Prostate cancer screening: facts, statistics, and interpretation in response to the US Preventive Services Task Force Review

How Can Guidelines Give Clearer Guidance on Prostate Cancer Screening?

This Viewpoint explores how guideline groups can come together to agree on a framework that produces clear and unified recommendations.

Personalizing approaches to the management of metastatic hormone sensitive prostate cancer: role of advanced imaging, genetics and therapeutics

PURPOSE

To summarize contemporary and emerging strategies for the diagnosis and management of metastatic hormone sensitive prostate cancer (mHSPC), focusing on diagnostic testing and therapeutics.

METHODS

Literature review using PUBMED-Medline databases as well as clinicaltrials.gov to include reported or ongoing clinical trials on treatment for mHSPC. We prioritized the findings from phase III randomized clinical trials, systematic reviews, meta-analyses and clinical practice guidelines.

RESULTS

There have been significant changes to the diagnosis and staging evaluation of mHSPC with the integration of increasingly accurate positron emission tomography (PET) imaging tracers that exceed the performance of conventional computerized tomography (CT) and bone scan. Germline multigene testing is recommended for the evaluation of patients newly diagnosed with mHSPC given the prevalence of actionable alterations that may create candidacy for specific therapies. Although androgen deprivation therapy (ADT) remains the backbone of treatment for mHSPC, approaches to first-line treatment include the integration of multiple agents including androgen receptor synthesis inhibitors (ARSI; abiraterone) Androgen Receptor antagonists (enzalutamide, darolutamide, apalautamide), and docetaxel chemotherapy. The combination of ADT, ARSI, and docetaxel chemotherapy has recently been evaluated in a randomized trial and was associated with significantly improved overall survival including in patients with a high burden of disease. The role of local treatment to the prostate with radiation has been evaluated in randomized trials with additional studies underway evaluating the role of cytoreductive radical prostatectomy.

CONCLUSION

The staging and initial management of patients with mHSPC has undergone significant advances in the last decade with advancements in the diagnosis, treatment and sequencing of therapies.

Predictors of cancer risky and preventive behaviors among the Nebraska farmers population

PURPOSE

Previous studies on cancer risk among agricultural producers have focused on occupational exposures, with only a few studies examining behavioral factors. The aim of this study was to understand cancer risky and preventative behaviors among the large farming population in Nebraska.

METHODS

A statewide cross-sectional study of farmers in Nebraska aged 19 and older was conducted in 2019 (n = 782). Multivariable logistic regression was used to examine factors associated with being up to date on cancer screening and with cancer risky and preventive behaviors.

FINDINGS

The 93.68% of the Nebraska farmers population do not meet the daily recommended consumption of fruits and vegetables, and 70.14% reported regular alcohol consumption. The proportion of adults up to date on cancer screening was 79.57% for breast, 67.55% for cervical, 85.54% for colorectal, and 46.05% for skin cancers. Compared to women, men had a higher odds of heavy alcohol consumption (aOR 2.96, 95% CI 1.94-4.56) and ever smoking 100 or more cigarettes (aOR 1.66, 95% CI 1.03-2.73). The odds of being current with skin cancer screening was higher among those with higher incomes (aOR 1.77, 95% CI 1.06-3.01). Compared to men aged 50-64, the odds of being current with prostate cancer screening was higher among men aged 65-74 (aOR: 2.65, 95% CI 1.10-7.31) and 75 and older (aOR: 7.73, 95% CI 2.03-51.73).

CONCLUSIONS

Disparities in cancer screening and risk and preventive behaviors exist among farmers in Nebraska. The study highlights a need for continuing efforts to improve preventive cancer behaviors targeted to the farming population.

Mitochondrial CPT1A: Insights into structure, function, and basis for drug development

Carnitine Palmitoyl-Transferase1A (CPT1A) is the rate-limiting enzyme in the fatty acid β-oxidation, and its deficiency or abnormal regulation can result in diseases like metabolic disorders and various cancers. Therefore, CPT1A is a desirable drug target for clinical therapy. The deep comprehension of human CPT1A is crucial for developing the therapeutic inhibitors like Etomoxir. CPT1A is an appealing druggable target for cancer therapies since it is essential for the survival, proliferation, and drug resistance of cancer cells. It will help to lower the risk of cancer recurrence and metastasis, reduce mortality, and offer prospective therapy options for clinical treatment if the effects of CPT1A on the lipid metabolism of cancer cells are inhibited. Targeted inhibition of CPT1A can be developed as an effective treatment strategy for cancers from a metabolic perspective. However, the pathogenic mechanism and recent progress of CPT1A in diseases have not been systematically summarized. Here we discuss the functions of CPT1A in health and diseases, and prospective therapies targeting CPT1A. This review summarizes the current knowledge of CPT1A, hoping to prompt further understanding of it, and provide foundation for CPT1A-targeting drug development.

Health Burdens and SES in Alabama: Using Geographic Information System to Examine Prostate Cancer Health Disparity

Socioeconomic disparities influence the risk of many diseases, including cancer. The cancer rate in Alabama is high, and the state has one of the highest rates of prostate cancer in the USA. Alabama's counties are embedded with socioeconomic disparities, politics, race, ethnicity, and oppression, among which social equity and socioeconomic status (SES) been closely associated with prostate cancer. The Geographic Information System (GIS) has become a valuable technology in understanding public health in many applications, including cancer. This study integrates Alabama's county-level prostate cancer incidence and mortality and its association with socioeconomic and health disparities. We conducted robust data mining from several data sources such as the Alabama State Cancer Profile data, Alabama Department of Health, American Cancer Society, Center for Disease Control, and National Cancer Institute. The research method is the Geographic Information System (GIS), and we employed prostate cancer data within GIS to understand Alabama's prostate cancer prevalence regarding SES. The GIS analysis indicated an apparent socioeconomic disparity between the Black Belt and Non-Black Belt counties of Alabama. The Black Belt counties' poverty rate is also remarkably higher than non-Black Belt counties. In addition, we analyzed the median household income by race. Our analysis demonstrates that the Asian background population in the state earned the highest median income compared to non-Hispanic whites and the African American population. Furthermore, the data revealed that the preexisting condition of diabetes and obesity is closely associated with prostate cancer. The GIS analysis suggests that prostate cancer incidence and mortality disparities are strongly related to SES. In addition, the preexisting condition of obesity and diabetes adds to prostate cancer incidences. Poverty also reflects inequalities in education, income, and healthcare facilities, particularly among African Americans, contributing to Alabama's health burden of prostate cancer.

