Non-metastatic castration resistant prostate cancer: a review of current and emerging medical therapies

Exploring the mechanism of action of Sparganii Rhizoma-Curcumae Rhizoma for in treating castration-resistant prostate cancer: a network-based pharmacology and experimental validation study

Sparganii Rhizoma-Curcumae Rhizoma (SR-CR) is a classic drug pair for the treatment of castration-resistant prostate cancer (CRPC), but its mechanism has not been clarified. The study aims to elucidate the potential mechanism of SR-CR in the management of CRPC. The present study employed the TCMSP as well as the SwissTargetPrediction platform to retrieve the chemical composition and targets of SR-CR. The therapeutic targets of CRPC were identified through screening the GeneCards, Disgenet, and OMIM databases. Subsequently, the Venny online platform was utilized to identify the shared targets between the SR-CR and CRPC. The shared targets were enrichment analysis using the Bioconductor and Kyoto encyclopedia of genes and genomes (KEGG) databases. The active ingredients and core targets were verified through molecular docking and were validated using PC3 cells in the experimental validation phase. A total of 7 active ingredients and 1126 disease targets were screened from SR-CR, leading to a total of 59 shared targets. Gene Ontology (GO) analysis resulted in 1309 GO entries. KEGG pathways analysis yielded 121 pathways, primarily involving cancer-related signaling pathways. The results from molecular docking revealed stable binding interactions between the core ingredients and the core targets. In vitro cellular assays further demonstrated that SR-CR effectively suppressed the activation of the Prostate cancer signaling pathway in PC3 cells, leading to the inhibition of cell proliferation and promotion of apoptosis. The SR-CR exert therapeutic effects on CRPC by inhibiting cell proliferation and promoting apoptosis through the Prostate cancer signaling pathway.

Current status of PSMA-targeted imaging and therapy

Currently, the incidence of prostate cancer is increasing, and it has become a great threat to men's health. The detection, staging, and follow-up of prostate cancer patients are inseparable from morphology or magnetic resonance imaging (MRI). However, these do not fully meet the needs of diagnosis and patient management. In particular, owing to the late diagnosis, metastatic castration-resistant prostate cancer (mCRPC) patients usually have poor survival and few options for further effective treatment. Prostate-specific membrane antigen (PSMA), because of its overexpression on prostate cancer cells, has gained interest due to its application in the imaging and theranostics field. Several PSMA radioligands have been developed for imaging and treating prostate cancer. Many clinical trials have assessed the efficacy and safety profiles of these radionuclide agents and show promise in patients who have exhausted other standard treatment options. To date, several small compounds for targeting PSMA have been developed, and 68Ga-PSMA-11 and 18F-DCFPyL have been approved by the United States (US) Food and Drug Administration (FDA) for imaging of prostate cancer. 111In- or 99mTc-labeled PSMA-ligand can guide surgeons searching for radioactive metastatic lymph nodes, and 177Lu- or 225Ac-labeled PSMA-ligand can be used for internal radiotherapy. Moreover, some molecules for therapeutic application are undergoing different stages of clinical trials. In this review, we present current perspectives on the use of PSMA-targeted imaging and theranostics in prostate cancer. As PSMA-targeted imaging and therapeutics are becoming the standard of care for prostate cancer patients, we emphasize the importance of integrating nuclear medicine physicians into multidisciplinary oncology teams.

Dosimetric comparison between intensity-modulated radiation therapy and volumetric-modulated arc therapy to enhance bladder and bowel

Prostate cancer is the second most common cancer in men. Two common radiotherapy techniques, intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc radiotherapy (VMAT), are used for treatment. This study aimed to compare the two techniques for sparing the bladder and bowel. Computed tomography data from prostate cancer patients were analyzed to define the clinical target volume (CTV) and planning target volume (PTV). Treatment plans were generated with Monte Carlo algorithms, and dosimetric analysis was performed using the Monaco Treatment Planning System (TPS). We compared IMRT and VMAT for prostate cancer PTV coverage (% Ref. Volume), with VMAT showing slightly better coverage (98.885±1.704) compared to IMRT (98.594±0.923). VMAT also demonstrated improved PTV conformity. Additionally, VMAT was superior in sparing the bladder (% V4500<40%), while IMRT performed better in bowel preservation (mean Ref. volume CC<195).

