Castration Resistance Research Articles

Predictive model of castration resistance in advanced prostate cancer by machine learning using genetic and clinical data: KYUCOG-1401-A study

BackgroundThe predictive power of the treatment efficacy and prognosis in primary androgen deprivation therapy (ADT) for advanced prostate cancer is not satisfactory. The objective of this study was to integrate genetic and clinical data to predict castration resistance in primary ADT for advanced prostate cancer by machine learning (ML).MethodsClinical and single nucleotide polymorphisms (SNP) data obtained in the KYUCOG-1401-A study (UMIN000022852) that enrolled Japanese patients with advanced prostate cancer were used. All patients were treated with primary ADT. A point-wise linear (PWL) algorithm, logistic regression with elastic-net regularization, and eXtreme Gradient Boosting were the ML algorithms used in this study. Area under the curve for castration resistance and C-index for prognoses were calculated to evaluate the utility of the models.ResultsAmong the three ML algorithms, the area under the curve values to predict castration resistance at 2 years was highest for the PWL algorithm with all the datasets. Three predictive models (clinical model, small SNPs model, and large SNPs model) were created by the PWL algorithm using the clinical data alone, and 2 and 46 SNPs in addition to clinical data. C-indices for overall survival by the clinical, small SNPs, and large SNPs models were 0.636, 0.621, and 0.703, respectively.ConclusionThe results demonstrated that the SNPs models created by ML produced excellent prediction of castration resistance and prognosis in primary ADT for advanced prostate cancer, and will be helpful in treatment choice.

Predictors of Progression to Castration-resistant Prostate Cancer After Radical Prostatectomy in High-risk Prostate Cancer Patients.

To examine the specific time frame and identify associated risk factors from commencement of hormonal therapy to the onset of castration-resistant prostate cancer among patients who have developed biochemical recurrence following radical prostatectomy. We retrospectively reviewed the records of 92 patients who developed biochemical recurrence and received hormonal therapy as initial salvage treatment after radical prostatectomy for high-risk localized prostate cancer from 2005 to 2021. The castration-resistant prostate cancer-free survival rates from the commencement of salvage hormonal therapy were analyzed using log-rank methods. Cox proportional hazard regression was performed to analyze the risk factors associated with acquiring castration resistance. The patients were stratified based on those risk factors. During a median follow-up duration of 57 months, 24 (26.1%) patients developed castration-resistant prostate cancer. The 5- and 10-year castration-resistant prostate cancer-free survival rates were 73.6% and 54.5%, respectively. A multivariate analysis showed that Grade Group of 5 and prostate-specific antigen doubling time at biochemical recurrence of ≤3 months were independent predictors of castration-resistant prostate cancer. The 5-year castration-resistant prostate cancer-free survival rates in the low- and high-risk groups, stratified according to the aforementioned factors, were 85.4% and 47.6%, respectively. Patients in high Grade Group and short prostate-specific antigen doubling time after radical prostatectomy are more likely to develop resistance to salvage hormonal therapy.

Impact of Neuroendocrine Differentiation (NED) on Enzalutamide and Abiraterone Efficacy in Metastatic Castration-Resistant Prostate Cancer (mCRPC): A Retrospective Analysis.

Neuroendocrine differentiation (NED) represents a possible androgen receptor pathway inhibitors (ARPI) resistance mechanism in metastatic castration resistance prostate cancer (mCRPC). As mCRPC with NED has been excluded from clinical trials evaluating ARPI efficacy, this study investigates the prognostic impact of NED in mCRPC patients treated with ARPIs. Methods: We retrospectively analyzed 327 mCRPC patient data treated with Enzalutamide or Abiraterone in the first and second or successive lines of treatment. NED was assessed using prostate biopsy samples through immunohistochemical staining. Results: NED was confirmed in 32/327 (9.8%) mCRPC patients. In the overall population, mCRPC with NED showed worse PFS (4.38 vs. 11.48 months HR 2.505 [1.71-3.68] p < 0.05), disease control rate (DCR), and PSA response. In the first line setting, mCRPC with NED demonstrated worse PFS (8.5 vs. 14.9 months HR 2.13 [1.18-3.88], p < 0.05). Similarly, in the second or successive lines, mCRPC with NED showed worse PFS (4.0 vs. 7.5 months HR 2.43 [1.45-4.05] p < 0.05), DCR, PSA response and OS (12.53 vs. 18.03 months HR 1.86 [1.12-3.10] p < 0.05). The adverse impact of NED on PFS was consistence across all subgroups; we also noted a trend of worse PFS in patients with high vs. low NED. Conclusions: In our study, mCRPC with NED treated with Enzalutamide or Abiraterone showed worse clinical outcomes. NED assessment should be considered to optimize treatment decisions in the mCRPC setting.

