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1.
Eur Urol Oncol ; 2024 May 10.
Article En | MEDLINE | ID: mdl-38734542

BACKGROUND AND OBJECTIVE: Polygenic risk scores (PRSs) have been developed to identify men with the highest risk of prostate cancer. Our aim was to compare the performance of 16 PRSs in identifying men at risk of developing prostate cancer and then to evaluate the performance of the top-performing PRSs in differentiating individuals at risk of aggressive prostate cancer. METHODS: For this case-control study we downloaded 16 published PRSs from the Polygenic Score Catalog on May 28, 2021 and applied them to Michigan Genomics Initiative (MGI) patients. Cases were matched to the Michigan Urological Surgery Improvement Collaborative (MUSIC) registry to obtain granular clinical and pathological data. MGI prospectively enrolls patients undergoing surgery at the University of Michigan, and MUSIC is a multi-institutional registry that prospectively tracks demographic, treatment, and clinical variables. The predictive performance of each PRS was evaluated using the area under the covariate-adjusted receiver operating characteristic curve (aAUC), and the association between PRS and disease aggressiveness according to prostate biopsy data was measured using logistic regression. KEY FINDINGS AND LIMITATIONS: We included 18 050 patients in the analysis, of whom 15 310 were control subjects and 2740 were prostate cancer cases. The median age was 66.1 yr (interquartile range 59.9-71.6) for cases and 56.6 yr (interquartile range 42.6-66.7) for control subjects. The PRS performance in predicting the risk of developing prostate cancer according to aAUC ranged from 0.51 (95% confidence interval 0.51-0.53) to 0.67 (95% confidence interval 0.66-0.68). By contrast, there was no association between PRS and disease aggressiveness. CONCLUSIONS AND CLINICAL IMPLICATIONS: Prostate cancer PRSs have modest real-world performance in identifying patients at higher risk of developing prostate cancer; however, they are limited in distinguishing patients with indolent versus aggressive disease. PATIENT SUMMARY: Risk scores using data for multiple genes (called polygenic risk scores) can identify men at higher risk of developing prostate cancer. However, these scores need to be refined to be able to identify men with the highest risk for clinically significant prostate cancer.

3.
Urology ; 187: 39-45, 2024 May.
Article En | MEDLINE | ID: mdl-38354914

OBJECTIVE: To project the proportion of the urology workforce that is from under-represented in medicine (URiM) groups between 2021-2061. METHODS: Demographic data were obtained from AUA Census and ACGME Data Resource Books. The number of graduating urology residents and proportion of URiM graduating residents were characterized with linear models. Stock and Flow models were used to project future population numbers and proportions of URiM practicing urologists, contingent on assumptions regarding trainee demographics, retirement trends, and growth in the field. RESULTS: Currently, there is an increase in the percentage of URiM graduates by 0.145% per year. If historical trends continue, URiM urologists will likely comprise 16.2% of urology residency graduates and 13.3% of the practicing urological workforce in 2061. These percentages would constitute an underrepresentation of URiM urologists relative to the projected 44.2% of the U.S. population who would identify as American Indian/Alaskan Native, Black/African American, Latinx/Hispanic and Native Hawaiian/Pacific Islander by 2060.1 An increase in the percentage of URiM graduates by 0.845% per year would result in 44.2% URiM urology residency graduates and 26.1% URiM practicing urologists by 2061. An interactive app was designed to allow for a range of assumptions to be explored and for future data to be incorporated. CONCLUSION: URiM physician representation within urology over the next 40years will remain disproportionately low compared to that of the projected share of people of color in the general U.S. POPULATION: In order to achieve the AUA's Diversity, Equity and Inclusion goals, a concerted effort to implement interventions to recruit, train, and retain a generation of racially diverse urologists appears necessary.


