Determinants of active surveillance uptake in a diverse population-based cohort of men with low-risk prostate cancer: The Treatment Options in Prostate Cancer Study (TOPCS)

BACKGROUND

Active surveillance (AS) is the preferred strategy for low-risk prostate cancer (LRPC); however, limited data on determinants of AS adoption exist, particularly among Black men.

METHODS

Black and White newly diagnosed (from January 2014 through June 2017) patients with LRPC ≤75 years of age were identified through metro-Detroit and Georgia population-based cancer registries and completed a survey evaluating factors influencing AS uptake.

RESULTS

Among 1688 study participants, 57% chose AS (51% of Black participants, 61% of White) over definitive treatment. In the unadjusted analysis, patient factors associated with initial AS uptake included older age, White race, and higher education. However, after adjusting for covariates, none of these factors was significant predictors of AS uptake. The strongest determinant of AS uptake was the AS recommendation by a urologist (adjusted prevalence ratio, 6.59, 95% CI, 4.84-8.97). Other factors associated with the decision to undergo AS included a shared patient-physician treatment decision, greater prostate cancer knowledge, and residence in metro-Detroit compared with Georgia. Conversely, men whose decision was strongly influenced by the desire to achieve "cure" or "live longer" with treatment and those who perceived their LRPC diagnosis as more serious were less likely to choose AS.

CONCLUSIONS

In this contemporary sample, the majority of patients with newly diagnosed LRPC chose AS. Although the input from their urologists was highly influential, several patient decisional and psychological factors were independently associated with AS uptake. These data shed new light on potentially modifiable factors that can help further increase AS uptake among patients with LRPC.

Can MRI Help Inform Which Men With a History of Multifocal High-Grade Prostatic Intraepithelial Neoplasia or Atypical Small Acinar Proliferation Remain at an Elevated Risk for Clinically Significant Prostate Cancer?

PURPOSE

We investigated the association of MRI findings in men with a previous diagnosis of atypical small acinar proliferation (ASAP) or multifocal high-grade intraepithelial neoplasia (HGPIN) with pathologic findings on repeat biopsy.

MATERIALS AND METHODS

We retrospectively reviewed patients with ASAP/multifocal HGPIN undergoing a repeat biopsy in the Michigan Urological Surgery Improvement Collaborative registry. We included men with and without an MRI after the index biopsy demonstrating ASAP/multifocal HGPIN but before the repeat biopsy. Men with an MRI prior to the index biopsy were excluded. We compared the proportion of men with ≥ GG2 CaP (Grade Group 2 prostate cancer) on repeat biopsy among the following groups with the χ2 test: no MRI, PIRADS (Prostate Imaging-Reporting and Data System) ≥ 4, and PIRADS ≤ 3. Multivariable models were used to estimate the adjusted association between MRI findings and ≥ GG2 CaP on repeat biopsy.

RESULTS

Among the 207 men with a previous diagnosis of ASAP/multifocal HGPIN that underwent a repeat biopsy, men with a PIRADS ≥ 4 lesion had a higher proportion of ≥ GG2 CaP (56%) compared with men without an MRI (12%, P < .001). A lower proportion of men with PIRADS ≤ 3 lesions had ≥ GG2 CaP (3.0%) compared with men without an MRI (12%, P = .13). In the adjusted model, men with a PIRADS 4 to 5 lesion had higher odds (OR: 11.4, P < .001) of ≥ GG2 CaP on repeat biopsy.

CONCLUSIONS

MRI is a valuable diagnostic tool to triage which men with a history of ASAP or multifocal HGPIN on initial biopsy should undergo or avoid repeat biopsy without missing clinically significant CaP.

Does Urologist-level Utilization of Active Surveillance for Low-risk Prostate Cancer Correspond with Utilization of Active Surveillance for Small Renal Masses?

Active surveillance (AS) for prostate cancer (CaP) or small renal masses (SRMs) helps in limiting the overtreatment of indolent malignancies. Implementation of AS for these conditions varies substantially across individual urologists. We examined the Michigan Urological Surgery Improvement Collaborative (MUSIC) registry to assess for correlation of AS between patients with low-risk CaP and patients with SRM managed by individual urologists. We identified 27 urologists who treated at least ten patients with National Comprehensive Cancer Network low-risk CaP and ten patients with SRMs between 2017 and 2021. For surgeons in the lowest quartile of AS use for low-risk CaP (<74%), 21% of their patients with SRMs were managed with AS, in comparison to 74% of patients of surgeons in the highest quartile (>90%). There was a modest positive correlation between the surgeon-level risk-adjusted proportions of patients managed with AS for low-risk CaP and for SRMs (Pearson correlation coefficient 0.48). A surgeon's tendency to use AS to manage one low-risk malignancy corresponds to their use of AS for a second low-risk condition. By identifying and correcting structural issues associated with underutilization of AS, interventions aimed at increasing AS use may have effects that influence clinical tendencies across a variety of urologic conditions. PATIENT SUMMARY: The use of active surveillance (AS) for patients with low-risk prostate cancer or small kidney masses varies greatly among individual urologists. Urologists who use AS for low-risk prostate cancer were more likely to use AS for patients with small kidney masses, but there is room to improve the use of AS for both of these conditions.

Adaptor proteins mediate CXCR4 and PI4KA crosstalk in prostate cancer cells and the significance of PI4KA in bone tumor growth

The chemokine receptor, CXCR4 signaling regulates cell growth, invasion, and metastasis to the bone-marrow niche in prostate cancer (PCa). Previously, we established that CXCR4 interacts with phosphatidylinositol 4-kinase IIIα (PI4KIIIα encoded by PI4KA) through its adaptor proteins and PI4KA overexpressed in the PCa metastasis. To further characterize how the CXCR4-PI4KIIIα axis promotes PCa metastasis, here we identify CXCR4 binds to PI4KIIIα adaptor proteins TTC7 and this interaction induce plasma membrane PI4P production in prostate cancer cells. Inhibiting PI4KIIIα or TTC7 reduces plasma membrane PI4P production, cellular invasion, and bone tumor growth. Using metastatic biopsy sequencing, we found PI4KA expression in tumors correlated with overall survival and contributes to immunosuppressive bone tumor microenvironment through preferentially enriching non-activated and immunosuppressive macrophage populations. Altogether we have characterized the chemokine signaling axis through CXCR4-PI4KIIIα interaction contributing to the growth of prostate cancer bone metastasis.

A Novel Interaction between Chemokine and Phosphoinositide Signaling in Metastatic Prostate Cancer

Prostate cancer commonly metastasizes to bone due to its favorable microenvironment for cell growth and survival. Currently, the standard of care for metastatic prostate cancer is medical castration in conjunction with chemotherapeutic agents and newer anti-androgen/androgen receptor therapies. While these therapies aim to improve the quality of life in patients with advanced disease, resistance to these therapies is inevitable prompting the development of newer therapies to contain disease progression. The CXCL12/CXCR4 axis has previously been shown to be involved in prostate cancer cell homing to bone tissue, and new investigations found a novel interaction of Phosphatidyl Inositol 4 kinase IIIa (PI4KA) downstream of chemokine signaling. PI4KA phosphorylates at the 4th position on phosphatidylinositol (PI), to produce PI4P and is localized to the plasma membrane (PM). At the PM, PI4KA provides precursors for the generation of PI(4,5)P2, and PI(3,4,5)P3 and helps maintain PM identity through the recruitment of lipids and signaling proteins. PI4KA is recruited to the PM through evolutionarily conserved adaptor proteins, and in PC cells, CXCR4 binds with adaptor proteins to recruit PI4KA to the PM. The objective of this review is to summarize our understanding of the role that phosphatidyl inositol lipid messengers in cancer cells.

Upgrading on Per Protocol versus For Cause surveillance prostate biopsies: An opportunity to decreasing the burden of active surveillance

BACKGROUND

Most prostate cancer (PC) active surveillance (AS) protocols recommend "Per Protocol" surveillance biopsy (PPSBx) every 1-3 years, even if clinical and imaging parameters remained stable. Herein, we compared the incidence of upgrading on biopsies that met criteria for "For Cause" surveillance biopsy (FCSBx) versus PPSBx.

METHODS

We retrospectively reviewed men with GG1 PC on AS in the Michigan Urological Surgery Improvement Collaborative (MUSIC) registry. Surveillance prostate biopsies obtained 1 year after diagnosis were classified as either PPSBx or FCSBx. Biopsies were retrospectively deemed FCSBx if any of these criteria were met: PSA velocity > 0.75 ng/mL/year; rise in PSA > 3 ng from baseline; surveillance magnetic resonance imaging (MRI) (sMRI) with a PIRADS ≥ 4; change in DRE. Biopsies were classified PPSBx if none of these criteria were met. The primary outcome was upgrading to ≥GG2 or ≥GG3 on surveillance biopsy. The secondary objective was to assess for the association of reassuring (PIRADS ≤ 3) confirmatory or surveillance MRI findings and upgrading for patients undergoing PPSBx. Proportions were compared with the chi-squared test.