Synthesis, preclinical evaluation, and first-in-human study of Al18F-PSMA-Q for prostate cancer imaging

PURPOSE

To investigate the potential of a novel Al¹⁸F-labeled PSMA-targeted radiotracer for PCa diagnosis through both preclinical and pilot clinical studies.

METHODS

Al¹⁸F-PSMA-Q was prepared automatically. The binding affinity to PSMA was evaluated in vitro using the 22Rv1 (PSMA +) and PC-3 (PSMA -) cell lines. Pharmacokinetics evaluation, biodistribution study, Micro-PET imaging of Al¹⁸F-PSMA-Q in normal mice and tumor-bearing mice, and a comparison with ¹⁸F-DCFPyL were performed. PET/CT imaging was performed on 8 healthy volunteers and 20 newly diagnosed PCa patients at 1 h post-injection (p.i.). The biodistribution in human and preliminary diagnostic efficacy of Al¹⁸F-PSMA-Q were evaluated, and the radiation dosimetry was estimated using OLINDA/EXM 2.0 software.

RESULT

Qualified Al¹⁸F-PSMA-Q was efficiently prepared with a non-decay-corrected radiochemical yield (RCY) of 22.0-28.3%, a specific activity (SA) of > 50 GBq/μmol. The hydrophilicity was comparably high with a log P value of - 3.69 ± 0.39. Al¹⁸F-PSMA-Q was found to bind to PSMA specifically with a Ki value of 17.05 ± 1.14 nM. The distribution and elimination half-lives of Al¹⁸F-PSMA-Q were 3.93 min and 14.22 min, respectively, which were shorter than those of ¹⁸F-DCFPyL. Micro-PET imaging of Al¹⁸F-PSMA-Q can clearly differentiate 22Rv1 tumors from PC-3 tumors and background with a high SUVmax of 2.17 ± 0.42 and a tumor-to-muscle ratio of 84.37 ± 31.62, which were higher than those of ¹⁸F-DCFPyL (1.79 ± 0.39 and 13.25 ± 1.65). The uptake of Al¹⁸F-PSMA-Q in 22Rv1 cells and tumors can be substantially blocked by 2-PMPA. High level accumulation of Al¹⁸F-PSMA-Q was observed in organs physiologically expressing PSMA. Twenty-six tumor lesions were detected in 20 PCa patients, and the mean SUVmax values of primary tumors, lymph node metastasis, bone metastases, and tumor-muscle ratios were 19.71 ± 16.52, 5.11, 31.30 ± 29.85, and 44.77 ± 22.29, respectively. The mean SUVmax of tumors in patients with PSA > 10 ng/mL was significantly higher than that in patients with PSA ≤ 10 ng/mL (25.97 ± 18.64 vs. 10.33 ± 3.74). Meanwhile, the mean SUVmax of tumors in patients with a Gleason score ≥ 8 was significantly higher than that in patients with a Gleason score < 8 (31.85 ± 22.09 vs. 13.18 ± 11.58). The kidneys received the highest estimated dose of 0.098 ± 0.006 mGy/MBq, and the effective dose was calculated as 0.0128 ± 0.007 mGy/MBq.

CONCLUSION

The novel qualified PSMA-targeted radiotracer Al¹⁸F-PSMA-Q was conveniently prepared with favorable yield and SA. The results of preclinical and pilot clinical studies exhibited a high specific uptake in PCa lesions and an excellent tumor-to-background ratio with a reasonable radiation exposure, which indicated the great potential of Al¹⁸F-PSMA-Q for PCa imaging.

TRIAL REGISTRATION

Chinese Clinical trial registry ChiCTR2100053507, Registered 23 November 2021, retrospectively registered.