Forecasting , Urology , Urology/statistics & numerical data , Urology/education , Urology/trends , Humans , United States , Workforce/statistics & numerical data , Workforce/trends , Internship and Residency/statistics & numerical data , Internship and Residency/trends , Health Workforce/statistics & numerical data , Health Workforce/trends , Racial Groups/statistics & numerical data , Urologists/statistics & numerical data , Urologists/supply & distribution , Urologists/trends , Ethnicity/statistics & numerical data , Male
4.
Prostate Cancer Prostatic Dis ; 27(1): 37-45, 2024 Mar.
Article En | MEDLINE | ID: mdl-37296271

Artificial intelligence (AI) applications have enabled remarkable advancements in healthcare delivery. These AI tools are often aimed to improve accuracy and efficiency of histopathology assessment and diagnostic imaging interpretation, risk stratification (i.e., prognostication), and prediction of therapeutic benefit for personalized treatment recommendations. To date, multiple AI algorithms have been explored for prostate cancer to address automation of clinical workflow, integration of data from multiple domains in the decision-making process, and the generation of diagnostic, prognostic, and predictive biomarkers. While many studies remain within the pre-clinical space or lack validation, the last few years have witnessed the emergence of robust AI-based biomarkers validated on thousands of patients, and the prospective deployment of clinically-integrated workflows for automated radiation therapy design. To advance the field forward, multi-institutional and multi-disciplinary collaborations are needed in order to prospectively implement interoperable and accountable AI technology routinely in clinic.


Artificial Intelligence , Prostatic Neoplasms , Male , Humans , Prostatic Neoplasms/diagnosis , Prostatic Neoplasms/therapy , Prospective Studies , Algorithms , Biomarkers
5.
JAMA Oncol ; 9(12): 1696-1701, 2023 Dec 01.
Article En | MEDLINE | ID: mdl-37796479

Importance: Randomized clinical trials have demonstrated the noninferiority of shorter radiotherapy (RT) courses (termed hypofractionation) compared with longer RT courses in patients with localized prostate cancer. Although shorter courses are associated with cost-effectiveness, convenience, and expanded RT access, their adoption remains variable. Objective: To identify the current practice patterns of external beam RT for prostate cancer in the US. Design, Setting, and Participants: This cohort study obtained data from the National Cancer Database, which collects hospital registry data from more than 1500 accredited US facilities on approximately 72% of US patients with cancer. Patients were included in the sample if they had localized prostate adenocarcinoma that was diagnosed between 2004 and 2020 and underwent external beam RT with curative intent. Analyses were conducted between February and March 2023. Exposures: Radiotherapy schedules, which were categorized as ultrahypofractionation (≤7 fractions), moderate hypofractionation (20-30 fractions), and conventional fractionation (31-50 fractions). Main Outcomes and Measures: Longitudinal pattern in RT fractionation schedule was the primary outcome. Multivariable logistic regression was performed to evaluate the variables associated with shorter RT courses. Covariables included age, National Comprehensive Cancer Network risk group, rurality, race, facility location, facility type, median income, insurance type or status, and Charlson-Deyo Comorbidity Index. Results: A total of 313 062 patients with localized prostate cancer (mean [SD] age, 68.8 [7.7] years) were included in the analysis. There was a temporal pattern of decline in the proportion of patients who received conventional fractionation, from 76.0% in 2004 to 36.6% in 2020 (P for trend <.001). From 2004 to 2020, use of moderate hypofractionation increased from 22.0% to 45.0% (P for trend <.001), and use of ultrahypofractionation increased from 2.0% to 18.3% (P for trend <.001). By 2020, the most common RT schedule was ultrahypofractionation for patients in the low-risk group and moderate hypofractionation for patients in the intermediate-risk group. On multivariable analysis, treatment at a community cancer program (compared with academic or research program; odds ratio [OR], 0.54 [95% CI, 0.52-0.56]; P < .001), Medicaid insurance (compared with Medicare; OR, 1.49 [95% CI, 1.41-1.57]; P < .001), Black race (compared with White race; OR, 0.90 [95% CI, 0.87-0.92]; P < .001), and higher median income (compared with lower median income; OR, 1.28 [95% CI, 1.25-1.31]; P < .001) were associated with receipt of shorter courses of RT. Conclusions and Relevance: Results of this cohort study showed an increase in the use of shorter courses of RT for prostate cancer from 2004 to 2020; a number of social determinants of health appeared to be associated with reduced adoption of shorter treatment courses. Realignment of reimbursement models may be necessary to enable broader adoption of ultrahypofractionation to support technology acquisition costs.


