Is it time to abandon the digital rectal examination? Lessons from the PLCO Cancer Screening Trial and peer-reviewed literature

Prostate Cancer Foundation Screening Guidelines for Black Men in the United States

BACKGROUND

In the United States, Black men are at highest risk for being diagnosed with and dying from prostate cancer. Given this disparity, we examined relevant data to establish clinical prostate-specific antigen (PSA) screening guidelines for Black men in the United States.

METHODS

A comprehensive literature search identified 1848 unique publications for screening. Of those screened, 287 studies were selected for full-text review, and 264 were considered relevant and form the basis for these guidelines. The numbers were reported according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines.

RESULTS

Three randomized controlled trials provided Level 1 evidence that regular PSA screening of men 50 to 74 years of age of average risk reduced metastasis and prostate cancer death at 16 to 22 years of follow-up. The best available evidence specifically for Black men comes from observational and modeling studies that consider age to obtain a baseline PSA, frequency of testing, and age when screening should end. Cohort studies suggest that discussions about baseline PSA testing between Black men and their clinicians should begin in the early 40s, and data from modeling studies indicate prostate cancer develops 3 to 9 years earlier in Black men compared with non-Black men. Lowering the age for baseline PSA testing to 40 to 45 years of age from 50 to 55 years of age, followed by regular screening until 70 years of age (informed by PSA values and health factors), could reduce prostate cancer mortality in Black men (approximately 30% relative risk reduction) without substantially increasing overdiagnosis.

CONCLUSIONS

These guidelines recommend that Black men should obtain information about PSA screening for prostate cancer. Among Black men who elect screening, baseline PSA testing should occur between ages 40 and 45. Depending on PSA value and health status, annual screening should be strongly considered. (Supported by the Prostate Cancer Foundation.).

Comparing the Performance of Digital Rectal Examination and Prostate-specific Antigen as a Screening Test for Prostate Cancer: A Systematic Review and Meta-analysis

BACKGROUND AND OBJECTIVE

Although digital rectal examination (DRE) is recommended in combination with prostate-specific antigen (PSA) for detection of prostate cancer (PCa), there are limited data to support its use as a screening/early detection test. Our objective was to assess the diagnostic value of DRE in screening for early detection of PCa.

METHODS

In August 2023, we queried the PubMed, Scopus, and Web of Science databases to identify prospective studies simultaneously investigating the diagnostic performance of DRE and PSA for PCa screening. The primary endpoints were the positive predictive value (PPV) and cancer detection rate (CDR) of DRE. Secondary endpoints included the PPV and CDR of both PSA alone and in combination with DRE. We conducted meta-regression analysis to compare the CDR and PPV of different screening strategies. This meta-analysis is registered on PROSPERO (CRD42023446940).

KEY FINDINGS AND LIMITATIONS

We identified eight studies involving 85 738 participants, of which three were randomized controlled trials and five were prospective diagnostic studies, that reported the PPV and CDR of both DRE and PSA for the same cohort. Our analysis revealed a pooled PPV of 0.21 (95% confidence interval [CI] 0.13-0.33) for DRE, which is similar to the PPV of PSA (0.22, 95% CI 0.15-0.30; p = 0.9), with no benefit from combining DRE and PSA (PPV 0.19, 95% CI 0.13-0.26; p = 0.5). However, the CDR of DRE (0.01, 95% CI: 0.01-0.02) was significantly lower than that of PSA (0.03, 95% CI 0.02-0.03; p < 0.05) and the combination of DRE and PSA (0.03, 95% CI 0.02-0.04; p < 0.05). The screening strategy combining DRE and PSA was not different to that of PSA alone in terms of CDR (p = 0.5) and PPV (p = 0.5).

CONCLUSIONS AND CLINICAL IMPLICATIONS

Our comprehensive review and meta-analysis indicates that both as an independent test and as a supplementary measure to PSA for PCa detection, DRE exhibits a notably low diagnostic value. The collective findings from the included studies suggest that, in the absence of clinical symptoms and signs, DRE could be potentially omitted from PCa screening and early detection strategies.