The Hospitalization-Related Costs of Adverse Events for Novel Androgen Receptor Inhibitors in Non-Metastatic Castration-Resistant Prostate Cancer: An Indirect Comparison

INTRODUCTION

Three novel androgen receptor inhibitors are approved in the USA for the treatment of non-metastatic castration-resistant prostate cancer (nmCRPC): apalutamide, enzalutamide, and darolutamide. All three therapies have demonstrated prolonged metastasis-free survival in their respective phase III trials, with differing safety profiles. The objective of this study was to compare the mean per-patient costs of all-cause adverse events (AEs) requiring hospitalization between darolutamide versus apalutamide and enzalutamide for nmCRPC in the USA.

METHODS

All-cause grade ≥ 3 AEs with corresponding any-grade AEs reported among at least 10% of patients in any arm of the ARAMIS (darolutamide), SPARTAN (apalutamide), and PROSPER (enzalutamide) trials were selected for inclusion in the primary analyses. After matching-adjusted indirect comparison, AE costs were calculated by multiplying the AE rates from the trials by their respective unit costs of hospitalization taken from the US Healthcare Cost and Utilization Project (HCUP) database. Sensitivity analyses which further included any-grade AEs reported among at least 5% of patients were also performed.

RESULTS

After reweighting and adjusting for the trials' placebo arms, the mean per-patient AE costs were $1021 and $387 lower for darolutamide than for apalutamide and enzalutamide, respectively, over the trials' duration (SPARTAN and PROSPER, 43 months; ARAMIS, 48 months). For darolutamide vs. apalutamide, the largest drivers of the per-patient cost differences were fracture (adjusted difference $416), hypertension ($143), and rash ($219); for darolutamide vs. enzalutamide, they were fatigue not including asthenia ($290) and hypertension including increased blood pressure (i.e., any AE of hypertension or with elevated blood pressure not yet classified as hypertension) ($60). The results of the sensitivity analyses were consistent with the primary results.

CONCLUSIONS

Patients with nmCRPC treated with darolutamide in ARAMIS incurred lower AE-related costs (USD), as determined using HCUP costing data, compared with patients treated with either apalutamide (in SPARTAN) or enzalutamide (in PROSPER).

miRNAs and androgen deprivation therapy for prostate cancer

Androgen deprivation therapy (ADT) is mainly used for the treatment of advanced, metastatic or recurrent prostate cancer (PCa). However, patients progress to ADT resistance and castration-resistant prostate cancer (CRPC) with a poor prognosis. Reliable validated markers of ADT resistance with proven clinical utility are necessary for timely correction of the therapy as well as for improvement of patient quality of life. MiRNAs involved in the ADT response and CRPC development via multiple mechanisms may act as biomarkers for patient outcomes. Available data on miRNAs associated with the ADT response (resistance and sensitivity) are summarized and analyzed in the manuscript, including analyses using bioinformatics resources. Molecular targets of miRNAs, as well as reciprocal relations between miRNAs and their targets, were studied using different databases. Special attention was dedicated to the mechanisms of ADT resistance and CRPC development, including testosterone, PI3K-AKT, VEGF pathways and associated genes. Several different approaches can be used to search for miRNAs associated with the ADT response, each of which focuses on the associated set of miRNAs - potential markers of ADT. The intersection of these approaches and combined analysis allowed us to select the most promising miRNA markers of the ADT response. Meta-analysis of the current data indicated that the selected 5 miRNAs (miRNAs - 125b, miR-21, miR-23b, miR-27b and miR-221) and 14 genes are involved in the regulation of key processes of CRPC development and represent the most promising predictors of the ADT response, further demonstrating their potential in combination therapy for advanced PCa.

