Radiographic progression with nonrising PSA in metastatic castration-resistant prostate cancer: post hoc analysis of PREVAIL

Management of advanced prostate cancer in the Asia-Pacific region: Summary of the Asia-Pacific Advanced Prostate Cancer Consensus Conference 2023

AIM

The aim of the third Asia-Pacific Advanced Prostate Cancer Consensus Conference (APAC APCCC 2023) was to discuss the application in the Asia-Pacific (APAC) region of consensus statements from the 4th Advanced Prostate Cancer Consensus Conference (APCCC 2022).

METHODS

The one-day meeting in July 2023 brought together 27 experts from 14 APAC countries. The meeting covered five topics: (1) Intermediate- and high-risk and locally advanced prostate cancer; (2) Management of newly diagnosed metastatic hormone-sensitive prostate cancer; (3) Management of non-metastatic castration-resistant prostate cancer; (4) Homologous recombination repair mutation testing; (5) Management of metastatic castration-resistant prostate cancer. Pre- and post-symposium polling gathered APAC-specific responses to APCCC consensus questions and insights on current practices and challenges in the APAC region.

RESULTS

APAC APCCC highlights APAC-specific considerations in an evolving landscape of diagnostic technologies and treatment innovations for advanced prostate cancer. While new technologies are available in the region, cost and reimbursement continue to influence practice significantly. Individual patient considerations, including the impact of chemophobia on Asian patients, also influence decision-making.

CONCLUSION

The use of next-generation imaging, genetic testing, and new treatment combinations is increasing the complexity and duration of prostate cancer management. Familiarity with new diagnostic and treatment options is growing in the APAC region. Insights highlight the continued importance of a multidisciplinary approach that includes nuclear medicine, genetic counseling, and quality-of-life expertise. The APAC APCCC meeting provides an important opportunity to share practice and identify APAC-specific issues and considerations in areas of low evidence where clinical experience is growing.

Real-world evaluation of access-driven Canadian treatment sequences in progressive prostate cancer (REACTIVATE)

INTRODUCTION

The results of the phase 3 ALSYMPCA trial showed that Radium-223 (Ra-223) improves overall survival (OS) and delays onset of first symptomatic skeletal event vs. placebo in patients with metastatic castration-resistant prostate cancer (mCRPC). The purpose of the REACTIVATE study was to inform the optimal placement of Ra-233 in the treatment sequence by evaluating clinical outcomes and healthcare resource utilization using real-world data from multiple Canadian provinces.

METHODS

This retrospective cohort study analyzed patient outcomes according to Ra-223 placement using administrative databases of four Canadian provinces, encompassing 4301 patients with mCRPC who received at least two lines of life-prolonging therapy (LPT) for mCRPC. Outcomes included OS, event-free survival (EFS), and healthcare resource utilization. Each province was analyzed separately.

RESULTS

OS, measured from the start of second-line LPT, differed between provinces: those in Ontario receiving second-line Ra-223 had a longer OS vs. those receiving it in third-line or later (hazard ratio [HR ] 0.79, 95% confidence interval [CI] 0.66-0.95). There was no difference between lines of therapy in patients in British Columbia (HR 1.165, 95% CI, 0.894-1.518, p=0.2576), and OS was numerically worse but not statistically significant in patients receiving Ra-223 in second-line in Quebec (HR 1.44, 95% CI, 0.93-2.24). Other outcomes also varied across provinces, with second-line use of Ra-223 being associated with longer EFS and reduced healthcare utilization vs. third-line use in Ontario but not in Quebec.

CONCLUSIONS

Significant heterogeneity exists in the management and outcomes of mCRPC between provinces, particularly regarding the placement of Ra-223 in the treatment sequence.

Early PSA decline after starting second-generation hormone therapy in the post-docetaxel setting predicts cancer-specific survival in metastatic castrate-resistant prostate cancer

BACKGROUND

The objective of this study was to evaluate the prognostic value of early PSA decline following initiation of second-generation hormone therapy (2nd HT), namely abiraterone acetate or enzalutamide, in patients with taxane-refractory metastatic castrate-resistant prostate cancer (mCRPC) and evaluate utility of this metric in informing intensified surveillance/imaging protocols.

METHODS

We retrospectively identified 75 mCRPC patients treated with 2nd HT following docetaxel failure (defined as PSA rise and radiographic progression). Patients were categorized patients into two cohorts based on the first PSA within 3 months after initiation of therapy: PSA reduction ≥50% (Group A) and PSA reduction <50% (Group B). The primary endpoint was cancer-specific mortality (CSM). The secondary endpoint was radiographic disease progression (rDP) on 2nd HT. In univariate and multivariate analyses, we investigated factors associated with rPD and CSM.

RESULTS

We included 75 patients (52 in Group A, 23 in Group B) in the analytic cohort. Baseline clinico-demographic characteristics, including median age, primary Gleason score risk group, median pre-treatment PSA, disease burden, site of metastases, and pre-treatment ECOG score were not statistically different between the two groups. Median follow up time was 30 months and the median time to radiographic disease progression was 28.1 and 12.5 months (p = 0.002) in cohorts A and B, respectively. On univariate and multivariate analyses, both PSA reduction ≥50% and volume of metastatic disease were significantly associated with a decreased risk of radiographic disease progression (HR 0.41, 95% CI 0.21-0.80, p = 0.0113) as well as a decreased risk of cancer-specific mortality (HR 0.29, 95% CI 0.09-0.87, p = 0.0325).

CONCLUSION

PSA reduction ≥50% within 3 months of starting 2nd HT was associated with significantly improved radiographic disease progression-free survival and 3-year cancer-specific mortality. This suggests using PSA 50%-decline metric in surveillance patients with on 2nd HT and identifies patients who require further evaluation with imaging.

Liquid biopsy to personalize treatment for metastatic prostate cancer

Liquid biopsy is an innovative approach that provides a more complete understanding of treatment response and prognosis in monitoring metastatic prostate cancer. It complements invasive tissue biopsy and involves the assessment of various biomarkers in body fluids such as blood, semen, and urine. Liquid biopsy analyzes circulating tumor cells, extracellular vesicles, circulating tumor DNA, and the secretome. This is particularly important given the heterogeneity of prostate cancer and the need for better prognostic biomarkers. Liquid biopsy can personalize the treatment of homonosensitive and castration-resistant metastatic prostate cancer by acting as a predictive and prognostic tool. This review discusses various biomarkers, assay techniques, and potential applications in daily clinical practice, highlighting the exciting possibilities that this emerging field holds for improving patient outcomes.

Radiographic Progression Without Corresponding Prostate-specific Antigen Progression in Patients with Metastatic Castration-sensitive Prostate Cancer Receiving Apalutamide: Secondary Analysis of the TITAN Trial

BACKGROUND AND OBJECTIVE

In prostate cancer treated with androgen deprivation therapy (ADT), the initial sign of treatment resistance is often prostate-specific antigen (PSA) progression, followed by radiographic progression. However, the association between these two forms of progression remains unclear, especially in patients with metastatic castration-sensitive prostate cancer (mCSPC) treated with androgen receptor pathway inhibitors. We sought to evaluate the association between radiographic progression, PSA progression, and outcomes of apalutamide therapy in mCSPC.

METHODS

We analyzed individual participant-level data for patients randomized within the TITAN trial who experienced radiographic progression during follow-up (N = 326). This study investigated radiographic progression without simultaneous or preceding PSA progression, as defined by the Prostate Cancer Working Group 2 (discordant progression), and explored the association of such progression with radiographic progression-free survival.

KEY FINDINGS AND LIMITATIONS

Among the patients who developed radiographic progression, 115 (35.3%) had been treated with apalutamide plus ADT (the apalutamide group) and 211 (64.7%) with placebo plus ADT (the placebo group). Discordant progression occurred in 52.2% of patients (60 of 115) in the apalutamide group and 27.5% (58 of 211) in the placebo group (p < 0.001). A multivariable logistic regression analysis showed that discordant progression was associated with apalutamide treatment. We found evidence of an association between discordant progression and shorter radiographic progression-free survival.

CONCLUSIONS AND CLINICAL IMPLICATIONS

This study found that nearly half of the patients with mCSPC treated with apalutamide who experienced radiographic progression developed it without corresponding PSA progression, suggesting that heavy reliance on PSA monitoring may be inadequate for assessing disease activity in this context.

PATIENT SUMMARY

In patients who have metastatic castration-sensitive prostate cancer (mCSPC) and are being treated with apalutamide, radiographic images may show cancer progression even if prostate-specific antigen tests indicate no change. This highlights the importance of regular imaging when using apalutamide to manage mCSPC.

