Screening for prostate cancer at low PSA range: the impact of digital rectal examination on tumor incidence and tumor characteristics

Risk-stratified multi-round PSA screening for prostate cancer integrating the screening reference level and subgroup-specific progression indicators

BACKGROUND

Although prostate-specific antigen (PSA) is widely used in prostate cancer (PCa) screening, nearly half of PCa cases are missed and less than one-third of cases are non-lethal. Adopting diagnostic criteria in population-based screening and ignoring PSA progression are presumed leading causes.

METHODS

A total of 31,942 participants with multi-round PSA tests from the PLCO trial were included. Time-dependent receiver-operating-characteristic curves and area under curves (tdAUCs) were performed to determine the screening reference level and the optimal subgroup-specific progression indicator. Effects of risk-stratified multi-round PSA screening were evaluated with multivariable Cox regression and measured with hazard ratio [HR (95%CIs)].

RESULTS

After a median follow-up of 11.6 years, a total of 3484 PCa cases and 216 PCa deaths were documented. The tdAUC of 10-year incidence PCa with PSA was 0.816, and the cut-off value was 1.61 ng/ml. Compared to subgroup with stable negative PSA in both first-round (FR) and last-round (LR) tests [FR(-)/LR(-)], HRs (95%CI) of PCa incidence were 1.66 (1.20-2.29), 8.29 (7.25-9.48), and 14.52 (12.95-16.28) for subgroups with loss of positive PSA[FR(+)/LR(-)], gain of positive PSA[FR(-)/LR(+)], and stable positive PSA[FR(+)/LR(+)]; while HRs(95%CI) of PCa mortality were 1.47 (0.52-4.15), 5.71 (3.68-8.86), and 5.01 (3.41-7.37). After excluding regressive PSA [(namely FR(+)/LR(-)], absolute velocity was the shared optimal progression indicator for subgroups with FR(-)/LR(-), FR(-)/LR(+), and FR(+)/LR(+), with tdAUCs of 0.665, 0.681 and 0.741, and cut-off values of 0.07, 0.21, and 0.33 ng/ml/year. After reclassifying participants into groups with positive and negative progression based on subgroup-specific progression indicators, incidence HR (95%CI) were 2.41 (1.87-3.10), 2.91 (2.43-3.48), and 3.16 (2.88-3.46) for positive progression compared to negative progression within subgroups of FR(-)/LR(-), FR(-)/LR(+), and FR(+)/LR(+), while mortality HR (95%CI) were 2.22 (0.91-5.38), 2.37 (1.28-4.38), and 2.98 (1.94-4.59). To improve screening performances by excluding regressive PSA and low-risk positive progression in FR(-)/LR(-), optimized screening strategy not only significantly reduce 32.4% of missed PCa (54.0% [1881/3484] vs. 21.6% [754/3484], P < 0.001), but also detected additional 8.0% of high-grade PCa (Gleason score 7-10: 36.0% [665/1849] vs. 28.0% [206/736], P < 0.001) than traditional screening strategy.

CONCLUSIONS

Risk-stratified multi-round PSA screening strategy integrating the screening reference level and the optimal subgroup-specific progression indicator of PSA could be recommended as a fundamental strategy to reduce missed diagnosis and improve the detection of high-grade PCa cases.

An Evaluation of Screening Pathways Using a Combination of Magnetic Resonance Imaging and Prostate-specific Antigen: Results from the IP1-PROSTAGRAM Study

BACKGROUND

The use of prostate-specific antigen (PSA) testing to screen for prostate cancer has been fraught with under- and overdiagnosis. Short, noncontrast magnetic resonance imaging (MRI) might detect more grade group ≥2 cancers with similar rates of biopsy.

OBJECTIVE

To evaluate strategies that combined PSA and MRI to select men based in the community for a prostate biopsy.

DESIGN, SETTING, AND PARTICIPANTS

IP1-PROSTAGRAM was a prospective, population-based, paired cohort study of 408 men aged 50-69 yr conducted at seven UK primary care practice and two imaging centres (from October 10, 2018 to May 15, 2019).

INTERVENTION

All participants underwent screening with a PSA test, MRI (T2-weighted and diffusion), and transrectal ultrasound (b-mode and elastography). If any test was screen positive, a systematic 12-core biopsy was performed. Additional image-fusion targeted biopsies were taken if the MRI or ultrasound was positive.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

We conducted an analysis, set out in the statistical plan a priori, comparing 13 different pathways including PSA-alone, MRI-alone, and a range of PSA thresholds and MRI scores. The performance of each pathway was evaluated focusing on the trade-offs between biopsy referral rates and detection of grade group ≥2 cancers. A targeted biopsy was performed only where the PROSTAGRAM MRI showed a lesion score of 3, 4, or 5.