RESULTS

We identified 1773 men with GG1 PC in MUSIC who underwent a surveillance biopsy. Men meeting criteria for FCSBx had more upgrading to ≥GG2 (45%) and ≥GG3 (12%) compared with those meeting criteria for PPSBx (26% and 4.9%, respectively, p < 0.001 and p < 0.001). Men with a reassuring confirmatory or surveillance MRI undergoing PPSBx had less upgrading to ≥GG2 (17% and 17%, respectively) and ≥GG3 (2.9% and 1.8%, respectively) disease compared with men without an MRI (31% and 7.4%, respectively).

CONCLUSIONS

Patients undergoing PPSBx had significantly less upgrading compared with men undergoing FCSBx. Confirmatory and surveillance MRI seem to be valuable tools to stratify the intensity of surveillance biopsies for men on AS. These data may help inform the development of a risk-stratified, data driven AS protocol.

Adaptor proteins mediate CXCR4 and PI4KA crosstalk in prostate cancer cells and the significance of PI4KA in bone tumor growth

The chemokine receptor, CXCR4 signaling regulates cell growth, invasion, and metastasis to the bone-marrow niche in prostate cancer (PCa). Previously, we established that CXCR4 interacts with phosphatidylinositol 4-kinase IIIα (PI4KIIIα encoded by PI4KA) through its adaptor proteins and PI4KA overexpressed in the PCa metastasis. To further characterize how the CXCR4-PI4KIIIα axis promotes PCa metastasis, here we identify CXCR4 binds to PI4KIIIα adaptor proteins TTC7 and this interaction induce plasma membrane PI4P production in prostate cancer cells. Inhibiting PI4KIIIα or TTC7 reduces plasma membrane PI4P production, cellular invasion, and bone tumor growth. Using metastatic biopsy sequencing, we found PI4KA expression in tumors correlated with overall survival and contributes to immunosuppressive bone tumor microenvironment through preferentially enriching non-activated and immunosuppressive macrophage populations. Altogether we have characterized the chemokine signaling axis through CXCR4-PI4KIIIα interaction contributing to the growth of prostate cancer bone metastasis.

Determining the impact of genomic classifier testing on patient-reported quality of life after prostatectomy: Results from the G-MINOR randomized trial

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Background: Decipher is a tissue-based genomic classifier (GC) developed and validated in the post-radical prostatectomy (RP) setting to help guide adjuvant treatment decisions for prostate cancer (PCa). We conducted the first prospective, randomized trial assessing the impact of GC testing on adjuvant therapy use. Here, we determine the impact of GC testing on patient reported (PRO) quality of life outcomes (QoL) in men at high-risk of post-RP recurrence. Methods: The G-MINOR trial is a prospective, unblinded, randomized trial which enrolled 356 patients from 12 centers in the Michigan Urological Surgery Improvement Collaborative (MUSIC). Patients were enrolled between Aug 2016-July 2018. Eligible patients had undergone RP within 9 months of enrollment, had pT3-4 disease and/or positive surgical margins, and a post-RP PSA <0.1ng/mL. Patients were assigned to either the GC or usual-care (UC) group using cluster-crossover block randomization assignments. Evaluable patients (338) were followed for at least 18 months. PROs were obtained using the Expanded Prostate Cancer Index Composite (EPIC-26) survey at baseline (before RP), 3, 6, 12, and 24 months after RP. Results: A total of 226/338 evaluable men (67%) had PRO data for this analysis (116 UC arm/110 GC arm). Median age was 65 years. Of the 226 men included in the PRO analysis, a total of 23 (9 UC arm/14 GC arm) had adjuvant treatment (p = 0.22). At 12 months follow-up, those in the GC arm had no significant change in adjusted mean difference in domain score from baseline compared to those in the UC arm for urinary irritative (UIR) function (1.0, 95% CI [-2.9– 4.9], p=0.6), urinary incontinence (UI) (0.8, 95% CI [-5.1– 6.7], p=0.8), or sexual function (SF) (0.5, 95% CI [-6.9– 7.9], p=0.9). This remained true at 24 months for all three domains [UIR; (2.3, 95% CI [-2.1– 6.6], p=0.3)], [UI; (-0.3, 95% CI [-7.3– 6.7], p=0.9)], [SF; (1.5, 95% CI [-6.8– 9.7], p=0.7)]. Conclusions: In the first ever randomized trial testing the clinical utility of a GC test in localized PCa, longitudinal patient reported QOL outcomes were not significantly different between men who underwent risk stratification with or without Decipher. Clinical trial information: NCT02783950 .

IL-15 Superagonist NAI in BCG-Unresponsive Non-Muscle-Invasive Bladder Cancer

IL-15 Superagonist NAI in BCG-Unresponsive NMIBCIn this trial, patients with BCG-unresponsive bladder CIS with or without Ta/T1 papillary disease or BCG-unresponsive high-grade Ta/T1 papillary NMIBC were treated with intravesical NAI, an IL-15 superagonist, plus BCG. Primary end points were CR at 3 or 6 months for patients with CIS disease and DFS rate at 12 months for those with high-grade Ta/T1 disease. CR rate was 71% (58 of 82 patients), and the DFS rate was 55.4%.

Trials in the Key of G: Building Level 1 Evidence on the Real-world Effectiveness of Prostate Biomarkers

A number of genomic classifiers are available to aid in shared decision-making for men with localized prostate cancer; however, there is no high-level evidence assessing their clinical utility. The two randomized controlled trials in this report prospectively evaluate the use of gene expression classifier testing at the time of cancer diagnosis and after surgical treatment.

The added influence of genomics and post-MRI confirmatory biopsy results to MRI results alone on medical decision making for men with favorable risk prostate cancer being considered for active surveillance

BACKGROUND

We examined how the results of genomic classifier (GC) or post-magnetic resonance imaging confirmatory biopsy (pMRI-CBx) influenced management strategy for men with an MRI considering active surveillance (AS).

METHODS

We reviewed the Michigan Urological Surgery Improvement Collaborative registry for men with favorable-risk prostate cancer. Among men with an MRI after the diagnostic biopsy (n = 1162) a subset also had GC (n = 126) or pMRI-CBx (n = 309). Results of MRI, GC, and pMRI-CBx were deemed reassuring (RA) or non-reassuring (Non-RA). We assess the association of the combination of test results obtained with the selection of AS. Proportions were compared with the Fisher's exact test. Multivariable logistic regression models were fit for an association of test results with the selection of AS.

RESULTS

The results of pMRI-CBx tended to influence management decisions greater than that of GC, especially in situation where testing results were discordant with the MRI result. Fewer men with a RA MRI and non-RA pMRI-CBx where managed with AS compared with RA MRI alone (31% vs. 86%, p < 0.001). non-RA genomics did not seem to have the same influence on management as non-RA pMRI-CBx as a similar proportion of men with RA MRI and non-RA genomics were managed with AS compared with RA MRI alone (85% vs. 86%, p = 0.753). More men with non-RA MRI and RA pMRI-CBx were managed with AS compared with non-RA MRI alone (89% vs. 40%, p < 0.001). Alternatively, a similar proportion of men with non-RA MRI and RA genomics were managed with AS compared with non-RA MRI alone (42% vs. 40%, p > 0.999). In the multivariable models, pMRI-CBx results influenced the decision for AS versus treatment.

CONCLUSIONS

In men with newly diagnosed prostate cancer and an MRI, the additional information provided by pMRI-CBx influenced the decision of AS versus treatment, while the addition of GC results were less influential.

Five-year follow-up study of a population-based prospective cohort of men with low-risk prostate cancer: the treatment options in prostate cancer study (TOPCS): study protocol

INTRODUCTION

Active surveillance (AS) is recommended for men with low-risk prostate cancer (LRPC) to reduce overtreatment and to maintain patients' quality of life (QOL). However, whether African American (AA) men can safely undergo AS is controversial due to concerns of more aggressive disease and lack of empirical data on the safety and effectiveness of AS in this population. Withholding of AS may lead to a lost opportunity for improving survivorship in AA men. In this study, peer-reviewed and funded by the US Department of Defense, we will assess whether AS is an equally effective and safe management option for AA as it is for White men with LRPC.

METHODS AND ANALYSIS

The project extends follow-up of a large contemporary population-based cohort of LRPC patients (n=1688) with a high proportion of AA men (~20%) and well-characterised baseline and 2-year follow-up data. The objectives are to (1) determine any racial differences in AS adherence, switch rate from AS to curative treatment and time to treatment over 5 years after diagnosis, (2) compare QOL among AS group and curative treatment group over time, overall and by race and (3) evaluate whether reasons for switching from AS to curative treatment differ by race. Validation of survey responses related to AS follow-up procedures is being conducted through medical record review. We expect to obtain 5-year survey from ~900 (~20% AA) men by the end of this study to have sufficient power. Descriptive and inferential statistical techniques will be used to examine racial differences in AS adherence, effectiveness and QOL.

ETHICS AND DISSEMINATION

The parent and current studies were approved by the Institutional Review Boards at Wayne State University and Emory University. Since it is an observational study, ethical or safety risks are low. We will disseminate our findings to relevant conferences and peer-reviewed journals.