Self-efficacy and importance of participation reasons as predictors for prostate cancer screening intention in African American men

Objective: African American men have higher lifetime risk of developing prostate cancer (PCa), and face more health burdens from this disease due in part to limited participation in cancer screening. Therefore, it is important to study psychosocial factors associated with screening intention in African American men. Guided by social cognitive theory, the current study aims to examine the role of self-efficacy and importance of participation reasons as predictors of PCa screening intention in African American men.Design: This is a primary analysis using data collected from African American men in northeast Ohio and the Southeastern United States. PCa screening intention and self-efficacy were measured by single-item questions. Importance of participation reasons was measured in four domains: psychological, convenience, awareness, and medical. Hierarchical binary logistic regression was used to predict PCa screening intention in African American men.Results: The sample size was 174. The average age was 46.52. Adding self-efficacy and reasons for participation significantly improved prediction for PCa screening intention in African American men (Δχ² = 55.28, p < .001). The final model had χ² = 69.63 (p < .001). Higher self-efficacy (OR = 2.56, p < .05), more perceived importance of psychological reasons (OR = 2.42, p < .001) and medical reasons (OR = 1.10, p < .05) were significant predictors. Also, the perceived chance of developing PCa predicted higher odds of PCa screening intention.Conclusions: Enhancing self-efficacy might be an important intervention focus for African American men to improve PCa screening intention. In addition, the findings suggest that African American men intend to have PCa screening because they experience worries or physical symptoms, and unlikely because it is convenient to get screening or recommended by family members and friends. Thus, intervention efforts could focus on enhancing PCa knowledge and informed decision-making about PCa screening among African American men.

Reference-free transcriptome exploration reveals novel RNAs for prostate cancer diagnosis

The use of RNA-sequencing technologies held a promise of improved diagnostic tools based on comprehensive transcript sets. However, mining human transcriptome data for disease biomarkers in clinical specimens are restricted by the limited power of conventional reference-based protocols relying on unique and annotated transcripts. Here, we implemented a blind reference-free computational protocol, DE-kupl, to infer yet unreferenced RNA variations from total stranded RNA-sequencing datasets of tissue origin. As a bench test, this protocol was powered for detection of RNA subsequences embedded into putative long noncoding (lnc)RNAs expressed in prostate cancer. Through filtering of 1,179 candidates, we defined 21 lncRNAs that were further validated by NanoString for robust tumor-specific expression in 144 tissue specimens. Predictive modeling yielded a restricted probe panel enabling more than 90% of true-positive detections of cancer in an independent The Cancer Genome Atlas cohort. Remarkably, this clinical signature made of only nine unannotated lncRNAs largely outperformed PCA3, the only used prostate cancer lncRNA biomarker, in detection of high-risk tumors. This modular workflow is highly sensitive and can be applied to any pathology or clinical application.

Mapping the Germline and Somatic Mutation Interaction Landscape in Indolent and Aggressive Prostate Cancers

BACKGROUND

A majority of prostate cancers (PCas) are indolent and cause no harm even without treatment. However, a significant proportion of patients with PCa have aggressive tumors that progress rapidly to metastatic disease and are often lethal. PCa develops through somatic mutagenesis, but emerging evidence suggests that germline genetic variation can markedly contribute to tumorigenesis. However, the causal association between genetic susceptibility and tumorigenesis has not been well characterized. The objective of this study was to map the germline and somatic mutation interaction landscape in indolent and aggressive tumors and to discover signatures of mutated genes associated with each type and distinguishing the two types of PCa.

MATERIALS AND METHODS

We integrated germline mutation information from genome-wide association studies (GWAS) with somatic mutation information from The Cancer Genome Atlas (TCGA) using gene expression data from TCGA on indolent and aggressive PCas as the intermediate phenotypes. Germline and somatic mutated genes associated with each type of PCa were functionally characterized using network and pathway analysis.

RESULTS

We discovered gene signatures containing germline and somatic mutations associated with each type and distinguishing the two types of PCa. We discovered multiple gene regulatory networks and signaling pathways enriched with germline and somatic mutations including axon guidance, RAR, WINT, MSP-RON, STAT3, PI3K, TR/RxR, and molecular mechanisms of cancer, NF-kB, prostate cancer, GP6, androgen, and VEGF signaling pathways for indolent PCa and MSP-RON, axon guidance, RAR, adipogenesis, and molecular mechanisms of cancer and NF-kB signaling pathways for aggressive PCa.

CONCLUSION

The investigation revealed germline and somatic mutated genes associated with indolent and aggressive PCas and distinguishing the two types of PCa. The study revealed multiple gene regulatory networks and signaling pathways dysregulated by germline and somatic alterations. Integrative analysis combining germline and somatic mutations is a powerful approach to mapping germline and somatic mutation interaction landscape.

Chemical and Biological Aspects of Garcinol and Isogarcinol: Recent Developments

The natural polyisoprenylated benzophenone derivatives garcinol and isogarcinol are secondary plant metabolites isolated from various Garcinia species including Garcinia indica. This review takes stock of the recent chemical and biological research into these interesting natural compounds over the last five years. New biological sources and chemical syntheses are discussed followed by new insights into the activity of garcinol and isogarcinol against cancer, pathogenic bacteria, parasite infections and various inflammatory diseases.

Evaluation of a Computer-Based Decision Aid for Promoting Informed Prostate Cancer Screening Decisions Among African American Men: iDecide

PURPOSE

To evaluate the effects of iDecide on prostate cancer knowledge, informed decision-making self-efficacy, technology use self-efficacy, and intention to engage in informed decision-making among African American men.

DESIGN

One-group, pretest/posttest.

SETTING

Community settings in South Carolina.

PARTICIPANTS

African American men, ages 40 years +, without a prior prostate cancer diagnosis (n = 354).

INTERVENTION

iDecide, an embodied conversational agent-led, computer-based prostate cancer screening decision aid.

MEASURES

Prostate cancer knowledge, informed decision-making self-efficacy, technology use self-efficacy, and intention to engage in informed decision-making.