Real-World Clinical Outcomes and Treatment Patterns Among Black and Non-Black Patients With Prostate Cancer Initiated on Apalutamide in a Urology Setting

Background: The use of androgen receptor signaling inhibitors, including apalutamide, in combination with androgen deprivation therapy is recommended for the treatment of metastatic castration-sensitive prostate cancer (mCSPC) and non-metastatic castration-resistant prostate cancer (nmCRPC). Objective: To describe real-world treatment patterns and clinical outcomes among patients with mCSPC or nmCRPC who initiated apalutamide in the United States. Methods: A retrospective cohort study of patients with mCSPC or nmCRPC who initiated apalutamide was conducted using electronic medical record data from US community-based urology practices (Feb. 1, 2017–April 1, 2022). Persistence with apalutamide was reported at 6-, 12-, and 18-months post treatment initiation. Clinical outcomes described up to 24 months after apalutamide initiation using Kaplan-Meier analyses included progression to castration resistance, castration resistance-free survival (CRFS), and metastasis-free survival (MFS). Outcomes were reported separately based on mCSPC or nmCRPC status and race (ie, Black or non-Black). Results: This study included 589 patients with mCSPC (mean age, 75.9 years) and 406 patients with nmCRPC (mean age, 78.8 years). Using a treatment gap of &gt;90 days, persistence with apalutamide at 12 months remained high for both the mCSPC (94.9%) and nmCRPC (92.7%) cohorts, and results were descriptively similar among Black and non-Black patients, and when a treatment gap of &gt;60 days was considered. In patients with mCSPC, overall progression to castration resistance rates at 12 and 24 months were 20.9% and 33.5%, and overall CRFS rates were 76.2% and 62.0%, respectively. In patients with nmCRPC, overall MFS rates at 12 and 24 months were 89.7% and 75.4%, respectively. Rates of these clinical outcomes were descriptively similar between Black and non-Black patients. Discussion: While clinical trials have demonstrated the efficacy and safety of apalutamide, there is limited real-world data describing treatment persistence and clinical outcomes among patients with mCSPC and nmCRPC who initiated apalutamide. Conclusions: In this real-world study of patients with mCSPC or nmCRPC initiated on apalutamide, treatment persistence was high and apalutamide demonstrated robust real-world effectiveness with respect to progression to castration resistance, CRFS, and MFS, overall and among Black and non-Black patients.

Real-World Clinical Outcomes and Treatment Patterns Among Black and Non-Black Patients With Prostate Cancer Initiated on Apalutamide in a Urology Setting.

Background: The use of androgen receptor signaling inhibitors, including apalutamide, in combination with androgen deprivation therapy is recommended for the treatment of metastatic castration-sensitive prostate cancer (mCSPC) and non-metastatic castration-resistant prostate cancer (nmCRPC). Objective: To describe real-world treatment patterns and clinical outcomes among patients with mCSPC or nmCRPC who initiated apalutamide in the United States. Methods: A retrospective cohort study of patients with mCSPC or nmCRPC who initiated apalutamide was conducted using electronic medical record data from US community-based urology practices (Feb.1, 2017-April 1, 2022). Persistence with apalutamide was reported at 6-, 12-, and 18-months post treatment initiation. Clinical outcomes described up to 24 months after apalutamide initiation using Kaplan-Meier analyses included progression to castration resistance, castration resistance-free survival (CRFS), and metastasis-free survival (MFS). Outcomes were reported separately based on mCSPC or nmCRPC status and race (ie, Black or non-Black). Results: This study included 589 patients with mCSPC (mean age, 75.9 years) and 406 patients with nmCRPC (mean age, 78.8 years). Using a treatment gap of >90 days, persistence with apalutamide at 12 months remained high for both the mCSPC (94.9%) and nmCRPC (92.7%) cohorts, and results were descriptively similar among Black and non-Black patients, and when a treatment gap of >60 days was considered. In patients with mCSPC, overall progression to castration resistance rates at 12 and 24 months were 20.9% and 33.5%, and overall CRFS rates were 76.2% and 62.0%, respectively. In patients with nmCRPC, overall MFS rates at 12 and 24 months were 89.7% and 75.4%, respectively. Rates of these clinical outcomes were descriptively similar between Black and non-Black patients. Discussion: While clinical trials have demonstrated the efficacy and safety of apalutamide, there is limited real-world data describing treatment persistence and clinical outcomes among patients with mCSPC and nmCRPC who initiated apalutamide. Conclusions: In this real-world study of patients with mCSPC or nmCRPC initiated on apalutamide, treatment persistence was high and apalutamide demonstrated robust real-world effectiveness with respect to progression to castration resistance, CRFS, and MFS, overall and among Black and non-Black patients.