Delayed radical prostatectomy after a period of active surveillance is not associated with the use of secondary treatments compared with immediate prostatectomy

BACKGROUND

We evaluated the use of secondary treatments in men with grade group (GG) 1 PC following a period of active surveillance (AS) compared with men undergoing immediate radical prostatectomy (RP) to evaluate what is potentially lost in terms of cancer control, if a patient trials AS and transitions to treatment.

METHODS

We reviewed the Michigan Urological Surgery Improvement Collaborative (MUSIC) registry for men with GG1 PC undergoing RP from April 2012 to July 2018. Men were classified into groups based on time from diagnosis to RP: immediate (surgery within 1 year of diagnosis) and delayed RP (surgery >1 year after initiation of AS). Time to secondary treatment was estimated using Kaplan-Meier curves and compared using the log-rank test. A multivariable Cox proportional hazards model was fit to assess the association between timing of RP and use of secondary treatments. A chi-squared test was used to assess the association between delayed RP and adverse pathology.

RESULTS

We identified 1878 men that underwent an RP during the study period, of which 1489 (79%) underwent immediate RP and 389 (21%) underwent delayed RP. The incidence of adverse pathology was higher in men with delayed versus immediate RP (49% vs. 36%, p < 0.0001, respectively). However, we noted only a small absolute difference in the estimated 24-month secondary treatment-free probability between men with delayed versus immediate RP (93% and 96%, respectively). On multivariable analysis, delayed RP was associated with increased use of secondary treatments (hazard ratio = 1.94, 95% confidence interval = 1.23-3.06, p = 0.004).

CONCLUSIONS

The use of secondary treatment after RP in men with GG1 PC undergoing immediate or delayed prostatectomy was rare. These data suggest that the burden of treatment is near equivalent in patients who progress to treatment on AS compared with those who underwent immediate RP.

Association of lymph node yield with overall survival in patients with pathologically node negative prostate cancer

We investigated the association between lymph node yield (LNY) with overall survival (OS) and post-radical prostatectomy (RP) secondary treatments among men with pathologically node negative (pN0) prostate cancer. We reviewed the National Cancer Database for men with Gleason Grade Group 2 or higher prostate cancer treated with RP and had pathologically node-negative disease. LNY was modeled as a continuous and categorical variable grouped by quartiles of LNY. Secondary treatment was defined as the use of radiation or systemic therapy post-RP. Multivariable Cox proportional hazards and logistic regression models were used to test for an association of LNY with OS and secondary treatments, respectively. We identified 89,416 men with pN0 prostate cancer treated with RP from 2010-2015. LNY was associated with improved OS when modeled as a categorical and continuous variable. The third (6-9 nodes) and fourth (≥10 nodes) quartiles of LNY were associated with improved OS (HR 0.87, 95% CI 0.79-0.96, P = 0.006 and HR 0.88, 95% CI 0.79-0.98, P= 0.017, respectively) when compared with the lowest quartile of LNY (≤3 nodes) and the hazard of death decreased by 1% for each benign lymph node removed (HR 0.99, 95% CI 0.98-0.99, P= 0.022). Additionally, categorical and continuous LNY was associated with significantly less use of post-RP secondary treatments. Removal of additional negative lymph nodes was associated with improved OS and less secondary treatments in patients with pN0 prostate cancer. These data suggest that removing a higher quantity of lymph nodes provides more accurate staging and prognosis.

Prospective randomized trial of gene expression classifier utility following radical prostatectomy (G-MINOR)

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Background: Decipher is a tissue-based genomic classifier (GC) developed and validated in the post-radical prostatectomy (RP) setting as a predictor of metastasis. We conducted the first prospective randomized controlled trial assessing the use of a prostate cancer GC, with a primary objective to determine the impact of test results on adjuvant treatment decisions. Methods: The Genomics in Michigan ImpactiNg Observation or Radiation (G-MINOR) randomized trial enrolled participants across 12 centers between January 2017-August 2018. Eligible patients had undergone RP within 9 months of enrollment, had pT3-4 disease and/or positive surgical margins, and a PSA < 0.1ng/mL. Patients were assigned to either the GC or Usual Care (UC) group using cluster-crossover block randomization. Patients and providers in both arms received a CAPRA-S recurrence risk score. Decipher scores were obtained on RP tissue of all patients, but patients and providers in the UC arm were blinded to the results. The primary endpoint was the impact of impact of GC test result on adjuvant treatment decisions compared to clinical factors alone within 18 months of RP. Results: 356 patients were randomized and 340 had at least 18 months of follow-up. Of these, all but 2 control (UC) patients had sufficient tissue to pass quality control for GC testing. Randomization resulted in 175 (51.5%) GC and 165 (48.5%) UC patients. There were no significant differences in clinical variables or Decipher scores between arms. At 18 months post-RP, 19 (10.9%) patients in the GC group and 12 (7.3%) patients in the UC group had received adjuvant treatment. In the primary analysis, availability of the GC score in the GC arm was significantly associated with adjuvant treatment in GC high-risk patients after controlling for CAPRA-S risk (OR 7.6, 95%CI 1.95-29.6, p = 0.009). In the GC arm, both GC score (OR 8.8, 95%CI 1.9-39.7, p = 0.005) and CAPRA-S score (OR 3.8, 95%CI 1.09-12.9, p = 0.04) were independently associated with adjuvant treatment in a multivariable logistic regression model. Conclusions: In the first ever randomized trial testing the impact of a prostate cancer genomic classifier on treatment decisions, the use of a GC post-RP impacted post-operative treatment in a manner concordant with classifier risk. Further follow-up will be necessary to assess the impact of GC testing on oncologic outcomes. Clinical trial information: NCT02783950. [Table: see text]

Urologists' Perceptions of Active Surveillance and Their Recommendations for Low-risk Prostate Cancer Patients

OBJECTIVE

To assess practicing urologists' attitudes and perceptions of active surveillance (AS) and other treatment options for low-risk prostate cancer.

METHODS

This was a cross-sectional survey of urologists practicing in Michigan and Georgia. Urologists were asked about perceptions and practices pertaining to AS.

RESULTS

Overall, 225 urologists completed the survey; 147 (65%) were from Michigan and 78 (35%) were from Georgia. Most urologists reported they provided (99%), discussed (97%), and offered (61%) AS to all of their low-risk patients. Most believed AS is effective (97%) and underused (90%), while 80% agreed that curative therapy (surgery, radiation) is overused in the United States. Although most (79%) endorse that Black men are more likely to have aggressive low-risk disease, 89% reported feeling comfortable recommending AS to Black men. In multivariable analysis, significant provider-related predictors of AS recommendation were practice location, number of years in practice, beliefs pertaining to survival benefit of prostatectomy and effectiveness of AS, and expectation that patients are not interested in AS. The patient characteristics of race, age, life expectancy, fear of cancer progression, and fear of treatment side effects were also significant predictors of AS recommendations.

CONCLUSION

Most urologists surveyed stated that AS is effective and underused for low-risk prostate cancer . Overall, urologists are much less likely to recommend AS to younger men and slightly less to Black men. AS recommendations varied by practice location and by years in practice. These findings indicate targeted educational efforts in the US are needed to influence urologists toward greater acceptance of AS.

Clinical Efficacy of Enzalutamide vs Bicalutamide Combined With Androgen Deprivation Therapy in Men With Metastatic Hormone-Sensitive Prostate Cancer: A Randomized Clinical Trial

IMPORTANCE

Black patients have been underrepresented in prospective clinical trials of advanced prostate cancer. This study evaluated the efficacy of enzalutamide compared with bicalutamide, with planned subset analysis of Black patients with metastatic hormone-sensitive prostate cancer (mHSPC), which is a disease state responsive to androgen deprivation therapy (ADT).

OBJECTIVE

To compare the efficacy of enzalutamide vs bicalutamide in combination with ADT in men with mHSPC, with a subset analysis of Black patients.

DESIGN, SETTING, AND PARTICIPANTS

In this randomized clinical trial, a phase 2 screening design enabled a nondefinitive comparison of the primary outcome by treatment. Patients were stratified by race (Black or other) and bone pain (present or absent). Accrual of at least 30% Black patients was required. This multicenter trial was conducted at 4 centers in the US. Men with mHSPC with no history of seizures and adequate marrow, renal, and liver function were eligible. Data analysis was performed from February 2019 to March 2020.

INTERVENTIONS

Participants were randomized 1:1 to receive oral enzalutamide (160 mg daily) or bicalutamide (50 mg daily) in addition to ADT.

MAIN OUTCOMES AND MEASURES

The primary end point was the 7-month prostate-specific antigen (PSA) response (SMPR) rate, a previously accepted surrogate for overall survival (OS) outcome. Secondary end points included adverse reactions, time to PSA progression, and OS.

RESULTS

A total of 71 men (median [range] age, 65 [51-86] years) were enrolled; 29 (41%) were Black, 41 (58%) were White, and 1 (1%) was Asian. Thirty-six patients were randomized to receive enzalutamide, and 35 were randomized to receive bicalutamide. Twenty-six patients (37%) had bone pain and 37 patients (52%) had extensive disease. SMPR was achieved in 30 of 32 patients (94%; 95% CI, 80%-98%) taking enzalutamide and 17 of 26 patients (65%; 95% CI, 46%-81%) taking bicalutamide (P = .008) (difference, 29%; 95% CI, 5%-50%). Among Black patients, the SMPR was 93% (95% CI, 69%-99%) among those taking enzalutamide and 42% (95% CI, 19%-68%) among those taking bicalutamide (P = .009); among non-Black patients, the SMPR was 94% (95% CI, 74%-99%) among those taking enzalutamide and 86% (95% CI, 60%-96%) among those taking bicalutamide. The 12-month PSA response rates were 84% with enzalutamide and 34% with bicalutamide.