RESULTS AND LIMITATIONS

The standard PSA pathway (PSA ≥3 ng/ml + systematic biopsy) would lead to 10% of men being referred for a biopsy and a 1.0% detection rate of grade group ≥2 cancers. Pathways that relied on MRI alone set at a threshold score of 3 for a biopsy led to higher biopsy rates, but with benefit of high cancer detection rates. The pathway that combined an initial low PSA threshold (≥1.0 ng/ml) and MRI score ≥4 accurately identified a high rate of grade group ≥2 cancers (2.5%, 95% confidence interval 1.3-4.6) while recommending fewer patients for a biopsy (7.1%, 95% confidence interval 4.9-10.2). The results are pertinent to only one screening round, the impact of repeat screening rounds is not evaluated, and the required MRI capacity is currently lacking.

CONCLUSIONS

Our results highlight the trade-off that exists between reducing excessive numbers of biopsies and maintaining grade group ≥2 cancer detection rates. A pathway that combines PSA ≥1 ng/ml and MRI score ≥4 maintains the detection of grade group ≥2 cancers while recommending fewer men for biopsies and would be the preferred strategy to evaluate in future studies at the first screening round.

PATIENT SUMMARY

The IP1-PROSTAGRAM study shows that PROSTAGRAM magnetic resonance imaging in men with a prostate-specific antigen level of ≥1.0 ng/ml could be a promising pathway to evaluate in future screening trials.

A cable driven robotic palpation system with contact force sensing based on cable tension observation

BACKGROUND

Prostate Cancer screening based on manual palpation is subjective. Robotic palpation systems can objectively acquire stiffness conditions of the prostate.

METHODS

A 2DoF cable driven robotic system for prostate palpation is proposed. An indirect method to estimate the contact force based on cable tension observation is presented. Kinematic models and a joint angle estimation method to determine the tip position of the probe are derived. Positioning accuracy was verified using an optical marker tracking system and by displacement measurement, respectively. The contact force estimation method was validated on silicone phantom samples.

RESULTS

A good consistence between the estimated and measured contact force was observed. The contact force was correlated with the elastic modulus of each silicone phantom. There was also a good agreement between the theoretical and the measured tip position.

CONCLUSION

In the proposed palpation system, the indirect contact force estimation method is viable and holds potential for the stiffness assessment of the prostate. The tip position vital for palpation can be determined through estimated joint angles.

Coronavirus disease 2019 and the cancellation of face-to-face prostate cancer active surveillance clinic reviews: Does the omission of digital rectal examination alone put patients at risk of missed detection of disease progression?

Objectives:

The coronavirus disease 2019 (COVID-19) pandemic has resulted in the cancellation or postponement of face-to-face clinic appointments, meaning patients on active surveillance (AS) for low- or intermediate-risk prostate cancer have been unable to undergo the recommended clinical assessment and digital rectal examination (DRE) during these times. This study aimed to determine whether the omission of DRE during the COVID-19 pandemic has put AS patients at risk by missing early detection of disease progression.

Methods:

This was a retrospective, regional study looking at the data of 142 men who qualified for placement on the Grampian AS protocol over a six-year span. It paid particular attention to the reasons for progression in those men who moved to active treatment (AT) during this six-year period.

Results:

The results showed that DRE played no role in triggering the move of these 42 patients onto AT. Nineteen (45%) of these patients moved to AT due to progression on trans-rectal ultrasound biopsy, 10 (24%) due to progression on multi-parametric magnetic resonance imaging, eight (19%) due to a rising prostate-specific antigen and five (12%) due to patient choice.

Conclusion:

This audit reassures us that those patients who cannot receive a timely DRE during the COVID-19 pandemic are unlikely to be at an increased risk of missing disease progression in our region.

Level of evidence:

Retrospective cohort study – level 3.

Hypoehoic lesions on Transrectal Ultrasound and its correlation to Gleason grade in the diagnosis of Clinically Significant Prostate Cancer: A Prospective Study

Context The importance of hypoechoic lesions on transrectal ultrasound (TRUS) merits re-assessment in the present era of widespread prostate-specific antigen (PSA) testing.

Aims We aimed to investigate the predictive accuracy of hypoechoic lesions on TRUS of prostate in the diagnosis of prostate cancer and to examine the association of hypoechoic lesions with the aggressiveness of prostate cancer.

Settings and Design This prospective study was conducted in a tertiary care center in South India from November 2017 to December 2019.

Methods and Material We included 151 patients undergoing TRUS-guided 12-core prostate biopsy in view of raised serum PSA with or without suspicious digital rectal examination (DRE) findings in the study. Age, DRE findings, serum PSA level, TRUS findings, and histopathology reports were documented. These were compared between patients with and without hypoechoic lesions on TRUS.

Statistical Analysis Used The statistical analysis for this study was performed using SPSS v20.0 software.