ANALYSIS

Descriptive statistics, paired t tests, general linear modeling, Spearman correlations.

RESULTS

On average, participants experienced significant improvements in their prostate cancer knowledge ( P ≤ .001), informed decision-making self-efficacy ( P ≤ .001), and technology use self-efficacy ( P ≤ .001), postintervention. Additionally, 67% of participants reported an intention to engage in informed decision-making.

CONCLUSION

Given the significant improvements across all measures, this research demonstrates that embodied conversational agent-led decision aids can be used to enhance the capacity for making informed prostate cancer screening decisions among African American men and increase their technology use self-efficacy. One critical limitation of this study is that most men had received prostate cancer screening prior to engaging in our intervention, so the implications of this intervention may be different for men who do not have a history of screening. Additionally, actual engagement in informed decision-making postintervention was not assessed.

Systematic Review of Commercially Available Mobile Phone Applications for Prostate Cancer Education

Prostate cancer is the most commonly diagnosed non-skin cancer among all men and the second most common cause of death. To ameliorate the burden of prostate cancer, there is a critical need to identify strategies for providing men with information about prostate cancer screening and the importance of informed decision making. With mobile phones becoming more ubiquitous, many individuals are adopting their phones as sources for health information. The objective of this systematic review is to identify and evaluate commercially available apps for promoting informed prostate cancer screening decisions. Two keywords "prostate cancer screening" and "prostate cancer" were entered into the search engines of Google and iOS app stores in May 2017. Evaluations were conducted on apps' (a) quality, (b) grade-level readability, (c) cultural sensitivity, and (d) usability heuristics. None of the 14 apps meeting the inclusion criteria contained the full breadth of information covered in the 2016 American Cancer Society's Prostate Cancer Prevention and Early Detection Guidelines, but over half were inclusive of topics consistent with these guidelines. Most apps' readability was higher than an eighth-grade reading level. Most apps were also not framed and had a neutral tone. Only four apps met most criteria for being culturally sensitive to African Americans. Usability among apps was variable, but some contained major usability concerns. Recommendations for improving educational apps for prostate cancer screening include: disseminating evidence-based information; using culturally sensitive language; knowing the implications of the one and framing of content; making apps interactive; and following common usability principles.

Unintended consequences of decreased PSA-based prostate cancer screening

BACKGROUND

In May 2012, the US Preventive Services Task Force issued a grade D recommendation against PSA-based prostate cancer screening. Epidemiologists have concerns that an unintended consequence is a problematic increase in high-risk disease and subsequent prostate cancer-specific mortality.

MATERIALS AND METHODS

To assess the effect of decreased PSA screening on the presentation of high-risk prostate cancer post-radical prostatectomy (RP). Nine high-volume referral centers throughout the United States (n = 19,602) from October 2008 through September 2016 were assessed and absolute number of men presenting with GS ≥ 8, seminal vesicle and lymph node invasion were compared with propensity score matching.

RESULTS

Compared to the 4-year average pre-(Oct. 2008-Sept. 2012) versus post-(Oct. 2012-Sept. 2016) recommendation, a 22.6% reduction in surgical volume and increases in median PSA (5.1-5.8 ng/mL) and mean age (60.8-62.0 years) were observed. The proportion of low-grade GS 3 + 3 cancers decreased significantly (30.2-17.1%) while high-grade GS 8 + cancers increased (8.4-13.5%). There was a 24% increase in absolute numbers of GS 8+ cancers. One-year biochemical recurrence rose from 6.2 to 17.5%. To discern whether increases in high-risk disease were due to referral patterns, propensity score matching was performed. Forest plots of odds ratios adjusted for age and PSA showed significant increases in pathologic stage, grade, and lymph node involvement.

CONCLUSIONS

All centers experienced consistent decreases of low-grade disease and absolute increases in intermediate and high-risk cancer. For any given age and PSA, propensity matching demonstrates more aggressive disease in the post-recommendation era.

The Influence of Ethnic Heterogeneity on Prostate Cancer Mortality After Radical Prostatectomy in Hispanic or Latino Men: A Population-based Analysis

OBJECTIVE

To determine if recently found disparities in prostate cancer-specific mortality (PCSM) among Mexican and Puerto Rican men remained true in patients undergoing radical prostatectomy (RP), where the true grade and extent of cancer are known and can be accounted for.

MATERIALS AND METHODS

Men diagnosed with localized-regional prostate cancer who had undergone RP as primary treatment were identified (N = 180,794). Patients were divided into the following racial and ethnic groups: non-Hispanic white (NHW) (n = 135,358), non-Hispanic black (NHB) (n = 21,882), Hispanic or Latino (n = 15,559), and Asian American or Pacific Islander (n = 7995). Hispanic or Latino men were further categorized into the following subgroups: Mexican (n = 3323) and South or Central American, excluding Brazilian (n = 1296), Puerto Rican (n = 409), and Cuban (n = 218). A multivariable analysis was conducted using competing risk regression in the prediction of PCSM.

RESULTS

This analysis revealed hidden disparities in surgical outcomes for prostate cancer. In the multivariable analysis, Hispanic or Latino men (hazard ratio [HR] = 0.88, P = .207) did not show a significant difference in PCSM compared with NHW men. When breaking Hispanic or Latino men into their country of origin or ancestry, Puerto Rican men were found to have significantly worse PCSM than NHW men (HR = 2.55, P = .004) and NHB men (HR = 2.33, P = .016).

CONCLUSION

Our findings reveal higher rates of PCSM for Puerto Rican men after RP than for both NHW and NHB men. At a minimum, these findings need further validation and should be considered in the screening and management of these men.

African-American and Caribbean-Born Men's Perceptions of Prostate Cancer Fear and Facilitators for Screening Behavior: a Pilot Study

This study describes how a concurrent exploratory mixed methodology (CEMM) approach was used to investigate perceptions of prostate cancer (CaP) fear and facilitators of screening behavior in African-American (AA) and Caribbean-born (CB) black men for instrument development. A quantitative paper-based questionnaire was modified, adapted, and administered to participants from the Personal Integrative Model of Prostate Cancer Disparity Survey and the Powe Fatalism Inventory. Focus groups and individual interviews were conducted and analyzed using thematic analysis. Of the 31 participants, 17 (55%) were CB black men and 14 (45%) were AA men. CB black men reported significantly higher mean perception of CaP treatment scores compared to AA men (8.23 versus 6.14, p < 0.05). Overall, the focus group and interview data revealed highly interrelated key themes. These themes included perceived barriers to CaP screening (e.g., health-care affordability), misconceptions about CaP (e.g., limited knowledge), and misinformation about CaP (e.g., conflicting CaP screening information from health-care providers). Feeling responsible to make sure family members were taken care of and the role of a significant other were reported as motivation for visiting the doctor. As a result of the CEMM design, a reliable survey instrument was developed to measure CaP fear and facilitators for screening behavior within subpopulations of AA men, which is important because despite their shared genetic ancestry, AA and CB black males may have very different lifestyles.

