The Role of Therapeutic Layering in Optimizing Treatment for Patients With Castration-resistant Prostate Cancer (Prostate Cancer Radiographic Assessments for Detection of Advanced Recurrence II)

Predictive and Prognostic 18F-Fluorocholine PET/CT Radiomics Nomogram in Patients with Castration-Resistant Prostate Cancer with Bone Metastases Treated with 223Ra

PURPOSE

We aimed to develop a nomogram able to predict treatment failure, skeletal events, and overall survival (OS) in patients with castration-resistant prostate cancer with bone metastases (CRPC-BM) treated with Radium-223 dichloride (223Ra).

PATIENTS AND METHODS

Patients from the Castilla-La Mancha Spanish region were prospectively included in the ChoPET-Rad multicenter study from January 2015 to December 2022. Patients underwent baseline, interim, and end-of-treatment bone scintigraphy (BS) and 18F-Fluorocholine PET/CT (FCH PET/CT) scans, obtaining multiple imaging radiomics as well as clinical and biochemical variables during follow-up and studying their association with the previously defined end-points. Survival analysis was performed using the Kaplan-Meier method and Cox regression. Multivariate logistic and Cox regression models were calculated, and these models were depicted by means of nomograms.

RESULTS

Median progression-free survival (PFS) and OS were 4 and 14 months (mo), respectively. The variables that showed independent and significant association with therapeutic failure were baseline alkaline phosphatase (AP) levels (p = 0.022) and the characteristics of BM on the CT portion of PET/CT (p = 0.017). In the case of OS, the significant variables were therapeutic failure (p = 0.038), the number of lines received after 223Ra (p < 0.001), average SUVmax (p = 0.002), bone marrow infiltration in FCH PET/CT (p = 0.006), and interim FCH PET/CT response (p = 0.048). Final nomograms included these variables, showing good discrimination among the 100 patients included in our study. In the study of skeletal events, only OS showed a significant association in the multivariate analysis, resulting in an inconsistent nomogram design.

CONCLUSIONS

FCH PET/CT appears to be a good tool for evaluating patients eligible for treatment with 223Ra, as well as for their follow-up. Thus, findings derived from it, such as the morphological characteristics of BM in the CT, bone marrow infiltration, or the response to 223Ra in the interim study, have proven to be solid and useful variables in the creation of nomograms for predicting therapeutic failure and OS.

Canonical and truncated transglutaminase-2 regulate mucin-1 expression and androgen independency in prostate cancer cell lines

Androgen independency is associated with poor prostate cancer (PCa) survival. Here we report that silencing of transglutaminase-2 (TG2) expression by CRISPR-Cas9 is associated with upregulation of androgen receptor (AR) transcription in PCa cell lines. Knockout of TG2 reversed the migratory potential and anchorage independency of PC3 and DU145 cells and revealed a reduced level of mucin-1 (MUC1) RNA transcript through unbiased multi-omics profiling, which was restored by selective add-back of the truncated TG2 isoform (TGM2_v2). Silencing of AR resulted into increased MUC1 in TG2KO PC3 cells showing that TG2 affects transcriptional regulation of MUC1 via repressing AR expression. Treatment of PC3 WT cell line with TG2 inhibitor ZDON led to a significant increase in AR expression and decrease in MUC1. ZDON also blocked the formation of MUC1-multimers labelled with TG amine-donor substrates in reducing conditions, revealing for the first time a role for TG2, which we show to be externalised via extracellular vesicles, in MUC1 stabilisation via calcium-dependent transamidation. A specific antibody towards TGM2_v2 revealed its restricted nuclear location compared to the canonical long form of TG2 (TGM2_v1), which is predominantly cytosolic, suggesting that this form contributes to the previously suggested TG2-mediated NF-κB activation and AR transcriptional repression. As TGM2_v2 transcription was increased in biopsies of early-stage prostate adenocarcinoma (PRAD) patients compared to subjects presenting inflammatory prostatitis, and total TG2 protein expression significantly increased in PRAD versus normal tissue, the role of TG2 and its truncated form as a prostate malignancy marker is suggested. In conclusion, this investigation has provided the first unbiased discovery of a novel pathway mediated by TG2 via MUC1, which is shown to contribute to androgen insensitivity and malignancy of PCa cells and be upregulated in PCa biopsies, with potential relevance to cancer immune evasion.

