more consistent specificity of 28.2%, 35.2%, and 45.7% for each cohort, respectively.

CONCLUSIONS

Unlike whole group-derived cutoffs, the use of volume-specific PSA-TZ cutoffs allows consistently high specificity in all volume-stratified cohorts. The discrepancies in the PSA-TZ and PSAD specificities in published reports are likely due to the application of published cutoffs to populations of differing prostate volumes. The use of volume-specific cutoffs results in reproducible specificity in populations with differing prostate volume distribution, and thereby definitively resolves the differences in PSA-TZ specificity reported in published reports.

Edge-guided boundary delineation in prostate ultrasound images

Accurate detection of prostate boundaries is required in many diagnostic and treatment procedures for prostate disease. In this paper, a new paradigm for guided edge delineation is described, which involves presenting automatically detected prostate edges as a visual guide to the observer, followed by manual editing. This approach enables robust delineation of the prostate boundaries, making it suitable for routine clinical use. The edge-detection algorithm is comprised of three stages. An algorithm called sticks is used to enhance contrast and at the same time reduce speckle in the transrectal ultrasound prostate image. The resulting image is further smoothed using an anisotropic diffusion filter. In the third stage, some basic prior knowledge of the prostate, such as shape and echo pattern, is used to detect the most probable edges describing the prostate. Finally, patient-specific anatomic information is integrated during manual linking of the detected edges. The algorithm was tested on 125 images from 16 patients. The performance of the algorithm was statistically evaluated by employing five expert observers. Based on this study, we found that consistency in prostate delineation increases when automatically detected edges are used as visual guide during outlining, while the accuracy of the detected edges was found to be at least as good as those of the human observers. The use of edge guidance for boundary delineation can also be extended to other applications in medical imaging where poor contrast in the images and the complexity in the anatomy limit the clinical usability of fully automatic edge-detection techniques.

The influence of prostate volume on the prostate-specific antigen (PSA) level adjusted for the transition zone volume and free-to-total PSA ratio: a prospective study

OBJECTIVES

To evaluate the influence of prostate volume on the prostate-specific antigen (PSA) level adjusted for the transition zone volume (PSAT) and free-to-total PSA ratio (f/tPSA) in detecting prostate cancer in men with intermediate PSA levels of 4.1-10.0 ng/mL.

PATIENTS AND METHODS

From March 1997 to June 1999, the f/tPSA and PSAT were measured in 105 patients who underwent ultrasound-guided systemic biopsies and had a PSA level of 4.1-10.0 ng/mL, with an apparently normal prostate on a digital rectal examination. The PSAT and f/tPSA were evaluated in all patients and in subgroups of patients with small (< 40 mL) or large (> or = 40 mL) prostates, using receiver operating characteristic (ROC) curves.

RESULTS

Total prostate volume was highly correlated with transition zone volume in all patients and in both subgroups (P < 0.001). In all 105 patients, PSAT had a sensitivity of 82% and its use would have avoided the largest number of unnecessary biopsies (87% specificity) at a threshold value of 0.35 ng. In men with small prostates f/tPSA and PSAT had a high sensitivity and specificity, at threshold values of 0.12 and 0.35 ng, respectively. In large prostates the PSAT was superior to f/tPSA in detecting prostate cancer.

CONCLUSIONS

These results suggest that both f/tPSA and PSAT are useful in detecting prostate cancer in men with small prostates, while PSAT is superior to f/tPSA in detecting prostate cancer in men with large prostates.

Prostate specific antigen adjusted for transition zone volume: the most powerful method for detecting prostate carcinoma

BACKGROUND

Several methods for the identification of patients with prostate carcinoma have been proposed to enhance the clinical usefulness of prostate specific antigen (PSA). However, it remains unclear which method is superior in practical use. The authors attempted prospectively to identify the most powerful method with which to detect prostate carcinoma, especially among patients with intermediate PSA levels.