Comparative Transcriptomes of Canine and Human Prostate Cancers Identify Mediators of Castration Resistance.

Prostate cancer continues to be one of the most lethal cancers in men. While androgen-deprivation therapy is initially effective in treating prostate cancer, most cases of advanced prostate cancer eventually progress to castration-resistant prostate cancer (CRPC), which is incurable. Similarly, the most aggressive form of prostatic carcinoma occurs in dogs that have been castrated. To identify molecular similarities between canine prostate cancer and human CRPC, we performed a comparative analysis of gene expression profiles. Through this transcriptomic analysis, we found that prostatic carcinoma in castrated dogs demonstrate an androgen indifferent phenotype, characterized by low androgen receptor and neuroendocrine associated genes. Notably, we identified two genes, ISG15 and AZGP1 that were consistently up- and downregulated, respectively, in both canine prostatic carcinoma and human CRPC. Additionally, we identified several other genes, including GPX3, S100P, and IFITM1, that exhibited similar expression patterns in both species. Protein-protein interaction network analysis demonstrated that these 5 genes were part of a larger network of interferon-induced genes, suggesting that they may act together in signaling pathways that are disrupted in prostate cancer. Accordingly, our findings suggest that the interferon pathway may play a role in the development and progression of CRPC in both dogs and humans and chart a new therapeutic approach.

Akkermansia muciniphila Metabolite Inosine Inhibits Castration Resistance in Prostate Cancer.

Prostate cancer (PCa) is initially sensitive to androgen deprivation therapy (ADT) but ultimately develops resistance and progresses to castration-resistant prostate cancer (CRPC) with a poor prognosis. This study indicated that some PCa patients and mice were more sensitive to ADT and entered CRPC later, which was related to the gut microbiota, especially the enrichment of Akkermansia muciniphila (AKK). Untargeted metabolomics analysis found that serum inosine level was upregulated in the treatment-sensitive group and significantly correlated with AKK. Furthermore, we revealed that intestinal permeability and serum lipopolysaccharide (LPS) levels increased in treatment-resistant mice. LPS stimulated the upregulation of p-NF-κB p65 and AR in tumors. Supplementing AKK metabolite inosine could alleviate intestinal barrier damage and reduce serum LPS level, ultimately inhibiting castration resistance via the LPS/NF-κB/AR axis. Finally, we constructed a predictive model for CRPC combining gut microbiota and clinical information (AUC = 0.729). This study revealed the potential mechanism of gut microbiota on CRPC and provided potential therapeutic targets and prognostic indicators.

Prostate cancer with BRCA2 pathogenic mutation: a clinicopathological analysis

Objective: To analyze the clinicopathological features of prostate cancers with BRCA2 pathogenic mutations, and the association between BRCA2 pathogenic mutation and clinicopathological characteristics. Patient survivals were also examined. Methods: Clinicopathological data of 249 prostate cancer patients who underwent genetic testing in West China Hospital of Sichuan University, Chengdu, China from June 2014 to August 2021 were collected. A retrospective analysis of histopathological morphology, clinicopathological characteristics, and patient survivals was conducted. Results: The genetic testing in the 249 prostate cancer patients showed a pathogenic mutation of DNA damage repair gene (DRG) in 73 cases (73/249, 29.3%), including 22 cases (8.8%) with BRCA2 pathogenic mutation and 51 cases with pathogenic mutations of other DRG. Among the 22 patients with BRCA2 pathogenic mutation, 14 patients (5.6%) harbored germline mutations and 8 patients (3.2%) somatic mutations. Their ages ranged from 48 to 91 years, with a median of 67 years. Seventeen patients (77.3%) had distant metastasis, including 16 cases with bone metastasis and 1 case with multiple metastases. Thirteen patients (59.1%) were castration-resistant prostate cancer. The histological type was mainly classical prostatic acinar adenocarcinoma, including 16 cases (72.7%) with intraductal carcinoma of the prostate (IDC-P). Six cases (27.3%) showed focal neuroendocrine differentiation. Perineural/vascular invasion and extraprostatic extension were seen in 11 cases (50.0%) and 8 cases (36.4%), respectively. The Gleason scores of 19 patients (86.4%) were≥8. IDC-P was more commonly found in patients with BRCA2 germline pathogenic mutation than those with BRCA2 somatic pathogenic mutation, other DRG pathogenic mutation or no-DRG pathogenic mutation (P=0.002). With a total follow-up time of 189 months, the median overall survival (OS) was 132.3 months. Patients with DRG pathogenic mutation had shorter OS than those with no-DRG pathogenic mutation (P=0.040). The OS of patients with BRCA2 germline pathogenic mutation did not significantly differ from that of patients with BRCA2 somatic pathogenic mutation, other DRG pathogenic mutation or no-DRG pathogenic mutation (P=0.216). Conclusions: The presence of BRCA2 gene pathogenic mutation is common in the prostate cancers with high Gleason grade, advanced clinical stage, and castration resistance. IDC-P is more commonly noted in cases with BRCA2 germline pathogenic mutation than those without. Patients with DRG pathogenic mutation have shorter OS than those with no-DRG pathogenic mutation, but there is no significant association between BRCA2 pathogenic mutations and OS.

