PSA Updated: Still Relevant in the New Millennium?

Development of an optical microfiber immunosensor for prostate specific antigen analysis using a high-order-diffraction long period grating

Fiber-optic biosensors are of great interest to many bio/chemical sensing applications. In this study, we demonstrate a high-order-diffraction long period grating (HOD-LPG) for the detection of prostate specific antigen (PSA). A HOD-LPG with a period number of less than ten and an elongated grating pitch could realize a temperature-insensitive and bending-independent biosensor. The bio-functionalized HOD-LPG was capable of detecting PSA in phosphate buffered saline with concentrations ranging from 5 to 500 ng/ml and exhibited excellent specificity. A limit of detection of 9.9 ng/ml was achieved, which is promising for analysis of the prostate specific antigen.

Diagnostic Performance of Multiparametric Transrectal Ultrasound in Localized Prostate Cancer: A Comparative Study With Magnetic Resonance Imaging

OBJECTIVES

The aim of this study was to compare the diagnostic performance of multiparametric transrectal ultrasound (TRUS), including grayscale imaging, color Doppler imaging, shear wave elastography, and contrast-enhanced ultrasound, to that of multiparametric magnetic resonance imaging (MRI), including T2-weighted, diffusion-weighted, and dynamic contrast-enhanced MRI, in the diagnosis of localized prostate cancer (PCa; lesions at stage T2 or lower).

METHODS

Seventy-eight patients were prospectively enrolled, including 40 in a benign prostate group and 38 in a localized PCa group (≤T2). The diagnostic performance of multiparametric TRUS and multiparametric MRI in detecting localized PCa was analyzed with surgical and biopsy pathologic results as the references.

RESULTS

Multiparametric TRUS had higher sensitivity, negative predictive value, and accuracy than multiparametric MRI (97.4% versus 94.7%, 96.9% versus 92.3%, and 87.2% versus 76.9%, respectively) for detecting localized PCa. The mean area under the receiver operating characteristic curve ± SD for multiparametric TRUS was 0.874 ± 0.043 (95% confidence interval, 0.790-0.959), and it was 0.774 ± 0.055 (95% confidence interval, 0.666-0.881) for multiparametric MRI.

CONCLUSIONS

Our results suggest that multiparametric TRUS has high diagnostic performance in the diagnosis of localized PCa. Multiparametric TRUS is compatible with multiparametric MRI in the detection of localized PCa (≤T2).

Imaging and Markers as Novel Diagnostic Tools in Detecting Insignificant Prostate Cancer: A Critical Overview

Recent therapeutic advances for managing low-risk prostate cancer include the active surveillance and focal treatment. However, locating a tumor and detecting its volume by adequate sampling is still problematic. Development of predictive biomarkers guiding individual therapeutic choices remains an ongoing challenge. At the same time, prostate cancer magnetic resonance imaging is gaining increasing importance for prostate diagnostics. The high morphological resolution of T2-weighted imaging and functional MRI methods may increase the specificity and sensitivity of diagnostics. Also, recent studies founded an ability of novel biomarkers to identify clinically insignificant prostate cancer, risk of progression, and association with poor differentiation and, therefore, with clinical significance. Probably, the above mentioned methods would improve tumor characterization in terms of its volume, aggressiveness, and focality. In this review, we attempted to evaluate the applications of novel imaging techniques and biomarkers in assessing the significance of the prostate cancer.

Diagnostic performance of contrast enhanced ultrasound in patients with prostate cancer: a meta-analysis

RATIONALE AND OBJECTIVES

We aimed to do a meta-analysis of the existing literature to assess the accuracy of prostate cancer (PCa) studies that use contrast-enhanced ultrasound (CEUS) as a diagnostic tool.

MATERIALS AND METHODS

The MEDLINE, EMBASE, and Cochrane Library databases were searched for relevant original articles published up to August 2012. Characteristics of Included studies were recorded. Methodological quality was assessed by using the quality assessment of diagnostic studies tool. Pooled weighted estimates of diagnostic odds ratio (DOR), sensitivity, specificity, and positive and negative likelihood ratio (LR) were calculated. A summary receiver operator characteristic (SROC) curve was constructed to calculate the area under the curve (AUC). Publication bias analysis was also performed.

RESULTS

Sixteen studies (2624 patients) were included in the meta-analysis. Various contrast agents and imaging modes were applied. The independent random-effects summary showed a variation in diagnostic values. The summary estimates of sensitivity, specificity, and DOR were 0.70, 0.74, and 9.09, respectively. The weighted positive and negative LR were 2.81 and 0.35, with statistically significant between-study heterogeneity (P < .001). Sensitivity was better in positive patient studies than positive biopsy cores ones (0.78 vs. 0.64). SROC plot displayed value for AUC (0.82). Begg's test (P = .822) and Egger's test (P = .198) did not show evidence of publication bias.