A multidisciplinary approach to address unmet needs in the management of patients with non-metastatic castration-resistant prostate cancer

BACKGROUND

With the availability of second-generation androgen receptor inhibitors (SGARIs), the treatment landscape has changed dramatically for patients with nonmetastatic castration-resistant prostate cancer (nmCRPC). In clinical trials, the SGARIs (apalutamide, enzalutamide, darolutamide) increased metastasis-free survival (MFS), overall survival (OS), and patient quality of life compared to placebo. These drugs were subsequently integrated into nmCRPC clinical practice guidelines. With advances in radiographic imaging, disease assessment, and patient monitoring, nmCRPC strategies are evolving to address limitations related to tracking disease progression using prostate-specific antigen (PSA) kinetics.

METHODS

A panel of 10 multidisciplinary experts in prostate cancer conducted reviews and discussions of unmet needs in the management and monitoring of patients with nmCRPC in order to develop consensus recommendations.

RESULTS

Across the SGARI literature, patient MFS and OS are generally comparable for all treatments, but important distinctions exist regarding short- and long-term drug safety profiles and drug-drug interactions. With respect to disease monitoring, a substantial proportion of patients using SGARIs may experience disease progression without rising PSA levels, suggesting a need for enhanced radiographic imaging in addition to PSA monitoring. Recent data also indicate that novel prostate-specific membrane antigen positron emission tomography radiotracers provide enhanced accuracy for disease detection, as compared to conventional imaging.

CONCLUSIONS

Clinical decision-making in nmCRPC has become more complex, with new opportunities to apply precision medicine to patient care. Multidisciplinary teams can ensure that patients with nmCRPC receive optimal and individualized disease management.

Low PSA radiographic disease progression on C11-choline PET

Background

For men with prostate cancer, radiographic progression may occur without a concordant rise in prostate-specific antigen (PSA). Our study aimed to assess the prevalence of radiographic progression using C-11 choline positron emission tomography (PET) imaging in patients achieving ultra-low PSA values and to evaluate clinical outcomes in this patient population.

Methods

In a single institution study, we reviewed the prospectively maintained Mayo Clinic C-11 Choline PET metastatic prostate cancer registry to identify patients experiencing radiographic disease progression (rDP) on C-11 choline PET scan while the PSA value was less than 0.5 ng/mL. Disease progression was confirmed by tissue biopsy or response to subsequent therapy. Clinicopathologic variables were abstracted by trained research personnel. Overall survival was estimated using the Kaplan-Meier method. Intergroup differences were assessed using the log-rank test. A univariate and multivariate Cox regression model was performed to investigate variables associated with poor survival after rDP.

Results

A total of 1323 patients within the registry experienced rDP between 2011 and 2021, including 220 (16.6%) men with rDP occurring at low PSA level. A median (interquartile range [IQR]) of 54.7 (19.7-106.9) months elapsed between the time of prostate cancer diagnosis and low PSA rDP, during which 173 patients (78%) developed castration-resistant prostate cancer (CRPC). Sites of low PSA rDP included local recurrence (n = 17, 8%), lymph node (n = 90, 41%), bone (n = 94, 43%) and visceral metastases (n = 19, 9%). Biopsy at the time of rDP demonstrated small-cell or neuroendocrine features in 21% of patients with available tissue. Over a median (IQR) follow-up of 49.4 (21.3-95.1) months from the time of low PSA rDP, 46% (n = 102) of patients died. Factors associated with poorer survival outcomes include advanced age at rDP, CRPC status, bone and visceral metastasis (p value <0.05). Visceral metastases were associated with decreased overall survival (p = 0.009 by log-rank) as compared with other sites of rDP.

Conclusions

Men with prostate cancer commonly experience metastatic progression at very low or even undetectable PSA levels. Periodic imaging, even at low absolute PSA values, may result in more timely identification of disease progression.

Preoperative cell-free DNA concentration in plasma as a diagnostic and prognostic biomarker of clear cell renal cell carcinoma

Introduction

Assessment of renal tumour masses is based on conventional imaging studies (computer tomography or magnetic resonance), which does not allow characterisation of the histopathological type. Moreover, the prediction of prognosis in localised and metastatic renal cell carcinoma requires improvement as well. Analysis of circulating free DNA (cfDNA) in blood is one of the variants of liquid biopsy that may improve diagnostics and prognosis issues of patients with renal tumour masses suspected to be renal cell carcinoma. The aim of the study was to assess the diagnostic and prognostic role of preoperative cfDNA concentration in the plasma samples of clear cell renal cell carcinoma (ccRCC) patients.

Material and methods

The preoperative plasma cfDNA concentration was assessed in ccRCC patients (n = 46) and healthy individuals (control group) (n = 17). The circulating free DNA concentration was reflected by the 90 bp DNA fragments determined by real-time polymerase chain reaction.

Results

The median cfDNA concentration was significantly higher in ccRCC patients (n = 46) compared to the control g roup (n = 17) (2588 ±2554 copies/ml vs. 960 ±490 copies/ml, p < 0.01). In multivariate analysis, the preoperative plasma cfDNA concentration was the significant factor increasing the probability of ccRCC detection (OR: 1.003; 95% CI: 1.001-1.005). The median cfDNA concentration depended on the stage of ccRCC; it was higher in metastatic ccRCC patients (n = 11) compared to non-metastatic ccRCC patients (n = 35) (3619 ±4059 copies/ml vs. 2473 ±1378 copies/ml, p < 0.03). Kaplan-Meier survival analysis demon-strated that patients with high cfDNA values (above 2913 copies/ml) had significantly worse cancer-specific survival (HR: 4.5; 95% CI: 1.3-16.9, log-rank Mantel-Cox test p = 0.015).

Conclusions

Preoperative plasma cfDNA concentration has diagnostic and prognostic potential in ccRCC pa-tients.

Application of Advanced Imaging to Prostate Cancer Diagnosis and Management: A Narrative Review of Current Practice and Unanswered Questions

Major advances in prostate cancer diagnosis, staging, and management have occurred over the past decade, largely due to our improved understanding of the technical aspects and clinical applications of advanced imaging, specifically magnetic resonance imaging (MRI) and prostate-cancer-specific positron emission tomography (PET). Herein, we review the established utility of these important and exciting technologies, as well as areas of controversy and uncertainty that remain important areas for future study. There is strong evidence supporting the utility of MRI in guiding initial biopsy and assessing local disease. There is debate, however, regarding how to best use the imaging modality in risk stratification, treatment planning, and assessment of biochemical failure. Prostate-cancer-specific PET is a relatively new technology that provides great value to the evaluation of newly diagnosed, treated, and recurrent prostate cancer. However, its ideal use in treatment decision making, staging, recurrence detection, and surveillance necessitates further research. Continued study of both imaging modalities will allow for an improved understanding of their best utilization in improving cancer care.

Progression-free survival, disease-free survival and other composite end points in oncology: improved reporting is needed

Composite outcome measures such as progression-free survival and disease-free survival are increasingly used as surrogate end points in oncology research, frequently serving as the primary end point of pivotal trials that form the basis for FDA and EMA approvals. Such outcome measures combine two or more distinct events (for example, tumour (re)growth, new lesions and/or death) into a single, time-to-event end point. The use of a composite end point can increase the statistical power of a clinical trial and decrease the follow-up period required to demonstrate efficacy, thus lowering costs; however, these end points have a number of limitations. Composite outcomes are often vaguely defined, with definitions that vary greatly between studies, complicating comparisons of results across trials. Altering the makeup of events included in a composite outcome can alter study conclusions, including whether treatment effects are statistically significant. Moreover, the events included in a composite outcome often vary in clinical significance, reflect distinct biological pathways and/or are affected differently by treatment. Therefore, knowing the precise breakdown of the component events is essential to accurately interpret trial results and gauge the true benefit of an intervention. In oncology clinical trials, however, such information is rarely provided. In this Perspective, we emphasize this deficiency through a review of 50 studies with progression-free survival as an outcome published in five top oncology journals, discuss the advantages and challenges of using composite end points, and highlight the need for transparent reporting of the component events.

Optimization Therapy by Coupling Intermittent Androgen Suppression with Impulsive Chemotherapy for a Prostate Cancer Model

Intermittent androgen suppression in the prostate cancer is often relapsed by the increasing of prostate specific antigen level during the on-treatment. Historically, chemotherapy has had a limited role in the treatment of prostate cancer. However, new agents are showing promise in patients with advanced disease. Intermittent androgen suppression plus chemotherapy in pulsed pattern has become an indispensable clinical scheme for prostate cancer, which is presented to describe the transformation mechanism for three kinds of cancer cells in this paper. The model is then extended to include the residual effect of chemotherapy which suppresses the cancer cells production, thereby preventing the relapse. The optimal controls represent the efficiencies of both intermittent androgen suppression and chemotherapy in suppressing relapse of prostate cancer. Based on an optimal algorithm, numerical simulations are implemented not only to show the optimal durations of on- and off-treatment and chemotherapy dosages but also to present the effectiveness of different strategies in inhibiting the relapse for three types of patients. Results reveal that the optimal intermittent androgen suppression scheme with alterable treatment cycles is pivotal for type I and II patients, in part because it can greatly reduce the on-treatment time and degrade the level of prostate specific antigen. Furthermore, optimal hybrid schedule even averts the relapse of prostate cancer for type II and III patients. Finally, comparing the prostate specific antigen under intermittent androgen suppression schedule with residual effect of chemotherapy to one without residual effect of chemotherapy demonstrates the validity of both our model and algorithms in lessening the prostate specific antigen and decreasing the chemotherapy dosages.