HSD3B1 genotype and outcomes in metastatic hormone-sensitive prostate cancer with androgen deprivation therapy and enzalutamide: ARCHES

HSD3B1 encodes 3β-hydroxysteroid dehydrogenase-1, which converts adrenal dehydroepiandrosterone to 5α-dihydrotestosterone and is inherited in adrenal-permissive (AP) or adrenal-restrictive forms. The AP allele is linked to castration resistance, mainly in low-volume tumors. Here, we investigate the association of HSD3B1 alleles with outcomes in ARCHES, a multinational, double-blind, randomized, placebo-controlled phase 3 trial that demonstrated clinical benefit with enzalutamide plus androgen deprivation therapy (ADT) in men with metastatic hormone-sensitive prostate cancer (mHSPC) compared to those treated with placebo plus ADT. There are no significant differences between genotypes for clinical efficacy endpoints. Enzalutamide significantly improves radiographic progression-free survival and overall survival vs. placebo irrespective of HSD3B1 status. Men with the AP genotype have higher post-progression mortality and treatment-emergent adverse events, including hypertension, cardiovascular events, and gynecomastia, but a lower fracture rate. Overall, enzalutamide is beneficial in men with mHSPC independent of the HSD3B1 genotype. Inherited polymorphisms of HSD3B1 may account for differential toxicities.

GATA2 promotes castration-resistant prostate cancer development by suppressing IFN-β axis-mediated antitumor immunity.

Castration-resistant prostate cancer (CRPC) nearly inevitably develops after long-term treatment with androgen deprivation therapy (ADT), leading to significant mortality. Investigating the mechanisms driving CRPC development is imperative. Here, we determined that the pioneer transcription factor GATA2, which is frequently amplified in CRPC patients, inhibits interferon (IFN)-β-mediated antitumor immunity, thereby promoting CRPC progression. Employing a genetically engineered mouse model (GEMM), we demonstrated that GATA2 overexpression hindered castration-induced cell apoptosis and tumor shrinkage, facilitating tumor metastasis and CRPC development. Notably, GATA2 drives castration resistance predominantly via repressing castration-induced activation of IFN-β signaling and CD8+ T-cell infiltration. This finding aligns with the negative correlation between GATA2 expression and IFNB1 expression, as well as CD8+ T-cell infiltration in CRPC patients. Mechanistically, GATA2 recruited PIAS1 as corepressor, and reprogramed the cistrome of IRF3, a key transcription factor of the IFN-β axis, in an androgen-independent manner. Furthermore, we identified a novel silencer element that facilitated the function of GATA2 and PIAS1 through looping to the IFNB1 promoter. Importantly, depletion of GATA2 augmented antitumor immunity and attenuated CRPC development. Consequently, our findings elucidate a novel mechanism wherein GATA2 promotes CRPC progression by suppressing IFN-β axis-mediated antitumor immunity, underscoring GATA2 as a promising therapeutic target for CRPC.

A randomised trial of short- vs long-term androgen deprivation with salvage radiotherapy for biochemical failure following radical prostatectomy: URONCOR 06-24.

Salvage radiotherapy (SRT) and androgen-deprivation therapy (ADT) are widely used in routine clinical practice to treat patients with prostate cancer who develop biochemical recurrence (BCR) after radical prostatectomy (RP). However, there is no standard-of-care consensus on optimal duration ADT. Investigators propose three distinct risk groups in patients with prostate cancer treated with SRT in order to better define the indications and duration of ADT combined with SRT. The URONCOR 06-24 trial (ClinicalTrials.gov identifier NCT05781217) is a prospective, multicentre, randomised, open-label, phase III, clinical trial. The aim of the trial is to determine the impact of short-term (6 months) vs long-term (24 months) ADT in combination with SRT on distant metastasis-free survival (MFS) in patients with prostate cancer with BCR after RP (intermediate and high risk). The primary endpoint is 5-year MFS rates in patients with prostate cancer treated with long- vs short-term ADT in combination with SRT. Secondary objectives are biochemical-relapse free interval, pelvic progression-free survival, time to start of systemic treatment, time to castration resistance, cancer-specific survival, overall survival, acute and late toxicity, and quality of life. Total of 534 patients will be randomised 1:1 to ADT 6 months or ADT 24 months with a luteinizing hormone-releasing hormone analogue in combination with SRT, stratified by risk group and pathological lymph node status. The study is conducted under the guiding principles of the World Medical Association Declaration of Helsinki. The results will be disseminated at research conferences and in peer-reviewed journals. EudraCT number 2021-006975-41.