CONCLUSION

CEUS is a promising tool in the detection of PCa, but it cannot completely replace systematic biopsy under the present circumstances. It is necessary to standardize imaging techniques, contrast agents and diagnostic criteria. Large samples, multi-center studies and high-quality prospective trials are necessary to assess its clinical value.

Recent developments in prostate cancer biomarker research: therapeutic implications

This review aims to present an overview of recent clinical trials targeting biomarkers in advanced prostate cancer. We searched ClinicalTrials.gov for early phase clinical trials on treatments of prostate cancer that have been recently completed, are ongoing or are actively recruiting participants. Drug targets and their mechanism of actions were assessed and summarized. Trials were categorized according to prostate cancer biomarkers that have potential as therapeutic targets. A total of 19 new therapeutic agents for the treatment of prostate cancer are included in this review. Trials are summarized according to the targeted biomarkers and are categorized into five therapeutic approaches: prostate cancer vaccine, epigenetic therapy, pro-apoptotic agents, prostate cancer antibodies and anti-angiogenesis approach. Some of the therapeutic agents reviewed showed promising results, warranting further investigation in late phase clinical trials. Recent novel prostate cancer biomarkers that made it through clinical trials and their relevance as drug targets are summarized. This review emphasizes the importance of specific prostate cancer biomarkers and their potentials as targets of the disease. Some clinical trials of targeted treatments in prostate cancer show promising results. Better understanding of disease mechanisms should potentially lead to more specific treatments for individual patients.

Peripheral zone prostate cancer in patients with elevated PSA levels and low free-to-total PSA ratio: detection with MR imaging and MR spectroscopy

PURPOSE

To retrospectively assess the value of endorectal magnetic resonance (MR) imaging and MR spectroscopy combined with the free-to-total prostate-specific antigen (PSA) ratio for detecting prostate cancer in men with elevated PSA levels.

MATERIALS AND METHODS

The institutional review board approved the study, and all patients provided informed written consent. Endorectal MR imaging and MR spectroscopy were performed in 54 patients with PSA levels greater than 3 ng/mL but less than 15 ng/mL and free-to-total PSA ratio of less than 20%, followed by sextant biopsy in the peripheral zone. For each patient, MR imaging and MR spectroscopic findings, PSA level, and free-to-total PSA ratio were analyzed and compared with biopsy results and/or histopathologic tumor maps with regard to a sextant-modified distribution. The likelihood of cancer in each sextant according to MR and MR spectroscopic findings was graded independently on a scale of 1 (benign) to 5 (malignant). Detection accuracy and a multivariate logistic regression analysis were used to determine the most accurate combination of imaging, and clinical tests were used to detect prostate cancer according to the area under the receiver operating characteristic curve (AUC).

RESULTS

The model incorporating MR imaging, MR spectroscopy, and free-to-total PSA ratio (AUC = 97.5%) was significantly more accurate in predicting prostate cancer than models using MR imaging alone (AUC = 85.1%; P = .007), MR spectroscopy alone (AUC = 87.2%; P = .041), or MR imaging and free-to-total PSA ratio combined (AUC = 90.8%; P = .038).

CONCLUSION

MR and MR spectroscopy combined with free-to-total PSA ratio improves the predictive value for prostate cancer detection.

Real-time quantitative RT-PCR assessment of PIM-1 and hK2 mRNA expression in benign prostate hyperplasia and prostate cancer

To investigate the expressions of PIM-1 and hK2 mRNA in normal prostate, benign prostatic glandular hyperplasia (BPH), and prostate cancer (PCa), and to explore the association of PIM-1 and hK2 expressions with PCa progression. The samples were harvested from 37 patients with BPH, 23 patients with PCa, and three with normal prostate tissues. Total RNA was extracted from their prostate tissues and analyzed for PIM-1 and hK2 mRNA levels using SYBR green I-based quantitative real-time RT-PCR (QRT-PCR) assays and Southern blot analysis. The differences of gene expressions were calculated based on standard curve. Quantitative expressions of PIM-1 and hK2 mRNA in normal prostate, BPH, and PCa were 1.05 +/- 0.04, 2.57 +/- 0.74, 4.45 +/- 0.63, and 1.02 +/- 0.03, 2.264 +/- 0.46, 5.905 +/- 0.78, respectively. PIM-1 and hK2 were expressed higher in PCa than those in BPH and normal prostate tissues, the differences among which had statistic significance (P < 0.05). Our results support the hypothesis that PIM-1 and hK2 play a significant role in the growth of PCa and the detection of PIM-1 and hK2 mRNA expressions by QRT-PCR provided more reliable and helpful information on diagnosis, treatment, and prognosis of PCa.

Contrast-enhanced ultrasound for diagnosis of prostate cancer and kidney lesions

PURPOSE OF REVIEW

Conventional ultrasonography of both, kidney and prostate, is limited due to the poor contrast of B-mode imaging for parenchymal disease and limited sensitivity of colour Doppler for the detection of capillaries and deep pedicular vessels. Contrast-enhanced ultrasound (CEUS) overcomes these limitations.