PATIENT SUMMARY

Our review shows that the screening performance of digital rectal examination for detection of prostate cancer is not particularly impressive, suggesting that it might not be necessary to conduct this examination routinely.

Automated prostate multi-regional segmentation in magnetic resonance using fully convolutional neural networks

OBJECTIVE

Automatic MR imaging segmentation of the prostate provides relevant clinical benefits for prostate cancer evaluation such as calculation of automated PSA density and other critical imaging biomarkers. Further, automated T2-weighted image segmentation of central-transition zone (CZ-TZ), peripheral zone (PZ), and seminal vesicle (SV) can help to evaluate clinically significant cancer following the PI-RADS v2.1 guidelines. Therefore, the main objective of this work was to develop a robust and reproducible CNN-based automatic prostate multi-regional segmentation model using an intercontinental cohort of prostate MRI.

METHODS

A heterogeneous database of 243 T2-weighted prostate studies from 7 countries and 10 machines of 3 different vendors, with the CZ-TZ, PZ, and SV regions manually delineated by two experienced radiologists (ground truth), was used to train (n = 123) and test (n = 120) a U-Net-based model with deep supervision using a cyclical learning rate. The performance of the model was evaluated by means of dice similarity coefficient (DSC), among others. Segmentation results with a DSC above 0.7 were considered accurate.

RESULTS

The proposed method obtained a DSC of 0.88 ± 0.01, 0.85 ± 0.02, 0.72 ± 0.02, and 0.72 ± 0.02 for the prostate gland, CZ-TZ, PZ, and SV respectively in the 120 studies of the test set when comparing the predicted segmentations with the ground truth. No statistically significant differences were found in the results obtained between manufacturers or continents.

CONCLUSION

Prostate multi-regional T2-weighted MR images automatic segmentation can be accurately achieved by U-Net like CNN, generalizable in a highly variable clinical environment with different equipment, acquisition configurations, and population.

KEY POINTS

• Deep learning techniques allows the accurate segmentation of the prostate in three different regions on MR T2w images. • Multi-centric database proved the generalization of the CNN model on different institutions across different continents. • CNN models can be used to aid on the diagnosis and follow-up of patients with prostate cancer.

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.

Magnetic Resonance Imaging-Based Predictive Models for Clinically Significant Prostate Cancer: A Systematic Review

Simple Summary

Magnetic resonance imaging (MRI) has allowed the early detection of PCa to evolve towards clinically significant PCa (csPCa), decreasing unnecessary prostate biopsies and overdetection of insignificant tumours. MRI identifies suspicious lesions of csPCa, predicting the semi-quantitative risk through the prostate imaging report and data system (PI-RADS), and enables guided biopsies, increasing the sensitivity of csPCa. Predictive models that individualise the risk of csPCa have also evolved adding PI-RADS score (MRI-PMs), improving the selection of candidates for prostate biopsy beyond the PI-RADS category. During the last five years, many MRI-PMs have been developed. Our objective is to analyse the current developed MRI-PMs and define their clinical usefulness through a systematic review. We have found high heterogeneity between MRI technique, PI-RADS versions, biopsy schemes and approaches, and csPCa definitions. MRI-PMs outperform the selection of candidates for prostate biopsy beyond MRI alone and PMs based on clinical predictors. However, few developed MRI-PMs are externally validated or have available risk calculators (RCs), which constitute the appropriate requirements used in routine clinical practice.