Medicare , Prostatic Neoplasms , Male , Humans , Aged , United States/epidemiology , Cohort Studies , Dose Fractionation, Radiation , Prostatic Neoplasms/pathology , White
6.
Learn Health Syst ; 7(2): e10327, 2023 Apr.
Article En | MEDLINE | ID: mdl-37066100

Clinical trials generate key evidence to inform decision making, and also benefit participants directly. However, clinical trials frequently fail, often struggle to enroll participants, and are expensive. Part of the problem with trial conduct may be the disconnected nature of clinical trials, preventing rapid data sharing, generation of insights and targeted improvement interventions, and identification of knowledge gaps. In other areas of healthcare, a learning health system (LHS) has been proposed as a model to facilitate continuous learning and improvement. We propose that an LHS approach could greatly benefit clinical trials, allowing for continuous improvements to trial conduct and efficiency. A robust trial data sharing system, continuous analysis of trial enrollment and other success metrics, and development of targeted trial improvement interventions are potentially key components of a Trials LHS reflecting the learning cycle and allowing for continuous trial improvement. Through the development and use of a Trials LHS, clinical trials could be treated as a system, producing benefits to patients, advancing care, and decreasing costs for stakeholders.

7.
JAMA Netw Open ; 6(1): e2250416, 2023 01 03.
Article En | MEDLINE | ID: mdl-36630135

Importance: As the field of medicine strives for equity in care, research showing the association of social determinants of health (SDOH) with poorer health care outcomes is needed to better inform quality improvement strategies. Objective: To evaluate the association of SDOH with prostate cancer-specific mortality (PCSM) and overall survival (OS) among Black and White patients with prostate cancer. Data Sources: A MEDLINE search was performed of prostate cancer comparative effectiveness research from January 1, 1960, to June 5, 2020. Study Selection: Two authors independently selected studies conducted among patients within the United States and performed comparative outcome analysis between Black and White patients. Studies were required to report time-to-event outcomes. A total of 251 studies were identified for review. Data Extraction and Synthesis: Three authors independently screened and extracted data. End point meta-analyses were performed using both fixed-effects and random-effects models. The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guideline was followed, and 2 authors independently reviewed all steps. All conflicts were resolved by consensus. Main Outcomes and Measures: The primary outcome was PCSM, and the secondary outcome was OS. With the US Department of Health and Human Services Healthy People 2030 initiative, an SDOH scoring system was incorporated to evaluate the association of SDOH with the predefined end points. The covariables included in the scoring system were age, comorbidities, insurance status, income status, extent of disease, geography, standardized treatment, and equitable and harmonized insurance benefits. The scoring system was discretized into 3 categories: high (≥10 points), intermediate (5-9 points), and low (<5 points). Results: The 47 studies identified comprised 1 019 908 patients (176 028 Black men and 843 880 White men; median age, 66.4 years [IQR, 64.8-69.0 years]). The median follow-up was 66.0 months (IQR, 41.5-91.4 months). Pooled estimates found no statistically significant difference in PCSM for Black patients compared with White patients (hazard ratio [HR], 1.08 [95% CI, 0.99-1.19]; P = .08); results were similar for OS (HR, 1.01 [95% CI, 0.95-1.07]; P = .68). There was a significant race-SDOH interaction for both PCSM (regression coefficient, -0.041 [95% CI, -0.059 to 0.023]; P < .001) and OS (meta-regression coefficient, -0.017 [95% CI, -0.033 to -0.002]; P = .03). In studies with minimal accounting for SDOH (<5-point score), Black patients had significantly higher PCSM compared with White patients (HR, 1.29; 95% CI, 1.17-1.41; P < .001). In studies with greater accounting for SDOH variables (≥10-point score), PCSM was significantly lower among Black patients compared with White patients (HR, 0.86; 95% CI, 0.77-0.96; P = .02). Conclusions and Relevance: The findings of this meta-analysis suggest that there is a significant interaction between race and SDOH with respect to PCSM and OS among men with prostate cancer. Incorporating SDOH variables into data collection and analyses are vital to developing strategies for achieving equity.