RECENT FINDINGS

CEUS investigates the blood flow of the prostate, allows for prostate cancer visualization and for targeted biopsies. Comparisons between systematic and CEUS-targeted biopsies have shown that the targeted approach detects more cancers with a lower number of biopsy cores and with higher Gleason scores compared with the systematic approach. Also the kidney offers promising applications as CEUS improves the detection of abnormal microvascular and macrovascular disorders.

SUMMARY

In recent literature CEUS has shown its value for diagnosis of both, prostate cancer and kidney lesions. This paper describes recent improvements and future perspectives of CEUS.

Transrectal contrast enhanced ultrasound for diagnosis of prostate cancer

The diagnosis of prostate cancer is based on histology. Prostate biopsies are obtained based on the triad of prostate specific antigen (PSA), digital rectal examination (DRE) and transrectal ultrasound. Because prostate biopsies still have a large percentage of negative outcomes, patient selection and biopsy direction need improvement. This paper describes the recent improvements in prostate cancer imaging, especially contrast-enhanced transrectal ultrasound.

Free/total PSA ratio can help in the prediction of high gleason score prostate cancer in men with total serum prostate specific antigen (PSA) of 3–10 ng/ml

PURPOSE

We evaluate the use of free/total prostate specific antigen (PSA) ratio in improving the prediction of cancers of higher Gleason scores.

PATIENTS AND METHODS

A total of 164 patients with total serum PSA of 3.0-10.0 ng/ml underwent extended TRUS-guided core biopsy. In each man serum free PSA was measured and the free/total (F/T) PSA ratio was calculated. Out of the 164 patients who underwent TRUS-biopsy, cancer was detected in 62 (37.8%) patients. The mean age for the 62 patients with histologically proven prostate cancer was 62.3+/-5.5 years (49-73). The histological findings were compared with the free/total PSA ratio. Pearson Correlation Coefficient test and Chi-Square test (chi2-test) were used for statistical analysis and p<0.05 was considered statistically significant.

RESULTS

Of the 62 patients, 37 (59.7%) patients had cancers of low Gleason scores (score 2-6) and 25 (40.3%) patients had cancers of high Gleason scores (score 7-10). Free PSA<0.15% was found in 19 (30.6%) patients, from 15 to 20% in 23 (37.1%) patients and >20% in 20 (32.3%) patients. There was a significant positive correlation between total PSA and Gleason score (Pearson Correlation Coefficient test, r=0.328, p<0.01). Also, there was a significant increase in Gleason score with lower F/T PSA ratio (r=-0.668, p<0.001). Among the 19 patients with free PSA ratio<15%, 14 (73.7%) patients had cancers of high Gleason score while 5 (26.3%) patients had cancers of low Gleason score. In patients (n=23) with free PSA ratio15-20%, 10 (43.5%) had cancers of high Gleason score and 13 (56.5%) had cancers of low Gleason score. In the 20 patients with free PSA ratio>20%, 1 patient (5%), had prostate cancer of high Gleason score and the remaining 19 (95%) patients had low Gleason scores. There was a significant relation between lower F/T PSA ratios and higher Gleason scores, Chi-Square test, chi2=19.3, p<0.01.

CONCLUSIONS

In this study, men with prostate cancer and lower F/T PSA ratio were at a higher risk of having higher Gleason scores (7-10) and those with higher F/T PSA ratio were more likely to have lower Gleason scores.

Using prostate-specific antigen screening and nomograms to assess risk and predict outcomes in the management of prostate cancer

We review the role of prostate-specific antigen (PSA) and the importance of patient education in the management of prostate cancer, based on discussions held at a European symposium on managing prostate cancer. Although PSA is the most widely used serum marker for detecting prostate cancer and for monitoring treatment responses, its use as a diagnostic marker is controversial due to concerns of over-diagnosis and low specificity. PSA isoforms, as well as PSA doubling time, might improve the specificity for earlier prostate cancer detection and can be used as surrogate markers for treatment efficacy. Patients can differ considerably in the importance they place on health-related quality of life aspects and fear of cancer progression. Consequently, there needs to be active, educated discussion of risk and outcomes between physicians and patients. Risk assessment tools, e.g. validated nomograms, enable clinicians to improve their decision analysis and form the basis for subsequent discussion of treatment options between the physician and patient, thereby enabling informed consent and appropriate decision-making.

Contemporary issues in the diagnosis of prostate cancer for the radiologist

Prostate cancer diagnostic techniques have improved considerably in recent years, but they must yet be optimised to ensure cancer detection at a potentially curable stage. Arrangements for prostate biopsy vary throughout Europe, and prostate biopsy may be undertaken by urologists or radiologists. This review discusses current issues relevant for radiologists involved in the detection of early prostate cancer. Prostate biopsy should be based on a systematic approach involving 8-12 cores obtained with peri-prostatic infiltration of local anaesthetic. Quality issues being considered by the United Kingdom Prostate Cancer Risk Management Programme are discussed.