Continuous enzalutamide after progression of metastatic castration-resistant prostate cancer treated with docetaxel (PRESIDE): an international, randomised, phase 3b study

BACKGROUND

Although androgen deprivation therapy is typically given long-term for men with metastatic prostate cancer, second-generation hormone therapies are generally discontinued before the subsequent line of treatment. We aimed to evaluate the efficacy of continuing enzalutamide after progression in controlling metastatic castration-resistant prostate cancer (mCRPC) treated with docetaxel and prednisolone.

METHODS

PRESIDE was a two-period, multinational, double-blind, randomised, placebo-controlled, phase 3b study done at 123 sites in Europe (in Austria, Belgium, Czech Republic, France, Germany, Greece, Italy, Netherlands, Norway, Poland, Russia, Spain, Sweden, Switzerland, Turkey, and the UK). Patients were eligible for period 1 (P1) of the study if they had histologically confirmed prostate adenocarcinoma without neuroendocrine differentiation or small-cell features, serum testosterone concentrations of 1·73 nmol/L or less, and had progressed during androgen deprivation therapy with a luteinising hormone-releasing hormone agonist or antagonist or after bilateral orchiectomy. In P1, patients received open-label enzalutamide 160 mg per day orally. At week 13, patients were assessed for either radiographic or prostate-specific antigen (PSA) progression (25% or more increase and 2 ng/mL or more above nadir). Patients who showed any decline in PSA at week 13 and subsequently progressed (radiographic progression, PSA progression, or both) were screened and enrolled in period 2 (P2), during which eligible patients were treated with up to ten cycles of intravenous docetaxel 75 mg/m² every 3 weeks and oral prednisolone 10 mg/day, and randomly assigned (1:1) to oral enzalutamide 160 mg/day or oral placebo. Patients were stratified by type of disease progression. The block size was four and the overall number of blocks was 400. Patients, investigators, and study organisers were masked to treatment assignment. The primary endpoint was progression-free survival analysed in all patients in P2. This trial is registered with ClinicalTrials.gov, NCT02288247, and is no longer recruiting.

FINDINGS

Between Dec 1, 2014, and Feb 15, 2016, 816 patients were screened for P1 of the study. 688 patients were enrolled in P1 and 687 received open-label enzalutamide. In P2, 271 patients were randomly assigned at 73 sites to receive enzalutamide (n=136) or placebo (n=135). The data cutoff for analysis was April 30, 2020. Median progression-free survival with enzalutamide was 9·5 months (95% CI 8·3-10·9) versus 8·3 months (6·3-8·7) with placebo (hazard ratio 0·72 [95% CI 0·53-0·96]; p=0·027). The most common grade 3 treatment-emergent adverse events were neutropenia (17 [13%] of 136 patients in the enzalutamide group vs 12 [9%] of 135 patients in the placebo group) and asthenia (ten [7%] vs six [4%]). The most common grade 4 treatment-emergent adverse event in P2 was neutropenia (23 [17%] of 136 patients in the enzalutamide group vs 28 [21%] of 135 patients in the placebo group). Serious treatment-emergent adverse events were reported in 67 (49%) of 136 patients in the enzalutamide group and 52 (39%) of 135 patients in the placebo group. Two (15%) of 13 deaths in the enzalutamide group (caused by septic shock and haematuria) and one (14%) of seven deaths in the placebo group (caused by actue kidney injury) were associated with docetaxel.

INTERPRETATION

PRESIDE met its primary endpoint and showed that continuing enzalutamide with docetaxel plus androgen deprivation therapy delayed time to progression compared with docetaxel plus androgen deprivation therapy alone, supporting the hypothesis that enzalutamide maintenance could control persistent androgen-dependent clones in men with mCRPC who progress after treatment with enzalutamide alone.

FUNDING

Astellas Pharma and Pfizer.

Real-World Effectiveness of Sipuleucel-T on Overall Survival in Men with Advanced Prostate Cancer Treated with Androgen Receptor-Targeting Agents

Introduction

The treatment landscape for metastatic castration-resistant prostate cancer (mCRPC) continues to evolve. Sipuleucel-T was the first immunotherapy approved by the US Food and Drug Administration (FDA) to treat asymptomatic or minimally symptomatic mCRPC. The androgen receptor-targeting agents (ARTAs) abiraterone acetate and enzalutamide were initially approved to treat mCRPC. Looking at chemotherapy-naïve men with mCRPC, we compared survival outcomes between the sipuleucel-T + ARTA cohort (men who received either sipuleucel-T or an ARTA in the first line, and then the other in the second line within 6 months) and the ARTA monotherapy cohort (men who only received ARTA monotherapy).