Synthesis, Preclinical Evaluation, and First-in-Human PET Study of Quinoline-Containing PSMA Tracers with Decreased Renal Excretion

The prostate-specific membrane antigen (PSMA) is considered to be an excellent theranostic target of prostate cancer (PCa). In this study, three 18F-labeled PSMA tracers with a more lipophilic quinoline functional spacer were designed, synthesized, and evaluated based on the Glu-Ureido-Lys binding motif. The effect of structure-related lipophilic difference on distribution and excretion of these tracers in vitro and in vivo (cells, rodent, primate, and human) was investigated by comparing with [18F]DCFPyL. There is no significant correlation between the renal elimination and the lipophilicity of the tracers in all species. However, the higher the lipophilicity of tracer, the higher the radioactivity accumulation in the liver of primate and human, and the less radioactivity is to excrete to the bladder with urine. The screened tracer [18F]8c, with a Ki value of 4.58 nM, displayed notable low bladder retention and demonstrated good imaging properties in patients with PCa.

Comparison of Systemic Treatments for Metastatic Castration-Sensitive Prostate Cancer: A Systematic Review and Network Meta-analysis

Importance

Multiple systemic treatments are available for metastatic castration-sensitive prostate cancer (mCSPC), with unclear comparative effectiveness and safety and widely varied costs.

Objective

To compare the effectiveness and safety determined in randomized clinical trials of systemic treatments for mCSPC.

Data Sources

Bibliographic databases (MEDLINE, Embase, and Cochrane Central), regulatory documents (US Food and Drug Administration and European Medicines Agency), and trial registries (ClinicalTrials.gov and European Union clinical trials register) were searched from inception through November 5, 2019.

Study Selection, Data Extraction, and Synthesis

Eligible studies were randomized clinical trials evaluating the addition of docetaxel, abiraterone acetate, apalutamide, or enzalutamide to androgen-deprivation therapy (ADT) for treatment of mCSPC. Two investigators independently performed screening. Discrepancies were resolved through consensus. A Cochrane risk-of-bias tool was used to assess trial quality. Relative effects of competing treatments were assessed by bayesian network meta-analysis and survival models. The Preferred Reporting Items for Systematic Reviews and Meta-analyses guideline was used.

Main Outcomes and Measures

Overall survival, radiographic progression-free survival, and serious adverse events (SAEs).

Results

Seven trials with 7287 patients comparing 6 treatments (abiraterone acetate, apalutamide, docetaxel, enzalutamide, standard nonsteroidal antiandrogen, and placebo/no treatment) were identified. Ordered from the most to the least effective determined by results of clinical trials, treatments associated with improved overall survival when added to ADT included abiraterone acetate (hazard ratio [HR], 0.61; 95% credible interval [CI], 0.54-0.70), apalutamide (HR, 0.67; 95% CI, 0.51-0.89), and docetaxel (HR, 0.79; 95% CI, 0.71-0.89); treatments associated with improved radiographic progression-free survival when added to ADT included enzalutamide (HR, 0.39; 95% CI, 0.30-0.50), apalutamide (HR, 0.48; 95% CI, 0.39-0.60), abiraterone acetate (HR, 0.51; 95% CI, 0.45-0.58), and docetaxel (HR, 0.67; 95% CI 0.60-0.74). Docetaxel was associated with substantially increased SAEs (odds ratio, 23.72; 95% CI, 13.37-45.15), abiraterone acetate with slightly increased SAEs (odds ratio, 1.42; 95% CI, 1.10-1.83), and other treatments with no significant increase in SAEs. Risk of bias was noted for 4 trials with open-label design, 3 trials with missing data, and 2 trials with potential unprespecified analyses.

Conclusions and Relevance

In this network meta-analysis, as add-on treatments to ADT, abiraterone acetate and apalutamide may provide the largest overall survival benefits with relatively low SAE risks. Although enzalutamide may improve radiographic progression-free survival to the greatest extent, longer follow-up is needed to examine the overall survival benefits associated with enzalutamide.

