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.

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.

The Use and Short-term Outcomes of Active Surveillance in Men With National Comprehensive Cancer Network Favorable Intermediate-risk Prostate Cancer: The Initial Michigan Urological Surgery Improvement Collaborative Experience.

PURPOSE: National Comprehensive Cancer Network favorable intermediate-risk prostate cancer is a heterogeneous disease with varied oncologic and survival outcomes. We describe the Michigan Urological Surgery Improvement Collaborative's experience with the use of active surveillance and the short-term oncologic outcomes for men with favorable intermediate-risk prostate cancer.Materials and Methods:We reviewed the Michigan Urological Surgery Improvement Collaborative registry for men diagnosed with favorable intermediate-risk prostate cancer from 2012-2020. The proportion of men with favorable intermediate-risk prostate cancer managed with active surveillance was calculated by year of diagnosis. For men selecting active surveillance, the Kaplan-Meier method was used to estimate treatment-free survival. To assess for the oncologic safety of active surveillance, we compared the proportion of patients with adverse pathology and biochemical recurrence-free survival between men undergoing delayed radical prostatectomy after a period of active surveillance with men undergoing immediate radical prostatectomy. RESULTS: Of the 4,275 men with favorable intermediate-risk prostate cancer, 1,321 (31%) were managed with active surveillance, increasing from 13% in 2012 to 45% in 2020. The 5-year treatment-free probability for men with favorable intermediate-risk prostate cancer on active surveillance was 73% for Gleason Grade Group 1 and 57% for Grade Group 2 disease. More men undergoing a delayed radical prostatectomy had adverse pathology (46%) compared with immediate radical prostatectomy (32%, P < .001), yet short-term biochemical recurrence was similar between groups (log-rank test, P = .131). CONCLUSIONS: The use of active surveillance for men with favorable intermediate-risk prostate cancer has increased markedly. Over half of men with favorable intermediate-risk prostate cancer on active surveillance remained free of treatment 5 years after diagnosis. Most men on active surveillance will not lose their window of cure and have similar short-term oncologic outcomes as men undergoing up-front treatment. Active surveillance is an oncologically safe option for appropriately selected men with favorable intermediate-risk prostate cancer.

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.

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.

Delayed Radical Prostatectomy is Not Associated with Adverse Oncologic Outcomes: Implications for Men Experiencing Surgical Delay Due to the COVID-19 Pandemic.

PURPOSE: The 2019 novel Coronavirus (COVID-19) pandemic has forced many health care organizations to divert efforts and resources to emergent patient care, delaying many elective oncologic surgeries. We investigated an association between delay in radical prostatectomy and oncologic outcomes. MATERIALS AND METHODS: This is a retrospective review of men with intermediate and high risk prostate cancer in the National Cancer Database undergoing radical prostatectomy from 2010 to 2016. Immediate radical prostatectomy was defined as radical prostatectomy within 3 months of diagnosis, while delayed radical prostatectomy was analyzed in 3-month intervals up to 12 months. Multivariable logistic regression models were fit to test for associations between levels of delayed radical prostatectomy and outcomes of interest (adverse pathology, upgrading on radical prostatectomy, node positive disease and post-radical prostatectomy secondary treatments) compared with men undergoing immediate radical prostatectomy. RESULTS: We identified 128,062 men with intermediate and high risk prostate cancer treated with radical prostatectomy. After adjustment, we did not appreciate a significant difference in odds of adverse pathology, upgrading, node positive disease or post-radical prostatectomy secondary treatments between men treated with immediate radical prostatectomy and any level of delay up to 12 months. Subgroup analysis of men with Grade Group 4 and 5 prostate cancer did not demonstrate an association between delayed radical prostatectomy and worse oncologic outcomes. CONCLUSIONS: In the National Cancer Database delayed radical prostatectomy was not associated with early adverse oncologic outcomes at radical prostatectomy. These results may provide reassurance to patients and urologists balancing care in the current pandemic.

Confirmatory Magnetic Resonance Imaging with or without Biopsy Impacts Decision Making in Newly Diagnosed Favorable Risk Prostate Cancer.

PURPOSE: We investigated how magnetic resonance imaging and post-magnetic resonance imaging biopsy impact decision making in men considering active surveillance. MATERIALS AND METHODS: We reviewed the records of men in the Michigan Urological Surgery Improvement Collaborative with newly diagnosed favorable risk prostate cancer. Following diagnostic biopsy the men were classified into 3 groups, including group 1-no magnetic resonance imaging, group 2-magnetic resonance imaging only and group 3-magnetic resonance imaging/post-magnetic resonance imaging biopsy. For the purposes of counseling and shared decision making magnetic resonance imaging results were deemed reassuring (PI-RADS™ [Prostate Imaging Reporting and Data System] 3 or less) or nonreassuring (PI-RADS 4 or greater). Similarly, if the diagnostic biopsy was GG (Grade Group) 1, post-magnetic resonance imaging biopsy results were deemed nonreassuring if there was any amount of GG 2 or greater. If the diagnostic biopsy was GG 2, post-magnetic resonance imaging biopsy results were deemed nonreassuring if more than 3 cores were GG 2, or there was more than 50% GG 2 in any individual core or any volume of GG 3 or greater. RESULTS: Of 1,461 men with favorable risk prostate cancer 1,223 (84%) did not undergo magnetic resonance imaging, 157 (11%) underwent magnetic resonance imaging alone and 81 (6%) underwent magnetic resonance imaging and post-magnetic resonance imaging biopsy. Of the men who underwent magnetic resonance imaging alone more with reassuring findings elected active surveillance than men with nonreassuring or magnetic resonance imaging findings (74% vs 35% and 42%, respectively). The highest rate of active surveillance was noted in men with reassuring post-magnetic resonance imaging biopsy regardless of whether magnetic resonance imaging was reassuring or nonreassuring (93% and 96%, respectively). CONCLUSIONS: Magnetic resonance imaging and post-magnetic resonance imaging biopsy drive decision making in men with newly diagnosed, favorable risk prostate cancer. Post-magnetic resonance imaging biopsy is a stronger driver of decision making than magnetic resonance imaging alone. This was demonstrated by the more than 90% of men with reassuring post-magnetic resonance imaging biopsies who elected active surveillance regardless of magnetic resonance imaging results.

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.

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.

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.

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.

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.

Prostate cancer family history and eligibility for active surveillance: a systematic review of the literature.

Active surveillance (AS) is an increasingly prevalent treatment choice for low grade prostate cancer. Eligibility criteria for AS are varied and it is unclear if family history of prostate cancer should be used as an exclusion criterion when considering men for AS. To determine whether family history plays a significant role in the progression of prostate cancer for men undergoing active surveillance, PubMed searches of 'family history and prostate cancer', 'family history and prostate cancer progression' and 'factors of prostate cancer progression' were used to identify research publications about the relationship between family history and prostate cancer progression. These searches generated 536 papers that were screened and reviewed. Six publications were ultimately included in this analysis. Review of the six publications suggests that family history does not increase the risk of prostate cancer progression, whilst a subgroup analysis in one study found that family history increases the risk of prostate cancer progression only in African-Americans. A family history of prostate cancer does not appear to increase a patient's risk of having more aggressive prostate cancer and is therefore unlikely to be an important factor in determining eligibility for AS. Further studies are needed to better understand the relationship between race, family history, and eligibility for AS.

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 Gαi2 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 Gαi2 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.

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.

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.