Abstract

MRI can identify suspicious lesions, providing the semi-quantitative risk of csPCa through the Prostate Imaging-Report and Data System (PI-RADS). Predictive models of clinical variables that individualise the risk of csPCa have been developed by adding PI-RADS score (MRI-PMs). Our objective is to analyse the current developed MRI-PMs and define their clinical usefulness. A systematic review was performed after a literature search performed by two independent investigators in PubMed, Cochrane, and Web of Science databases, with the Medical Subjects Headings (MESH): predictive model, nomogram, risk model, magnetic resonance imaging, PI-RADS, prostate cancer, and prostate biopsy. This review was made following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) criteria and studied eligibility based on the Participants, Intervention, Comparator, and Outcomes (PICO) strategy. Among 723 initial identified registers, 18 studies were finally selected. Warp analysis of selected studies was performed with the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. Clinical predictors in addition to the PI-RADS score in developed MRI-PMs were age, PCa family history, digital rectal examination, biopsy status (initial vs. repeat), ethnicity, serum PSA, prostate volume measured by MRI, or calculated PSA density. All MRI-PMs improved the prediction of csPCa made by clinical predictors or imaging alone and achieved most areas under the curve between 0.78 and 0.92. Among 18 developed MRI-PMs, 7 had any external validation, and two RCs were available. The updated PI-RADS version 2 was exclusively used in 11 MRI-PMs. The performance of MRI-PMs according to PI-RADS was only analysed in a single study. We conclude that MRI-PMs improve the selection of candidates for prostate biopsy beyond the PI-RADS category. However, few developed MRI-PMs meet the appropriate requirements in routine clinical practice.

The Impact of Lifestyle on Prostate Cancer: A Road to the Discovery of New Biomarkers

Prostate cancer (PCa) is one of the most common cancers among men, and its incidence has been rising through the years. Several risk factors have been associated with this disease and unhealthy lifestyles and inflammation were appointed as major contributors for PCa development, progression, and severity. Despite the advantages associated with the currently used diagnostic tools [prostate-specific antigen(PSA) serum levels and digital rectal examination (DRE)], the development of effective approaches for PCa diagnosis is still necessary. Finding lifestyle-associated proteins that may predict the development of PCa seems to be a promising strategy to improve PCa diagnosis. In this context, several biomarkers have been identified, including circulating biomarkers (CRP, insulin, C-peptide, TNFα-R2, adiponectin, IL-6, total PSA, free PSA, and p2PSA), urine biomarkers (PCA3, guanidine, phenylacetylglycine, and glycine), proteins expressed in exosomes (afamin, vitamin D-binding protein, and filamin A), and miRNAs expressed in prostate tissue (miRNA-21, miRNA-101, and miRNA-182). In conclusion, exploring the impact of lifestyle and inflammation on PCa development and progression may open doors to the identification of new biomarkers. The discovery of new PCa diagnostic biomarkers should contribute to reduce overdiagnosis and overtreatment.

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.

Radiomics for Identification and Prediction in Metastatic Prostate Cancer: A Review of Studies

Metastatic Prostate Cancer (mPCa) is associated with a poor patient prognosis. mPCa spreads throughout the body, often to bones, with spatial and temporal variations that make the clinical management of the disease difficult. The evolution of the disease leads to spatial heterogeneity that is extremely difficult to characterise with solid biopsies. Imaging provides the opportunity to quantify disease spread. Advanced image analytics methods, including radiomics, offer the opportunity to characterise heterogeneity beyond what can be achieved with simple assessment. Radiomics analysis has the potential to yield useful quantitative imaging biomarkers that can improve the early detection of mPCa, predict disease progression, assess response, and potentially inform the choice of treatment procedures. Traditional radiomics analysis involves modelling with hand-crafted features designed using significant domain knowledge. On the other hand, artificial intelligence techniques such as deep learning can facilitate end-to-end automated feature extraction and model generation with minimal human intervention. Radiomics models have the potential to become vital pieces in the oncology workflow, however, the current limitations of the field, such as limited reproducibility, are impeding their translation into clinical practice. This review provides an overview of the radiomics methodology, detailing critical aspects affecting the reproducibility of features, and providing examples of how artificial intelligence techniques can be incorporated into the workflow. The current landscape of publications utilising radiomics methods in the assessment and treatment of mPCa are surveyed and reviewed. Associated studies have incorporated information from multiple imaging modalities, including bone scintigraphy, CT, PET with varying tracers, multiparametric MRI together with clinical covariates, spanning the prediction of progression through to overall survival in varying cohorts. The methodological quality of each study is quantified using the radiomics quality score. Multiple deficits were identified, with the lack of prospective design and external validation highlighted as major impediments to clinical translation. These results inform some recommendations for future directions of the field.