A novel prognostic model of de novo metastatic hormone-sensitive prostate cancer to optimize treatment intensity.

The treatment and prognosis of de novo metastatic hormone-sensitive prostate cancer (mHSPC) vary. We established and validated a novel prognostic model for predicting cancer-specific survival (CSS) in patients with mHSPC using retrospective data from a contemporary cohort. 1092 Japanese patients diagnosed with de novo mHSPC between 2014 and 2020 were registered. The patients treated with androgen deprivation therapy and first-generation anti-androgens (ADT/CAB) were assigned to the Discovery (N = 467) or Validation (N = 328) cohorts. Those treated with ADT and androgen-receptor signaling inhibitors (ARSIs) were assigned to the ARSI cohort (N = 81). Using the Discovery cohort, independent prognostic factors of CSS, the extent of disease score ≥ 2 or the presence of liver metastasis; lactate dehydrogenase levels > 250U/L; a primary Gleason pattern of 5, and serum albumin levels ≤ 3.7g/dl, were identified. The prognostic model incorporating these factors showed high predictability and reproducibility in the Validation cohort. The 5-year CSS of the low-risk group was 86% and that of the high-risk group was 22%. Approximately 26.4%, 62.7%, and 10.9% of the patients in the Validation cohort defined as high-risk by the LATITUDE criteria were further grouped into high-, intermediate-, and low-risk groups by the new model with significant differences in CSS. In the ARSIs cohort, high-risk group had a significantly shorter time to castration resistance than the intermediate-risk group. The novel model based on prognostic factors can predict patient outcomes with high accuracy and reproducibility. The model may be used to optimize the treatment intensity of de novo mHSPC.

An 18-gene signature of recurrence-associated endothelial cells predicts tumor progression and castration resistance in prostate cancer

BackgroundThe prognostic and therapeutic implications of endothelial cells (ECs) heterogeneity in prostate cancer (PCa) are poorly understood.MethodsWe investigated associations of EC heterogeneity with PCa recurrence and castration resistance in 8 bulk transcriptomic and 4 single-cell RNA-seq cohorts. A recurrence-associated EC (RAEC) signature was constructed by comparing 11 machine learning algorithms through nested cross-validation. Functional relevances of RAEC-specific genes were also tested.ResultsA subset of ECs was significantly associated with recurrence in primary PCa and named RAECs. RAECs were characteristic of tip and immature cells and were enriched in migration, angiogenesis, and collagen-related pathways. We then developed an 18-gene RAEC signature (RAECsig) representative of RAECs. Higher RAECsig scores independently predicted tumor recurrence and performed better or comparably compared to clinicopathological factors and commercial gene signatures in multiple PCa cohorts. Of the 18 RAECsig genes, FSCN1 was upregulated in ECs from PCa with higher Gleason scores; and the silencing of FSCN1, TMEME255B, or GABRD in ECs either attenuated tube formation or inhibited PCa cell proliferation. Finally, higher RAECsig scores predicted castration resistance in both primary and castration-resistant PCa.ConclusionThis study establishes an endothelial signature that links a subset of ECs to prostate cancer recurrence and castration resistance.

Survival of patients with lymph node versusbone versus visceral metastases according to CHAARTED/LATITUDE criteria in the era of intensified combination therapies for metastatic hormone-sensitive prostate cancer.

The first approvals of novel systemic therapies within recent years for metastatic hormone-sensitive (mHSPC) were mainly based on improved overall survival (OS) and time to castration resistance (ttCRPC) in mHSPC patients stratified according to CHAARTED low (LV) versus high volume (HV) and LATITUDE low (LR) versus high-risk (HR) disease. Relying on our institutional tertiary-care database we identified all mHSPC stratified according to CHAARTED LV versus HV, LATITUDE LR versus HR and the location of the metastatic spread (lymph nodes (M1a) versus bone (M1b) versus visceral/others (M1c) metastases. OS and ttCRPC analyses, as well as Cox regression models were performed according to different metastatic categories. Of 451 mHSPC, 14% versus 27% versus 48% versus 12% were classified as M1a LV versus M1b LV versus M1b HV versus M1c HV with significant differences in median OS: 95 versus 64 versus 50 versus 46 months (p < 0.001). In multivariable Cox regression models HV M1b (Hazard Ratio: 2.4, p = 0.03) and HV M1c (Hazard Ratio: 3.3, p < 0.01) harbored significant worse than M1a LV mHSPC. After stratification according to LATITUDE criteria, also significant differences between M1a LR versus M1b LR versus M1b HR versus M1c HR mHSPC patients were observed (p < 0.01) with M1b HR (Hazard Ratio: 2.7, p = 0.03) and M1c HR (Hazard Ratio: 3.5, p < 0.01), as predictor for worse OS. In comparison between HV M1b and HV M1c, as well as HR M1b versus HR M1c no differences in ttCRPC or OS were observed. Significant differences exist between different metastatic patterns of HV and LV and HR and LR criteria. Best prognosis is observed within M1a LV and LR mHSPC patients.