Repeat prostate biopsies prior to radical prostatectomy do not impact erectile function recovery and mid- to long-term continence

BACKGROUND

A growing number of men undergo repeat biopsies prior to radical prostatectomy for prostate cancer. However, the long-term impact of repeat biopsies on functional outcomes in this patient population remains unelucidated. Thus, we compared functional outcomes between patients who underwent single biopsy versus repeat biopsies before radical prostatectomy.

METHODS

From 1996 to 2015, 1015 consecutive patients underwent radical prostatectomy, and subsequently had urinary continence and erectile function assessed for >2 years follow-up. One-fourth of patients (275; 27%) had ≥2 biopsies before prostatectomy. Logistic regression models tested whether repeat biopsy before prostatectomy predicted continence or erectile function recovery.

RESULTS

For the overall cohort, continence rates were 84%, 92%, 96%, and 98% at 3, 6, 12, and 24 months, respectively. Repeat biopsy before prostatectomy was associated with lower continence rate at 3 months compared to single biopsy (P = 0.03); however, no significant differences were observed at 6, 12, or 24 months. In multivariable analyses adjusting for age, body mass index and diabetes/cardiovascular disease/smoking, the association between repeat biopsy and lower likelihood of continence at 3 months remained (odds ratio 0.67, 95% confidence interval 0.47-0.97; P = 0.03). Overall erectile function recovery rates were 16%, 33%, 51%, and 55% at 3, 6, 12, and 24 months, respectively. No difference in erectile function recovery rates was seen at any time point for single biopsy versus repeat biopsy. In multivariable analyses, repeat biopsy was not predictive of erectile function recovery at any time point.

CONCLUSIONS

Repeat biopsy before radical prostatectomy impairs early continence after surgery. However, erectile function recovery and mid-term to long-term continence are not affected. These data support the current trend towards active surveillance and delayed local treatment in patients with low- to intermediate-risk prostate cancer.

Prostate cancer screening-when to start and how to screen?

Prostate-specific antigen (PSA) screening reduces prostate cancer (PCa) mortality; however such screening may lead to harm in terms of overdiagnosis and overtreatment. Therefore, upfront shared decision making involving a discussion about pros and cons between a physician and a patient is crucial. Total PSA remains the most commonly used screening tool and is a strong predictor of future life-threatening PCa. Currently there is no strong consensus on the age at which to start PSA screening. Most guidelines recommend PSA screening to start no later than at age 55 and involve well-informed men in good health and a life expectancy of at least 10–15 years. Some suggest to start screening in early midlife for men with familial predisposition and men of African-American descent. Others suggest starting conversations at age 45 for all men. Re-screening intervals can be risk-stratified as guided by the man’s age, general health and PSA-value; longer intervals for those at lower risk and shorter intervals for those at higher risk. Overdiagnosis and unnecessary biopsies can be reduced using reflex tests. Magnetic resonance imaging in the pre-diagnostic setting holds promise in pilot studies and large-scale prospective studies are ongoing.

Future Perspectives and Challenges of Prostate MR Imaging

MR imaging is an important part of prostate cancer diagnosis. Variations in quality and skill in general practice mean results are not as impressive as they were in academic centers. This observation provides an impetus to improve the method. Improved quality assurance will likely result in better outcomes. Improved characterization of clinically significant prostate cancer may assist in making MR imaging more useful. Improved methods of registering MR imaging with transrectal ultrasound imaging and robotic arms controlling the biopsy can reduce the impact of inexperienced operators and make the entire system of MR imaging-guided biopsies more robust.

Social constraints and psychological well-being after prostate cancer: A follow-up at 12 and 24 months after surgery

OBJECTIVE

Studies indicate that social constraints (barriers to emotional expression) may be a risk factor for psychological morbidity. We aimed to investigate the association between prostate cancer-related social constraints and psychological well-being following prostate cancer surgery.

METHODS

In a group of 3478 partnered patients, participating in the Laparoscopic Prostatectomy Robot Open trial, a prospective multicenter comparative study of robot-assisted laparoscopic and retropubic radical prostatectomy for prostate cancer, we used log-binomial regression analysis to investigate the links between prostate cancer-related social constraints at 3 months after surgery and psychological well-being at 12 and 24 months.

RESULTS

A total of 1086 and 1093 men reported low well-being at 12 and 24 months, respectively. Prostate cancer-related social constraints by partner predicted low psychological well-being at 12 months (adjusted RR: 1.4; 95% CI, 1.1-1.9) and by others (adjusted RR: 1.9; 95% CI, 1.1-3.5). Intrusive thoughts mediated the association.

CONCLUSIONS

Negative responses from the social environment, especially from partner to talking about the prostate cancer experience affected patients' psychological well-being 2 years after radical prostatectomy. Results emphasize the importance of helping patients mobilize psychosocial resources within their social network, especially among those with a lack of quality psychosocial support.

US Preventive Services Task Force prostate-specific antigen screening guidelines result in higher Gleason score diagnoses

Purpose

To evaluate the impact that the 2012 US Preventive Services Task Force (USPSTF) prostate-specific antigen (PSA) screening guidelines have had on the diagnosis of prostate cancer, we compared the incidence and distribution of new cases diagnosed in 2011-before the USPSTF PSA screening recommendations versus 2014 at which time the guidelines were widely adopted.

Materials and Methods

We identified all prostate biopsies performed by a large urology group practice utilizing a centralized pathology lab. We examined total biopsies performed, percentage of positive biopsies, and for those with positive biopsies examined for differences in patient age, PSA, and Gleason score.