The prognostic value of digital rectal exam for the existence of advanced pathologic features after prostatectomy

BACKGROUND

Accurate staging at the time of prostate cancer diagnosis is fundamental to risk stratification and management counseling. Digital rectal exam (DRE) is foundational in clinical staging of prostate cancer, even with a known limited interexaminer agreement and poor sensitivity for detecting extraprostatic disease. We sought to evaluate the prognostic value of DRE for the presence of advanced pathologic features (APFs) following radical prostatectomy (RP).

METHODS

All patients undergoing RP as primary treatment for clinically localized prostate cancer in the National Cancer Database between 2008 and 2014 were identified. Patients with additional malignancies, prior treatment with radiation or systemic therapy, incongruent clinical staging and DRE findings or without fully evaluable clinical staging were excluded. The primary outcome was the presence of postsurgical APFs, defined as positive surgical margins, nodal disease, or pathologic stage T3 or greater. Multivariable logistic regression analysis was performed to account for prostate-specific antigen (PSA), biopsy grade group, percent of positive biopsy cores, and clinical stage.

RESULTS

In total, 91,525 patients consisting of 69,182 cT1, 20,641 cT2, and 1702 cT3-T4 were included. The average age was 61.1 ± 7.0 years, and the average PSA was 8.6 ± 10.3 ng/ml. On multivariable analysis, cT3 and T4 were associated with the presence of APFs (odds ratio [OR] 11.12, p < .01 and 5.28, p = .04), however, cT2 was only slightly associated with the presence of APFs when compared with cT1 (OR 1.15, p < .01). Furthermore, cT2 was associated with more node-positive disease (OR 1.63, p < .01), positive margins (OR 1.06, p < .01), and more than or equal to pT3 disease (OR 1.22, p < .01).

CONCLUSIONS

Overall, advanced clinical stage as assessed by DRE was independently associated with an increasing risk of APFs. For individual APFs, the greatest effect is noticed between clinical stage and nodal positivity and less so between clinical stage and positive margins. DRE continues to hold value, particularly for patients with locally advanced disease and potential lymph node disease.

Prostate Cancer From a Sex and Gender Perspective: A Review

INTRODUCTION

Factors influencing patient behavior regarding risk of prostate cancer (PCa) and outcomes of PCa treatments are poorly understood. Similarly, how PCa treatments affect patient sexual function and sense of their masculinity has not been fully investigated. A better understanding of the relationship between sex and gender for patients with PCa could significantly improve their care and quality of life.

OBJECTIVES

To review how concerns about sex and gender influence men's attitudes toward PCa screening, diagnosis, and treatment. To explore how PCa influences sexual function and self-perceived masculine identity. To examine contexts for PSA screening for transgender individuals.

METHODS

We reviewed biomedical and sociological literature exploring the impact of PCa on patient sexual function and self-perceived masculinity using OVID, PubMed, and other databases. We similarly reviewed how masculine gender norms influence patient willingness to engage with PCa screening, diagnoses, and treatment.

RESULTS

Gender norms and sexual function concerns influence patient engagement in all aspects of PCa care. This includes PSA screening, digital rectal examinations, active surveillance, and androgen deprivation therapy (ADT) amongst others. ADT is particularly challenging to sexual function, self-esteem, and masculine identity. Our research suggests that sex and gender are not separate concepts, but rather tightly intertwined, particularly when dealing with the realities experienced by patients with PCa.

CONCLUSION

Interventions to help patients deal with the challenges of PCa and its treatment are likely to be most effective if they concurrently address patients' sexual needs and understanding of gender norms. PSA screening should be considered for transgender individuals who are at greater risk of cancer and on long-term hormone therapy. More research is needed on how concerns over sex and gender influence PCa screening, diagnosis, and treatment. There is also a need for long term data on the oncological outcomes of prolonged exposure to hormone therapy for patients who are transgender. Muermann MM, Wassersug RJ. Prostate Cancer From a Sex and Gender Perspective: A Review. Sex Med Rev 2021;XX:XXX-XXX.