Prostate Cancer in Latin America: Challenges and Recommendations

Prostate cancer (PCa) is the most frequent tumor among Latin American (LATAM) men. The incidence of de novo metastatic PCa is higher in LATAM than other parts of the world, and demographic changes in the region have increased disease burden. However, region-specific information regarding prevalence, progression, and treatment effectiveness is not currently available for nonmetastatic, castration-resistant PCa (nmCRPC). Nonmetastatic, castration-resistant PCa is a heterogeneous disease with varying potential to develop metastasis with limited treatments available, until recently. New clinical trials with promising results have allowed second-generation antiandrogen drugs to be used as first-line treatments, rendering guidelines outdated. As a result, this panel of experts reviewed the current status and challenges and developed recommendations for nmCRPC diagnosis and management in LATAM. The Americas Health Foundation (AHF) conducted a literature review and identified LATAM scientists and clinicians who have published in the field of PCa since 2012. The AHF convened a panel of 7 chosen experts urologists and medical oncologists from the region. The AHF developed specific questions relating to nmCRPC, which were answered by the experts prior to the multiday meeting. Each narrative was discussed and edited by the panel, through numerous rounds of discussion until a consensus was reached in a final manuscript. The panel proposes specific and realistic recommendations for improving access to diagnosis and management of PCa in LATAM. No treatment has yet shown improvement in overall survival; however, when including metastasis-free survival as an end point, second-generation antiandrogen drugs have emerged as effective treatment options and are currently included as first-line treatment. Although nmCRPC is a specific disease that represents a small percentage of patients with PCa, effective diagnostic and treatment strategies can contribute toward increasing quality of life and survival rates of patients with PCa in LATAM.

Consensus on diagnosis and management of non-metastatic castration resistant prostate cancer in Brazil: focus on patient, selection, treatment efficacy, side effects and physician's perception according to patient comorbidities

BACKGROUND

Non-metastatic castration resistant prostate cancer (M0 CRPC) has seen important developments in drugs and diagnostic tools in the last two years. New hormonal agents have demonstrated improvement in metastasis free survival in M0 CRPC patients and have been approved by regulatory agencies in Brazil. Additionally, newer and more sensitive imaging tools are able to detect metastasis earlier than before, which will impact the percentage of patients staged as M0 CRPC. Based on the available international guidelines, a group of Brazilian urology and medical oncology experts developed and completed a survey on the diagnosis and treatment of M0 CRPC in Brazil. These results are reviewed and summarized and associated recommendations are provided.

OBJECTIVE

To present survey results on management of M0 CRPC in Brazil.

DESIGN, SETTING, AND PARTICIPANTS

A panel of six Brazilian prostate cancer experts determined 64 questions concerning the main areas of interest: 1) staging tools, 2) treatments, 3) side effects of systemic treatment/s, and 4) osteoclast-targeted therapy. A larger panel of 28 Brazilian prostate cancer experts answered these questions in order to create country-specific recommendations discussed in this manuscript. Outcome measurements and statistical analysis: The panel voted publicly but anonymously on the predefined questions. These answers are the panelists' opinions, not a literature review or meta-analysis. Therapies not yet approved in Brazil were excluded from answer options. Each question had five to seven relevant answers including two non-answers. Results were tabulated in real time.

CONCLUSIONS

The results and recommendations presented can be used by Brazilian physicians to support the management of M0 CRPC patients. Individual clinical decision making should be supported by available data, however, for Brazil, guidelines for diagnosis and management of M0 CRPC patients have not been developed. This document will serve as a point of reference when confronting this disease stage.

Tumor Suppressive Maspin-Sensitized Prostate Cancer to Drug Treatment Through Negative Regulating Androgen Receptor Expression