Results

A total of 4,178 biopsies were identified - 2,513 in 2011 and 1,665 in 2014. The percentage of positive biopsies was 27% in 2011 versus 34% in 2014 (p<0.0001). Among patients with positive biopsies, we found statistically significant differences between the 2 cohorts in the median ages and Gleason scores. Patients were about 1 year younger in 2014 compared to 2011 (t-test; p=0.043). High Gleason scores (8-10) were diagnosed in 19% of the 2014 positive biopsies versus 9% in the 2011 positive biopsies (chi square; p<0.0001).

Conclusions

After the widespread implementation of the 2011 USPTF PSA screening guidelines, 34% fewer biopsies were performed with a 29% increase in positive biopsy rates. We found a significantly higher incidence of high grade disease in 2014 compared with 2011. The percentage of patients with positive biopsies having Gleason scores 8-10 more than doubled in 2014. The higher incidence of these more aggressive cancers must be part of the discussion regarding PSA screening.

Economic Analysis of Prostate-Specific Antigen Screening and Selective Treatment Strategies

IMPORTANCE

Prostate-specific antigen (PSA) screening for prostate cancer is controversial. Experts have suggested more personalized or more conservative strategies to improve benefit-risk tradeoffs, but the value of these strategies-particularly when combined with increased conservative management for low-risk cases-is uncertain.

OBJECTIVES

To evaluate the potential cost-effectiveness of plausible PSA screening strategies and to assess the value added by increased use of conservative management among low-risk, screen-detected cases.

DESIGN, SETTING, AND PARTICIPANTS

A microsimulation model of prostate cancer incidence and mortality was created. A simulated contemporary cohort of US men beginning at 40 years of age underwent 18 strategies for PSA screening. Treatment strategies included (1) contemporary treatment practices based on age and cancer stage and grade observed in the Surveillance, Epidemiology, and End Results program in 2010 or (2) selective treatment practices whereby cases with a Gleason score lower than 7 and clinical T2a stage cancer or lower are treated only after clinical progression, and all other cases undergo contemporary treatment practices. National and trial data on PSA growth, screening and biopsy patterns, incidence of prostate cancer, treatment distributions, treatment efficacy, mortality, health-related quality of life, and direct medical expenditure were analyzed. Data were collected from March 18, 2009, to August 15, 2014, and analyzed from November 20, 2012, to December 11, 2015.

INTERVENTIONS

Eighteen screening strategies that vary by start and stop age, screening interval, and criteria for biopsy referral and contemporary or selective treatment practices.

MAIN OUTCOMES AND MEASURES

Life-years (LYs), quality-adjusted life-years (QALYs), direct medical expenditure, and cost per LY and QALY gained.

RESULTS

All 18 screening strategies were associated with increased LYs (range, 0.03-0.06) and costs ($263-$1371) compared with no screening, with the cost ranging from $7335 to $21 649 per LY. With contemporary treatment, only strategies with biopsy referral for PSA levels higher than 10.0 ng/mL or age-dependent thresholds were associated with increased QALYs (0.002-0.004), and only quadrennial screening of patients aged 55 to 69 years was potentially cost-effective in terms of cost per QALY (incremental cost-effectiveness ratio, $92 446). With selective treatment, all strategies were associated with increased QALYs (0.002-0.004), and several strategies were potentially cost-effective in terms of cost per QALY (incremental cost-effectiveness ratio, $70 831-$136 332).

CONCLUSIONS AND RELEVANCE

For PSA screening to be cost-effective, it needs to be used conservatively and ideally in combination with a conservative management approach for low-risk disease.

Anti-Tumorigenic Potential of a Novel Orlistat-AICAR Combination in Prostate Cancer Cells

Prostate cancer (PCa) is one of the leading causes of cancer-related deaths in men worldwide. Fatty acid synthase (FASN) is reported to be overexpressed in several cancers including PCa, and this has led to clinical cancer treatments that utilize various FASN inhibitors such as the anti-obesity drug, Orlistat. However, pharmacological limitations have impeded the progress in cancer treatments expected thus far with FASN inhibition. In this study, we investigated a novel therapeutic combination to enhance the toxic potential of Orlistat in three different PCa cell-lines (DU145, PC3, and LNCaP). We show that Orlistat and 5-Aminoimidazole-4-carboxamide ribonucleotide (AICAR) (AMP-activated protein kinase [AMPK] activator) co-treatment induces significant downregulation of two key fatty acid synthesis regulatory proteins (FASN, Sterol regulatory element-binding protein 1 [SREBP-1c]) as compared to control and Orlistat alone. Orlistat and AICAR co-treatment induced a significant decrease in cell viability and proliferation, and a significant increase in apoptosis in all three PCa cell-lines. Apoptosis induction was preceded by a marked increase in reactive oxygen species (ROS) production followed by G0/G1 cell cycle arrest and activation of pro-apoptotic caspases. We also observed a significant decrease in migration potential and VEGF expression in Orlistat and AICAR co-treated samples in all three PCa cell-lines. Compound C (AMPK inhibitor) negatively affected some of the enhanced anti-cancer effects observed with Orlistat treatment. We conclude that AICAR co-treatment potentiates the anti-proliferative effects of Orlistat at a low dose (100 µM), and this combination has the potential to be a viable and effective therapeutic option in PCa treatment. J. Cell. Biochem. 118: 3834-3845, 2017. © 2017 Wiley Periodicals, Inc.

A novel microRNA-1207-3p/FNDC1/FN1/AR regulatory pathway in prostate cancer

Prostate cancer (PCa) is the second most common cause of cancer-specific deaths in the U.S. Unfortunately, the underlying molecular mechanisms for its development and progression remain unclear. Studies have established that microRNAs (miRNAs) are dysregulated in PCa. The intron-derived microRNA-1207-3p (miR-1207-3p) is encoded at the non-protein coding gene locus PVT1 on the 8q24 human chromosomal region, an established PCa susceptibility locus. However, miR-1207-3p in PCa had not previously been investigated. Therefore, we explored if miR-1207-3p plays any regulatory role in PCa. We discovered that miR-1207-3p is significantly underexpressed in PCa cell lines in comparison to normal prostate epithelial cells, and that increased expression of microRNA-1207-3p in PCa cells significantly inhibits proliferation, migration, and induces apoptosis via direct molecular targeting of fibronectin type III domain containing 1 (FNDC1). Our studies also revealed significant overexpression of FNDC1, fibronectin (FN1) and the androgen receptor (AR) in human PCa cell lines as well as tissues, and FNDC1, FN1, and AR positively correlate with aggressive PCa. These findings, recently published in Experimental Cell Research, are the first to describe a novel miR-1207-3p/FNDC1/FN1/AR novel regulatory pathway in PCa.