Real-world analysis of metastatic prostate cancer demonstrates increased frequency of PSA-imaging discordance with visceral metastases and upfront ARAT/docetaxel therapy

BACKGROUND

The objective of this study was to evaluate the background and treatment course of patients with metastatic prostate cancer (PC), with a particular focus on radiographic progression in the absence of prostate-specific antigen (PSA) progression.

METHODS

The study population consisted of 229 patients with metastatic hormone-sensitive PC (HSPC), who received prostate biopsy and androgen deprivation therapy at Kobe University Hospital between January 2008 and June 2022. Clinical characteristics were retrospectively evaluated using medical records. PSA progression-free status was defined as ≤1.05 times greater than that from 3 months before. Multivariate analyses were performed using the Cox proportional hazards regression model to identify parameters associated with time to progression on imaging without PSA elevation.

RESULTS

A total of 227 patients with metastatic HSPC without neuroendocrine PC were identified. The median follow-up period was 38.0 months, with a median overall survival of 94.9 months. Six patients exhibited disease progression on imaging without PSA elevation during HSPC treatment, three during first-line castration-resistant PC (CRPC) treatment, and two during late-line CRPC treatment. The rate of disease progression without PSA elevation at 3 years after treatment initiation was 7.4%. Multivariate analysis revealed that organ metastases and upfront treatment with docetaxel or androgen receptor axis-targeted therapy were independent prognostic factors for imaging progression without PSA elevation.

CONCLUSIONS

Disease progression on imaging without PSA elevation occurred not only during HSPC treatment and first-line CRPC treatment, but also during late-line CRPC treatment. Patients with visceral metastases or those treated with upfront androgen receptor axis-targeted or docetaxel may be more prone to such progression.

Circulating Tumor DNA Analysis on Metastatic Prostate Cancer with Disease Progression

The positivity rate of circulating tumor DNA (ctDNA) next-generation sequencing (NGS) varies among patients with metastatic prostate cancer (mPC), complicating its incorporation into regular practice. This retrospective study analyzed the ctDNA sequencing results of 100 mPC patients from May 2021 to March 2023 to identify the factors associated with positive ctDNA. Three custom gene panels were used for sequencing. Overall, 63% of the patients exhibited tier I/II somatic alterations, while 12% had pathogenic/likely pathogenic germline alterations. The key genes that were altered included AR, TP53, RB1, PTEN, and APC. Mutations in BRCA1/2, either germline or somatic, were observed in 21% of the patients. Among the metastatic castration-resistant prostate cancer (mCRPC) patients, the ctDNA-positive samples generally showed higher median prostate-specific antigen (PSA) levels and were more likely to be at the radiographic and clinical progressive disease stages, although they were not significantly associated with PSA progression. Our results suggest that ctDNA analysis could detect meaningful genetic changes in mPC patients, especially during disease progression.

[Management of metastatic hormone-sensitive prostate cancer - Current treatment options, criteria for prgoression and switch of therapy]

Based on convincing data with an increase in overall survival (OS), the current national and international European Guidelines (S3, ESMO, EAU) recommend a combination therapy with ADT plus Docetaxel or plus the next-generation antiandrogens abiraterone (plus prednisone/prednisolone), apalutamide or enzalutamide as standard treatment for mHSPC patients with a good performance status (ECOG 0-1). Abiraterone received approval only for use in patients with newly diagnosed (de novo) high-risk mHSPC. There is no restrictive approval status for docetaxel in mHSPC. However, the current S3 guideline differentiates in the level of recommendation with regard to tumour volume: a "strong" recommendation is given in high-volume mHSPC, while only a "may" recommendation is given for low-volume mHSPC due to inconsistent data. Apalutamide and enzalutamide are treatment options in a broad range of mHSPC patients. It can be difficult in clinical practice to determine disease progression under ongoing treatment. Generally, a rising PSA level is the first sign of progression, followed by radiographic and clinical progress. In the hormone-sensitive situation, the decision of when to change treatment can be based on the progression to castration-resistant prostate cancer as defined by the EAU guidelines; in the castration-resistant situation, it can be based on progression as per PCWG3 criteria of the Prostate Cancer Clinical Trials Working Group. At least two of the three criteria (PSA progression, radiographic progression, and clinical deterioration) should be met to determine progression and to change treatment. However, since advanced prostate cancer is a very heterogeneous disease, the decision to change treatment in clinical practice must ultimately be made on a case-by-case basis.

Management of patients with advanced prostate cancer-metastatic and/or castration-resistant prostate cancer: Report of the Advanced Prostate Cancer Consensus Conference (APCCC) 2022

BACKGROUND

Innovations in imaging and molecular characterisation together with novel treatment options have improved outcomes in advanced prostate cancer. However, we still lack high-level evidence in many areas relevant to making management decisions in daily clinical practise. The 2022 Advanced Prostate Cancer Consensus Conference (APCCC 2022) addressed some questions in these areas to supplement guidelines that mostly are based on level 1 evidence.

OBJECTIVE

To present the voting results of the APCCC 2022.

DESIGN, SETTING, AND PARTICIPANTS

The experts voted on controversial questions where high-level evidence is mostly lacking: locally advanced prostate cancer; biochemical recurrence after local treatment; metastatic hormone-sensitive, non-metastatic, and metastatic castration-resistant prostate cancer; oligometastatic prostate cancer; and managing side effects of hormonal therapy. A panel of 105 international prostate cancer experts voted on the consensus questions.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The panel voted on 198 pre-defined questions, which were developed by 117 voting and non-voting panel members prior to the conference following a modified Delphi process. A total of 116 questions on metastatic and/or castration-resistant prostate cancer are discussed in this manuscript. In 2022, the voting was done by a web-based survey because of COVID-19 restrictions.

RESULTS AND LIMITATIONS

The voting reflects the expert opinion of these panellists and did not incorporate a standard literature review or formal meta-analysis. The answer options for the consensus questions received varying degrees of support from panellists, as reflected in this article and the detailed voting results are reported in the supplementary material. We report here on topics in metastatic, hormone-sensitive prostate cancer (mHSPC), non-metastatic, castration-resistant prostate cancer (nmCRPC), metastatic castration-resistant prostate cancer (mCRPC), and oligometastatic and oligoprogressive prostate cancer.

CONCLUSIONS

These voting results in four specific areas from a panel of experts in advanced prostate cancer can help clinicians and patients navigate controversial areas of management for which high-level evidence is scant or conflicting and can help research funders and policy makers identify information gaps and consider what areas to explore further. However, diagnostic and treatment decisions always have to be individualised based on patient characteristics, including the extent and location of disease, prior treatment(s), co-morbidities, patient preferences, and treatment recommendations and should also incorporate current and emerging clinical evidence and logistic and economic factors. Enrolment in clinical trials is strongly encouraged. Importantly, APCCC 2022 once again identified important gaps where there is non-consensus and that merit evaluation in specifically designed trials.

PATIENT SUMMARY

The Advanced Prostate Cancer Consensus Conference (APCCC) provides a forum to discuss and debate current diagnostic and treatment options for patients with advanced prostate cancer. The conference aims to share the knowledge of international experts in prostate cancer with healthcare providers worldwide. At each APCCC, an expert panel votes on pre-defined questions that target the most clinically relevant areas of advanced prostate cancer treatment for which there are gaps in knowledge. The results of the voting provide a practical guide to help clinicians discuss therapeutic options with patients and their relatives as part of shared and multidisciplinary decision-making. This report focuses on the advanced setting, covering metastatic hormone-sensitive prostate cancer and both non-metastatic and metastatic castration-resistant prostate cancer.

TWITTER SUMMARY

Report of the results of APCCC 2022 for the following topics: mHSPC, nmCRPC, mCRPC, and oligometastatic prostate cancer.

TAKE-HOME MESSAGE

At APCCC 2022, clinically important questions in the management of advanced prostate cancer management were identified and discussed, and experts voted on pre-defined consensus questions. The report of the results for metastatic and/or castration-resistant prostate cancer is summarised here.

Addressing the need for more therapeutic options in neuroendocrine prostate cancer

INTRODUCTION

Neuroendocrine prostate cancer (NEPC) is an aggressive form of prostate cancer frequently seen after prolonged treatment of castration resistant prostate cancer (CRPC). NEPC has become increasingly prevalent over the last 20 years, with a poor prognosis caused by a late diagnosis and limited treatment options. Recent advances in PET/CT imaging and targeted radioimmunotherapy are promising, but more research into additional treatment options is needed.