Overactivation of androgen receptor (AR)-mediated signal has been extensively implicated in prostate cancer (CaP) development, progression, and recurrence, which makes it an attractive therapeutic target. Meanwhile, as an endogenous inhibitor of histone deacetylase 1 (HDAC 1), tumor-suppressive mammary serine protease inhibitor (maspin) was reported to sensitize drug-induced apoptosis with a better therapeutic outcome in CaP, but the relationship between AR and maspin remains unclear. In the current study, treatment of 5'-Aza or MS-275/enzalutamide induced poly (ADP-ribose) polymerase (PARP) cleavage and p-H2A.X in CaP cells with an increase of maspin expression but a decrease of AR. Then, treatment with protease inhibitor MG132 did not rescue the above drug-induced loss of AR. In addition, modulation of maspin expression by gene recombinant or siRNA technology showed an inverse correlation between expression of maspin and AR, consequently affecting the AR-regulated downstream gene transcription (e.g., NKX3.1 and TMPRSS2). Bioinformatics analysis of the data extracted from the National Center for Biotechnology Information Gene Expression Omnibus (NCBI GEO) database also revealed an inverse correlation between low maspin expression and high AR level in advanced CaP. Furthermore, chromatin immunoprecipitation (ChIP) assay using anti-maspin antibody identified that a portion of AR promoter sequence was co-precipitated and presented in the immunoprecipitated complex. Finally, maspin-mediated repression of AR was induced by treatment of MS-275, which promoted enzalutamide treatment efficacy with decrease of prostate-specific antigen (PSA) expression in LNCaP and 22RV1 cells. Taken together, the data not only demonstrated maspin-mediated repression of AR to augment drug anti-tumor activity but also provided in-depth support for combination of HDAC inhibitors with AR antagonist in CaP therapy.

Ganoderma lucidum put forth anti-tumor activity against PC-3 prostate cancer cells via inhibition of Jak-1/STAT-3 activity

Background

Prostate cancer (PCA) is a frequent cancer that mainly affects the men. Studying growth feature pathways modified during PCA development may facilitate researchers to expand embattled therapeutic strategies for prostate cancer. In present study, we examined the anticancer potentials of Ganoderma lucidum against the prostate cancer (PC-3) cells by inflection of JAK-1/STAT-3 signalling pathway.

Methods

The cytotoxicity of G. lucidum against the PC-3 cells was examined by MTT assay. The ROS production was monitored by using DCFH-DA staining. The apoptotic morphological alterations stimulatory potential of G. lucidum on PC-3 cells was inspected through the dual staining. The expression of Bcl-2, JAK-1, STAT3, Bax and CyclinD1 proteins were measured by western blotting. The caspase-3 and 9 functions were condensed by assay kit.

Results

Findings demonstrates the Ganoderma lucidum convince cytotoxicity, accretion of ROS, and apoptosis stimulation in PC-3 cells. In addition, signal transducer and activating transcription (STAT-3) is a successive oncogenic transcriptional factor that regularizes multiplication and apoptosis in cells. Discretion of STAT-3 transcription deliberated as original approach to hinder prostate cell growth. In present exploration, we ascertain that Ganoderma lucidum hold back STAT-3 translocation, in that way dropping the eminent expression of, BCL-2, cyclin-D1 and declined the Bax, caspase-3 and 9 expressions in PC-3 cells.

Conclusion

In the end our finding concluded that Ganoderma lucidum hinder prostate cell development and convinces apoptosis via hampering the translocation STAT-3.

Abiraterone and enzalutamide had different adverse effects on the cardiovascular system: a systematic review with pairwise and network meta-analyses

BACKGROUND

Abiraterone and enzalutamide may increase the risk of cardiovascular events in patients with castration-resistant prostate cancer (CRPC).

METHODS

A comprehensive literature search was performed using a combination of keywords related to "abiraterone," "enzalutamide," "prostate cancer," and "adverse events." Phase II-IV randomized controlled trials (RCTs) on abiraterone or enzalutamide for patients with nonmetastatic or metastatic CRPC were included. Outcome measures included (1) any grade cardiac disorder, (2) severe grade cardiac disorder, (3) any grade hypertension, and (4) severe grade hypertension, as defined by the Common Terminology Criteria for Adverse Events. Pairwise meta-analysis and Bayesian network meta-analyses were performed to investigate the risk ratios (RRs) of abiraterone and enzalutamide. Surface under cumulative ranking curves (SUCRAs) and cumulative ranking probability plots based on the probability of developing cardiac disorders or hypertension were presented.