Methods

This retrospective cohort analysis used longitudinal, adjudicated claims data from the US Medicare Fee-for-Service 100% research identifiable dataset that includes both urologic and oncologic practice settings. Eligible men started their first mCRPC treatment with either sipuleucel-T or ARTA in either 2014 or 2015 and had continuous Medicare Parts A, B, and D eligibility for the subsequent 3 years. A multivariable Cox proportional hazards regression model was used to analyze overall survival (OS), both overall and by index year, and to control for differences.

Results

The sipuleucel-T + ARTA and ARTA monotherapy cohorts comprised 773 and 4642 men, respectively, with different characteristics at treatment start. The most commonly used ARTAs were enzalutamide in the former and abiraterone in the latter cohort. Median OS was 30.4 and 14.3 months in the sipuleucel-T + ARTA and ARTA monotherapy cohorts, respectively, with the sipuleucel-T + ARTA cohort having a 28.3% lower risk of death than the ARTA monotherapy cohort (hazard ratio 0.717; 95% CI 0.648, 0.793; p < 0.01).

Conclusions

This real-world study of mCRPC treatment indicates that men receiving sipuleucel-T and ARTAs had a longer median OS than patients receiving treatment with an ARTA alone, suggesting that leveraging mechanisms of action can be beneficial in treating patients with mCRPC.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12325-022-02085-6.

The treatment landscape for metastatic castration-resistant prostate cancer (mCRPC) continues to evolve. There are multiple treatments for mCRPC, including sipuleucel-T, the first US Food and Drug Administration (FDA)-approved immunotherapy, and the androgen receptor-targeting agents (ARTAs) abiraterone acetate and enzalutamide. Although sipuleucel-T uses a unique mechanism of action that may be useful in developing a treatment strategy for mCRPC, an optimal treatment algorithm for prostate cancer remains undefined. Therefore, survival was compared in men with mCRPC who received sipuleucel-T and an ARTA in the first 6 months of treatment with those who received only ARTA monotherapy. A retrospective longitudinal study was conducted using the US Medicare Fee-for-Service 100% research identifiable dataset linked to the National Death Index. Eligible men started their first mCRPC treatment with either sipuleucel-T or ARTA in either 2014 or 2015 and had continuous Medicare eligibility for the subsequent 3 years. Men who received treatment with both sipuleucel-T and an ARTA had a longer median survival (30.4 months) than men who received an ARTA without sipuleucel-T (14.3 months). This represents a 28% reduced risk of death with sipuleucel-T. This real-world study of mCRPC treatment indicates that men receiving sipuleucel T and an ARTA survive longer than men who only receive an ARTA, suggesting that changing the mechanism of action can be beneficial in treating patients with mCRPC.

Pharmacometabolomics Applied to Personalized Medicine in Urological Cancers

Prostate cancer (PCa), bladder cancer (BCa), and renal cell carcinoma (RCC) are the most common urological cancers, and their incidence has been rising over time. Surgery is the standard treatment for these cancers, but this procedure is only effective when the disease is localized. For metastatic disease, PCa is typically treated with androgen deprivation therapy, while BCa is treated with chemotherapy, and RCC is managed primarily with targeted therapies. However, response rates to these therapeutic options remain unsatisfactory due to the development of resistance and treatment-related toxicity. Thus, the discovery of biomarkers with prognostic and predictive value is needed to stratify patients into different risk groups, minimizing overtreatment and the risk of drug resistance development. Pharmacometabolomics, a branch of metabolomics, is an attractive tool to predict drug response in an individual based on its own metabolic signature, which can be collected before, during, and after drug exposure. Hence, this review focuses on the application of pharmacometabolomic approaches to identify the metabolic responses to hormone therapy, targeted therapy, immunotherapy, and chemotherapy for the most prevalent urological cancers.