Results Among 151 men, prostate cancer was diagnosed in 68 (45.03%) with mean age at presentation 69.81 ± 6.49 years. Fifty-eight cases (38.41%) had hypoechoic lesion on TRUS and the cancer detection rate (68.96%) amongst this group was significantly higher than in those without hypoechoic lesion ( p <0.0001). Patients with hypoechoic lesion were more likely to have higher grade cancer. Abnormal DRE findings and hypoechoic lesion on TRUS were independent predictors of a clinically significant cancer ( p <0.05).

Conclusion Hypoechoic lesion on TRUS can be considered as an indicator of clinically significant prostate cancer.

Development of a tendon driven robotic probe for prostate palpation

Palpation is a clinical diagnosis method utilized by physicians to acquire valuable information about the pathological condition of an organ using the sense of touch. This method, however, is subjective. The accuracy depends on the physician's experience and skill. Therefore, to make palpation objective and minimize variability in prostate cancer diagnosis among physicians, an automated palpation system is required. This paper describes the design and experimental evaluation of a 2 Degrees of Freedom (2DoF) tendon driven robotic palpation probe. The probe's palpation motion is controlled by actuating driving tendons using a cable-differential pulley transmission system and a return spring. A kinematic model of the robotic probe was derived. Furthermore, a tendon path length model was geometrically determined, and an optimization method for guide arc center placement to minimize change in tendon length was presented. Preliminary experimental and theoretical results were compared to determine the positioning accuracy. The difference between theoretical pitch angles [0°,80°] and measured values for the yaw angle range of [0°, 40°] was found to be in the range of 0.03° ~ 5.06°.Clinical Relevance- Diagnosis based on manual palpation is often subjective and palpation sensitivity depends on the physician's level of experience and skill. Therefore, an objective method for acquiring tactile information is relevant. Robotic palpation system provides objective and quantitative information for better understanding of the pathological and physiological changes in the tissue using mechanical properties as biomarkers.

Digital rectal examination in prostate cancer screening at PSA level 3.0-3.9 ng/ml: long-term results from a randomized trial

OBJECTIVE

To evaluate digital rectal examination (DRE) as a predictor of prostate cancer (PC) at serum PSA level 3.0-3.9 ng/ml. We compared the PC incidence rates of men with different screening test results in this PSA range and analyzed DRE in comparison with free/total PSA ratio as an additional screening test.

MATERIALS AND METHODS

Using data from the FinRSPC trial, PC incidence rate ratios (IRR) for groups defined by the secondary screening test results (DRE vs. free/total PSA) were calculated for 17-year follow-up, using adjustment for age, family history of PC and place of residence. Screening test performance was evaluated by calculating sensitivity, specificity, positive and negative predictive value, and likelihood ratio.

RESULTS

The IRR for men with a positive DRE compared to those with a negative result was 1.40 (95% confidence interval (CI) 1.00-1.96), while the IRR for men with a positive free/total PSA result compared to those with a negative one was 1.62 (95% CI 1.08-2.43). The estimated sensitivity was 0.15 (95% CI 0.11-0.20, 40/270) for DRE and 0.32 (95% CI 0.23-0.41, 36/113) for free/total PSA, and the specificity 0.91 (95% CI 0.88-0.93, 419/461) for DRE and 0.85 (95% CI 0.78-0.90, 134/158) for free/total PSA.

CONCLUSIONS

Our results do not support utility of DRE as a screening test for PC at serum PSA level 3.0-3.9 ng/ml, while the results regarding free/total PSA determination were more encouraging and reconfirm the decision to switch from DRE to free/total PSA.

The times they are a-changin': The evolution of prostate cancer screening practices and beliefs among primary care physicians in Victoria, British Columbia

INTRODUCTION

Prostate cancer screening practices remain controversial among primary care practitioners (PCPs). Inconsistent guidelines and publication of large prostate cancer screening trials have failed to provide definitive guidance. This study investigates the evolution of prostate cancer screening practices and beliefs over 12 years, in Victoria, British Columbia.

METHODS

Questionnaires were delivered to 119 randomly selected PCPs in 2019. Descriptive analysis together with exploratory graphs and Pearson Chi-squared test for independence was calculated. The 2008 data was compared by determining if their value fell within the 2019 data's 95% confidence interval.

RESULTS

Response rate was 69.8% (83/119); 30.1% of PCPs reported regularly screening asymptomatic men with prostate-specific antigen (PSA) testing and 37.3% reported regularly performing digital rectal exam (DRE). The combination of PSA and DRE was the most used (48.2 %) screening modality. Most (73.5%) reported that guidelines influence their screening practices, with the most popular choice being those published by The Canadian Task Force on Preventive Health Care (CTF) (32.5%).

CONCLUSIONS

The results demonstrate a movement away from prostate cancer screening among PCPs when compared to 2008. PCPs believe that DRE and PSA are less valuable as screening tools and that there is insufficient evidence to support their use. The most used initial screening modality was the combination of PSA/DRE, however, we found a decrease in their use between the two study periods. Clinical guidelines continue to influence PCPs screening practices, but the shift of more PCPs following the CTF guidelines since 2008 has likely led to the reciprocal decrease in prostate cancer screening.