AREAS COVERED

The aim of this review is to analyze the current imaging and treatment options for NEPC, and to highlight future potential treatment strategies. A Pubmed search for 'Neuroendocrine Prostate Cancer' was performed and relevant articles were reviewed.

EXPERT OPINION

The recent FDA approval and success of 177 PSMA Lutetium in CRPC is promising, as 177 Lutetium could potentially be paired with a NEPC specific biomarker for targeted therapy. Recent laboratory studies pairing DLL3, which is overexpressed in NEPC, with 177 Lutetium and new PET agents have showed good efficacy in identifying and treating NEPC. The success of future development of NEPC therapies may depend on the availability of 177 Lutetium, as current supplies are limited. Further research into additional imaging and treatment options for NEPC is warranted.

Case Series: "Silent" Spinal Epidural Metastases in Metastatic Castrate-Resistant Prostate Cancer

Introduction

Spinal epidural metastases (SEM) are an uncommon phenomenon and traditionally occur as a preterminal event in heavily pre-treated patients. The introduction of novel anti-androgen therapies, such as enzalutamide and abiraterone acetate, has greatly improved the survival of patients with metastatic prostate cancer but may be changing the pattern of disease.

Case Presentation

Four patients diagnosed with metastatic castrate-resistant prostate cancer (CRPC) were commenced on enzalutamide prior to chemotherapy. Baseline scans in all patients demonstrated extensive bony disease and lymph node involvement. All patients experienced a moderate initial PSA response to treatment (median PSA at baseline 53.5 ng/mL to median nadir 24.5 ng/mL). In all four cases, clinical presentation of spinal cord compression was unexpected with no prodromal neurological symptoms, PSA levels either stable or slowly rising, and CT scans and whole-body bone scans showing stable disease at other metastatic sites. Whole-spine MRI on presentation of neurological deficits showed epidural and dural metastases on the background of stable bone disease. Spinal cord compression occurred at a median of 11.4 months after starting enzalutamide.

Conclusion

Clinicians should be aware of this change in the pattern of CRPC in patients treated with novel anti-androgen therapy. Onset of "silent" spinal cord compression due to SEM rather than bone metastases, can occur relatively early with minimal warning despite stable disease on PSA and standard imaging. Differential progression in nontraditional sites suggests that research into the androgen microenvironment in a wide range of tissue sites should be undertaken, and may explain why prostate cancer metastasizes preferentially to bone and lymph nodes.

Radiographic paradoxical response in metastatic castrate-resistant prostate cancer (mCRPC) managed with new generation anti-androgens: a retrospective analysis

BACKGROUND

Prostatic specific antigen (PSA) has well-recognized limitations as a marker for treatment response and disease progression. Post hoc analysis of the PREVAIL trial reported 24.5% of chemotherapy naïve metastatic castration-resistant prostate cancer (mCRPC) patients on enzalutamide had radiographic progression on conventional imaging with nonrising PSA. In this study, we sought to study the discordance of imaging with PSA kinetics in mCRPC patients on second generation anti-androgens (SGA) post-chemotherapy using combined conventional imaging, and new generation imaging in the form of C-11 choline positron emission tomography/computed tomography (C[11] choline PET/CT) scan.

METHODS

We retrospectively reviewed the medical records of 123 patients with mCRPC treated with SGA (Abiraterone or Enzalutamide) after docetaxel between 2016 and 2019. Patients underwent PSA testing, and C[11] choline PET/CT scan at baseline level before starting treatment with SGA, then every 3-6 months as part of their follow up evaluation. Loss of response to SGA was defined by increase in corrected maximum standardized uptake value (SUVmax) of pretreatment lesions on C-11 Choline PET/CT, and/or development of new lesions. Suspicious new lesions were confirmed by biopsy and/or conventional imaging.

RESULTS

We identified 123 mCRPC patients who received SGA (Abiraterone, n = 106; Enzalutamide, n = 17) after docetaxel. Median duration of therapy was 13.9 months (interquartile range: 8.75-21.14). Approximately 43% (n = 53) of subjects in this study exhibited an increase in choline avidity while on SGA. Of this group, 60.4% of patients experienced a parallel rise in PSA (Group-A), whereas 39.6% displayed a paradoxical response (PR) (Group-B), defined as increased choline avidity combined with stable or down-trending PSA. Median PSA at time of increase in choline avidity was 3.1 ng/ml for Group-A, and 1.3 ng/ml for Group-B (p = 0.0176). Median SUVmax was similar in both groups (4.9 for Group-A, 4.6 for Group-B; p = 0.6072). The median time for increase in choline avidity was 9.5 versus 3.9 months for Group-A versus Group-B, respectively (Log-Rank = 0.0063).

CONCLUSION

Nearly 40% of mCRPC patients placed on SGA post docetaxel chemotherapy will exhibit paradoxical responses to therapy, therefore, warranting close follow up with imaging. C-11 choline PET/CT imaging is a useful tool that can help in early predication of disease progression or treatment failure.

Towards clinical implementation of circulating tumor DNA in metastatic prostate cancer: Opportunities for integration and pitfalls to interpretation

Plasma circulating tumor DNA (ctDNA) represents short fragments of tumor-derived DNA released into the bloodstream primarily from cancer cells undergoing apoptosis. In metastatic castration-resistant prostate cancer (mCRPC), characterizing genomic alterations in ctDNA identifies mutations, copy number alterations, and structural rearrangements with predictive and prognostic biomarker utility. These associations with clinical outcomes have resulted in ctDNA increasingly incorporated into routine clinical care. In this review, we summarize current and emerging applications for ctDNA analysis in metastatic prostate cancer, including outcome prediction, treatment selection, and characterization of treatment resistance. We also discuss potential pitfalls with interpreting ctDNA findings, namely false negatives arising from low tumor content and optimal assay design, including correction for clonal hematopoiesis of indeterminate potential and germline variants. Understanding the influence of these limitations on interpretation of ctDNA results is necessary to overcome barriers to clinical implementation. Nevertheless, as assay availability and technology continue to improve, recognizing both opportunities and shortcomings of ctDNA analysis will retain relevance with informing the implementation of precision-oncology initiatives for metastatic prostate cancer.

Characteristics of BRCA2 Mutated Prostate Cancer at Presentation

Genetic alterations of DNA repair genes, particularly BRCA2 in patients with prostate cancer, are associated with aggressive behavior of the disease. It has reached consensus that somatic and germline tests are necessary when treating advanced prostate cancer patients. Yet, it is unclear whether the mutations are associated with any presenting clinical features. We assessed the incidences and characteristics of BRCA2 mutated cancers by targeted sequencing in 126 sets of advanced prostate cancer tissue sequencing data. At the time of diagnosis, cT3/4, N1 and M1 stages were 107 (85%), 54 (43%) and 35 (28%) samples, respectively. BRCA2 alterations of clinical significance by AMP/ASCO/CAP criteria were found in 19 of 126 samples (15.1%). The BRCA2 mutated cancer did not differ in the distributions of TNM stage, Gleason grade group or histological subtype compared to BRCA2 wild-type cancers. Yet, they had higher tumor mutation burden, and higher frequency of ATM and BRCA1 mutations (44% vs. 10%, p = 0.002 and 21% vs. 4%, p = 0.018, respectively). Of the metastatic subgroup (M1, n = 34), mean PSA was significantly lower in BRCA2 mutated cancers than wild-type (p = 0.018). In the non-metastatic subgroup (M0, n = 64), PSA was not significantly different (p = 0.425). A similar trend was noted in multiple metastatic prostate cancer public datasets. We conclude that BRCA2 mutated metastatic prostate cancers may present in an advanced stage with relatively low PSA.

Up-regulation of secretory leukocyte protease inhibitor in human samples might have a potential role of predicting prostate cancer recurrence and progression after surgery and hormonal therapy

Using new castration-resistant prostate cancer (CRPC) cell lines developed from LNCaP cells as a model for CRPC, we searched for novel biomarkers by analyzing the proteins secreted in culture supernatants. The results showed that the levels of secretory leukocyte protease inhibitor (SLPI) in these cell lines were 4.7-6.7 times higher than those secreted in parental LNCaP. Patients with localized prostate cancer (PC) and who expressed SLPI had a significantly lower prostate-specific antigen (PSA) progression-free survival rate than those who did not. Multivariate analysis revealed that SLPI expression was an independent risk factor for PSA recurrence. By contrast, when immunostaining of SLPI was performed on consecutive prostate tissue samples obtained from 11 patients, both in hormone naive (HN) and castration resistant (CR) conditions, only one patient expressed SLPI in the HNPC state; however, four of the 11 patients expressed SLPI in the CRPC state. In addition, two of these four patients were resistant to enzalutamide, and there was a discrepancy between their serum PSA levels and radiographic progression of the disease. These results suggest that SLPI can be a predictor of prognosis in patients with localized PC and disease progression in CRPC patients.