African Immigrant Health: Prostate Cancer Attitudes, Perceptions, and Barriers

Prostate cancer (PCa) is the second leading cause of cancer-related death among Black men who present with higher incidence, mortality, and survival compared to other racial groups. African immigrant men, however, are underrepresented in PCa research and thus this research sought to address that gap. This study applied a social determinants of health framework to understand the knowledge, perceptions, and behavioral tendencies regarding PCa in African immigrants. African immigrant men and women residing in different parts of the country (California, Texas, Colorado, Oklahoma, and Florida) from various faith-based organizations, African community groups, and social groups were recruited to participate in key informant interviews (n = 10) and two focus groups (n = 23). Four themes were identified in this study: (a) PCa knowledge and attitudes-while knowledge is very limited, perceptions about prostate health are very strong; (b) culture and gender identity strongly influence African health beliefs; (c) preservation of manhood; and (d) psychosocial stressors (e.g., financial, racial, immigration, lack of community, and negative perceptions of invasiveness of screening) are factors that play a major role in the overall health of African immigrant men. The results of this qualitative study unveiled perceptions, attitudes, beliefs, and knowledge of PCa among African immigrants that should inform the planning, development, and implementation of preventive programs to promote men's health and PCa awareness.

Digital rectal examination and its associated factors in the early detection of prostate cancer: a cross-sectional population-based study

BACKGROUND

Digital rectal examination (DRE) is one of the most common strategies for prostate cancer early detection. However, the use for screening purposes has a controversial benefit and potential harms can occur due to false-positive results, overdiagnosis and overtreatment. The objective of this study is to calculate the prevalence and identify factors associated with the receipt of DRE in Brazilian men.

METHODS

We selected men older than 40 from a nationwide population-based survey (13,625 individuals) excluding those with prostate cancer diagnosis. Information was extracted from the most recent database of the Brazilian National Health Survey (PNS 2013). Statistical analysis was carried out to calculate incidence rate ratios, with 95% confidence intervals and p values, through multivariate analysis with Poisson regression and robust variance.

RESULTS

Men having private health insurance (63.3%; CI = 60.5-66.0) presented higher prevalence of DRE than those in the public health system (41.6%; CI = 39.8-43.4). The results show a positive association between DRE and men having private health insurance, aged 60-69, living with a spouse, never smokers, and living in urban areas. Among public health services users, this positive association was observed among men aged 70-79, living with a spouse, having bad/very bad health self-perception, abstainers, ex-smokers, with undergraduate studies, presenting four or more comorbidities, and residing in urban areas.

CONCLUSIONS

Prostate cancer screening with DRE is quite frequent in Brazil, specially among men with private health plans and better access to health services, healthier lifestyle and at more advanced ages, characteristics which increase the risk of overdiagnosis and overtreatment.

Digital Rectal Examination for Prostate Cancer Screening in Primary Care: A Systematic Review and Meta-Analysis

PURPOSE

Although the digital rectal examination (DRE) is commonly performed to screen for prostate cancer, there is limited data to support its use in primary care. This review and meta-analysis aims to evaluate the diagnostic accuracy of DRE in screening for prostate cancer in primary care settings.

METHODS

We searched MEDLINE, Embase, DARE (Database of Abstracts of Reviews of Effects), Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, and CINAHL (Cumulative Index to Nursing and Allied Health Literature) from their inception to June 2016. Six reviewers, in pairs, independently screened citations for eligibility and extracted data. Pooled estimates were calculated for sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of DRE in primary care settings using an inverse-variance meta-analysis. We used QUADAS-2 (Quality Assessment of Diagnostic Accuracy Studies 2) and GRADE (Grades of Recommendation Assessment, Development, and Evaluation) guidelines to assess study risk of bias and quality.