Real-world economic burden associated with disease progression from metastatic castration-sensitive to castration-resistant prostate cancer on treatment in the United States.

The advent of next-generation imaging will likely reduce nonmetastatic prostate cancer (PC) prevalence and increase identification of metastatic prostate cancer cases, resulting in two predominant advanced stages in the metastatic setting. There is a need to characterize changes in health care resource utilization (HRU) and costs when metastatic castration-sensitive PC (mCSPC) progresses to metastatic castration-resistant PC (mCRPC) to identify value drivers from current and new treatments. To describe treatment patterns, HRU, and total health care costs among patients with mCSPC, before and after progression to mCRPC. Clinical data from the Flatiron Metastatic PC Core Registry (January 1, 2013, to December 1, 2021) and linked claims from Komodo Health (January 1, 2014, to December 1, 2021) were used to identify patients with progression from mCSPC to mCRPC (date of progression was the index date) and subsequently initiated first-line mCRPC therapy on/after January 1, 2017. Treatment patterns and all-cause/PC-related HRU and health care costs were described per-patient-per-month (PPPM), separately for no more than 12 months pre-index (mCSPC disease state) and post-index (mCRPC disease state). Costs (payer's perspective) included those for services/procedures from medical claims and costs from pharmacy claims. Continuous HRU and costs were compared between the mCSPC and mCRPC disease states using Wilcoxon signed rank tests. Among 296 patients with mCSPC progressing to mCRPC (median age 69.0 years, 60.5% White, 15.9% Black), use of systemic therapies with androgen deprivation therapy increased dramatically from 35.1% in the mCSPC disease state to 92.9% in the mCRPC disease state, and use of androgen deprivation therapy monotherapy decreased from 25.7% to 2.4%, respectively. Although 39.2% received none of these therapies in the mCSPC disease state, this proportion decreased to 4.7% after transition to mCRPC. The mean number of days with PC-related outpatient visits increased from 1.57 to 2.16 PPPM in the mCSPC and mCRPC disease states (P < 0.001). From the mCSPC to mCRPC disease states, mean all-cause total health care costs PPPM increased from $4,424 (medical costs: $2,846) to $9,717 (medical costs: $4,654), and mean PC-related total health care costs PPPM increased from $2,859 (medical costs: $1,626) to $8,012 (medical costs: $3,285; all P < 0.001). In this real-world study of patients with disease progression from mCSPC to mCRPC in US clinical practice, nearly 2-in-3 patients did not receive treatment with additional systemic therapies before progression to castration resistance. Post-progression, mean PC-related total costs increased nearly 3-fold, with a more than 2-fold increase in PC-related medical costs. Use of additional systemic therapies may delay the time and cost associated with disease progression to castration resistance.

Is it possible to detect cribriform adverse pathology in prostate cancer with magnetic resonance imaging machine learning-based radiomics?

Rationale and objectives: Cribriform patterns are accepted as aggressive variants of prostate cancer. These adverse pathologies are closely associated with early biochemical recurrence, metastasis, castration resistance, and poor disease-related survival. A few publications exist to diagnose these two adverse pathologies with multiparametric magnetic resonance imaging (mpMRI). Most of these publications are retrospective and are not studies that have made a difference in diagnosing adverse pathology. It is also known that fusion biopsies taken from lesions detected in mpMRI are insufficient to detect these adverse pathologies. Our study aims to diagnose this adverse pathology using machine learning-based radiomics data from MR images. Materials and methods: A total of 88 patients who had pathology results indicating the presence of cribriform pattern and prostate adenocarcinoma underwent preoperative MRI examinations and radical prostatectomy. Manual slice-by-slice 3D volumetric segmentation was performed on all axial images. Data processing and machine learning analysis were conducted using Python 3.9.12 (Jupyter Notebook, Pycaret Library). Results: Two radiologists, SE and MAG, with 7 and 8 years of post-graduate experience, respectively, evaluated the images using the 3D-Slicer software without knowledge of the histopathological findings. One hundred seventeen radiomic tissue features were extracted from T1 weighted (T1W) and apparent diffusion coefficient (ADC) sequences for each patient. The interobserver agreement for these features was analyzed using the intraclass correlation coefficient (ICC). Features with excellent interobserver agreement (ICC &gt; 0.90) were further analyzed for collinearity between predictors using Pearson’s correlation. Variables showing a very high correlation (r ≥ ±0.80) were disregarded. The selected features for T1W and ADC images were First-order maximum, First-order skewness, First-order 10th percentile for ADC, and Gray level size zone matrix, Large area low gray level emphasis for T1W.As a result of the classification of PyCaret, the three best models were found. A single model was obtained by blending these three models. AUC, accuracy, recall, precision, and F1 scores were 0.79, 0.77, 0.85, 0.82, and 0.83, respectively. Conclusion: ML-based MRI radiomics of prostate cancer can predict the cribriform pattern. This prognostic factor cannot be determined through qualitative radiological evaluation and may be overlooked in preoperative histopathological specimens.