[CARD study: relevance for the treatment of advanced prostate cancer]

BACKGROUND

 Various life-prolonging therapy options are available for the treatment of metastatic castration-resistant prostate cancer (mCRPC).

OBJECTIVE

 The optimal therapy sequence for mCRPC has been discussed for years. With the final results of the CARD study, important prospective data are available to enlighten the discussion about the therapy sequence.

MATERIAL AND METHOD

 CARD is a randomised phase IV trial in patients with mCRPC who were previously treated with docetaxel and an anti-androgen receptor (ARTA). The study showed significant efficacy benefits in favour of further treatment with cabazitaxel versus a second ARTA therapy. The study results are presented and discussed in the context of previous study data with regard to their importance for everyday clinical practice.

RESULTS

 The CARD study data confirm cabazitaxel as an effective therapy option for mCRPC patients previously treated with docetaxel and an ARTA. Cabazitaxel was safe to apply. The study results confirm the cross resistance between the two ARTAs Abiraterone and Enzalutamide.

CONCLUSION

In mCRPC patients eligible for chemotherapy, the therapy sequence should be chosen so that the patients also receive cabazitaxel. A direct therapy sequence with two ARTAs should be avoided or, at least, only considered if other substances are contraindicated.

Correlation Between Imaging-Based Intermediate Endpoints and Overall Survival in Men With Metastatic Castration-Resistant Prostate Cancer: Analysis of 28 Randomized Trials Using the Prostate Cancer Clinical Trials Working Group (PCWG2) Criteria in 16,511 Patients

INTRODUCTION/BACKGROUND

Radiographic progression-free survival (rPFS) based on Prostate Cancer Working Group 2 (PCWG2) has been increasingly used as a meaningful imaging-based intermediate endpoint (IBIE) for overall survival (OS) in patients with metastatic castration-resistant prostate cancer (mCRPC). In randomized phase III trials, rPFS showed good correlation with OS at the individual trial level. We aimed to assess the correlation between the hazard ratios (HR) of IBIE and OS among PCWG2-based randomized trials.

MATERIALS AND METHODS

PubMed and EMBASE databases were systematically searched for randomized trials evaluating systemic treatments on mCRPC using PCWG2 up to April 15, 2020. Hazard ratios for OS and IBIEs were extracted and their correlation was assessed using weighted linear regression. Subgroup analyses were performed according to various clinical settings: prior chemotherapy, drug category, type of IBIE (rPFS vs. composite IBIE, latter defined as progression by imaging and one or a combination of PSA, pain, skeletal-related events, and performance status), and publication year.

RESULTS

Twenty-eight phase II-III randomized trials (16,511 patients) were included. Correlation between OS and IBIE was good (R² = 0.57, 95% confidence interval [CI], 0.35-0.78). Trials using rPFS showed substantially higher correlation than those using a composite IBIE (R² = 0.58, 95% CI, 0.32-0.82 vs. 0.00, 95% CI, -0.01 to 0.01). Correlations between OS and IBIE in other subgroups were at least moderate in nearly all subgroups (R² = 0.32-0.91).

CONCLUSION

IBIEs in the era of PCWG2 correlate well with OS in randomized trials for systemic drugs in patients with mCRPC. PCWG2-based rPFS should be used instead of a composite IBIE that includes PSA and other clinical variables.

Lack of consensus identifies important areas for future clinical research: Advanced Prostate Cancer Consensus Conference (APCCC) 2019 findings

BACKGROUND

Innovations in treatments, imaging and molecular characterisation have improved outcomes for people with advanced prostate cancer; however, many aspects of clinical management are devoid of high-level evidence. At the Advanced Prostate Cancer Consensus Conference (APCCC) 2019, many of these topics were addressed, and consensus was not always reached. The results from clinical trials will most reliably plus the gaps.

METHODS

An invited panel of 57 experts voted on 123 multiple-choice questions on clinical management at APCCC 2019. No consensus was reached on 88 (71.5%) questions defined as <75% of panellists voting for the same answer option. We reviewed clinicaltrials.gov to identify relevant ongoing phase III trials in these areas of non-consensus.

RESULTS

A number of ongoing phase III trials were identified that are relevant to these non-consensus issues. However, many non-consensus issues appear not to be addressed by current clinical trials. Of note, no phase III but only phase II trials were identified, investigating side effects of hormonal treatments and their management.

CONCLUSIONS

Lack of consensus almost invariably indicates gaps in existing evidence. The high percentage of questions lacking consensus at APCCC 2019 highlights the complexity of advanced prostate cancer care and the need for robust, clinically relevant trials that can fill current gaps with high-level evidence. Our review of these areas of non-consensus and ongoing trials provides a useful summary, indicating areas in which future consensus may soon be reached. This review may facilitate academic investigators to identify and prioritise topics for future research.

Impact of Serum γ-Glutamyltransferase on Overall Survival in Men with Metastatic Castration-Resistant Prostate Cancer Treated with Docetaxel

Simple Summary

γ-Glutamyltransferase (GGT) is a biomarker of oxidative stress and its elevation in the serum is linked to poor survival in various malignancies; however, reports on metastatic castration-resistant prostate cancer (mCRPC) are scarce. Moreover, the source of serum GGT in men with mCRPC is largely unknown. The aims of this study were to determine the impact of serum GGT on overall survival in men with mCRPC receiving docetaxel therapy, and to examine the association between systemic and local GGT levels using immunohistochemistry. Of note, high serum GGT was associated with adverse overall survival as were low hemoglobin and high prostate-specific antigen levels. Additionally, tissue GGT expression status in prostate specimens was moderately positively associated with serum GGT. We demonstrated that pre-therapeutic serum GGT was an independent prognosticator in men with mCRPC receiving docetaxel therapy, and that overexpression of GGT in cancer cells might be responsible for the elevation of serum GGT.

Abstract

Background: Reports on the prognostic significance of serum γ-glutamyltransferase (GGT) in men with metastatic castration-resistant prostate cancer (mCRPC) are limited. In addition, GGT expression status in cancer tissues has not been well characterized regardless of cancer types. Methods: This retrospective study included 107 consecutive men with mCRPC receiving docetaxel therapy. The primary endpoints were associations of serum GGT with overall survival (OS) and prostate-specific antigen (PSA) response. The secondary endpoint was an association of serum GGT with progression-free survival (PFS). Additionally, GGT expression status was immunohistochemically semi-quantified using tissue microarrays. Results: A total of 67 (63%) men died during follow-up periods (median 22.5 months for survivors). On multivariable analysis, high Log GGT was independently associated with adverse OS (HR 1.49, p = 0.006) as were low hemoglobin (HR 0.79, p = 0.002) and high PSA (HR 1.40, p < 0.001). In contrast, serum GGT was not significantly associated with PSA response or PFS. Moreover, incorporation of serum GGT into established prognostic models (i.e., Halabi and Smaletz models) increased their C-indices for predicting OS from 0.772 to 0.787 (p = 0.066) and from 0.777 to 0.785 (p = 0.118), respectively. Furthermore, there was a positive correlation between serum and tissue GGT levels (ρ = 0.53, p = 0.003). Conclusions: Serum GGT may be a prognostic biomarker in men with mCRPC receiving docetaxel therapy. GGT overexpression by prostate cancer cells appears to be responsible for the elevation of GGT in the serum.

The Triple-Tracer strategy against Metastatic PrOstate cancer (3TMPO) study protocol

OBJECTIVE

To determine the prevalence of intra-patient inter-metastatic heterogeneity based on positron emission tomography (PET)/computed tomography (CT) in patients with metastatic castration-resistant prostate cancer (mCRPC) and to determine the prevalence of neuroendocrine disease in these patients and their eligibility for radioligand therapies (RLTs).

PATIENTS AND METHODS

This multicentre observational prospective clinical study will include 100 patients with mCRPC from five Canadian academic centres. Patients with radiological or biochemical progression and harbouring at least three metastases by conventional imaging will be accrued. Intra-patient inter-metastatic heterogeneity will be determined with triple-tracer imaging using fluorine-18 fluorodeoxyglucose (¹⁸ F-FDG), gallium-68-(⁶⁸ Ga)-prostate-specific membrane antigen (PSMA)-617 and ⁶⁸ Ga-DOTATATE, which are a glucose analogue, a PSMA receptor ligand and a somatostatin receptor ligand, respectively. The ⁶⁸ Ga-PSMA-617 and ¹⁸ F-FDG PET/CT scans will be performed first. If at least one PSMA-negative/FDG-positive lesion is observed, an additional PET/CT scan with ⁶⁸ Ga-DOTATATE will be performed. The tracer uptake of individual lesions will be assessed for each PET tracer and patients with lesions presenting discordant uptake profiles will be considered as having inter-metastatic heterogeneous disease and may be offered a biopsy.