Prostatic Neoplasms , Social Determinants of Health , Aged , Humans , Male , Prostate , Prostatic Neoplasms/epidemiology , Prostatic Neoplasms/therapy , United States/epidemiology , White , Black or African American
8.
Eur Urol ; 83(4): 307-310, 2023 04.
Article En | MEDLINE | ID: mdl-35688664

Active surveillance (AS) is recommended as a management option for men with favorable-risk (low risk and favorable intermediate risk) prostate cancer; however, national rates remain low. The Michigan Urological Surgery Improvement Collaborative (MUSIC) established a quality improvement (QI) initiative in June 2014 to increase AS utilization. In this report, we analyze the rates of AS utilization over time in the state of Michigan (MUSIC) for men with favorable-risk prostate cancer and compare these to rates for other men diagnosed with favorable-risk prostate cancer in the USA outside the state of Michigan. While the variables that influence AS utilization were the same in both cohorts, we found that the AS utilization rates and the rate of increase were significantly higher in MUSIC. We conclude that the QI initiative started in MUSIC should serve as a roadmap to increasing AS use nationwide. PATIENT SUMMARY: Active surveillance (AS), which involves close monitoring with blood tests and scans, is recommended for management of favorable-risk prostate cancer to avoid or delay unnecessary treatment. Our results show that a quality improvement program in Michigan increased AS use for prostate cancer patients in the state. This program should be used to increase AS uptake throughout the USA.


Prostatic Neoplasms , Watchful Waiting , Male , Humans , Prostatic Neoplasms/epidemiology , Prostatic Neoplasms/therapy , Michigan/epidemiology
9.
NEJM Evid ; 1(6)2022 Jun.
Article En | MEDLINE | ID: mdl-35721307

BACKGROUND: Prostate-specific antigen screening has profoundly affected the epidemiology of prostate cancer in the United States. Persistent racial disparities in outcomes for Black men warrant re-examination of the harms of screening relative to its cancer-specific mortality benefits in this population. METHODS: We estimated overdiagnoses and overtreatment of prostate cancer for men of all races and for Black men 50 to 84 years of age until 2016, the most recent year with treatment data available, using excess incidence relative to 1986 based on the Surveillance, Epidemiology, and End Results registry and U.S. Census data as well as an established microsimulation model of prostate cancer natural history. Combining estimates with plausible mortality benefit, we calculated numbers needed to diagnose (NND) and treat (NNT) to prevent one prostate cancer death. RESULTS: For men of all races, we estimated 1.5 to 1.9 million (range between estimation approaches) overdiagnosed and 0.9 to 1.5 million overtreated prostate cancers by 2016. Assuming that half of the 270,000 prostate cancer deaths avoided by 2016 were attributable to screening, the NND and the NNT would be 11 to 14 and 7 to 11 for men of all races and 8 to 12 and 5 to 9 for Black men, respectively. Alternative estimates incorporating a lag between incidence and mortality resulted in a NND and a NNT for Black men that reached well into the low single digits. CONCLUSIONS: Complementary approaches to quantifying overdiagnosis indicate a harm-benefit tradeoff of prostate-specific antigen screening that is more favorable for Black men than for men of all races considered together. Our findings highlight the need to account for the increased value of screening in Black men in clinical guidelines. (Funded by the Patient-Centered Outcomes Research Institute, the National Cancer Institute, the Bristol Myers Squibb Foundation, and the Damon Runyon Cancer Research Foundation.).

11.
Urology ; 163: 107-111, 2022 05.
Article En | MEDLINE | ID: mdl-34418408

Currently, Black men in the United States are greater than 1.5 times as likely to be diagnosed with prostate cancer and more than twice as likely to succumb to the disease. While racial disparities in prostate cancer have been well documented, we must analyze these disparities in the correct context. Discussion of these disparities without correctly describing race as a social construct and acknowledging the impact of structural racism is insufficient. This article reviews the disparities seen in screening, treatment, outcomes, and clinical trial participation. We conclude by outlining future steps to help understand and study disparities, as we strive toward equitable outcomes.