RESULTS

Our search yielded 8,217 studies, of which 7 studies with 9,241 patients were included after the screening process. All patients analyzed underwent both DRE and biopsy. Pooled sensitivity of DRE performed by primary care clinicians was 0.51 (95% CI, 0.36-0.67; I² = 98.4%) and pooled specificity was 0.59 (95% CI, 0.41-0.76; I² = 99.4%). Pooled PPV was 0.41 (95% CI, 0.31-0.52; I² = 97.2%), and pooled NPV was 0.64 (95% CI, 0.58-0.70; I² = 95.0%). The quality of evidence as assessed with GRADE was very low.

CONCLUSION

Given the considerable lack of evidence supporting its efficacy, we recommend against routine performance of DRE to screen for prostate cancer in the primary care setting.

Review of Gallium-68 PSMA PET/CT Imaging in the Management of Prostate Cancer

Over 90% of prostate cancers over-express prostate specific membrane antigen (PSMA) and these tumor cells may be accurately targeted for diagnosis by 68Ga-PSMA-positron emission tomography/computed tomography (68Ga-PSMA-PET/CT) imaging. This novel molecular imaging modality appears clinically to have superseded CT, and appears superior to MR imaging, for the detection of metastatic disease. 68Ga-PSMA PET/CT has the ability to reliably stage prostate cancer at presentation and can help inform an optimal treatment approach. Novel diagnostic applications of 68Ga-PSMA PET/CT include guiding biopsy to improve sampling accuracy, and guiding surgery and radiotherapy. In addition to facilitating the management of metastatic castrate resistant prostate cancer (mCRPC), 68Ga-PSMA can select patients who may benefit from targeted systemic radionuclide therapy. 68Ga-PSMA is the diagnostic positron-emitting theranostic pair with the beta emitter Lutetium-177 PSMA (177Lu-PSMA) and alpha-emitter Actinium-225 PSMA (225Ac-PSMA) which can both be used to treat PSMA-avid metastases of prostate cancer in the molecular tumor-targeted approach of theranostic nuclear oncology.

Use of Digital Rectal Examination as an Adjunct to Prostate Specific Antigen in the Detection of Clinically Significant Prostate Cancer

PURPOSE

Guidelines from the NCCN^® (National Comprehensive Cancer Network®) advocate digital rectal examination screening only in men with elevated prostate specific antigen. We investigated the effect of prostate specific antigen on the association of digital rectal examination and clinically significant prostate cancer in a large American cohort.

MATERIALS AND METHODS

We evaluated the records of the 35,350 men who underwent digital rectal examination in the screening arm of the Prostate, Lung, Colorectal and Ovarian Cancer Screening trial for the development of clinically significant prostate cancer (Gleason 7 or greater). Followup was 343,273 person-years. The primary outcome was the rate of clinically significant prostate cancer among men with vs without suspicious digital rectal examination. We performed competing risks regression to evaluate the interaction between time varying suspicious digital rectal examination and prostate specific antigen.

RESULTS

A total of 1,713 clinically significant prostate cancers were detected with a 10-year cumulative incidence of 5.9% (95% CI 5.6-6.2). Higher risk was seen for suspicious vs nonsuspicious digital rectal examination. Increases in absolute risk were small and clinically irrelevant for normal (less than 2 ng/ml) prostate specific antigen (1.5% vs 0.7% risk of clinically significant prostate cancer at 10 years), clinically relevant for elevated (3 ng/ml or greater) prostate specific antigen (23.0% vs 13.7%) and modestly clinically relevant for equivocal (2 to 3 ng/ml) prostate specific antigen (6.5% vs 3.5%).

CONCLUSIONS

Digital rectal examination demonstrated prognostic usefulness when prostate specific antigen was greater than 3 ng/ml, limited usefulness for less than 2 ng/ml and marginal usefulness for 2 to 3 ng/ml. These findings support the restriction of digital rectal examination to men with higher prostate specific antigen as a reflex test to improve specificity. It should not be used as a primary screening modality to improve sensitivity.