EXPECTED RESULTS

The proposed triple-tracer approach will allow whole-body mCRPC characterisation, investigating the inter-metastatic heterogeneity in order to better understand the phenotypic plasticity of prostate cancer, including the neuroendocrine transdifferentiation that occurs during mCRPC progression. Based on ⁶⁸ Ga-PSMA-617 or ⁶⁸ Ga-DOTATATE PET positivity, the potential eligibility of patients for PSMA and DOTATATE-based RLT will be assessed. Non-invasive whole-body determination of mCRPC heterogeneity and transdifferentiation is highly innovative and might establish the basis for new therapeutic strategies. Comparison of molecular imaging findings with biopsies will also link metastasis biology to radiomic features.

CONCLUSION

This study will add novel, biologically relevant dimensions to molecular imaging: the non-invasive detection of inter-metastatic heterogeneity and transdifferentiation to neuroendocrine prostate cancer by using a multi-tracer PET/CT strategy to further personalise the care of patients with mCRPC.

A European, prospective, observational study of enzalutamide in patients with metastatic castration-resistant prostate cancer: PREMISE

In randomized clinical trials, the androgen‐receptor inhibitor enzalutamide has demonstrated efficacy and safety in metastatic castration‐resistant prostate cancer (mCRPC). This study captured efficacy, safety and patient‐reported outcomes (PROs) of enzalutamide in mCRPC patients in a real‐world European setting. PREMISE (NCT0249574) was a European, long‐term, prospective, observational study in mCRPC patients prescribed enzalutamide as part of standard clinical practice. Patients were categorized based on prior docetaxel and/or abiraterone use. The primary endpoint was time to treatment failure (TTF), defined as time from enzalutamide initiation to permanent treatment discontinuation for any reason. Secondary endpoints included prostate‐specific antigen (PSA) response, time to PSA progression, time to disease progression and safety. PROs included EuroQol 5‐Dimension, 5‐Level questionnaire, Functional Assessment of Cancer Therapy—Prostate and Brief Pain Inventory—Short Form. Overall, 1732 men were enrolled. Median TTF with enzalutamide was 12.9 months in the chemotherapy‐ and abiraterone‐naïve cohort (Cohort 1) and 8.4 months in the postchemotherapy and abiraterone‐naïve cohort (Cohort 2). Clinical outcomes based on secondary endpoints also varied between cohorts. Cohorts 1 and 2 showed small improvements in health‐related quality of life and pain status. The proportions of patients reporting treatment‐emergent adverse events (TEAEs) were 51.0% and 62.2% in Cohorts 1 and 2, respectively; enzalutamide‐related TEAEs were similar in both cohorts. The most frequent TEAE across cohorts was fatigue. These data from unselected mCRPC patients in European, real‐world, clinical‐practice settings confirmed the benefits of enzalutamide previously shown in clinical trial outcomes, with safety results consistent with enzalutamide's known safety profile.

What's new?

In clinical trials, the androgen‐receptor inhibitor enzalutamide has demonstrated efficacy and safety in metastatic castration‐resistant prostate cancer (mCRPC). However, results in the real world may differ from those in controlled studies. This large, prospective study thus assessed unselected mCRPC patients with different prior treatment histories, who were then treated with enzalutamide. The results confirm and validate the benefits of enzalutamide in real‐world, clinical‐practice settings that were previously seen in clinical‐trial outcomes. These include improved health‐related quality of life (HRQoL).

Imaging features of the evolving patterns of metastatic prostate cancer

The pattern of metastases in prostate cancer (PC) is evolving. Increased use of imaging, newer imaging techniques with higher sensitivity for disease detection and patients receiving multiple lines of novel therapies with increased life expectancy are likely to be contributory. Awareness of metastatic disease patterns improves early diagnosis, accurate staging, and initiation of appropriate therapy, and can inform prognostic information and anticipate potential disease complications. The aim of this review is to document the spectrum of metastases in PC including emerging and unusual patterns, and to highlight the role of novel imaging including prostate-specific membrane antigen (PSMA)-positron-emission tomography (PET) and whole-body magnetic resonance imaging (WB-MRI) to improve diagnostic and response assessment accuracy.

Efficacy and Safety of Abiraterone Acetate and Enzalutamide for the Treatment of Metastatic Castration-Resistant Prostate Cancer: A Systematic Review and Meta-Analysis

OBJECTIVE

The androgen receptor-targeting drugs abiraterone acetate and enzalutamide have shown positive results as treatments for metastatic castration-resistant prostate cancer (mCRPC). Therefore, a meta-analysis was conducted to compare the efficacy and safety of abiraterone acetate and enzalutamide in patients with mCRPC.

METHODS

We retrieved relevant articles from PubMed, Cochrane, and EMBASE published before December 31, 2020. Eleven articles were initially selected, and four phase III, double-blind, randomized controlled trials of abiraterone acetate and enzalutamide that involved 5199 patients with mCRPC were included. The end points were time to prostate-specific antigen progression (TTPP), according to the prostate-specific antigen working group criteria; overall survival (OS); and radiographic progression-free survival (rPFS).

RESULTS

Four randomized, controlled clinical trials involving 5199 patients were included in this study. The results of the meta-analysis showed that compared with placebo alone, abiraterone significantly improved OS (HR=0.69, 95% CI: 0.60-0.8, P<0.00001), rPFS (HR=0.64, 95% CI: 0.57-0.71, P < 0.00001), and TTPP (HR=0.52, 95% CI: 0.45-0.59, P < 0.00001) in patients with mCRPC. Compared with placebo, enzalutamide significantly improved OS (HR=0.67, 95% CI: 0.59-0.75, P<0.00001), rPFS (HR=0.33, 95% CI: 0.29-0.37, P< 0.00001), and TTPP (HR=0.19, 95% CI: 0.17-0.22, P < 0.00001). An indirect comparison was performed to compare the efficacy of abiraterone and enzalutamide. The results showed that there was no significant difference between abiraterone and enzalutamide with regard to improving the OS of patients with mCRPC (HR=1.03, 95% CI: 0.854-1.242). Enzalutamide was superior to abiraterone with regard to improving rPFS in patients with mCRPC (HR=0.516, 95% CI: 0.438-0.608). With regard to improving TTPP, the efficacy of enzalutamide was better than that of abiraterone (HR=0.365, 95% CI: 0.303-0.441). In sAE, there was no difference between abiraterone and enzalutamide (P=0.21, I2 = 38%).

CONCLUSIONS

Compared with placebo, both abiraterone and enzalutamide significantly prolonged OS, rPFS, and TTPP in patients with mCRPC. There was no difference in safety between abiraterone and enzalutamide. In addition, enzalutamide had better efficacy than abiraterone with regard to improving rPFS and TTPP but not OS, but the level of evidence was low. Therefore, a large direct comparison trial is needed to compare the efficacy of the two drugs.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO, identifier (CRD42021226808).

Response Assessment and Prediction of Progression-Free Survival by 68Ga-PSMA-11 PET/CT Based on Tumor-to-Liver Ratio (TLR) in Patients with mCRPC Undergoing 177Lu-PSMA-617 Radioligand Therapy

At present, little is known about the molecular imaging-based response assessment of prostate-specific membrane antigen (PSMA)-targeted radioligand therapy with ¹⁷⁷Lutetium (¹⁷⁷Lu-PSMA-617 RLT) in metastatic castration-resistant prostate cancer (mCRPC). Our study evaluated the response to RLT using both molecular imaging and biochemical response assessments, and their potential prediction of progression-free survival (PFS). Fifty-one consecutive patients given two cycles of RLT at 6-week intervals were analyzed retrospectively. ⁶⁸Ga-PSMA-11 PET/CT was obtained about 2 weeks prior to the first and 4–6 weeks after the second cycle. Molecular imaging-based response using SUV_peak and tumor-to-liver ratio (TLR) was determined by modified PERCIST criteria. ∆TLR and ∆SUV were significantly correlated with ∆PSA (p < 0.001, each). After a median follow-up of 49 months, the median PFS (95% CI) was 8.0 (5.9–10.1) months. In univariate analysis, responders showing partial remission (PR_PSA and PR_TLR) had significantly (p < 0.001, each) longer PFS (median: 10.5 and 9.3 months) than non-responders showing either stable or progressive disease (median: 4.0 and 3.5 months). Response assessment using SUV_peak failed to predict survival. In multivariable analysis, response assessment using TLR was independently associated with PFS (p < 0.001), as was good performance status (p = 0.002). Molecular imaging-based response assessment with ⁶⁸Ga-PSMA-11 PET/CT using normalization of the total lesion PSMA over healthy liver tissue uptake (TLR) could be an appropriate biomarker to monitor RLT in mCRPC patients and to predict progression-free survival (PFS) of this treatment modality.

Does PSA level affect the choice of prostate puncture methods among MRI-ultrasound fusion targeted biopsy, transrectal ultrasound systematic biopsy or the combination of both?

OBJECTIVES

To explore whether prostate-specific antigen (PSA) affects the choice of prostate puncture methods by comparing MRI-ultrasound fusion targeted biopsy (MRI-TBx) with transrectal ultrasound systematic biopsy (TRUS-SBx) in the detection of prostate cancer (PCa), clinically significant prostate cancer (csPCa) and non-clinically significant prostate cancer (nsPCa) in different PSA groups (<10.0,10.0-20.0 and>20.0 ng ml-1).