What's new in screening in 2015?

PURPOSE OF REVIEW

The aim of this review was to highlight important articles in the field of prostate cancer screening published during 2015 and early 2016. Four major areas were identified for the purpose: screening strategies, post-United States Preventive Services Task Force (USPSTF) 2011-2012, screening trends/patterns, and shared decision making.

RECENT FINDINGS

Several studies furthered the evidence that screening reduces the risk of metastasis and death from prostate cancer. Multiplex screening strategies are of proven benefit; genetics and MRI need further evaluation. Prostate-specific antigen (PSA) screening rates declined in men above age of 50 years, as did the overall prostate cancer incidence following the USPSTF 2011-2012 recommendation against PSA. The consequences of declining screening rates will become apparent in the next few years. More research is needed to identify the most optimal approach to engage in, and implement, an effective shared decision-making in clinical practice.

SUMMARY

Data emerging in 2015 provided evidence on the question of how best to screen and brought more steps in the right direction of 'next-generation prostate cancer screening'. Screening is an ongoing process in all men regardless of whether or not they might benefit from early detection and treatment. After the USPSTF 2011-2012 recommendation, the rates of PSA testing are declining; however, this decline is observed in all men and not solely in those who will not benefit from the screening. The long-term effect of this recommendation might not be as anticipated. More studies are needed on how to implement the best available evidence on who, and when, to screen in clinical practice.

Contemporary outcomes in the detection of prostate cancer using transrectal ultrasound-guided 12-core biopsy in Singaporean men with elevated prostate specific antigen and/or abnormal digital rectal examination

Objective

Despite being the third commonest cancer in Singaporean men, there is a dearth of basic data on the detection rate of prostate cancer and post-procedure complication rates locally using systematic 12-core biopsy. Our objective is to evaluate prostate cancer detection rates using 12-core prostate biopsy based on serum prostate specific antigen (PSA) levels and digital rectal examination (DRE) findings in Singaporean men presenting to a single tertiary centre. The secondary objective is to evaluate the complication rates of transrectal prostate biopsies.

Methods

We retrospectively examined 804 men who underwent first transrectal-ultrasound (TRUS) guided 12-core prostate biopsies from January 2012 to April 2014. Prostate biopsies were performed on men presenting to a tertiary institution when their PSA levels were ≥4.0 ng/mL and/or when they had suspicious DRE findings.

Results

Overall prostate cancer detection rate was 35.1%. Regardless of DRE findings, patients were divided into four subgroups based on their serum PSA levels: 0–3.99 ng/mL, 4.00–9.99 ng/mL, 10.00–19.99 ng/mL and ≥20.00 ng/mL and their detection rates were 9.5%, 20.9%, 38.4% and 72.3%, respectively. The detection rate of cancer based on suspicious DRE findings alone was 59.2% compared to 36.5% based on serum PSA cut-off of 4.0 ng/mL alone. The post-biopsy admission rate for sepsis was 1.5%.

Conclusion

In conclusion, using contemporary 12-core biopsy methods, the local prostate cancer detection rate based on serum PSA and DRE findings has increased over the past decade presumably due to multiple genetic and environmental factors. Post-biopsy sepsis remains an important complication worldwide.

Oxymatrine inhibits the proliferation of prostate cancer cells in vitro and in vivo

Oxymatrine is an alkaloid, which is derived from the traditional Chinese herb, Sophora flavescens Aiton. Oxymatrine has been shown to exhibit anti-inflammatory, antiviral, and anticancer properties. The present study aimed to investigate the anticancer effects of oxymatrine in human prostate cancer cells, and the underlying molecular mechanisms of these effects. An MTT assay demonstrated that oxymatrine significantly inhibited the proliferation of prostate cancer cells in a time- and dose-dependent manner. In addition, flow cytometry and a terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling assay suggested that oxymatrine treatment may induce prostate cancer cell apoptosis in a dose-dependent manner. Furthermore, western blot analysis demonstrated a significant increase in the expression of p53 and bax, and a significant decrease in that of Bcl-2, in prostrate cancer cells in a dose-dependent manner. In vivo analysis demonstrated that oxymatrine inhibited tumor growth following subcutaneous inoculation of prostate cancer cells into nude mice. The results of the present study suggested that the antitumor properties of oxymatrine, may be associated with the inhibition of cell proliferation, and induction of apoptosis, via the regulation of apoptosis-associated gene expression. Therefore, the results may provide a novel approach for the development of prostate cancer therapy using oxymatrine, which is derived from the traditional Chinese herb, Sophora flavescens.