Particle Swarm Optimized Gaussian Process Classifier for Treatment Discontinuation Prediction in Multicohort Metastatic Castration-Resistant Prostate Cancer Patients

Prostate cancer is the second leading cancer in men, according to the WHO world cancer report. Its prevention and treatment demand proper attention. Despite numerous attempts for disease prevention, prostate tumours can still become metastatic by blood circulation to other organs. Several treatments have been adopted. However, findings show that the docetaxel treatment induces adverse reactions in patients. Particle Swarm Optimized Gaussian Process Classifier (PSO-GPC) is proposed to determine when to discontinue treatment. Based on three cohorts of prostate cancer patients, we propose and compare several classifiers for the best performance in determining treatment discontinuation. Given the data skewness and class imbalance, the models are evaluated based on both the area under receiver operating characteristics curve (AUC) and area under precision recall curve (AUPRC). With the AUCs ranging between 0.6717 - 0.8499, and AUPRCs ranging between 0.1392 - 0.5423, PSO-GPC performs better than the state-of-the-art. We have carried out statistical analysis for ranking methods and analyzed independent cohort data with PSO-GPC, demonstrating its unbiased performance. A proper determination of treatment discontinuation in metastatic castration-resistant prostate cancer patients will reduce the mortality rate in cancer patients.

Interim and end-treatment 18F-Fluorocholine PET/CT and bone scan in prostate cancer patients treated with Radium 223 dichloride

To assess the predictive and prognostic aim of interim and end-treatment 18F-fluorocholine PET/CT (FCH-PET/CT) and 99mTc-methilen diphosphonate bone scintigraphy (BS) in patients with castration-resistant prostate cancer and bone metastases (CRPC-BM) treated with Radium 223 dichloride (223Ra). Prospective and multicentre ChoPET-Rad study including 82 patients with CRPC-BM. Baseline, after 3 (interim) and 6 doses (end-treatment) BS and FCH PET/CT were performed in patients who meet the study criteria. Clinical variables, imaging and clinical progression were obtained and their association with progression free survival (PFS), and overall survival (OS) was studied. Agreement between BS and FCH PET/CT response was assessed using Kappa (K) analysis. Median of PFS and OS was 3 and 16 months, respectively. Agreement between interim BS and FCH PET/CT was weak (K: 0.28; p = 0.004). No agreement was observed between end-treatment diagnostic studies. Interim and end-treatment FCH PET/CT were related to PFS (p = 0.011 and p < 0.001, respectively). Therapeutic failure and interim BS and FCH PET/CT showed association with OS (p < 0.001, p = 0.037 and p = 0.008, respectively). Interim and end-treatment FCH PET/CT were good predictors of biochemical progression in patients treated with 223Ra. Therapeutic failure and progression in interim BS or FCH PET/CT were adverse factors for OS.

Molecular and metabolic imaging of castration-resistant prostate cancer: state of art and future prospects

Prostate cancer (PCa) represents the most common tumor in male and one of the most relevant causes of death in Western countries. Androgen deprivation therapy (ADT) constitutes a widely used approach in advanced PCa. When PCa progresses in spite of ADT and castrate levels of testosterone, the severe clinical condition termed as metastatic castration-resistant prostate cancer (mCRPC) takes place. The only approach to mCRPC has been represented by chemotherapy with taxanes for many years. Nevertheless, recently introduced treatments such as 2nd generation antiandrogens (i.e. enzalutamide and abiraterone), cell immunotherapy with sipuleucel-T or targeted alpha therapy with 223Ra-dichloride, have dramatically changed mCRPC prognosis. These novel therapies call for an unmet need for imaging biomarkers suitable for patients' pre-treatment stratification and response assessment. In this scenario, nuclear medicine can provide several metabolic and molecular probes for investigating pathological processes at a cellular and sub-cellular level. The aim of this paper is to review the most relevant findings of the literature published to date on this topic, giving particular emphasis to the pros and cons of each tracer and also covering future prospects for defining personalized therapeutic approaches.

Optimizing the management of castration-resistant prostate cancer patients: A practical guide for clinicians

BACKGROUND

Advanced prostate cancer (PC) patients, especially those with metastatic prostate cancer (mPC), often require complex management pathways. Despite the publication of clinical practice guidelines by leading urological and oncological organizations that provide a substantial and comprehensive framework, there are numerous clinical scenarios that are not always addressed, especially as new treatments become available, new imaging modalities are developed, and advances in genetic testing continue.

METHODS

A 14-member expert review panel comprised of urologists and medical oncologists were chosen to provide guidance on addressing specific topics and issues regarding metastatic castration-resistant prostate cancer (mCRPC) patients. Panel members were chosen based upon their experience and expertise in the management of PC patients. Four academic members (two urologists and two medical oncologists) of the panel served as group leaders; the remaining eight panel members were from Large Urology Group Practice Association (LUGPA) practices with proven experience in leading their advanced PC clinics. The panel members were assigned to four separate working groups, each assigned a specific mCRPC topic to review and discuss with the entire panel.