Commentary: Building an Evidence Base for Promoting Informed Prostate Cancer Screening Decisions: An Overview of a Cancer Prevention and Control Program

African American (AA) men have significantly higher mortality rates from prostate cancer (PrCA) than other racial groups. Therefore, there is a critical need to identify strategies for promoting informed PrCA screening decisions among this population. This article details the community-driven, social and behavioral research being implemented by a Statewide Cancer Prevention and Control Program (CPCP) to support the development of person-to-person and technological interventions to improve the dissemination of PrCA information to AA men and their families. This article concludes with four recommendations to advance future research and practice related to the use of interventions for promoting informed PrCA decision-making among AAs. These recommendations include: 1) informing men about controversial screening recommendations; 2) including families in educational interventions about PrCA; 3) using technology as a modality for disseminating PrCA information when appropriate; and 4) aiming to create interventions that can be translated into community and clinical settings.

The effect of the USPSTF PSA screening recommendation on prostate cancer incidence patterns in the USA

Guidelines regarding recommendations for PSA screening for early detection of prostate cancer are conflicting. In 2012, the United States Preventive Services Task Force (USPSTF) assigned a grade of D (recommending against screening) for men aged ≥75 years in 2008 and for men of all ages in 2012. Understanding temporal trends in rates of screening before and after the 2012 recommendation in terms of usage patterns in PSA screening, changes in prostate cancer incidence and biopsy patterns, and how the recommendation has influenced physician's and men's attitudes about PSA screening and subsequent ordering of other screening tests is essential within the scope of prostate cancer screening policy. Since the 2012 recommendation, rates of PSA screening decreased by 3-10% in all age groups and across most geographical regions of the USA. Rates of prostate biopsy and prostate cancer incidence have declined in unison, with a shift towards tumours being of higher grade and stage upon detection. Despite the recommendation, some physicians report ongoing willingness to screen appropriately selected men, and many men report intending to continue to ask for the PSA test from their physician. In the coming years, we expect to have an improved understanding of whether these decreased rates of screening will affect prostate cancer metastasis and mortality.

PRECISION MANAGEMENT OF LOCALIZED PROSTATE CANCER

INTRODUCTION

The vast majority of men who are diagnosed with prostate cancer die of other causes, highlighting the importance of determining which patient has a risk of death from prostate cancer. Precision management of prostate cancer patients includes distinguishing which men have potentially lethal disease and employing strategies for determining which treatment modality appropriately balances the desire to achieve a durable response while preventing unnecessary overtreatment.

AREAS COVERED

In this review, we highlight precision approaches to risk assessment and a context for the precision-guided application of definitive therapy. We focus on three dilemmas relevant to the diagnosis of localized prostate cancer: screening, the decision to treat, and postoperative management.

EXPERT COMMENTARY

In the last five years, numerous precision tools have emerged with potential benefit to the patient. However, to achieve optimal outcome, the decision to employ one or more of these tests must be considered in the context of prevailing conventional factors. Moreover, performance and interpretation of a molecular or imaging precision test remains practitioner-dependent. The next five years will witness increased marriage of molecular and imaging biomarkers for improved multi-modal diagnosis and discrimination of disease that is aggressive versus truly indolent.

Randomized trial finds that prostate cancer genetic risk score feedback targets prostate-specific antigen screening among at-risk men

BACKGROUND

Prostate-specific antigen (PSA) screening may reduce death due to prostate cancer but leads to the overdiagnosis of many cases of indolent cancer. Targeted use of PSA screening may reduce overdiagnosis. Multimarker genomic testing shows promise for risk assessment and could be used to target PSA screening.

METHODS

To test whether counseling based on the family history (FH) and counseling based on a genetic risk score (GRS) plus FH would differentially affect subsequent PSA screening at 3 months (primary outcome), a randomized trial of FH versus GRS plus FH was conducted with 700 whites aged 40 to 49 years without prior PSA screening. Secondary outcomes included anxiety, recall, physician discussion at 3 months, and PSA screening at 3 years. Pictographs versus numeric presentations of genetic risk were also evaluated.

RESULTS

At 3 months, no significant differences were observed in the rates of PSA screening between the FH arm (2.1%) and the GRS-FH arm (4.5% with GRS-FH vs. 2.1% with FH: χ2 = 3.13, P = .077); however, PSA screening rates at 3 months significantly increased with given risk in the GRS-FH arm (P = .013). Similar results were observed for discussions with physicians at 3 months and PSA screening at 3 years. Average anxiety levels decreased after the individual cancer risk was provided (P = .0007), with no differences between groups. Visual presentation by pictographs did not significantly alter comprehension or anxiety.

CONCLUSIONS

This is likely the first randomized trial of multimarker genomic testing to report genomic targeting of cancer screening. This study found little evidence of concern about excess anxiety or overuse/underuse of PSA screening when multimarker genetic risks were provided to patients. Cancer 2016;122:3564-3575. © 2016 American Cancer Society.

Estimating the harms and benefits of prostate cancer screening as used in common practice versus recommended good practice: A microsimulation screening analysis

BACKGROUND

Prostate-specific antigen (PSA) screening and concomitant treatment can be implemented in several ways. The authors investigated how the net benefit of PSA screening varies between common practice versus "good practice."

METHODS

Microsimulation screening analysis (MISCAN) was used to evaluate the effect on quality-adjusted life-years (QALYs) if 4 recommendations were followed: limited screening in older men, selective biopsy in men with elevated PSA, active surveillance for low-risk tumors, and treatment preferentially delivered at high-volume centers. Outcomes were compared with a base model in which annual screening started at ages 55 to 69 years and were simulated using data from the European Randomized Study of Screening for Prostate Cancer.

RESULTS

In terms of QALYs gained compared with no screening, for 1000 screened men who were followed over their lifetime, recommended good practice led to 73 life-years (LYs) and 74 QALYs gained compared with 73 LYs and 56 QALYs for the base model. In contrast, common practice led to 78 LYs gained but only 19 QALYs gained, for a greater than 75% relative reduction in QALYs gained from unadjusted LYs gained. The poor outcomes for common practice were influenced predominantly by the use of aggressive treatment for men with low-risk disease, and PSA testing in older men also strongly reduced potential QALY gains.