B-mode and acoustic radiation force impulse (ARFI) imaging of prostate zonal anatomy: comparison with 3T T2-weighted MR imaging

Prostate cancer (PCa) is the most common non-cutaneous malignancy among men in the United States and the second leading cause of cancer-related death. Multi-parametric magnetic resonance imaging (mpMRI) has gained recent popularity to characterize PCa. Acoustic Radiation Force Impulse (ARFI) imaging has the potential to aid PCa diagnosis and management by using tissue stiffness to evaluate prostate zonal anatomy and lesions. MR and B-mode/ARFI in vivo imaging datasets were compared with one another and with gross pathology measurements made immediately after radical prostatectomy. Images were manually segmented in 3D Slicer to delineate the central gland (CG) and prostate capsule, and 3D models were rendered to evaluate zonal anatomy dimensions and volumes. Both imaging modalities showed good correlation between estimated organ volume and gross pathologic weights. Ultrasound and MR total prostate volumes were well correlated (R(2) = 0.77), but B-mode images yielded prostate volumes that were larger (16.82% ± 22.45%) than MR images, due to overestimation of the lateral dimension (18.4% ± 13.9%), with less significant differences in the other dimensions (7.4% ± 17.6%, anterior-to-posterior, and -10.8% ± 13.9%, apex-to-base). ARFI and MR CG volumes were also well correlated (R(2) = 0.85). CG volume differences were attributed to ARFI underestimation of the apex-to-base axis (-28.8% ± 9.4%) and ARFI overestimation of the lateral dimension (21.5% ± 14.3%). B-mode/ARFI imaging yielded prostate volumes and dimensions that were well correlated with MR T2-weighted image (T2WI) estimates, with biases in the lateral dimension due to poor contrast caused by extraprostatic fat. B-mode combined with ARFI imaging is a promising low-cost, portable, real-time modality that can complement mpMRI for PCa diagnosis, treatment planning, and management.

microRNA-155 promotes the proliferation of prostate cancer cells by targeting annexin 7

Micro (mi)RNAs are a group of small non-coding RNA molecules that have been demonstrated to regulate the expression of genes involved in tumorigenesis. The relevance of microRNAs in the development, progression and prognosis of prostate cancer is not fully understood. miR-155 has been implicated in the induction of breast, lung and liver cancer, but its role in prostate cancer has not been investigated. In the present study, the biological function of miR-155 was investigated in prostate cancer for the first time, to the best of our knowledge. It was demonstrated that the expression of miR-155 was upregulated in prostate cancer tissues and cell lines as determined by quantitative reverse transcription-polymerase chain reaction. Furthermore, overexpression of miR-155 promoted cell proliferation, as indicated by MTT assay. Flow cytometric analysis demonstrated that inhibition of miR-155 induced cell cycle arrest and promoted apoptosis in prostate cancer cells. In addition, western blot analysis indicated that annexin (ANX)7 was significantly downregulated in prostate cancer tissues and cells. A luciferase reporter assay indicated that ANX7 was a target of miR-155, which suggested that miRNA-155 promoted the proliferation of prostate cancer cells by regulating ANX7 expression levels.

Are hypoechoic lesions on transrectal ultrasonography a marker for clinically significant prostate cancer?

Purpose

To investigate the relationship of transrectal ultrasound (TRUS) findings with the pathological characteristics of prostate cancer (PCa).

Materials and Methods

The study was conducted retrospectively by analyzing the data for 970 patients who underwent prostate biopsies. Gleason scores and other clinical variables were compared between PCa patients with and without hypoechoic lesions on TRUS.

Results

Of the 970 patients, PCa was diagnosed in 291 (30%). Of these, high-grade PCa (Gleason score of 7 or more) was diagnosed in 190 (65%). The cancer detection rate was higher in patients with hypoechoic lesions (43.9%) than in those without hypoechoic lesions (21.4%, p<0.001). High-grade PCa was detected more often in patients with hypoechoic lesions than in those without hypoechoic lesions (p<0.001). Independent predictors for high-grade PCa by logistic regression analysis included hypoechoic lesions on TRUS and abnormal digital rectal examination findings.

Conclusions

Patients with PCa who had hypoechoic lesions on TRUS had more aggressive pathological disease than did those without lesions. Therefore, hypoechoic lesions on TRUS could be a marker for clinically significant PCa.

Early detection of high-grade prostate cancer using digital rectal examination (DRE) in men with a prostate-specific antigen level of <2.5 ng/mL and the risk of death

Study Type--Prognosis (inception cohort) Level of Evidence 2a. What's known on the subject? and What does the study add? There is little data on the utility of digital rectal examination (DRE) as a diagnostic tool in the era of prostate-specific antigen (PSA) testing. Using a population-based database, we found that detection of prostate cancer while still localized among men with high-grade PSA-occult disease may result in survival benefit.

OBJECTIVE

• To determine whether detection of high-grade prostate cancer while still clinically localised on digital rectal examination (DRE) can improve survival in men with a normal prostate-specific antigen (PSA) level.