Androgen deprivation-induced senescence confers sensitivity to a senolytic strategy in prostate cancer

We have previously demonstrated that androgen-dependent prostate cancer (PCa) cell lines enter a state of senescence following exposure to androgen deprivation therapies (ADT). ADT-induced senescence was found to be transient, as senescent cells develop castration resistance and re-emerge into a proliferative state even under continuous androgen deprivation in vitro. Moreover, the BCL-XL/BCL-2 inhibitor, ABT-263 (navitoclax), an established senolytic agent, promoted apoptosis of senescent PCa cells, suppressing proliferative recovery and subsequent tumor cell outgrowth. As this strategy has not previously been validated in vivo, we used a clinically relevant, syngeneic murine model of PCa, where mice were either castrated or castrated followed by the administration of ABT-263. Our results largely confirm the outcomes previously reported in vitro; specifically, castration alone results in a transient tumor growth suppression with characteristics of senescence, which is prolonged by exposure to ABT-263. Most critically, mice that underwent castration followed by ABT-263 experienced a statistically significant prolongation in survival, with an increase of 14.5 days in median survival time (56 days castration alone vs. 70.5 days castration + ABT-263). However, as is often the case in studies combining the promotion of senescence with a senolytic (the “one-two” punch approach), the suppression of tumor growth by the inclusion of the senolytic agent was transient, allowing for tumor regrowth once the drug treatment was terminated. Nevertheless, the results of this work suggest that the “one-two” punch senolytic strategy in PCa may effectively interfere with, diminish, or delay the development of the lethal castration-resistant phenotype.

Prostate-specific membrane antigen PET/CT-guided, metastasis-directed radiotherapy for oligometastatic castration-resistant prostate cancer.

e17057 Background: Systemic treatments for metastatic castration-resistant prostate cancer (mCRPC) include androgen deprivation therapy (ADT), androgen receptor pathway inhibitors (ARPIs), chemotherapy, and radiopharmaceutical therapy, all of which have associated toxicity. We hypothesized that prostate-specific membrane antigen (PSMA) PET/CT-guided, metastasis-directed radiotherapy may offer durable disease control with low toxicity rates in patients with mCRPC who have a limited number of metastatic sites. Methods: We retrospectively screened 7 prospective databases of PSMA PET/CT scans conducted between 1/2016-2/2023 for patients with mCRPC who had ≤5 sites of oligorecurrent or oligoprogressive disease and received metastasis-directed radiotherapy to all sites of disease. Castration resistance was defined as either radiographic progression or biochemical progression (two consecutive prostate-specific antigen [PSA] increases ≥3 weeks apart) while on ADT with serum testosterone &lt;50 ng/dL. Progression-free survival (PFS), freedom from new lines of systemic therapy, and overall survival (OS) were calculated from the start of metastasis-directed radiotherapy using Kaplan-Meier analysis. Progression was defined as the first instance of biochemical progression (PSA increase of 25% and 2 ng/mL above nadir, confirmed by repeat measurement ≥3 weeks later), radiographic progression, biopsy-proven recurrence, new systemic or local therapy, or death. Toxicity was graded according to Common Terminology Criteria for Adverse Events (CTCAE), Version 5. Results: Twenty-six patients met inclusion criteria with a median follow-up of 34.6 months (interquartile range, 28.1-47.2 months). All patients previously received ADT, 20 (77%) received ARPIs, and 3 (12%) had prior chemotherapy. Median PSA was 1.2 ng/mL, median time from initial diagnosis was 6.2 years, and median time from castration resistance was 1.8 years. Between 10/2017-4/2023, 12 patients (46.2%) had one treated metastatic site, 11 patients (42.3%) had two, and 3 patients (11.5%) had three. Twenty-four patients (92.3%) received concurrent systemic therapy. Median PFS was 16.4 months (95% confidence interval [CI], 11.4-21.4 months). Four-year PFS was 26.7% (95% CI, 8.9-44.5%). Median time to initiation of a new line of systemic therapy was 18.0 months (95% CI, 0-36.2 months). Four-year freedom from new lines of systemic therapy was 36.1% (95% CI, 15.5-56.7%). Median OS was not reached. Four-year OS was 72.5% (95% CI, 51.1-93.9%). Grade 2 and ≥3 toxicity rates were 3.8% and 0%, respectively. Conclusions: For patients with oligometastatic CRPC, PSMA PET/CT-guided metastasis-directed radiotherapy appears to offer durable disease control with low toxicity. Further prospective studies are needed to compare PSMA PET/CT-guided versus conventional imaging-guided radiotherapy.