CONCLUSIONS AND RELEVANCE

The findings of this randomized clinical trial comparing enzalutamide with bicalutamide suggest that enzalutamide is associated with improved outcomes compared with bicalutamide, in terms of the rate and duration of PSA response, in Black patients with mHSPC.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02058706.

Association of Surgical Delay and Overall Survival in Patients With T2 Renal Masses: Implications for Critical Clinical Decision-making During the COVID-19 Pandemic

Objective

To test for an association between surgical delay and overall survival (OS) for patients with T2 renal masses. Many health care systems are balancing resources to manage the current COVID-19 pandemic, which may result in surgical delay for patients with large renal masses.

Methods

Using Cox proportional hazard models, we analyzed data from the National Cancer Database for patients undergoing extirpative surgery for clinical T2N0M0 renal masses between 2004 and 2015. Study outcomes were to assess for an association between surgical delay with OS and pathologic stage.

Results

We identified 11,848 patients who underwent extirpative surgery for clinical T2 renal masses. Compared with patients undergoing surgery within 2 months of diagnosis, we found worse OS for patients with a surgical delay of 3-4 months (hazard ratio [HR] 1.12, 95% confidence interval [CI] 1.00-1.25) or 5-6 months (HR 1.51, 95% CI 1.19-1.91). Considering only healthy patients with Charlson Comorbidity Index = 0, worse OS was associated with surgical delay of 5-6 months (HR 1.68, 95% CI 1.21-2.34, P= .002) but not 3-4 months (HR 1.08, 95% CI 0.93-1.26, P = 309). Pathologic stage (pT or pN) was not associated with surgical delay.

Conclusion

Prolonged surgical delay (5-6 months) for patients with T2 renal tumors appears to have a negative impact on OS while shorter surgical delay (3-4 months) was not associated with worse OS in healthy patients. The data presented in this study may help patients and providers to weigh the risk of surgical delay versus the risk of iatrogenic SARS-CoV-2 exposure during resurgent waves of the COVID-19 pandemic.

Impact of Early Confirmatory Tests on Upgrading and Conversion to Treatment in Prostate Cancer Patients on Active Surveillance

OBJECTIVES

To assess the impact of confirmatory tests on active surveillance (AS) biopsy disease reclassification and progression to treatment in men with favorable risk prostate cancer (FRPC).

METHODS

We searched the MUSIC registry for men with FRPC managed with AS without or with a confirmatory test. Confirmatory tests included (1) repeat prostate biopsy, (2) genomic tests, (3) prostate magnetic resonance imaging (MRI), or (4) MRI followed by a post-MRI biopsy. Confirmatory test results were deemed reassuring (RA) or nonreassuring (nonRA) according to predefined criteria. Kaplan-Meier curves and multivariable Cox regression models were used to compare surveillance biopsy disease reclassification-free survival and treatment-free survival.

RESULTS

Of the 2,514 men with FRPC who were managed on AS, 1211 (48%) men obtained a confirmatory test. We noted differences in the 12-month unadjusted surveillance biopsy disease reclassification-free probability (68%, 83%, and 90%, P < .0001) and 24-month unadjusted treatment-free probability (55%, 81%, and 79%, P < .0001), for men with nonRA confirmatory tests, no confirmatory test, and RA confirmatory tests, respectively. Excluding patients with genomic confirmatory tests, men with RA confirmatory tests were associated with a lower hazard (hazard ratio [HR] 0.57, 95% confidence interval [CI] 0.38-0.84, P = .005) and men with nonRA confirmatory tests had an increased hazard (HR 1.97, 95% CI 1.22-3.19, P = .006) of surveillance disease reclassification compared with men without confirmatory tests in the multivariable model.

CONCLUSION

These data suggest men with RA confirmatory tests have less surveillance biopsy reclassification and remain on AS longer than men with nonRA test results. Confirmatory tests may help risk stratify men considering active surveillance.

Should all prostate needle biopsy Gleason score 4 + 4 = 8 prostate cancers be high risk? Implications for shared decision-making and patient counselling

OBJECTIVES

To estimate the probability of downgrading to Gleason score ≤7 at radical prostatectomy for men with a prostate needle biopsy demonstrating Gleason score 8 (4 + 4).

METHODS

This is a retrospective review of men with Gleason score 8 (4 + 4) prostate cancer on needle biopsy who then underwent a radical prostatectomy at the Karmanos Cancer Institute or the University of Michigan. Men with any pattern 5 on the diagnostic biopsy were excluded. The objective was to estimate the proportion of patients whose tumors were downgraded to Gleason score ≤7 at radical prostatectomy and to identify clinical and biopsy parameters associated with downgrading.

RESULTS

Median age of our cohort was 63 years (IQR: 59, 67.5) and median follow-up was 15 months (IQR: 7, 37). Of the 105 men that met inclusion criteria, 59% (62/105) were downgraded to Gleason score ≤7 at radical prostatectomy. Having ≤2 cores demonstrating Gleason score 8, ≤50% maximal tumor involvement of any individual core positive for Gleason score 8, or the presence of Gleason pattern 3 (such as 3 + 4, 4 + 3, or 3 + 3) in other biopsy cores were all independently associated with downgrading in our multivariable model. Depending on the absence, presence, or combination of these 3 factors, patients had an estimated 6% to 82% probability of having their tumor downgraded at radical prostatectomy.

CONCLUSIONS

Men with low volume Gleason 8 (4 + 4) and/or the presence Gleason pattern 3 on prostate needle biopsy often have their tumors downgraded at radical prostatectomy. The presence of these preoperative biopsy parameters could affect pretreatment counseling and impact patient management.

TMPRSS2-ERG fusions confer efficacy of enzalutamide in an in vivo bone tumor growth model

BACKGROUND

Castrate Resistant Prostate Cancer (CRPC) is an advanced disease resistant to systemic traditional medical or surgical castration, and resistance is primarily attributed to reactivation of AR through multiple mechanisms. TMPRSS2-ERG fusions have been shown to regulate AR signaling, interfere with pro-differentiation functions, and mediate oncogenic signaling. We have recently shown that ERG regulates intra-tumoral androgen synthesis and thereby facilitates AR function in prostate cancer cells. We hypothesize that enzalutamide treatment will be more effective in cells/tumors with TMPRSS2-ERG translocations because these tumors have increased AR signaling.

METHODS

ERG knockdown was performed with VCaP cells using lentiviral infections to generate VCaP ERGshRNA cells and control VCaP scr cells with scrambled shRNA. Cell-growth analysis was performed to determine the effect of enzalutamide. Reverse transcription, quantitative real-time PCR (RT-qPCR) was used to determine the expression of AR responsive genes. Luciferase tagged VCaP scr and shRNA infected cells were used in an intra-tibial animal model for bone tumor growth analysis and enzalutamide treatment used to inhibit AR signaling in bone tumors. Western blotting analyzed VCaP bone tumor samples for ERG, AR, AKR1C3 and HSD3B1 and HSD3B2 expression.

RESULTS

Enzalutamide inhibited the growth of VCaP scr cells more effectively than shERG cells. Analysis of AR responsive genes shows that Enzalutamide treatment at 5 micromolar concentration inhibited by 85-90% in VCaP Scr cells whereas these genes were inhibited to a lesser extent in VCaP shERG cells. Enzalutamide treatment resulted in severe growth inhibition in VCaP scr shRNA cells compared to VCaP shERG cells. In bone tumor growth experiment, VCaP ERG shRNA cells grew at slower than VCaP scr shRNA cells. Androgen biosynthetic enzyme expression is lower VCaP shERG bone tumors compared to VCaP scr shRNA bone tumors and enzalutamide inhibited the enzyme expression in both types of tumors.

CONCLUSIONS

These data suggest that ERG transcription factor regulates androgen biosynthetic enzyme expression that enzalutamide treatment is more effective against VCaP bone tumors with an intact ERG expression, and that knocking down ERG in VCaP cells leads to a lesser response to enzalutamide therapy. Thus, ERG expression status in tumors could help stratify patients for enzalutamide therapy.

Utilization of Salvage Radiation Therapy for Biochemical Recurrence After Radical Prostatectomy

PURPOSE

For men with biochemical recurrence after radical prostatectomy (RP), salvage radiation therapy (SRT), especially "early" SRT (PSA level ≤0.5 ng/mL), is a potentially curative option; however, its utilization is not well defined. We sought to determine factors associated with SRT utilization as well as variation in its administration.

MATERIALS AND METHODS

Patients with localized prostate cancer undergoing RP at 33 practices participating in the statewide Michigan Urological Surgery Improvement Collaborative between 2012 and 2016 were prospectively followed. Eligible patients had at least 1 post-RP PSA level ≥0.1 ng/mL with ≥6 months of follow-up after the first detectable PSA level. Patients undergoing adjuvant radiation therapy were excluded. SRT utilization and clinical and pathologic patient characteristics were examined.