Healthcare Disparities , Prostatic Neoplasms , Black People , Humans , Male , Prostatic Neoplasms/diagnosis , Prostatic Neoplasms/therapy , United States/epidemiology
12.
Prostate Cancer Prostatic Dis ; 25(4): 677-683, 2022 04.
Article En | MEDLINE | ID: mdl-34285350

BACKGROUND: Decipher Biopsy is a commercially available gene expression classifier used in risk stratification of newly diagnosed prostate cancer (PCa). Currently, there are no prospective data evaluating its clinical utility. We seek to assess the clinical utility of Decipher Biopsy in localized PCa patients. METHODS: A multi-institutional study of 855 men who underwent Decipher Biopsy testing between February 2015 and October 2019. All patients were tracked through the prospective Michigan Urological Surgery Improvement Collaborative and linked to the Decipher Genomics Resource Information Database (GRID®; NCT02609269). Patient matching was performed by an independent third-party (ArborMetrix Inc.) using two or more unique identifiers. Cumulative incidence curves for time to treatment (TTT) and time to failure (TTF) were constructed using Kaplan-Meier estimates. Multivariable Cox proportional hazard models were used to evaluate the independent association of high-risk Decipher scores with the conversion from AS to radical therapy and treatment failure (biochemical failure or receipt of salvage therapy). RESULTS AND LIMITATIONS: Eight hundred fifty-five patients underwent Decipher Biopsy testing during the study period. Of the 855 men, 264 proceeded to AS (31%), and 454 (53%) received radical therapy. In men electing AS, after adjusting for NCCN risk group, age, PSA, prostate volume, body mass index, and percent positive cores, a high-risk Decipher score was independently associated with shorter TTT (HR 2.51, 95% CI 1.52-4.13 p < 0.001). Similarly, in patients that underwent radical therapy, a high-risk Decipher score was independently associated with TTF (HR 2.98, 95% CI 1.22-7.29, p = 0.01) on multivariable analysis. Follow-up time was a limitation. CONCLUSION: In a prospective statewide registry, high-risk Decipher Biopsy score was strongly and independently associated with conversion from AS to definitive treatment and treatment failure. These real-world data support the clinical utility of Decipher Biopsy. An ongoing phase 3 randomized trial (NCT04396808) will provide level 1 evidence of the clinical impact of Decipher biopsy testing.


Prostatic Neoplasms , Humans , Male , Biopsy , Proportional Hazards Models , Prostate-Specific Antigen , Prostatectomy/adverse effects , Prostatic Neoplasms/diagnosis , Prostatic Neoplasms/epidemiology , Prostatic Neoplasms/therapy , Risk Factors
13.
Eur Urol Open Sci ; 29: 30-35, 2021 Jul.
Article En | MEDLINE | ID: mdl-34337531

BACKGROUND: Serum prostate-specific antigen (PSA), used in prostate cancer screening, is nonspecific for cancer and is affected by age and prostate volume. More specific biomarkers could be more accurate for early detection of prostate cancer and reduce unnecessary prostate biopsies. OBJECTIVE: To evaluate the association of age and prostate volume with urinary MyProstateScore (MPS) in a screened, longitudinal cohort without evidence of prostate cancer. DESIGN SETTING AND PARTICIPANTS: The Olmsted County Study included men aged 40-79 yr who underwent biennial prostate cancer screening. PSA ≥4.0 ng/ml or abnormal rectal examination triggered prostate biopsy, and patients with cancer were excluded. The remaining men submitted urinary specimens for PCA3 and TMPRSS2:ERG testing. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: MPS was calculated using the validated, locked model for grade group ≥2 cancer that includes serum PSA, urinary PCA3, and urinary TMPRSS2:ERG. The associations of age and volume with biomarkers were assessed in multivariable regression models. The t statistic was used to quantify the strength of associations independent of the unit of measurement, and R 2 values were used to estimate the proportion of biomarker variance explained by each factor. RESULTS AND LIMITATIONS: The study included 314 screened men without evidence of cancer. In multivariable models including age and volume, PCA3 score was significantly associated with age (t = 7.51; p < 0.001), while T2:ERG score was not associated with age or volume. MPS was significantly associated with both age (t = 7.45; p < 0.001) and volume (t = 3.56; p < 0.001), but accounting for age alone explained the variability observed (R 2 = 0.29) in a similar way to the model including age and volume (R 2 = 0.31). The variability of PCA3, T2:ERG, and MPS was less dependent on age and volume than the variability for PSA (R 2 = 0.45). CONCLUSIONS: In a cohort of longitudinally screened men without evidence of cancer, we found that MPS demonstrated less variability with noncancer factors (age, prostate volume) than PSA did. These findings support the biology of these markers as more cancer-specific than PSA and highlight their promise in reducing the morbidity associated with PSA-based screening. PATIENT SUMMARY: In a group of men with no evidence of prostate cancer, we found that each of three urine-based markers of cancer-PCA3, T2:ERG, and the commercially available MyProstateScore test-showed less variability with noncancer factors (age and prostate volume) than serum PSA (prostate-specific antigen) did. These findings support their proposed use as noninvasive markers of prostate cancer that could improve the accuracy of early detection.