RESULTS

A total of 7103 patients from seven RCTs were included. Upon pairwise meta-analysis, abiraterone was associated with increased risks of any grade (RR = 1.34, 95% confidence interval (CI) = 1.05-1.73) and severe grade cardiac disorders (RR = 1.71, 95% CI = 1.16-2.53); enzalutamide was associated with increased risks of any grade (RR = 2.66, 95% CI = 1.93-3.66) and severe grade hypertension (RR = 2.79, 95% CI = 1.86-4.18). Based on the SUCRA rankings, abiraterone had a higher probability of cardiac disorders (84.84% for any grade and 85.12% for severe grade) than enzalutamide (62.83% for any grade and 50.76% for severe grade); whereas enzalutamide had a higher probability of hypertension (99.43% for any grade and 89.71% for severe grade) than abiraterone (49.08% for any grade and 49.37% for severe grade).

CONCLUSIONS

Abiraterone and enzalutamide had different adverse effects on the cardiovascular system. We should take this into consideration when we are deciding on the choice of novel hormonal agents for patients with CRPC.

Patient and caregiver benefit-risk preferences for nonmetastatic castration-resistant prostate cancer treatment

Background

Recently approved second‐generation androgen receptor inhibitors (SGARIs) for non‐metastatic castration‐resistant prostate cancer (nmCRPC) have similar efficacy but differ in safety profiles. We used a discrete choice experiment (DCE) to examine how nmCRPC patients and caregivers perceive the benefits versus risks of these new treatments.

Methods

An online DCE survey with 14 treatment choice questions was administered to nmCRPC patients and caregivers. Each choice question compared two hypothetical medication profiles varying in terms of 5 safety attributes (risk or severity of adverse events [AEs]: fatigue, skin rash, cognitive problems, serious fall, and serious fracture) and two efficacy attributes (duration of overall survival [OS] and time to pain progression). Random parameters logit models were used to estimate each attribute's relative importance. We also estimated the amounts of OS that respondents were willing to forego for a reduction in AEs.

Results

In total, 143 nmCRPC patients and 149 caregivers viewed the AEs in following order of importance (most to least): serious fracture, serious fall, cognitive problems, fatigue, and skin rash. On average, patients were willing to trade 5.8 and 4.0 months of OS to reduce the risk of serious fracture and fall, respectively, from 3% to 0%; caregivers were willing to trade 6.6 and 5.4 months of OS.

Conclusions

nmCRPC patients and caregivers preferred treatments with lower AE burdens and were willing to forego OS to reduce the risk and severity of AEs. Our results highlight the importance of carefully balancing risks and benefits when selecting treatments in this relatively asymptomatic population.

Mechanisms of Androgen Receptor Agonist- and Antagonist-Mediated Cellular Senescence in Prostate Cancer

The androgen receptor (AR) plays a leading role in the control of prostate cancer (PCa) growth. Interestingly, structurally different AR antagonists with distinct mechanisms of antagonism induce cell senescence, a mechanism that inhibits cell cycle progression, and thus seems to be a key cellular response for the treatment of PCa. Surprisingly, while physiological levels of androgens promote growth, supraphysiological androgen levels (SAL) inhibit PCa growth in an AR-dependent manner by inducing cell senescence in cancer cells. Thus, oppositional acting ligands, AR antagonists, and agonists are able to induce cellular senescence in PCa cells, as shown in cell culture model as well as ex vivo in patient tumor samples. This suggests a dual AR-signaling dependent on androgen levels that leads to the paradox of the rational to keep the AR constantly inactivated in order to treat PCa. These observations however opened the option to treat PCa patients with AR antagonists and/or with androgens at supraphysiological levels. The latter is currently used in clinical trials in so-called bipolar androgen therapy (BAT). Notably, cellular senescence is induced by AR antagonists or agonist in both androgen-dependent and castration-resistant PCa (CRPC). Pathway analysis suggests a crosstalk between AR and the non-receptor tyrosine kinase Src-Akt/PKB and the PI3K-mTOR-autophagy signaling in mediating AR-induced cellular senescence in PCa. In this review, we summarize the current knowledge of therapeutic induction and intracellular pathways of AR-mediated cellular senescence.