RESULTS

Of 1010 eligible patients with a detectable PSA level, 29.5% underwent SRT. Of patients who received SRT, 46.9% either reached a PSA ≥0.2 ng/mL or were treated before reaching that PSA level. A total of 30.6% of patients had a PSA level ≥0.5 ng/mL without undergoing prior SRT; of this group, 42.1% later received SRT. After adjusting for patient and practice level factors, positive surgical margins, higher T stage, and higher grade group were all associated with receipt of SRT (P < .05). Even after adjusting for patient and tumor characteristics, significant variation remained in the adjusted rate of SRT utilization across practices sites, ranging from 7% (95% confidence interval, 3%-17%) to 73% (95% confidence interval, 45%-90%, P < .001). Practices were grouped into tertiles based on SRT utilization, and those practices that used SRT more frequently overall were more likely to administer SRT across all patient-based predictors of SRT utilization.

CONCLUSIONS

SRT utilization is low among men with a detectable post-RP PSA level, with significant variation in practice-level SRT utilization that cannot be explained by patient factors alone. Factors suggesting higher-risk disease were predictors of SRT administration. These data support the potential to expand the use of SRT, particularly among sites with low utilization.

Pathological upgrading at radical prostatectomy for patients with Grade Group 1 prostate cancer: implications of confirmatory testing for patients considering active surveillance

OBJECTIVE

To examine the association between National Comprehensive Cancer Network (NCCN) risk, number of positive biopsy cores, age, and early confirmatory test results on pathological upgrading at radical prostatectomy (RP), in order to better understand whether early confirmatory testing and better risk stratification are necessary for all men with Grade Group (GG) 1 cancers who are considering active surveillance (AS).

PATIENTS AND METHODS

We identified men in Michigan initially diagnosed with GG1 prostate cancer, from January 2012 to November 2017, who had a RP within 1 year of diagnosis. Our endpoints were: (i) ≥GG2 cancer at RP and (ii) adverse pathology (≥GG3 and/or ≥pT3a). We compared upgrading according to NCCN risk, number of positive biopsy cores, and age. Last, we examined if confirmatory test results were associated with upgrading or adverse pathology at RP.

RESULTS

Amongst 1966 patients with GG1 cancer at diagnosis, the rates of upgrading to ≥GG2 and adverse pathology were 40% and 59% (P < 0.001), and 10% and 17% (P = 0.003) for patients with very-low- and low-risk cancers, respectively. Upgrading by volume ranged from 49% to 67% for ≥GG2, and 16% to 23% for adverse pathology. Generally, more patients aged ≥70 vs <70 years had adverse pathology. Unreassuring confirmatory test results had a higher likelihood of adverse pathology than reassuring tests (35% vs 18%, P = 0.017).

CONCLUSIONS

Upgrading and adverse pathology are common amongst patients initially diagnosed with GG1 prostate cancer. Early use of confirmatory testing may facilitate the identification of patients with more aggressive disease ensuring improved risk classification and safer selection of patients for AS.

Risk of Becoming Lost to Follow-up During Active Surveillance for Prostate Cancer

Active surveillance (AS) has emerged as the preferred management strategy for many men with prostate cancer (PC); however, insufficient longitudinal monitoring may increase the risk of poor outcomes. We sought to determine rates of patients becoming lost to follow-up (LTFU) and associated risk factors in a large AS cohort. The Michigan Urologic Surgery Improvement Collaborative (MUSIC) maintains a prospective registry of PC patients from 44 academic and community urology practices. Over a 6-yr period (2011-2017), we identified patients managed with AS. LTFU was defined as any 18-mo period where no pertinent surveillance testing was entered in the registry. With a median surveillance period of 32 mo, the estimated 2-yr LTFU-free probability calculated by Kaplan-Meier method was 90% (95% confidence interval [CI]=89-92%). Both African American race (hazard ratio [HR]: 2.77, 95% CI=1.81-4.24) and Charlson comorbidity index ≥1 (HR: 1.55, 95% CI=1.08-2.23) were independently associated with increased risk of LTFU. There was variability in rates of estimated 2-yr LTFU-free survival across MUSIC practices, ranging from 52% (95% CI=21-100%) to 99% (95% CI=97-100%), with a median of 96% (interquartile range: 94-98%), although this did not reach statistical significance (p=0.076). These data reveal opportunities for urology practices to identify systems to reduce rates of LTFU and improve the long-term safety of AS. PATIENT SUMMARY: With a median observation period of 32 mo, an estimated 10% of patients will be lost to follow-up at the 2 yr time point while on AS. African American men and generally unhealthy patients were at increased risk, and there was variability from one urology practice to another. There is ample opportunity to improve the quality of the performance of AS.

National Trends in Active Surveillance for Prostate Cancer: Validation of Medicare Claims-based Algorithms

OBJECTIVE

To better describe the real-world use of active surveillance. Active surveillance is a preferred management option for low-risk prostate cancer, yet its use outside of high-volume institutions is poorly understood. We created multiple claims-based algorithms, validated them using a robust clinical registry, and applied them to Medicare claims to describe national utilization.

MATERIALS AND METHODS

We identified men with prostate cancer from 2012-2014 in a 100% sample of Michigan Medicare data and linked them with the Michigan Urologic Surgery Improvement Collaborative (MUSIC) registry. Using MUSIC treatment assignment as the standard, we determined the performance of 8 claims-based algorithms to identify men on active surveillance. We selected 3 algorithms (the most sensitive, the most specific, and a balanced algorithm incorporating age and comorbidity) and applied them to a 20% national Medicare sample to describe national trends.

RESULTS

We identified 1186 men with incident prostate cancer and completely linked data. Eight algorithms were tested with sensitivity ranging from 23.5% to 88.2% and specificity ranging from 93.5% to 99.1%. We found that the use of surveillance for men with incident prostate cancer increased from 2007 to 2014, nationally. However, among all men in the population, there was a large decrease in the rate of prostate cancer diagnosis and an increased or stable rate in the use of active surveillance, depending on the algorithm used. Less than 25% of men on active surveillance underwent a confirmatory prostate biopsy.

CONCLUSION

We describe the performance of claims-based algorithms to identify active surveillance.

Observation versus treatment among men with favorable risk prostate cancer in a community-based integrated health care system: a retrospective cohort study

Background

The objective of this study was to describe overall survival and the management of men with favorable risk prostate cancer (PCa) within a large community-based health care system in the United States.

Methods

A retrospective cohort study was conducted using linked electronic health records from men aged ≥40 years with favorable risk PCa (T1 or 2, PSA ≤15, Gleason ≤7 [3 + 4]) diagnosed between January 2005 and October 2013. Cohorts were defined as receiving any treatment (IMT) or no treatment (OBS) within 6 months after index PCa diagnosis. Cohorts’ characteristics were compared between OBS and IMT; monitoring patterns were reported for OBS within the first 18 and 24 months. Cox Proportional Hazards models were used for multivariate analysis of overall survival.

Results

A total of 1425 men met the inclusion criteria (OBS 362; IMT 1063). The proportion of men managed with OBS increased from 20% (2005) to 35% (2013). The OBS group was older (65.6 vs 62.8 years, p < 0.01), had higher Charlson comorbidity index scores (CCI ≥2, 21.5% vs 12.2%, p < 0.01), and had a higher proportion of low-risk PCa (65.2% vs 55.0%, p < 0.01). For the OBS cohort, 181 of the men (50%) eventually received treatment. Among those remaining on OBS for ≥24 months (N = 166), 88.6% had ≥1 follow-up PSA test and 26.5% received ≥1 follow-up biopsy within the 24 months. The unadjusted mortality rate was higher for OBS compared with IMT (2.7 vs 1.3/100 person-years [py]; p < 0.001). After multivariate adjustment, there was no significant difference in all-cause mortality between OBS and IMT groups (HR 0.73, p = 0.138).

Conclusions

Use of OBS management increased over the 10-year study period. Men in the OBS cohort had a higher proportion of low-risk PCa. No differences were observed in overall survival between the two groups after adjustment of covariates. These data provide insights into how favorable risk PCa was managed in a community setting.