PATIENTS AND METHODS

• From the Surveillance, Epidemiology and End Results database, 166,104 men with prostate cancer diagnosed between 2004 and 2007 were identified. • Logistic regression was used to identify factors associated with the occurrence of palpable, PSA-occult (PSA level of <2.5 ng/mL), Gleason score 8-10 prostate cancer. • Fine and Gray's and Cox multivariable regressions were used to analyse whether demographic, treatment, and clinicopathological factors were associated with the risk of prostate cancer-specific mortality (PCSM) and all-cause mortality (ACM), respectively.

RESULTS

• Both increasing age (adjusted odds ratio [aOR] 1.02, 95% confidence interval (CI) 1.01-1.03; P < 0.001) and White race (aOR 1.26, 95% CI 1.03-1.54; P = 0.027) were associated with palpable, Gleason 8-10 prostate cancer. Of 166,104 men, 685 (0.4%) had this subset of prostate cancer. • Significant factors associated with risk of PCSM included PSA level (adjusted hazard ratio [aHR] 0.71, 95% CI 0.51-0.99; P = 0.04), higher Gleason score (aHR 2.20, 95% CI 1.25-3.87; P = 0.006), and T3-T4 vs T2 disease (aHR 3.11, 95% CI 1.79-5.41; P < 0.001). • Significant factors associated with risk of ACM included age (aHR 1.03, 95% CI 1.01-1.06; P = 0.006), higher Gleason score (aHR 2.05, 95% CI 1.36-3.09; P < 0.001), and T3-T4 vs T2 disease (aHR 2.11, 95% CI 1.38-3.25, P < 0.001)

CONCLUSIONS

• Clinically localised disease on DRE among men with PSA-occult high-grade prostate cancer was associated with improved PCSM and ACM, suggesting that DRE in this cohort (older age and White race) may have the potential to improve survival.

Predictive value of digital rectal examination for prostate cancer detection is modified by obesity

The American Cancer Society's updated screening guidelines for prostate cancer (CaP) render digital rectal examination (DRE) optional. We investigated the impact of DRE on CaP detection among obese men. Data from 2794 men undergoing initial prostate biopsy at three centers were analyzed to assess CaP risk attributed to abnormal DRE across body mass index (BMI) categories. Predictive accuracies of a combination of PSA, age, race, center and biopsy year including or excluding DRE findings were compared by areas under the receiver-operating characteristics curves. In all cohorts, obese men were less likely to have abnormal DREs diagnosed than non-obese men. As BMI category increased, abnormal DREs became stronger predictors for overall CaP in individual (P-trends ≤ 0.05) and combined (P-trend<0.001) cohorts, and for high-grade CaP in the Italian (P-trend=0.03) and combined (P-trend=0.03) cohorts. DRE inclusion improved the predictive accuracy for overall and high-grade CaP detection among all obese men (P ≤ 0.032) but not normal-weight men (P ≥ 0.198). DRE inclusion also near-significantly improved overall CaP detection in obese men with PSA<4 ng ml(-1) (P=0.081). In conclusion, the predictive value of DRE is dependent on obesity and is significantly higher among obese men than normal-weight men.

Robotic palpation-based mechanical property mapping for diagnosis of prostate cancer

PURPOSE

The aim of this study was to estimate the mechanical properties (elasticity) of normal and cancer prostate tissues and to develop a tissue elasticity map for the diagnosis and localization of prostate cancer.

MATERIALS AND METHODS

A total of 735 sites from 35 radical prostatectomy specimens were used in the experiments using a robotic palpation system, and the elasticities of the specimens were estimated by a tissue characterization algorithm. The estimated elasticities from 21 regions were separated into normal and cancer tissues using the pathological information, and a tissue elasticity map was developed using numerical functions and a nonlinear surface-fitting method.

RESULTS

The mean elastic moduli of the normal and cancer tissues were 15.25 ± 5.88 and 28.80 ± 11.20 kPa, respectively. The base region had the highest elasticity, followed by the medial and apex regions. These results demonstrated the ability to separate the cancer tissue from the normal tissue based on its elastic modulus. The tissue elasticity mapping was carried out using the estimated elasticity and nonlinear surface fitting. The proposed map showed the elasticity and was used to estimate the elastic modulus of the prostate at any given region.

CONCLUSION

Tissue elasticity may be an important indicator of prostate cancer because the pathologic changes alter the tissue properties, including cell integrity and intercellular matrix. This work provides quantitative and objective information for the diagnosis of prostate cancer. In addition, these results may have implications for the localization of prostate cancers.

Comparison of observed biochemical recurrence-free survival in patients with low PSA values undergoing radical prostatectomy and predictions of preoperative nomogram

OBJECTIVES

A preoperative nomogram is an effective tool for assessing the risk of disease progression after radical prostatectomy for localized prostate cancer. To better understand the performance of nomograms for patients with a low prostate-specific antigen (PSA) level, we examined whether patients with a PSA level <2.5 ng/mL had outcomes different than predicted by a validated preoperative nomogram.