14.
Urology ; 156: 96-103, 2021 10.
Article En | MEDLINE | ID: mdl-34280438

OBJECTIVE: To improve prostate cancer screening for high-risk men, we developed an early detection clinic for patients at high genetic risk of developing prostate cancer. Despite the rapidly growing understanding of germline variants in driving aggressive prostate cancer and the increased availability of genetic testing, there is little evidence surrounding how best to screen these men. METHODS: We are reporting on the first 45 patients enrolled, men between the ages of 35-75, primarily with known pathogenic germline variants in prostate cancer susceptibility genes. Screening consists of an intake lifestyle survey, PSA, DRE, and SelectMDx urine assay. A biopsy was recommended for any of the following indications: 1) abnormal DRE, 2) PSA above threshold, or 3) SelectMDx above threshold. The primary outcomes were number needed to screen, and number needed to biopsy to diagnose a patient with prostate cancer. RESULTS: Patients enrolled in the clinic included those with BRCA1 (n=7), BRCA2 (n=16), Lynch Syndrome (n=6), and CHEK2 (n = 4) known pathogenic germline variants. The median age and PSA were 58 (range 35-71) and 1.4 ng/ml (range 0.1-11.4 ng/ml), respectively. 12 patients underwent a prostate needle biopsy and there were 4positive biopsies for prostate cancer. CONCLUSION: These early data support the feasibility of opening a dedicated clinic for men at high genetic risk of prostate cancer. This early report on the initial enrollment of our long-term study will help optimize early detection protocols and provide evidence for personalized prostate cancer screening in men with key pathogenic germline variants.


Early Detection of Cancer , Genetic Predisposition to Disease , Prostatic Neoplasms/diagnosis , Prostatic Neoplasms/genetics , Adult , Aged , BRCA1 Protein/genetics , BRCA2 Protein/genetics , Biopsy , Checkpoint Kinase 2/genetics , Colorectal Neoplasms, Hereditary Nonpolyposis/genetics , Digital Rectal Examination , Genetic Testing , Germ-Line Mutation , Humans , Life Style , Male , Medical History Taking , Middle Aged , Nutrition Surveys , Prostate/pathology , Prostate-Specific Antigen/blood , Prostatic Neoplasms/metabolism , Prostatic Neoplasms/pathology , Risk Factors , Urinalysis
15.
J Urol ; 206(3): 593-594, 2021 09.
Article En | MEDLINE | ID: mdl-34137274
18.
Curr Opin Urol ; 29(6): 598-604, 2019 11.
Article En | MEDLINE | ID: mdl-31584886

PURPOSE OF REVIEW: The clinical course of localized prostate cancer varies widely, ranging from indolent disease unlikely to require treatment to aggressive cancers meriting intensive, multimodal therapy. Management recommendations have traditionally been determined based on clinical and pathologic factors, including serum prostate - specific antigen (PSA), clinical stage, and Gleason score. Unfortunately, these factors have limited ability to describe the underlying biology of a given tumor. Tissue-based genomic tests have emerged as a promising tool to more accurately characterize prostate cancer biology and projected clinical course. The current review article summarizes available data describing the clinical use of genomic assays, with a specific focus on three critical scenarios. RECENT FINDINGS: We reviewed the potential role of tissue-based genomic assays in determining: the appropriateness of active surveillance versus definitive therapy, patients that will benefit from adjuvant radiation therapy following radical prostatectomy, and men most likely to benefit from concurrent androgen deprivation therapy with primary radiotherapy. SUMMARY: Current literature suggests that commercially available genomic tests provide prognostic information independent of traditional risk factors that may augment clinical decision-making. Additional data will better clarify the optimal use of each test across common clinical scenarios.