METHODS

A total of 190 patients with 215 lesions who underwent both MRI-TBx and TRUS-SBx were included in this retrospective study. PSA was measured pre-operatively and stratified to three levels. The detection rates of PCa, csPCa and nsPCa through different methods (MRI-TBx, TRUS-SBx, or MRI-TBx +TRUS SBx) were compared with stratification by PSA.

RESULTS

Among the 190 patients, the histopathological results revealed PCa in 126 cases, including 119 csPCa. In PSA <10.0 ng ml-1 group, although the detection rates of PCa and csPCa by MRI-TBx were higher than those of TRUS-SBx, no significant differences were observed (p = 0.741; p = 0.400). In PSA 10.0-20.0 ng ml-1 group, difference between the detection rate of csPCa with TRUS-SBx and the combined method was statistically significant (p = 0.044). As for PSA >20.0 ng ml-1, MRI-TBx had a higher csPCa rate than TRUS-SBx with no statistical significance noted (p = 0.600).

CONCLUSION

MRI-TBx combined with TRUS-SBx could be suitable as a standard detection approach for csPCa in patients with PSA 10.0-20.0 ng ml-1. As for PSA >20.0 and <10.0 ng ml-1, both MRI-TBx and TRUS-SBx might provide effective solutions for tumor detection.

ADVANCES IN KNOWLEDGE

This study gives an account of choosing appropriate prostate puncture methods through PSA level.

Efficacy and Haematologic Toxicity of Palliative Radioligand Therapy of Metastatic Castrate-Resistant Prostate Cancer with Lutetium-177-Labeled Prostate-Specific Membrane Antigen in Heavily Pre-Treated Patients

Background: Metastatic castration-resistant prostate cancer (mCRPC) remains a significant contributor to the global cancer burden. lutetium-177-prostate-specific membrane antigen radioligand therapy (¹⁷⁷Lu-PSMA RLT) is an effective salvage treatment. However, studies have highlighted haematologic toxicity as an adverse event of concern. We report our single-centre experience of compassionate access palliative ¹⁷⁷Lu-DOTAGA-(I-y)fk(Sub-KuE) (¹⁷⁷Lu-PSMA I&T) with respect to efficacy and haematologic safety. Methods: Patients with mCRPC and adequate bone marrow/liver function were included. All patients included underwent baseline and response assessment by Gallium-68-PSMA-11 positron emission tomography/computed tomography (⁶⁸Ga-PSMA-11 PET/CT). Prescribed activity of therapy was a median 6.24 GBq per patient per cycle (IQR1.29 GBq), administered in 8-week intervals, up to four cycles. Response was assessed by prostate specific antigen (PSA) and a week-12 PET/CT. Incidence of grade ≥ 3 haematologic toxicity, including association with risk factors (age ≥ 70 years, prior/concurrent therapy, presence of metastases, and number of cycles completed), was analysed. Results: One hundred patients completed one cycle of ¹⁷⁷Lu PSMA I&T and underwent response assessment by both PSA and PET/CT. Two patients had an uninterpretable week-12 PET/CT. Median age was 70 (50–89), median number of prior therapies was three (1–6), and median follow up was 12-months. Fifty-four percent achieved a PSA response. Disease control rate (DCR) by PET/CT was 64% (29% SD, 34% PR, and 1% CR). Disease control by PET/CT was associated with an improved one-year overall survival (OS) compared to non-responders, median OS not-reached vs 10-months (p < 0.0001; 95% CI: 0.08–0.44). Regarding haematologic toxicity, 11% experienced a grade ≥ 3 cytopenia (self-limiting). No cases of myelodysplasia/acute leukaemia (MDS/AL) have been recorded. No association with risk factors was demonstrated. Conclusion: ¹⁷⁷Lu-PSMA I&T is a safe and effective palliative outpatient treatment for mCRPC. ⁶⁸Ga-PSMA-11 PET/CT response is associated with an improved one-year OS and may be used to adapt therapy.

Pain Progression at Initiation of Cabazitaxel in Metastatic Castration-Resistant Prostate Cancer (mCRPC): A Post Hoc Analysis of the PROSELICA Study

BACKGROUND

In the PROSELICA phase III trial (NCT01308580), cabazitaxel 20 mg/m² (CABA20) was non-inferior to cabazitaxel 25 mg/m² (CABA25) in mCRPC patients previously treated with docetaxel (DOC). The present post hoc analysis evaluates how the type of progression at randomization affected outcomes.

METHODS

Progression type at randomization was defined as follows: PSA progression only (PSA-p; no radiological progression (RADIO-p), no pain), RADIO-p (±PSA-p, no pain), or pain progression (PAIN-p, ±PSA-p, ±RADIO-p). Relationships between progression type and overall survival (OS), radiological progression-free survival (rPFS), and PSA response (confirmed PSA decrease ≥ 50%) were analyzed.

RESULTS

All randomized patients (n = 1200) had received prior DOC, and 25.7% had received prior abiraterone or enzalutamide. Progression type at randomization was evaluable in 1075 patients (PSA-p = 24.4%, RADIO-p = 20.8%, PAIN-p = 54.8%). Pain progression was associated with clinical and biological features of aggressive disease. Median OS from CABA initiation or date of mCRPC diagnosis, all arms combined, was shorter in the PAIN-p group than in the RADIO-p or the PSA-p groups (12.0 versus 16.8 and 18.4 months, respectively, p < 0.001). In multivariate analysis, all arms combined, PAIN-p was an independent predictor of poor OS (HR = 1.44, p < 0.001). PSA response, rPFS, and OS were numerically higher with CABA25 versus CABA20 in patients with PAIN-p.

CONCLUSIONS

This post hoc analysis of the PROSELICA phase III study shows that pain progression at initiation of CABA in mCRPC patients previously treated with DOC is associated with a poor prognosis. Disease progression should be carefully monitored, even in the absence of PSA rise.

Metastatic Diffusion Volume Based on Apparent Diffusion Coefficient as a Prognostic Factor in Castration-Resistant Prostate Cancer

BACKGROUND

Whole-body diffusion-weighted MRI (WB-DWI) is useful for assessing disease activity in castration-resistant prostate cancer (CRPC). MET-RADS-P is a subjective assessment-based reporting system proposed to standardize the interpretation of WB-DWI. However, a quantitative evaluation of WB-DWI has not been fully investigated.

PURPOSE

To investigate the validity, and analyze the prognostic value, of quantitative evaluation of WB-DWI based on apparent diffusion coefficient (ADC) values for CRPC.

STUDY TYPE

Retrospective.

POPULATION

Sixty-six patients with CRPC. The median age was 75 years. During the median follow-up period of 25.2 months, 23 of 66 patients (34.8%) died of prostate cancer.

FIELD STRENGTH/SEQUENCE

A 1.5 T WB-DWI was used with two b-values (0 s/mm² -1000 s/mm² ). A single-shot echo-planar imaging sequence was used.

ASSESSMENT

WB-DWI were evaluated by three readers according to MET-RADS-P scoring system. Using imaging software, Attractive BDScore, tumor diffusion volume (mDV) and ADC value of metastatic lesion (mADC) was calculated by two readers. The mDV was calculated with ADC values (×10^-3  mm² /sec) of 0.4-0.9 (mDV_0.4-0.9 ), 0.9-1.4 (mDV_0.9-1.4 ), and 1.4-1.8 (mDV_1.4-1.8 ), respectively.

STATISTICAL TESTS

Spearman's rank correlation coefficient was used to assess the correlation. The relationships between the variables with cancer-specific survival (CSS) were evaluated. Multivariate analysis was performed using the Cox proportional hazards model.

RESULTS

mDVs showed a strong positive correlation with MET-RADS-P scores (r = 0.90/0.87, P < 0.05 for both). mDV showed a statistically significant association with CSS (hazard ratio [HR]: 1.01, P < 0.05). When the mDVs calculated based on the ADC values were included, mDV_0.4-0.9 (HR: 1.02, P < 0.05) and the number of therapeutic lines (HR: 1.35, P < 0.05) were significant independent indicators of CSS shortening.

CONCLUSION

Assessment of metastatic tumor volume based on ADC values can be used in the prognostic evaluation of patients with CRPC. WB-DWI might be a potential prognostic imaging biomarker for CRPC.

EVIDENCE LEVEL

4 TECHNICAL EFFICACY: Stage 2.

Evolving Natural History of Metastatic Prostate Cancer

Introduction

The systemic therapies available to patients with metastatic prostate cancer (mPC) have improved dramatically over the past decade. Anecdotal experience suggests that the increased available lines of therapy have changed the profile of mPC to include a higher prevalence of visceral metastases.