CONCLUSIONS

Commonly used PSA screening and treatment practices are associated with little net benefit. Following a few straightforward clinical recommendations, particularly greater use of active surveillance for low-risk disease and reducing screening in older men, would lead to an almost 4-fold increase in the net benefit of prostate cancer screening. Cancer 2016;122:3386-3393. © 2016 American Cancer Society.

Molecular mechanisms underlying resistance to androgen deprivation therapy in prostate cancer

Prostate cancer (PCa) is the most widely diagnosed male cancer in the Western World and while low- and intermediate-risk PCa patients have a variety of treatment options, metastatic patients are limited to androgen deprivation therapy (ADT). This treatment paradigm has been in place for 75 years due to the unique role of androgens in promoting growth of prostatic epithelial cells via the transcription factor androgen receptor (AR) and downstream signaling pathways. Within 2 to 3 years of ADT, disease recurs-at which time, patients are considered to have castration-recurrent PCa (CR-PCa). A universal mechanism by which PCa becomes resistant to ADT has yet to be discovered. In this review article, we discuss underlying molecular mechanisms by which PCa evades ADT. Several major resistance pathways center on androgen signaling, including intratumoral and adrenal androgen production, AR-overexpression and amplification, expression of AR mutants, and constitutively-active AR splice variants. Other ADT resistance mechanisms, including activation of glucocorticoid receptor and impairment of DNA repair pathways are also discussed. New therapies have been approved for treatment of CR-PCa, but increase median survival by only 2-8 months. We discuss possible mechanisms of resistance to these new ADT agents. Finally, the practicality of the application of "precision oncology" to this continuing challenge of therapy resistance in metastatic or CR-PCa is examined. Empirical validation and clinical-based evidence are definitely needed to prove the superiority of "precision" treatment in providing a more targeted approach and curative therapies over the existing practices that are based on biological "cause-and-effect" relationship.

Psychological impact of serial prostate-specific antigen tests in Japanese men waiting for prostate biopsy

BACKGROUND

It is common to repeat prostate-specific antigen (PSA) measurements for men with intermediate PSA elevation before prostate biopsy. In this scenario, men with persistently elevated PSA values may have considerable psychological distress. We attempted to determine whether elevated PSA values have psychological effects on these men in association with the timing of measurement, PSA kinetics, and biopsy results.

METHODS

In order to investigate the initial and late effects of PSA tests on psychological distress during serial measurements, two groups of men with screen-positive results (PSA ≥3 ng/ml) were studied-205 men whose first questionnaires regarding anxiety and depression were taken at initial screening (group A), and 103 men whose questionnaires were taken at repeated measurement for prior PSA elevation (group B).

RESULTS

The level of distress was generally low. There were no significant differences in distress between the two groups, suggesting a constant psychological effect by elevated PSA values over a long period of time. The distress of men in group A increased significantly as PSA levels rose and decreased when they fell to normal range. On the other hand, the distress of men in group B did not change regardless of PSA kinetics, indicating that their psychological condition seemed susceptible to subtle PSA change only in the initial phase of measurements. Unexpectedly, men with benign results showed insignificant but higher distress after prostate biopsy.

CONCLUSIONS

Although a small fraction of men have psychological distress caused by changes in PSA levels, the benefits, risks (psychological and physical), and limitations of PSA tests must be adequately explained to the patients before entering the screening program.

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.

Aberrant Lipid Metabolism Promotes Prostate Cancer: Role in Cell Survival under Hypoxia and Extracellular Vesicles Biogenesis

Prostate cancer (PCa) is the leading malignancy among men in United States. Recent studies have focused on the identification of novel metabolic characteristics of PCa, aimed at devising better preventive and therapeutic approaches. PCa cells have revealed unique metabolic features such as higher expression of several enzymes associated with de novo lipogenesis, fatty acid up-take and β-oxidation. This aberrant lipid metabolism has been reported to be important for PCa growth, hormone-refractory progression and treatment resistance. Furthermore, PCa cells effectively use lipid metabolism under adverse environmental conditions for their survival advantage. Specifically, hypoxic cancer cells accumulate higher amount of lipids through a combination of metabolic alterations including high glutamine and fatty acid uptake, as well as decreased fatty acid oxidation. These stored lipids serve to protect cancer cells from oxidative and endoplasmic reticulum stress, and play important roles in fueling cancer cell proliferation following re-oxygenation. Lastly, cellular lipids have also been implicated in extracellular vesicle biogenesis, which play a vital role in intercellular communication. Overall, the new understanding of lipid metabolism in recent years has offered several novel targets to better target and manage clinical PCa.

Incidental prostate cancer diagnosed at radical cystoprostatectomy for bladder cancer: disease-specific outcomes and survival

Background

The current standard of care for men with muscle-invasive bladder cancer is radical cystoprostatectomy (RCP). One-third of RCP specimens demonstrate incidental prostate cancer, primarily reported in small series with limited follow-up. The aim of this study is to report mature outcomes, including patterns of failure and disease-specific recurrence rates, and survival, for a large cohort of men with incidental prostate cancer at RCP performed at a tertiary referral center.

Methods

This retrospective study describes cancer control and survival rates for men who underwent RCP for bladder cancer and were found incidentally to have prostate cancer. Analysis of patient-, tumor-, and treatment-specific factors were analyzed for association with disease control and survival endpoints.

Results

Between 2002 and 2010, 94 patients with incidental discovery of prostate cancer postRCP were identified for inclusion in this study. Forty-five patients (45%) underwent RCP for recurrent (rather than initial presentation of) bladder carcinoma. At a median follow-up of 40.3 months (71.2 months for survivors; range, 8.9–155.5 months), 42 patients were alive without recurrence and 52 patients had died (25 associated with disease). The estimated 5-year bladder cancer disease-free, urinary tract malignancy disease-free, and prostate specific antigen (PSA) relapse-free survivals were 76% [95% confidence interval (CI), 65–84%], 64% (52–74%), and 97% (79–100%), respectively. The estimated 5-year urinary tract malignancy-specific and overall survivals were 61% (49–71%) and 52% (41–62%), respectively. Univariate analysis demonstrated associations between pathologic T/N-stage and nodal ratio with bladder cancer disease-free, urinary tract malignancy disease-specific, and overall survivals, with patient age at diagnosis as an additional adverse factor associated with overall survival. Multivariate analysis confirmed pN-stage and age as independently associated with worse survival.