Prospective randomized trial of genomic classifier impact on treatment decisions in patients at high risk of recurrence following radical prostatectomy (G-MINOR)

TPS154

Background: Approximately 30% of patients will have ≥pT3 disease and/or positive surgical margins at radical prostatectomy (RP), indicating a high risk of local recurrence. While current guidelines recommend consideration of adjuvant radiotherapy (aRT) in this setting, < 10% undergo aRT. The Decipher assay is a novel, tissue-based genomic classifier (GC) developed and validated in the post-RP setting as a predictor of metastasis. Current retrospective evidence suggests that patients with a high GC score may benefit from aRT, while observation may be safe for those with a lower GC score. However, there are no randomized prospective data evaluating the clinical utility of biomarkers in men with adverse features after RP. Here we see to determine the impact of GC test results on adjuvant treatment decisions for high-risk post-RP patients vs. clinical factors alone. Methods: Genomics in Michigan ImpactiNg Observation or Radiation (G-MINOR) is a 4-year (12-month enrollment, 3-year follow-up) prospective, cluster-crossover, unblinded, study of 350 subjects from twelve Urology practices in the Michigan Urological Surgery Improvement Collaborative (MUSIC). MUSIC is a physician-led quality improvement consortium nearly all academic and community urology practices within the state of Michigan. Each clinical center participating in this trial will be randomly assigned to either a Genomic Classifier (GC)-based strategy or control arm for a period of 3 months. Patients in both arms will receive a predicted risk of recurrence based on a validated clinical nomogram, the CAPRA-S score, enabling a head-to-head comparison of the Decipher assay with a freely-available validated prognostic tool. Random assignments will be generated centrally by a study statistician and provided to centers immediately before commencing enrollment in each 3-month period. Each center will have two GC and two UC enrollment periods, maintaining study-wide balance and blinding of assignments in subsequent periods. Patients will be followed for receipt of adjuvant therapy as well as oncologic (recurrence, metastasis, and death) and patient-reported quality of life. Clinical trial information: NCT02783950.

Randomized trial of enzalutamide versus bicalutamide in combination with androgen deprivation in metastatic hormone sensitive prostate cancer: A Prostate Cancer Clinical Trials Consortium trial

190

Background: Addition of abiraterone or docetaxel has overall survival (OS) benefit in metastatic hormone sensitive prostate cancer (mHSPC). The clinical outcomes with early enzalutamide in mHSPC are unknown. We compared the combinations of enzalutamide (Arm A) or bicalutamide (Arm B) each with LHRH analogue therapy in mHSPC. Methods: The primary endpoint was PSA nadir < 4 ng/ml after 7 months of therapy, as this has been recognized as a powerful surrogate for overall survival (OS) outcomes. A minimum of 29 African American (AA) patients were required to be enrolled to evaluate the effect of race on the primary endpoint. Secondary endpoints were toxicities, biochemical and radiologic progression free survival (PFS), and OS. Stratification was by presence of bone pain and race; AA or other. PSA was monitored monthly for first 7 months and then every 3 months. The target sample size was 82 evaluable patients but the study was stopped when early abiraterone showed OS benefit in mHSPC. Metastatic site biopsies were mandatory pretherapy and optional post therapy. Results: 71 men; 29 black, 41 white and 1 Asian were enrolled. The median age was 67 years (range 46-87 years) and median baseline PSA was 56.3 ng/ml in Arm A (4.2-10,431 ng/ml) and 60 (4.9-12,030 ng/ml) in Arm B. 27 pts (38.5%) had bone pain and 13 had visceral metastases. No seizures were noted in either arm. Grade 3+ AE’s on Arm A were: Hypertension (13%), infection (7%), and Snycope (7%) and on Arm B were: Hypertension (21%), Fatigue (7%), and Hematuria (7%). By intent to treat PSA nadir < 4ng/ml at month 7 was achieved in 96.3% pts in arm A and 66.7% pts in arm B and in 71.7% of AA men and 89.7% of Caucasians. The 6-month PSA remission duration rates after month 7 on Arms A and B were 86% and 79%, respectively. 53 (75%) biopsy samples had tumor tissue available. Tmprss2-Erg fusion gene expression and androgen biosynthetic enzyme levels were determined in metastatic biopsies and will be correlated with clinical endpoints. Conclusions: Early enzalutamide use in mHSPC has the potential to improve PSA remission rates and subsequently improve PFS and OS outcomes. Clinical trial information: NCT02058706.

Avoidance of androgen deprivation therapy in radiorecurrent prostate cancer as a clinically meaningful endpoint for salvage cryoablation

BACKGROUND

To investigate the ability of salvage cryoablation of the prostate (SCAP) to delay the need for androgen deprivation therapy (ADT) in local recurrence after radiation therapy to the prostate using the Cryo-On-Line Database (COLD) registry.

METHODS

The COLD registry is comprised of a combination of retrospectively and prospectively collected data on patients undergoing primary and SCAP. Patients with local recurrence after radiation therapy were identified. Kaplan-Meier analysis was used to calculate ADT-free survival.

RESULTS

We identified 898 patients that have undergone SCAP in the COLD registry. Overall, the calculated 5-year ADT-free survival probability was 0.713. When stratified by D'Amico risk group, 264 high-risk patients (71.9%), 234 intermediate-risk (86.7%),and 228 low-risk (87.7%) were free of ADT post-SCAP. This correlates with a 5-year ADT-free survival of 60.7, 73.9, and 82.4%, respectively. Patients with post-SCAP PSA nadir of <0.2 ng/mL had a 5 year ADT-free survival of 87.1% compared to 48.7% with a PSA nadir ≥0.2 ng/mL. Pre-operative ADT use or full versus partial gland SCAP did not have an effect on ADT use post-operatively. In 118 (55.4%) of patients with post-operative biochemical recurrence, ADT was not used.

CONCLUSION

For patients with local recurrence after radiation, SCAP is an option that provides a high chance of avoiding or delaying ADT. The potential to delay ADT and its associated side effects should be a part of counseling sessions with the patient when discussing treatment options for locally recurrent prostate cancer after radiation. Avoidance of ADT is more clinically relevant than PSA elevation.

Prospective assessment of positioning-related pain in robotic urologic surgery

This was a prospective study to assess positioning-related pain in 20 awake volunteers in the dorsal lithotomy (DL) and lateral decubitus (LD) positions. Each volunteer was put through the series of discrete, sequential steps used to achieve a final position; each step had two options. The Wong-Baker scale (WB) was used to rate pain for each option and the preferred option and ad lib comments were recorded. We found that awake volunteers could clearly and immediately distinguish differences in pain levels between position options. For the DL position, volunteers favored having the arms slightly flexed and pronated as opposed to being straight and supinated reflected by statistically less painful WB scores and option preference. Volunteers preferred having the neck flexed as opposed to being flat. For the LD position, volunteers reported statistically lower pain scores and preference for a foam roll for axilla support as opposed to a rolled blanket, the table flexed without the kidney rest as opposed to a raised kidney rest, and the over arm board as oppose to stacked blankets for contralateral arm support. Ad lib comments from the volunteers supported the above findings. To our knowledge, ours is the first study to demonstrate objective preferences for variations in surgical positioning using awake volunteers. This exercise with awake volunteers resulted in immediate changes in positioning for real robotic surgery patients in our practice.

Infection-Related Hospital Admissions After Prostate Biopsy in United States Men

Antibiotic prophylaxis during prostate biopsy is widespread; however, rates of postbiopsy infections have been rising. In an analysis of insurance claims data for 515045 prostate biopsies, 1.55% were hospitalized with infectious complications, with a mean total payment $14498.96. Infection was the second most common reason for 30-day hospital readmission.

Pharmacological targeting of CXCL12/CXCR4 signaling in prostate cancer bone metastasis

Background

The CXCL12/CXCR4 axis transactivates HER2 and promotes intraosseous tumor growth. To further explore the transactivation of HER2 by CXCL12, we investigated the role of small GTP protein G_αi2 in Src and HER2 phosphorylation in lipid raft membrane microdomains and the significance of CXCR4 in prostate cancer bone tumor growth.

Methods

We used a variety of methods such as lipid raft isolation, invasion assays, an in vivo model of intratibial tumor growth, bone histomorphometry, and immunohistochemistry to determine the role of CXCR4 signaling in lipid raft membrane microdomains and effects of targeting of CXCR4 for bone tumor growth.

Results

We determined that (a) CXCL12/CXCR4 transactivation of EGFR and HER2 is confined to lipid raft membrane microdomains, (b) CXCL12 activation of HER2 and Src is mediated by small GTP proteins in lipid rafts, (c) inhibition of the CXCL12/CXCR4 axis through plerixafor abrogates the initial establishment of tumor growth without affecting the growth of established bone tumors, and (d) inhibition of EGFR signaling through gefitinib leads to inhibition of established bone tumor growth.

Conclusions

These data suggest that lipid raft membrane microdomains are key sites for CXCL12/CXCR4 transactivation of HER2 via small GTP binding protein G_αi2 and Src kinase. The initial establishment of prostate cancer is supported by the endosteal niche, and blocking the CXCL12/CXCR4 axis of this niche along with its downstream signaling severely compromises initial establishment of tumors in the bone microenvironment, whereas expanding bone tumors are sensitive only to the members of growth factor receptor inhibition.

Electronic supplementary material

The online version of this article (doi:10.1186/s12943-016-0552-0) contains supplementary material, which is available to authorized users.

Appropriateness Criteria for Active Surveillance of Prostate Cancer

PURPOSE

The adoption of active surveillance varies widely across urological communities, which suggests a need for more consistency in the counseling of patients. To address this need we used the RAND/UCLA Appropriateness Method to develop appropriateness criteria and counseling statements for active surveillance.

MATERIALS AND METHODS

Panelists were recruited from MUSIC urology practices. Combinations of parameters thought to influence decision making were used to create and score 160 theoretical clinical scenarios for appropriateness of active surveillance. Recent rates of active surveillance among real patients across the state were assessed using the MUSIC registry.