METHODS

Between October 1997 and August 1999, systematic sextant biopsies were performed on 281 patients, including 147 with PSA levels between 4.1 ng/mL and 10.0 ng/mL. The clinical values of PSA, the free PSA to total PSA ratio (free/total PSA ratio), alpha-1-antichymotrypsin-PSA complex (PSA-ACT), the calculated derivatives, PSA density (PSAD), and PSA density of the transition zone (PSATZD) for the detection of prostate carcinoma were compared by using receiver operating characteristic (ROC) curves and logistic regression analyses.

RESULTS

According to ROC curve analysis, PSATZD had the greatest area under the curve in the overall patient population and in patients with intermediate PSA levels. In patients with intermediate PSA levels, at the sensitivity of 90%, PSATZD would have prevented unnecessary biopsies in 68 of 117 patients who were without prostate carcinoma, whereas PSA, free/total PSA ratio, and PSA-ACT would have prevented unnecessary biopsies in 25, 28, and 25 patients, respectively. Stepwise logistic regression analysis showed that PSATZD and findings on digital rectal examination were significant independent predictors.

CONCLUSIONS

PSATZD had the most useful validity in the differentiation between prostate carcinoma and benign prostatic enlargement in the overall patient population and in patients with intermediate PSA levels.

Prospective evaluation of prostate specific antigen (PSA), PSA density, free-to-total PSA ratio and a new formula (prostate malignancy index) for detecting prostate cancer and preventing negative biopsies in patients with normal rectal examinations and intermediate PSA levels

OBJECTIVE

To improve the specificity and sensitivity of prostatic cancer detection, we prospectively evaluated total prostate specific antigen (PSA) level, PSA density, free-to-total PSA ratio and a new formula called prostate malignancy index (PMI) as a discriminator of prostate cancer in patients with intermediate PSA levels and normal digital rectal examinations.

MATERIALS AND METHODS

Between November 1995 and October 1997, 95 patients who had serum PSA levels of 4.0 to 10.0 ng/ml with normal digital rectal examinations were prospectively evaluated. All patients underwent one or two times transrectal ultrasound guided prostate biopsies. Based on age specific reference range of PSA, PSA density and % free PSA ratio, PMI was calculated for each patient. The free and total serum PSA concentrations were determined by an Immulite assay system. (Diagnostic Product Corp., Los Angeles, California).

RESULTS

Overall 20 of 95 (21%) patients had prostate cancer. There were no significant differences in patient mean age and mean total PSA between those with benign and those with malignant biopsies (p>0.05). However, there were significant differences in mean PSAD, mean free-to-total PSA ratio and mean PMI (p<0.01, p<0.05, p<0.01, respectively). Benign condition specificities for PM index, percent free PSA, PSA density and total PSA at a 90% sensitivity for prostate cancer were 48%, 10.6%, 8% and 4%, respectively. Of 95 patients, 27 (28.4%) had a PMI of equal or more than 3.1, including 12 of 75 (16%) with negative biopsy and 15 of 20 (75%) with positive biopsy. Furthermore a cutoff MI 0.86 P correctly identified 24% of benign cases without missing any prostate cancer cases. The comparison of receiver operating characteristic (ROC) curve areas showed that PMI was better than total PSA (p<0.01). Although, the area under the ROC curve of % free PSA and PSAD were higher than the area of total PSA, these differences were not statistically significant (p>0.05).

CONCLUSIONS

We concluded that the prostate malignancy index could be utilized to differentiate benign conditions from prostate cancer in patients with intermediate PSA levels and normal digital rectal examination. Also significant numbers of negative biopsies can be prevented in these patients.

Prostate-specific antigen

Prostate-specific antigen (PSA) has revolutionized the diagnosis and management of men with prostate cancer. Significant advances have been made since the early development of immunoassays. While PSA is useful for staging and monitoring of established disease, it has shown the greatest utility in the realm of early detection realm. PSA is the most important tumor marker; its importance in evaluating men for the possibility of prostate cancer is irrefutable. Enhancing specificity is a pressing need. In this regard, the recognition of the molecular forms of free PSA and complex PSA have shown the most promise and undoubtedly will result in fewer false-positive PSA test results. The salient literature is reviewed and commentary made on the current status of PSA with particular emphasis on methods to enhance its specificity in early detection and applications.