Physician preferences for non-metastatic castration-resistant prostate cancer treatment

BACKGROUND

Recent approvals of second-generation androgen receptor inhibitors (SGARIs) have changed the treatment landscape for non-metastatic castration-resistant prostate cancer (nmCRPC). These SGARIs have similar efficacy but differ in safety profiles. We used a discrete choice experiment to explore how United States physicians make treatment decisions between adverse events (AEs) and survival gains in nmCRPC, a largely asymptomatic disease.

METHODS

Treating physicians (n = 149) participated in an online survey that included 14 treatment choice questions, each comparing 2 hypothetical treatment profiles, which varied in terms of 5 safety and 2 efficacy attributes. We described safety attributes (fatigue, skin rash, cognitive problems, falls, and fractures) in terms of severity and frequency, and efficacy attributes (overall survival [OS] and time to pain progression) in terms of duration of effect. We used a random parameters logit model to estimate preference weights and importance scores for each attribute. We also estimated the amount of survival gain physicians were willing to trade for a reduction in specific AEs between treatment options.

RESULTS

Physicians placed more importance on survival than on time to pain progression, and viewed a reduction in cognitive problems from severe to none, a reduction in risk of a serious fracture from 8% to none, and a reduction in fatigue from severe to none as the most important safety attributes. Physicians were willing to forego 9.1 and 6.6 months of OS, respectively, to reduce cognitive problems and fatigue from severe to mild-to-moderate. To reduce the risk of a serious fracture from 8 to 5% and 5% to none, physicians were willing to trade 3.9 and 5.3 months of OS, respectively.

CONCLUSIONS

Physicians were willing to trade substantial amounts of survival to avoid AEs between hypothetical treatments. These results emphasize the importance of carefully balancing therapies' benefits and risks to ultimately optimize the overall quality of nmCRPC patients' survival. Nonetheless, it is noted that the results from the study sample of 149 physicans may not be representative of the viewpoints of all nmCRPC-treating physicians.

Treatment of non-metastatic castration resistant prostate cancer in 2020: What is the best?

Lately the development of 3 novel second-generation androgen receptor antagonists (enzalutamide, apalutamide, and darolutamide) chanced the treatment landscape of nonmetastatic castration-resistant prostate cancer. After proofing their clinical efficacy in large phase III registration trials with good compatibilities and tolerable side effects currently all 3 substances are Food and Drug Administration-approved in nonmetastatic castration-resistant prostate cancer. The present short review article provides an overview about these new treatment options and discusses their use in daily routine focusing on patient selection as well as on the impact of novel sensitive imaging modalities like prostate-specific membrane antigen-positron-emission tomography for detection of this stage of disease.

Dysregulated Transcriptional Control in Prostate Cancer

Recent advances in whole-genome and transcriptome sequencing of prostate cancer at different stages indicate that a large number of mutations found in tumors are present in non-protein coding regions of the genome and lead to dysregulated gene expression. Single nucleotide variations and small mutations affecting the recruitment of transcription factor complexes to DNA regulatory elements are observed in an increasing number of cases. Genomic rearrangements may position coding regions under the novel control of regulatory elements, as exemplified by the TMPRSS2-ERG fusion and the amplified enhancer identified upstream of the androgen receptor (AR) gene. Super-enhancers are increasingly found to play important roles in aberrant oncogenic transcription. Several players involved in these processes are currently being evaluated as drug targets and may represent new vulnerabilities that can be exploited for prostate cancer treatment. They include factors involved in enhancer and super-enhancer function such as bromodomain proteins and cyclin-dependent kinases. In addition, non-coding RNAs with an important gene regulatory role are being explored. The rapid progress made in understanding the influence of the non-coding part of the genome and of transcription dysregulation in prostate cancer could pave the way for the identification of novel treatment paradigms for the benefit of patients.