Materials and Methods

A retrospective review of 472 patients with prostate cancer who died in 2009 and in 2016 was performed. Patients with metastatic disease who had imaging within six months of death were included. A total of 164 patients were eligible for analysis.

Results

Overall rates of visceral and distant metastases, including the lung, liver, adrenal, brain, renal, spleen, and thyroid, were higher in patients who died in 2016 as compared to those who died in 2009 (40.0% and 26.1%, respectively, p-value = 0.07). Forty-four percent of patients who died in 2016 used five or more lines of systemic treatments compared to 26.1% of patients in 2009.

Conclusion

The emergence of new systemic therapies for mPC is changing the natural history of the disease. Visceral metastases are being seen with increasing frequency than in the past. This observation is important for clinicians who are monitoring patients with prostate cancer to maintain a high suspicion for visceral disease.

Whole-body magnetic resonance imaging (WB-MRI) reporting with the METastasis Reporting and Data System for Prostate Cancer (MET-RADS-P): inter-observer agreement between readers of different expertise levels

BACKGROUND

The METastasis Reporting and Data System for Prostate Cancer (MET-RADS-P) guidelines are designed to enable reproducible assessment in detecting and quantifying metastatic disease response using whole-body magnetic resonance imaging (WB-MRI) in patients with advanced prostate cancer (APC). The purpose of our study was to evaluate the inter-observer agreement of WB-MRI examination reports produced by readers of different expertise when using the MET-RADS-P guidelines.

METHODS

Fifty consecutive paired WB-MRI examinations, performed from December 2016 to February 2018 on 31 patients, were retrospectively examined to compare reports by a Senior Radiologist (9 years of experience in WB-MRI) and Resident Radiologist (after a 6-months training) using MET-RADS-P guidelines, for detection and for primary/dominant and secondary response assessment categories (RAC) scores assigned to metastatic disease in 14 body regions. Inter-observer agreement regarding RAC score was evaluated for each region by using weighted-Cohen's Kappa statistics (K).

RESULTS

The number of metastatic regions reported by the Senior Radiologist (249) and Resident Radiologist (251) was comparable. For the primary/dominant RAC pattern, the agreement between readers was excellent for the metastatic findings in cervical, dorsal, and lumbosacral spine, pelvis, limbs, lungs and other sites (K:0.81-1.0), substantial for thorax, retroperitoneal nodes, other nodes and liver (K:0.61-0.80), moderate for pelvic nodes (K:0.56), fair for primary soft tissue and not assessable for skull due to the absence of findings. For the secondary RAC pattern, agreement between readers was excellent for the metastatic findings in cervical spine (K:0.93) and retroperitoneal nodes (K:0.89), substantial for those in dorsal spine, pelvis, thorax, limbs and pelvic nodes (K:0.61-0.80), and moderate for lumbosacral spine (K:0.44).

CONCLUSIONS

We found inter-observer agreement between two readers of different expertise levels to be excellent in bone, but mixed in other body regions. Considering the importance of bone metastases in patients with APC, our results favor the use of MET-RADS-P in response to the growing clinical need for monitoring of metastasis in these patients.

What's New for Clinical Whole-body MRI (WB-MRI) in the 21st Century

Whole-body MRI (WB-MRI) has evolved since its first introduction in the 1970s as an imaging technique to detect and survey disease across multiple sites and organ systems in the body. The development of diffusion-weighted MRI (DWI) has added a new dimension to the implementation of WB-MRI on modern scanners, offering excellent lesion-to-background contrast, while achieving acceptable spatial resolution to detect focal lesions 5 to 10 mm in size. MRI hardware and software advances have reduced acquisition times, with studies taking 40-50 min to complete.The rising awareness of medical radiation exposure coupled with the advantages of MRI has resulted in increased utilization of WB-MRI in oncology, paediatrics, rheumatological and musculoskeletal conditions and more recently in population screening. There is recognition that WB-MRI can be used to track disease evolution and monitor response heterogeneity in patients with cancer. There are also opportunities to combine WB-MRI with molecular imaging on PET-MRI systems to harness the strengths of hybrid imaging. The advent of artificial intelligence and machine learning will shorten image acquisition times and image analyses, making the technique more competitive against other imaging technologies.

Patterns of Cancer Progression of Metastatic Hormone-sensitive Prostate Cancer in the ECOG3805 CHAARTED Trial

BACKGROUND

ECOG3805 is a randomized trial of testosterone suppression with or without docetaxel for metastatic hormone-sensitive prostate cancer (mHSPC). Deeper prostate-specific antigen (PSA) suppression is prognostic for outcome. However, the concordance of PSA rise and radiographic progression has not been examined previously in mHSPC, whereas this has been reported in metastatic castration-resistant prostate cancer.

OBJECTIVE

To determine the patterns of progression by PSA and radiographic parameters in patients in ECOG3805.

DESIGN, SETTING, AND PARTICIPANTS

We conducted a retrospective analysis of all patients in ECOG3805. Patients were classified according to the PSA level at progression (whether PSA level was below 2.0 ng/mL or not) and the type of progression event in the study (either PSA progression as defined by the study with or without clinical progression, or clinical progression alone). Baseline demographics, clinical outcomes, and patterns of progression were compared between the groups.

RESULTS AND LIMITATIONS

One in eight patients had clinical progression below a PSA level of 2 ng/mL, and approximately 25% developed clinical progression in the absence of confirmed PSA progression. Overall survival from randomization was shorter in patients with clinical progression without confirmed PSA progression than in patients with PSA progression alone as the first progression. Patient demographics at study entry were not predictive of the pattern of progression. Study limitations include its retrospective and post hoc nature.

CONCLUSIONS

Clinical progression prior to PSA rise or at low PSA levels is a relatively frequent phenomenon in mHSPC and is associated with poorer overall survival. Further biological and clinical studies of these patients are warranted.

PATIENT SUMMARY

Reliance on prostate-specific antigen (PSA) alone is an inadequate strategy to monitor patients undergoing treatment for metastatic hormone-sensitive prostate cancer. Prostate cancer can get worse on scans even with low PSA and/or no or small changes in PSA. Imaging should be added to PSA testing to monitor patients with metastatic prostate cancer.

Liquid Biopsy by Next-Generation Sequencing: a Multimodality Test for Management of Cancer

PURPOSE OF REVIEW

While liquid biopsy is still relatively a new concept, the advent of next-generation sequencing (NGS) technologies has recently generated a revolution in the field and will be the focus of this review.

RECENT FINDINGS

Circulating tumor DNA (ctDNA) derives from tumor cells and provides information about the genetic alterations of tumors. However, ctDNA concentration in plasma can be below the level of detection by conventional methods; therefore, screening for actionable genetic information is challenging. Clinical trials exploring targeted and untargeted sequencing to improve the outcomes of ctDNA detection are showing promising results, having reached a limit of detection as low as 0.001% of ctDNA in a background of normal circulating DNA. Most of the challenges related to the sensitivity of detection of ctDNA have been defeated by dint of NGS-based approaches. Despite all the efforts, these methods are still expensive, time-consuming, and require advanced skills for appropriate interpretation. Nevertheless, the technology is rapidly improving, and the expectations for the implementation of liquid biopsy into the clinical practice in the near future are high.

Current Imaging Techniques for and Imaging Spectrum of Prostate Cancer Recurrence and Metastasis: A Pictorial Review

Relapsing level of prostate-specific antigen (PSA) after initial curative-intent local therapy for organ-confined prostate cancer is often the first sign of recurrence. However, PSA level recurrence does not enable accurate differentiation of locally recurrent tumor from metastatic disease or a combination of both. Metastatic prostate cancer most frequently involves bones and lymph nodes, followed by other organs such as the liver, lung, pleura, adrenal gland, ureter, peritoneum, penis, testis, and meninges. Conventional imaging including CT and bone scintigraphy has long been the standard of care but has limited sensitivity in depicting early local recurrence or metastatic disease. Multiparametric MRI has been shown to be more sensitive in detecting locally recurrent tumor in the prostatectomy bed as well as in situ recurrence in a prostate gland that has been treated with radiation therapy or thermal ablation. In addition, lesions detected with multiparametric MRI may be amenable to targeted biopsy for definitive diagnosis of recurrence. PET/CT or PET/MRI using the U.S. Food and Drug Administration (FDA)-approved tracers carbon 11 choline or fluorine 18 fluciclovine has demonstrated markedly increased sensitivity and specificity for diagnosis of early metastatic disease such as small-volume lymph node metastasis, as have a range of investigational gallium 68 prostate-specific membrane antigen (PSMA) radioactive PET tracers. With recent advances in imaging modalities and techniques, more accurate early detection, localization, and characterization of recurrent prostate cancer have become possible. The authors present a contemporary review of the strengths and limitations of conventional and advanced imaging modalities in evaluation of patients with recurrent prostate cancer and a systematic review of the clinical and imaging features of locally recurrent and metastatic disease.^©RSNA, 2020See discussion on this article by Barwick and Castellucci.