Somatic tissue testing in prostate cancer using the Oncomine V3 panel: A single-institution retrospective analysis.

e17002 Background: Approximately 20-30% of prostate cancer (PC) patients have a mutation in the homologous recombination repair or mismatch repair genes, 50% of which are somatic. These mutations have prognostic and predictive implications. Somatic tissue testing (STT) was implemented at Sunnybrook Health Sciences Centre using the Oncomine V3 panel, which includes 161 genes, but only four genes (BRCA1/2, ATM, PALB2) are reported due to funding restrictions. We describe our centre’s testing experience and the utility of reporting beyond these four genes. Methods: Sixty-two PC patients between May 1, 2021 - January 31, 2023 were included. Clinical characteristics were gathered via chart review. Somatic variants of genes of interest (GOI) within the Oncomine V3 panel were extracted by an annotation specialist. Results: STT was ordered at diagnosis in 69.4% of cases (n=42) vs. at progression in 27.4% (n=17), 3 cases were external and lacked clinical context. Tests were ordered in the locoregional disease setting in 46.8% (n=29), 37.1% (n=23) in the metastatic castrate-sensitive setting, 8.1% (n=5) in the metastatic castrate-resistant (CR) setting and 3.2% (n=2) in the non-metastatic CR setting. Tests were ordered by Urology or Pathology (reflex testing) in 64.5% (n=40), by Medical Oncology in 16% (n=10), by Radiation Oncology in 13% (n=8) and by others in 6.5% (n=4). Fifty-one samples (82.2%) were of the prostate and 11 (17.7%) were of metastatic sites. The median sample age was 8 days (range 0-5781). The median test turn-around time was 28.5 days (range 5-57). There were 378 variants within the GOI and meeting the limit of detection [1] , of which 63 (16.7%) were tier 1 or 2 and are listed by gene in the table. Eight of 63 variants (12.7%) were within the four funded genes whereas 55/63 (87.3%) were within unfunded genes of clinical significance. CDK12, FANCA, NBN (n=7, 11.2%) are investigated in poly (ADP-ribose) polymerase inhibitor trials and PMS2 deficiency (n=1, 1.6%) can select for immune checkpoint inhibitors. PIK3R1/PIK3CA/AKT1-mutated tumors (n=11, 17.7%) have shown response to AKT-inhibitors. SPOP-mutated tumors (n=6, 9.7%) are associated with prolonged response to androgen receptor blockade whereas PTEN/TP53/RB1-negative tumors (n=12, 19.4%) are associated with anti-androgen resistance and worse prognosis. Conclusions: The majority of STT variants identified were beyond the currently funded genes in Ontario, and many have important prognostic and predictive implications. This highlights that STT early in the disease course using expanded gene panels may help in delivering personalized PC care. [Table: see text]

Intraprostatic hormone dosage: Validation of a novel prostate biopsy technique

BackgroundAdvances in chromatography and mass spectrometry have allowed us to develop a novel technique for measuring intraprostatic hormone concentrations directly on prostate needle biopsies, rather than using traditional punch excision. This has significant clinical implications as intraprostatic dihydrotestosterone and testosterone levels could help monitor prostate growth, neoplasia and castration resistance. MethodsPatients undergoing radical cystoprostatectomy for bladder cancer were prospectively included. Each prostate specimen received one 90mg punch excision and six needle biopsies. Intraprostatic hormones were dosed through gas chromatography-mass spectrometry. ResultsWe included twenty patients, of which eleven were incidentally diagnosed with prostate cancer; four had ISUP 1 (20%) and seven had ISUP 2 (35%). The prostate biopsy technique was unable to obtain measures for testosterone, Delta-4-androsterone and androstenedione. Tissue concentrations of DHEA, DHT, E1 and E2 can be obtained with no significant difference from the reference established on a punch from a single biopsy core sample. ConclusionsOur study demonstrates that intraprostatic concentrations of DHEA, DHT, E1 and E2 can be measured without significant difference from the reference established on a single punch excision. This finding opens the way to research on the interactions between endocrinology and prostate oncogenesis and particularly on the mechanisms of resistance to hormone therapies in vivo. Level of evidence2