RESULTS

Low volume Gleason 6 was deemed highly appropriate for active surveillance whereas high volume Gleason 6 and low volume Gleason 3+4 were deemed appropriate to uncertain. No scenario was deemed inappropriate or highly inappropriate. Prostate specific antigen density, race and life expectancy impacted scores for intermediate and high volume Gleason 6 and low volume Gleason 3+4. The greatest degree of score dispersion (disagreement) occurred in scenarios with long life expectancy, high volume Gleason 6 and low volume Gleason 3+4. Recent rates of active surveillance use among real patients ranged from 0% to 100% at the provider level for low or intermediate biopsy volume Gleason 6, demonstrating a clear opportunity for quality improvement.

CONCLUSIONS

By virtue of this work urologists have the opportunity to present specific recommendations from the panel to their individual patients. Community-wide efforts aimed at increasing rates of active surveillance and reducing practice and physician level variation in the choice of active surveillance vs treatment are warranted.

Gene expression analysis of bone metastasis and circulating tumor cells from metastatic castrate-resistant prostate cancer patients

Background

Characterization of genes linked to bone metastasis is critical for identification of novel prognostic or predictive biomarkers and potential therapeutic targets in metastatic castrate-resistant prostate cancer (mCRPC). Although bone marrow core biopsies (BMBx) can be obtained for gene profiling, the procedure itself is invasive and uncommon practice in mCRPC patients. Conversely, circulating tumor cells (CTCs), which are likely to stem from bone metastases, can be isolated from blood. The goals of this exploratory study were to establish a sensitive methodology to analyze gene expression in BMBx and CTCs, and to determine whether the presence or absence of detectable gene expression is concordant in matching samples from mCRPC patients.

Methods

The CellSearch^® platform was used to enrich and enumerate CTCs. Low numbers of PC3 prostate cancer (PCa) cells were spiked into normal blood to assess cell recovery rate. RNA extracted from recovered PC3 cells was amplified using an Eberwine-based procedure to obtain antisense mRNA (aRNA), and assess the linearity of the RNA amplification method. In this pilot study, RNAs extracted from CTCs and PCa cells microdissected from formalin-fixed paraffin-embedded BMBx, were amplified to obtain aRNA and assess the expression of eight genes functionally relevant to PCa bone metastasis using RT-PCR.

Results

RNAs were successfully extracted from as few as 1–5 PCa cells in blood samples. The relative expression levels of reference genes were maintained after RNA amplification. The integrity of the amplified RNA was also demonstrated by RT-PCR analysis using primer sets that target the 5′-end, middle, and 3′-end of reference mRNA. We found that in 21 out of 28 comparisons, the presence or absence of detectable gene expression in CTCs and PCa cells microdissected from single bone lesions of the same patients was concordant.

Conclusions

This exploratory analysis suggests that aRNA amplification through in vitro transcription may be useful as a method to detect gene expression in small numbers of CTCs and tumor cells microdissected from bone metastatic lesions. In some cases, gene expression in CTCs and BMBxs was not concordant, raising questions about using CTC gene expression to make clinical decisions.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-016-0829-5) contains supplementary material, which is available to authorized users.

Variation in the use of postoperative radiotherapy among high-risk patients following radical prostatectomy

BACKGROUND

We used data from the Michigan Urological Surgery Improvement Collaborative (MUSIC) to investigate the use of adjuvant and salvage radiotherapy (ART, SRT) among patients with high-risk pathology following radical prostatectomy (RP).

METHODS

For patients with pT3a disease or higher and/or positive surgical margins, we examined post-RP radiotherapy administration across MUSIC practices. We excluded patients with <6 months follow-up, and those that failed to achieve a postoperative PSA nadir ⩽0.1. ART was defined as radiation administered within 1 year post RP, with all post-nadir PSA levels <0.1 ng ml(-1). Radiation administered >1 year post RP and/or after a post-nadir PSA ⩾0.1 ng ml(-1) was defined as SRT. We used claims data to externally validate radiation administration.

RESULTS

Among 2337 patients undergoing RP, 668 (28.6%) were at high risk of recurrence. Of these, 52 (7.8%) received ART and 56 (8.4%) underwent SRT. Patients receiving ART were younger (P=0.027), more likely to have a greater surgical Gleason sum (P=0.009), higher pathologic stage (P<0.001) and received treatment at the smallest and largest size practices (P=0.011). Utilization of both ART and SRT varied widely across MUSIC practices (P<0.001 and P=0.046, respectively), but practice-level rates of ART and SRT administration were positively correlated (P=0.003) with lower ART practices also utilizing SRT less frequently. Of the 88 patients not receiving ART and experiencing a PSA recurrence ⩾0.2 ng ml(-1), 38 (43.2%) progressed to a PSA ⩾0.5 ng ml(-1) and 20 (22.7%) to a PSA ⩾1.0 ng ml(-1) without receiving prior SRT. There was excellent concordance between registry and claims data κ=0.98 (95% CI: 0.94-1.0).

CONCLUSIONS

Utilization of ART and SRT is infrequent and variable across urology practices in Michigan. Although early SRT is an alternative to ART, it is not consistently utilized in the setting of post-RP biochemical recurrence. Quality improvement initiatives focused on current postoperative radiotherapy administration guidelines may yield significant gains for this high-risk population.

ERG/AKR1C3/AR Constitutes a Feed-Forward Loop for AR Signaling in Prostate Cancer Cells

PURPOSE

Intratumoral androgen synthesis in prostate cancer contributes to the development of castration-resistant prostate cancer (CRPC). Several enzymes responsible for androgen biosynthesis have been shown to be overexpressed in CRPC, thus contributing to CRPC in a castrated environment. The TMPRSS2-ERG transcription factor has been shown to be present in primary prostate cancer tumors as well as CRPC tumors. We hypothesize that TMPRSS2-ERG fusions regulate androgen biosynthetic enzyme (ABE) gene expression and the production of androgens, which contributes to the development of CRPC.

EXPERIMENTAL DESIGN

We used a panel of assays, including lentivirus transduction, gene expression, chromatin immunoprecipitation and sequencing, liquid chromatography-mass spectrometric quantitation, immunocytochemistry, immunohistochemistry, and bioinformatics analysis of gene microarray databases, to determine ERG regulation of androgen synthesis.

RESULTS

We found that ERG regulated the expression of the ABE AKR1C3 in prostate cancer cells via direct binding to the AKR1C3 gene. Knockdown of ERG resulted in reduced AKR1C3 expression, which caused a reduction in both DHT synthesis and PSA expression in VCaP prostate cancer cells treated with 5α-androstanedione (5α-Adione), a DHT precursor metabolite. Immunohistochemical staining revealed that ERG was coexpressed with AKR1C3 in prostate cancer tissue samples.

CONCLUSIONS

These data suggest that AKR1C3 catalyzes the biochemical reduction of 5α-Adione to DHT in prostate cancer cells, and that ERG regulates this step through upregulation of AKR1C3 expression. Elucidation of ERG regulation of ABEs in CRPC may help to stratify TMPRSS2-ERG fusion-positive prostate cancer patients in the clinic for anti-androgen receptor-driven therapies; and AKR1C3 may serve as a valuable therapeutic target in the treatment of CRPC.

MUSIC: patterns of care in the radiographic staging of men with newly diagnosed low risk prostate cancer

PURPOSE

MUSIC is a statewide consortium of 42 urology practices that aims to improve the quality of prostate cancer care in Michigan. As an initial priority, we examined patterns of care in the radiographic staging of men with newly diagnosed prostate cancer. We determined whether collaborative-wide data review and performance feedback would decrease the imaging rate in men with low risk prostate cancer.

MATERIALS AND METHODS

Practices submitted standardized data, including the use and results of staging computerized tomography and bone scan, to a web based clinical registry of all men with newly diagnosed prostate cancer. We identified all patients with low risk prostate cancer and compared imaging use patterns before and after practice level performance feedback and guideline review, which were provided at collaborative-wide meetings.

RESULTS

In MUSIC 813 patients were newly diagnosed with low risk prostate cancer during the 19-month study period. Of 410 patients diagnosed in the prefeedback period (phase I) 15 (3.7%) and 21 (5.2%) underwent bone scan and computerized tomography, respectively. Of 403 patients diagnosed after feedback (phase II) radiographic staging was done in 5 men (1.3%) with bone scan and in 13 (3.2%) with computerized tomography (p = 0.03 and 0.17, respectively).

CONCLUSIONS

The overall rate of radiographic staging in men with newly diagnosed low risk prostate cancer was appropriately low. The imaging rate decreased even further after collaborative education and performance feedback. MUSIC appears to be a successful tool for quality improvement, affecting practice patterns and increasing efficiency of care.