METHODS

A cohort of 6130 patients from 2 referral centers was analyzed. Kaplan-Meier methods were used to estimate the recurrence-free probabilities stratified by PSA group (<2.5 vs >or=2.5 ng/mL). Cox proportional hazards regression analysis was used to evaluate whether the PSA grouping was associated with biochemical recurrence, controlling for preoperative nomogram probability.

RESULTS

Of 6130 patients, 399 (6.5%) had a PSA level <2.5 ng/mL. Patients with a PSA level of <or=0.5 ng/mL had a high rate of nonorgan-confined disease (33% vs 15% for PSA levels of 0.6-2.5 ng/mL). The median follow-up for recurrence-free patients was 2.4 years, and 10 patients with a PSA level of <2.5 ng/mL and 597 patients with a PSA level >2.5 ng/mL developed recurrence (total 607/6130). With adjustment for the preoperative nomogram probability, no significant difference was found in recurrence by PSA grouping (hazard ratio 0.78 for PSA <2.5 vs >or=2.5 ng/mL; 95% confidence interval 0.42-1.48; P = .5).

CONCLUSIONS

Patients with a low PSA comprise a small proportion of those treated, and most have palpable disease. Patients with especially low PSA values (<or=0.5 ng/mL) have a high rate of nonorgan-confined disease. We saw no evidence that patients with low PSA levels have worse outcomes, after the stage and grade were taken into account.

Percent free prostate-specific antigen (PSA) is an accurate predictor of prostate cancer risk in men with serum PSA 2.5 ng/mL and lower

BACKGROUND

Up to 17% of men with a prostate-specific antigen (PSA) level below the accepted prostate biopsy cutoff of 2.5 ng/mL may have prostate cancer. Because identification of these patients represents a difficult task, we assessed the ability of percent free PSA to discriminate between benign and malignant prostate biopsy outcomes in men with PSA < or =2.5 ng/mL.

METHODS

Between 1999 and 2006, 543 men with a PSA < or =2.5 ng/mL were referred for initial prostate biopsy. Age, total PSA, percent free PSA, and digital rectal examination findings represented predictors of prostate cancer at biopsy in logistic regression models. The area under the receiver operating characteristics curve (AUC) quantified the discriminative ability of the predictors. The pathological characteristics of the detected cancers were assessed in individuals treated with radical prostatectomy.

RESULTS

Of all, 23% had prostate cancer on biopsy, 16.5% of patients treated with radical prostatectomy had pT3 stage, and 35.6% had a pathological Gleason score of 3 + 4 or higher. The most accurate predictor of prostate cancer on biopsy was percent free PSA (0.68) versus age (0.50), total PSA (0.57), or rectal examination findings (0.58). Of patients with percent free PSA below 14%, 59% had prostate cancer. In multivariate models, percent free PSA (P < .001) and rectal examination findings (P = .001) were the only independent predictors of prostate cancer. The combined AUC of all predictors (0.69) was not significantly (P = .7) higher than that of percentage of free PSA alone (0.68).

CONCLUSIONS

The risk of prostate cancer is clearly non-negligible in patients with PSA < or =2.5 ng/mL. The percent free PSA can accurately predict the prevalence of prostate cancer at prostate biopsy in these individuals.

Clinical Impact of New Prostate-Specific Antigen WHO Standardization on Biopsy Rates and Cancer Detection

Background: Clinicians may be unaware that replacement of the historical total prostate-specific antigen (tPSA) standard with the WHO 96/670 international standard leads to difficulties in interpreting tPSA results. Our aim was to investigate the relationship between the Hybritech and WHO calibrations of the Beckman Coulter tPSA assay, and to assess the impact on prostate cancer (PCa) detection.

Methods: tPSA concentrations were measured in 106 serum samples with both Hybritech and WHO calibrations. The established relationships were used for an in silico experiment with a cohort of 5865 men. Differences in prostate biopsy rates, PCa detection, and characteristics of missed cancers were calculated at biopsy thresholds of 3.0 and 4.0 μg/L.

Results: A linear relationship was observed between the 2 calibrations, with a 20.3% decrease in tPSA values with the WHO standard compared with the Hybritech calibration. Applying the WHO calibration to the cohort of 5865 men yielded a 20% or 19% decrease in prostate biopsies and a 19% or 20% decrease in detected cancers compared with the Hybritech calibration, at a cutoff for biopsy of 3.0 or 4.0 μg/L, respectively. The decrease in detected cancers declined to 9% or 11% if an abnormal result in a digital rectal examination or a transrectal ultrasound evaluation was used as trigger for prostate biopsy (cutoff of 3.0 or 4.0 μg/L, respectively).

Conclusions: Application of the WHO standard for tPSA assays with commonly used tPSA thresholds leads to a significant decrease in PCa detection. Careful assessment of the relationship between the WHO standard and the thresholds used for prostate biopsy is hence necessary.