Genomics , Prostate-Specific Antigen , Prostatic Neoplasms/diagnosis , Androgen Antagonists , Humans , Male , Neoplasm Staging , Prostatectomy , Prostatic Neoplasms/genetics , Watchful Waiting
19.
Transl Androl Urol ; 8(6): 703-711, 2019 Dec.
Article En | MEDLINE | ID: mdl-32038967

BACKGROUND: The deleterious effects of chronic ischemia on bladder function have been extensively studied; however, evaluation and characterization of the effects of acute ischemia and hypoxia are lacking. The present study examined pig and human detrusor smooth muscle (DSM) strips, in combination with an isolated perfused working pig bladder model to evaluate the relationship between transient ischemia and bladder function. METHODS: Organ bath and myographic studies were performed using pig and human DSM strips exposed to starvation/hypoxia conditions. Analogous conditions were then recreated in the ex vivo bladder preparation. Filled bladders were then treated with intravascular carbachol to induce contraction and subsequent void. An intravesical transducer continuously monitored changes in bladder pressure, while a tissue pO2 monitor analyzed changes in oxygenation. RESULTS: After 120 min in starved/hypoxic conditions, both pig and human DSM strips demonstrated significantly increased resting tone, with a greater than two-fold increase in force over control. This was effectively blocked with atropine. DSM strips also demonstrated significantly weaker contractions; however, contractile force was nearly recovered following 15-min exposure to replete/oxygenated buffer. In the ex vivo bladder preparation, filling under ischemic conditions yielded a 225% increase in end-fill vesical pressures (Pves) compared to controls. End-fill Pves returned to baseline with reperfusion during a subsequent filling cycle. CONCLUSIONS: Transient ischemia/hypoxia leads to an acute increase in tone in both DSM strips and ex vivo pig bladder. Remarkably, the effect is reversible with re-perfusion and may be blocked with anticholinergics, suggesting a relationship between acute ischemia and increased local acetylcholine release.

20.
Neurourol Urodyn ; 37(8): 2425-2433, 2018 11.
Article En | MEDLINE | ID: mdl-29777585

AIMS: Chronic ischemia is a recognized factor in the pathophysiology of underactive bladder (UAB). Although relative ischemia (ie, low blood flow) is known to occur during filling, little is known regarding the pathophysiology that leads to UAB. Therefore, we developed an ex vivo functional porcine model to investigate the role of transient ischemia and whether autoregulation, a mechanism that maintains tissue oxygenation in certain vital organs, also exists in the bladder. METHODS: Using bladders from slaughtered pigs, we prepared an isolated perfused model where we studied the effects of bladder perfusion flow rate on perfusion pressure and tissue oxygenation during the filling phase. Bladders were perfused at an initial flow rate of 20 mL/min and then clamped in a sequentially decreasing stepwise manner down to no flow and back to the initial flow rate. RESULTS: We found a linear relationship between flow rate and perfusion pressure until the flow rate decreased below 5 mL/min at which point the vascular resistance decreased; however, tissue pO2 remained stable after an initial decline. CONCLUSIONS: These findings suggest that there may be an intrinsic autoregulatory mechanism in the bladder that allows it to undergo cyclic episodes of relative ischemia during its normal function. Factors that overcome this mechanism such as complete or chronic ischemia may be critical in the progression to detrusor underactivity and thereby highlight the importance of intervention during the early phases of this disease process.


Blood Vessels/physiology , Urinary Bladder/blood supply , Urinary Bladder/physiology , Animals , Blood Pressure/physiology , Disease Models, Animal , Female , Homeostasis , In Vitro Techniques , Ischemia/physiopathology , Models, Biological , Oxygen Consumption/physiology , Perfusion , Pressure , Swine , Urinary Bladder, Underactive/physiopathology , Vascular Resistance/physiology
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