Conclusion

For men undergoing RCP for bladder cancer, the present study suggests that incidentally discovered prostate cancers, irrespective of pathologic stage, Gleason score, or clinical significance, do not impact 5-year disease control or survival outcomes.

The PROFILE Feasibility Study: Targeted Screening of Men With a Family History of Prostate Cancer

BACKGROUND

A better assessment of individualized prostate cancer (PrCa) risk is needed to improve screening. The use of the prostate-specific antigen (PSA) level for screening in the general population has limitations and is not currently advocated. Approximately 100 common single nucleotide polymorphisms (SNPs) have been identified that are associated with the risk of developing PrCa. The PROFILE pilot study explored the feasibility of using SNP profiling in men with a family history (FH) of PrCa to investigate the probability of detecting PrCa at prostate biopsy (PB). The primary aim of this pilot study was to determine the safety and feasibility of PrCa screening using transrectal ultrasound-guided PB with or without diffusion-weighted magnetic resonance imaging (DW-MRI) in men with a FH. A secondary aim was to evaluate the potential use of SNP profiling as a screening tool in this population.

PATIENTS AND METHODS

A total of 100 men aged 40-69 years with a FH of PrCa underwent PB, regardless of their baseline PSA level. Polygenic risk scores (PRSs) were calculated for each participant using 71 common PrCa susceptibility alleles. We treated the disease outcome at PB as the outcome variable and evaluated its associations with the PRS, PSA level, and DW-MRI findings using univariate logistic regression.

RESULTS

Of the 100 men, 25 were diagnosed with PrCa, of whom 12 (48%) had clinically significant disease. Four adverse events occurred and no deaths. The PSA level and age at study entry were associated with PrCa at PB (p = .00037 and p = .00004, respectively).

CONCLUSION

The results of the present pilot study have demonstrated that PB is a feasible and safe method of PrCa screening in men with a FH, with a high proportion of PrCa identified requiring radical treatment. It is feasible to collect data on PrCa-risk SNPs to evaluate their combined effect as a potential screening tool. A larger prospective study powered to detect statistical associations is in progress.

IMPLICATIONS FOR PRACTICE

Prostate biopsy is a feasible and safe approach to prostate cancer screening in men with a family history and detects a high proportion of prostate cancer that needs radical treatment. Calculating a polygenic risk score using prostate cancer risk single nucleotide polymorphisms could be a potential future screening tool for prostate cancer.

New RESOLVE-Based Diffusional Kurtosis Imaging in MRI-Visible Prostate Cancer: Effect of Reduced b Value on Image Quality and Diagnostic Effectiveness

OBJECTIVE

The purpose of this article was to investigate whether a new readout segmentation of long variable echo-trains (RESOLVE)-based diffusional kurtosis imaging (DKI) with reduced b value technique can affect image quality and diagnostic effectiveness in MRI-visible prostate cancer (PCA).

SUBJECTS AND METHODS

Prostatic RESOLVE DKI (0-1400 s/mm2) was prospectively performed for 12 volunteers. The optimal protocol was then performed in 108 MRI-visible PCAs to determine whether it can compete against a preferred b-value set (0-2000 s/mm(2)) regarding image quality and diagnostic effectiveness. Images were interpreted by two independent radiologists using the prostate imaging reporting and data system (PI-RADS). Readers' concordance and diagnostic effectiveness were tested with the Fleiss kappa and area under the ROC curve (Az) analyses.

RESULTS

A b value of 1400 s/mm(2) generated a larger apparent diffusion coefficient of gaussian distribution (Dapp) (1.35 ± 0.31 vs 1.30 ± 0.30 mm(2)/s; p < 0.001) and apparent kurtosis coefficient (Kapp) (1.11 ± 0.26 vs 1.00 ± 0.21; p < 0.001) in PCA than did a b value of 2000 s/mm(2). Interreader agreement using PI-RADS was relatively low when Dapp and Kapp maps were excluded from image interpretations (κ = 0.39-0.41 vs κ = 0.66-0.68 with Dapp and Kapp maps). Interreader agreement in staging PCA was relatively high (κ > 0.80) and was not influenced by reducing the b value. The power of Dapp and Kapp to differentiate PCA from normal tissue (Az = 0.97-0.98), tissue with a Gleason score less than or equal to 3 + 4 from tissue with a Gleason score greater than 3 + 4 (Az = 0.77-0.82), and PCA stage lower than pT3 from stage pT3 and higher PCA (Az = 0.70-0.75) was not significantly degraded by reducing the b value.

CONCLUSION

We found that b values significantly influenced image quality, PI-RADS score, and DKI outputs but did not degrade the diagnostic effectiveness of DKI parameters to detect and classify PCA.

The high prevalence of undiagnosed prostate cancer at autopsy: implications for epidemiology and treatment of prostate cancer in the Prostate-specific Antigen-era

Widespread prostate-specific antigen (PSA) screening detects many cancers that would have otherwise gone undiagnosed. To estimate the prevalence of unsuspected prostate cancer, we reviewed 19 studies of prostate cancer discovered at autopsy among 6,024 men. Among men aged 70-79, tumor was found in 36% of Caucasians and 51% of African-Americans. This enormous prevalence, coupled with the high sensitivity of PSA screening, has led to the marked increase in the apparent incidence of prostate cancer. The impact of PSA screening on clinical practice is well-recognized, but its effect on epidemiologic research is less appreciated. Before screening, a larger proportion of incident prostate cancers had lethal potential and were diagnosed at advanced stage. However, in the PSA era, overall incident prostate cancer mainly is indolent disease, and often reflects the propensity to be screened and biopsied. Studies must therefore focus on cancers with lethal potential, and include long follow-up to accommodate the lead time induced by screening. Moreover, risk factor patterns differ markedly for potentially lethal and indolent disease, suggesting separate etiologies and distinct disease entities. Studies of total incident or indolent prostate cancer are of limited clinical utility, and the main focus of research should be on prostate cancers of lethal potential.