Cryotherapy with concurrent CpG oligonucleotide treatment controls local tumor recurrence and modulates HER2/neu immunity

Percutaneous cryoablation is a minimally invasive procedure for tumor destruction, which can potentially initiate or amplify antitumor immunity through the release of tumor-associated antigens. However, clinically efficacious immunity is lacking and regional recurrences are a limiting factor relative to surgical excision. To understand the mechanism of immune activation by cryoablation, comprehensive analyses of innate immunity and HER2/neu humoral and cellular immunity following cryoablation with or without peritumoral CpG injection were conducted using two HER2/neu(+) tumor systems in wild-type (WT), neu-tolerant, and SCID mice. Cryoablation of neu(+) TUBO tumor in BALB/c mice resulted in systemic immune priming, but not in neu-tolerant BALB NeuT mice. Cryoablation of human HER2(+) D2F2/E2 tumor enabled the functionality of tumor-induced immunity, but secondary tumors were refractory to antitumor immunity if rechallenge occurred during the resolution phase of the cryoablated tumor. A step-wise increase in local recurrence was observed in WT, neu-tolerant, and SCID mice, indicating a role of adaptive immunity in controlling residual tumor foci. Importantly, local recurrences were eliminated or greatly reduced in WT, neu tolerant, and SCID mice when CpG was incorporated in the cryoablation regimen, showing significant local control by innate immunity. For long-term protection, however, adaptive immunity was required because most SCID mice eventually succumbed to local tumor recurrence even with combined cryoablation and CpG treatment. This improved understanding of the mechanisms by which cryoablation affects innate and adaptive immunity will help guide appropriate combination of therapeutic interventions to improve treatment outcomes.

Bone-induced c-kit expression in prostate cancer: a driver of intraosseous tumor growth

Loss of BRCA2 function stimulates prostate cancer (PCa) cell invasion and is associated with more aggressive and metastatic tumors in PCa patients. Concurrently, the receptor tyrosine kinase c-kit is highly expressed in skeletal metastases of PCa patients and induced in PCa cells placed into the bone microenvironment in experimental models. However, the precise requirement of c-kit for intraosseous growth of PCa and its relation to BRCA2 expression remain unexplored. Here, we show that c-kit expression promotes migration and invasion of PCa cells. Alongside, we found that c-kit expression in PCa cells parallels BRCA2 downregulation. Gene rescue experiments with human BRCA2 transgene in c-kit-transfected PCa cells resulted in reduction of c-kit protein expression and migration and invasion, suggesting a functional significance of BRCA2 downregulation by c-kit. The inverse association between c-kit and BRCA2 gene expressions in PCa cells was confirmed using laser capture microdissection in experimental intraosseous tumors and bone metastases of PCa patients. Inhibition of bone-induced c-kit expression in PCa cells transduced with lentiviral short hairpin RNA reduced intraosseous tumor incidence and growth. Overall, our results provide evidence of a novel pathway that links bone-induced c-kit expression in PCa cells to BRCA2 downregulation and supports bone metastasis.

Transcriptional regulation of CXCR4 in prostate cancer: significance of TMPRSS2-ERG fusions

CXCR4 is a chemokine receptor that mediates invasion and metastasis. CXCR4 expression is transcriptionally regulated in cancer cells and is associated with aggressive prostate cancer phenotypes. Previously, we and others have shown that the transcription factor ERG regulates CXCR4 expression in prostate cancer cells and that androgens modulate CXCR4 expression via increasing ERG expression. Herein, the molecular mechanisms of ERG-mediated CXCR4 promoter activation, phosphorylation of ERG by intracellular kinases and subsequent CXCR4 expression, as well as the status of ERG and CXCR4 in human prostate cancer specimens were investigated. Using multiple molecular strategies, it was demonstrated that (i) ERG expressed in TMPRSS2-ERG fusion positive VCaP cells selectively binds to specific ERG/Ets bindings sites in the CXCR4 promoter; (ii) distal binding sites mediate promoter activation; (iii) exogenously expressed ERG promotes CXCR4 expression; (iv) ERG is phosphorylated at Serine-81 and -215, by both IKK and Akt kinases, and Akt mediates CXCR4 expression; (v) ERG-induced CXCR4 drives CXCL12-dependent adhesion to fibronectin; and (vi) ERG and CXCR4 were coexpressed in human prostate cancer tissue, consistent with ERG-mediated transcriptional activation of CXCR4. These data demonstrate that ERG activates CXCR4 expression by binding to specific ERG/Ets responsive elements and via intracellular kinases that phosphorylate ERG at discrete serine residues.

IMPLICATIONS

These findings provide a mechanistic link between TMPRSS2-ERG translocations and intracellular kinase-mediated phosphorylation of ERG on enhanced metastasis of tumor cells via CXCR4 expression and function in prostate cancer cells.

PTEN loss mediated Akt activation promotes prostate tumor growth and metastasis via CXCL12/CXCR4 signaling

Introduction

The chemokine CXCL12, also known as SDF-1, and its receptor, CXCR4, are overexpressed in prostate cancers and in animal models of prostate-specific PTEN deletion, but their regulation is poorly understood. Loss of the tumor suppressor PTEN (phosphatase and tensin homolog) is frequently observed in cancer, resulting in the deregulation of cell survival, growth, and proliferation. We hypothesize that loss of PTEN and subsequent activation of Akt, frequent occurrences in prostate cancer, regulate the CXCL12/CXCR4 signaling axis in tumor growth and bone metastasis.

Methods

Murine prostate epithelial cells from PTEN^+/+, PTEN^+/−, and PTEN^−/− (prostate specific knockdown) mice as well as human prostate cancer cell lines C4-2B, PC3, and DU145 were used in gene expression and invasion studies with Akt inhibition. Additionally, HA-tagged Akt1 was overexpressed in DU145, and tumor growth in subcutaneous and intra-tibia bone metastasis models were analyzed.

Results

Loss of PTEN resulted in increased expression of CXCR4 and CXCL12 and Akt inhibition reversed expression and cellular invasion. These results suggest that loss of PTEN may play a key role in the regulation of this chemokine activity in prostate cancer. Overexpression of Akt1 in DU145 resulted in increased CXCR4 expression, as well as increased proliferation and cell cycle progression. Subcutaneous injection of these cells also resulted in increased tumor growth as compared to neo controls. Akt1 overexpression reversed the osteosclerotic phenotype associated with DU145 cells to an osteolytic phenotype and enhanced intra-osseous tumor growth.

Conclusions

These results suggest the basis for activation of CXCL12 signaling through CXCR4 in prostate cancer driven by the loss of PTEN and subsequent activation of Akt. Akt1-associated CXCL12/CXCR4 signaling promotes tumor growth, suggesting that Akt inhibitors may potentially be employed as anticancer agents to target expansion of PC bone metastases.

Abstract 4088: PTEN loss mediated Akt activation promotes prostate tumor growth via CXCL12/CXCR4 signaling

Introduction: Chemokines are a family of cytokines known to regulate the migration of cells. The chemokine CXCL12, also known as SDF-1, and its receptor CXCR4 are associated with prostate cancer bone metastasis. The tumor suppressor PTEN (phosphatase and tensin homolog) is a critical regulator of growth factors and inhibitor of PI3K. Loss of PTEN is frequently observed in cancer, resulting in the deregulation of cell survival, growth, and proliferation. Previous studies have found that PTEN is lost or mutated in 30-80% of primary prostate cancer, and 50% of prostate cancer bone metastases. In mouse models of prostate cancer, it has been shown that loss of PTEN is critical for tumor initiation, and the level of PTEN expression is inversely associated with prostate tumorigenesis. Murine epithelial cells from PTEN-deficient prostate tumors also display increased expression of CXCR4 and CXCL12. We hypothesize that loss of PTEN and subsequent activation of Akt, frequent occurrences in prostate cancer, regulate the CXCL12/CXCR4 signaling axis in prostate cancer progression.

Methods: Prostate-specific deletion of floxed exon 5 of PTEN was achieved by Cre recombinase expressed under the control of an androgen-responsive probasin promoter. Stable cell lines were developed from PTEN+/+, PTEN+/−, and PTEN−/− murine prostate epithelial cells isolated from prostates of corresponding mice at 8 weeks of age. PTEN status in these cell lines was confirmed by genotyping and immunoblot analyses. Human prostate cancer cell lines BPH-1, C4-2B, PC3, and DU145 were also utilized. Gene expression and invasion were analyzed in the presence or absence of Akt inhibitor. Additionally, DU145 with overexpressed HA-tagged Akt1 was also utilized in a subcutaneous injection model.

Results: Loss of PTEN resulted in increased expression of CXCR4 and CXCL12, suggesting that loss of PTEN may play a key role in the regulation of these chemokines in prostate cancer. Upon treatment of PTEN-null cells with Akt inhibitor, the induction of CXCL12/CXCR4 was reversed, further demonstrating the role of the PTEN regulated pathway in the expression of these genes. Akt inhibition also resulted in decreased invasion in response to CXCL12. Overexpression of Akt1 in DU145 resulted increased CXCR4 expression, as well as increased proliferation and cell cycle progression. Subcutaneous injection of these cells also resulted in increased tumor growth as compared to neo controls.

Conclusions: These results suggest the basis for activation of CXCL12 signaling through CXCR4 in prostate cancer driven by the loss of PTEN and subsequent activation of Akt.

Citation Format: Katie Conley-Lacomb, Allen Saliganan, Yong Q. Chen, Hyeong-Reh C. Kim, Michael L. Cher, Sreenivasa R. Chinni. PTEN loss mediated Akt activation promotes prostate tumor growth via CXCL12/CXCR4 signaling. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4088. doi:10.1158/1538-7445.AM2013-4088