Contemporary prostate cancer prevalence among T1c biopsy-referred men with a prostate-specific antigen level < or = 4.0 ng per milliliter

OBJECTIVE

To investigate the prostate cancer (PCa) prevalence and risk factors of men with prostate-specific antigen (PSA) level< or =4.0 ng/ml and an unsuspicious digital rectal examination (DRE) in a large biopsy referral cohort.

MATERIALS AND METHODS

Between 1997 and 2005, 855 men underwent initial transrectal ultrasound (TRUS)-guided prostate biopsy at the University Hospital Hamburg-Eppendorf. Patients with any previous surgical or medical treatment were excluded from analyses. Logistic regression analyses were performed to determine risk factors of PCa at biopsy and high-grade PCa defined as biopsy Gleason sum> or =7.

RESULTS

Overall PCa detection rate was 23.1%. The majority had a biopsy Gleason sum of 6 (79.5%) and 20.5% had a biopsy Gleason sum> or =7. Total PSA (tPSA) and percentage of free PSA (%fPSA) were statistically significantly different in men with and without PCa (all p<0.001). In tPSA strata < or = 0.5, 0.6-1.0, 1.1-2.0, 2.1-3.0, and 3.1-4.0 ng/ml, PCa prevalence was 4.0%, 10.6%, 14.8%, 24.5%, and 32.1%, respectively. In logistic regression analyses addressing PCa and Gleason sum > or = 7 at biopsy, %fPSA and prostate volume represented independent and most informative risk factors.

CONCLUSION

Our data demonstrate that a substantial percentage (23.1%) of men with a PSA< or =4.0 ng/ml and an unsuspicious DRE in a biopsy referral population harbor PCa, with 20.5% being high grade. Low %fPSA and low prostate volume represent important parameters in PCa and in high grade disease detection at biopsy, respectively.

[Incidence of locally invasive prostate cancer in patients with intermediate values of prostate-specific antigen]

BACKGROUND/AIM

Feasibility of radical prostatectomy (RP) in patients with locally invasive prostate cancer (PC) is assessed by the standard parameters such as the stage of the disease, serum prostate-specific antigen (PSA) and bioptic Gleason grade (GG). Intermediate values of PSA are important in predicting the local confines of the tumor, but can also be detected in more than 30% of patients with locally advanced PC. The aim of this study was to find out the incidence of locally advanced PC in the patients with intermediate serum PSA in whom RP had been performed.

METHODS

We used the biopsy cores and the tissue obtained after RP from 46 patients who had intermidiate PSA values which were defined as PSA from 2.6-10 ng/ml. In all the patients classical regional lymphadenectomy was performed. In all the patients, preoperative stage was determined according to the Partin tables (PT) from 2001.

RESULTS

In 52, 17% of the patients biopsy GG was < or = 6, while it was 7 in 47.83% of the patients. Clinically localized disease (cT2b) was found in 86.96% of patients; other 13.04% of the patients had locally advanced PC. After RP, the incidence of localized PC was 47.83%, while the advanced disease was found in 52.17%. Metastasis in one or two regional lymph nodes (N1) was found in 10.87% of the patients with the advanced PC. According to PT, the expected incidence of positive lymph nodes should have been 8% for pT3 stage. Positive correlation between the assumed N1 stage according to PT and N1 stage in our radical prostatectomies was statistically significant (p = 0.012).

CONCLUSION

In more than 50% of patients with intermediate values of PSA locally advanced disease can be expected after RP. The use of the Partin tables have an important predictive value in assessing the local confines of the cancer and metastasis in regional lymph nodes.

Digital rectal examination as a prostate cancer-screening method in a country with a low incidence of prostate cancer

The objective of this study was to evaluate the value of using digital rectal examination (DRE) for prostate cancer diagnosis in an Asian population. Patients with serum prostate-specific antigen (PSA) levels ranging from 2.5 to 19.9 ng/ml underwent transrectal ultrasonography-guided prostate biopsies. Patients were divided into two groups: the normal DRE group (n=721) and the abnormal DRE group (n=192). The cancer detection rate was higher in the abnormal DRE group (47.4%) than in the normal DRE group (23.0%) (P<0.001). However, the detection rates in these two groups were not significantly different in men 45-59 years old as well as in men with low PSA levels (2.5-3.9 ng/ml). In all subjects, the areas under the receiver operating characteristic curves for positive biopsies were 60.0% (95% confidence interval (CI), 55.7-64.3%, P<0.001). However, in the subgroup analysis, the predictive power of the DRE was not significant in men 45-59 years old. In addition, DREs of patients with low PSA levels had no discriminative ability. The pathological features of the prostate biopsies were not significantly different between the two groups in subjects 45-59 years old and in subjects with PSA levels from 2.5 to 3.9 ng/ml. Our data indicate that DREs increase the probability of cancer detection. However, our findings also raise the question, 'Are DREs really useful for cancer detection in younger men and men with low PSA levels in the Asian population?'