RESULTS

This article describes the practical recommendations of an expert panel on the management of mCRPC patients. The target reading audience for this publication is all providers (urologists, medical oncologists, radiation oncologists, or advanced practice providers) who evaluate and manage advanced PC patients, regardless of their practice setting.

CONCLUSION

The panel has provided recommendations for managing mCRPC with regard to specific issues: (a) biomarker monitoring and the role of genetic and molecular testing; (b) rationale, current strategies, and optimal sequencing of the various approved therapies, including hormonal therapy, cytotoxic chemotherapy, radiopharmaceuticals and immunotherapy; (c) adverse event management and monitoring; and (d) imaging advanced PC patients. These recommendations seek to complement national guidelines, not replace them, and a discussion of where the panel agreed or disagreed with national guidelines is included.

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.

Real-world outcomes of sipuleucel-T treatment in PROCEED, a prospective registry of men with metastatic castration-resistant prostate cancer

BACKGROUND

The large registry, PROVENGE Registry for the Observation, Collection, and Evaluation of Experience Data (PROCEED)(NCT01306890), evaluated sipuleucel-T immunotherapy for asymptomatic/minimally symptomatic metastatic castration-resistant prostate cancer (mCRPC).

METHODS

PROCEED enrolled patients with mCRPC receiving 3 biweekly sipuleucel-T infusions. Assessments included overall survival (OS), serious adverse events (SAEs), cerebrovascular events (CVEs), and anticancer interventions (ACIs). Follow-up was for ≥3 years or until death or study withdrawal.

RESULTS

In 2011-2017, 1976 patients were followed for 46.6 months (median). The median age was 72 years, and the baseline median prostate-specific antigen level was 15.0 ng/mL; 86.7% were white, and 11.6% were African American. Among the patients, 1902 had 1 or more sipuleucel-T infusions. The median OS was 30.7 months (95% confidence interval [CI], 28.6-32.2 months). Known prognostic factors were independently associated with OS in a multivariable analysis. Among the 1255 patients who died, 964 (76.8%) died of prostate cancer (PC) progression. The median time from the first infusion to PC death was 42.7 months (95% CI, 39.4-46.2 months). The incidence of sipuleucel-T-related SAEs was 3.9%. The incidence of CVEs was 2.8%, and the rate per 100 person-years was 1.2 (95% CI, 0.9-1.6). The CVE incidence among 11,972 patients with mCRPC from the Surveillance, Epidemiology, and End Results-Medicare database was 2.8%; the rate per 100 person-years was 1.5 (95% CI, 1.4-1.7). One or more ACIs (abiraterone, enzalutamide, docetaxel, cabazitaxel, or radium 223) were received by 77.1% of the patients after sipuleucel-T; 32.5% and 17.4% of the patients experienced 1- and 2-year treatment-free intervals, respectively.

CONCLUSIONS

PROCEED provides contemporary survival data for sipuleucel-T-treated men in a real-world setting of new life-prolonging agents, which will be useful in discussing treatment options with patients and in powering future trials with sipuleucel-T. The safety and tolerability of sipuleucel-T in PROCEED were consistent with previous findings.

Efficacy and safety of abiraterone acetate plus prednisone vs. cabazitaxel as a subsequent treatment after first-line docetaxel in metastatic castration-resistant prostate cancer: results from a prospective observational study (CAPRO)

BACKGROUND

To describe the patterns of second-line treatment of patients with metastatic castration-resistant prostate cancer (mCRPC) after docetaxel treatment in a Spanish population, to identify the factors associated with those patterns, and to compare the efficacy and safety of the treatments most frequently administered.

METHODS

Observational, prospective study conducted in patients with histologically or cytologically confirmed prostate adenocarcinoma; documented metastatic castration-resistant disease; progression after first-line, docetaxel-based chemotherapy with or without other agents.

RESULTS

Of the 150 patients recruited into the study, 100 patients were prescribed abiraterone acetate plus prednisone (AAP), 44 patients received cabazitaxel plus prednisone (CP), and 6 patients received other treatments. Age (odds ratio [OR] 1.06, 95% [confidence interval] CI 1.01 to 1.11) and not elevated lactate dehydrogenase (LDH) levels (OR 0.33, 95% CI 0.14 to 0.76) were independently associated with the administration of AAP. Treatment with AAP was associated with significantly longer clinical/radiographic progression-free survival (hazard ratio [HR] 0.57, 95% CI 0.38 to 0.85) and overall survival (OS; HR 0.40, 95% CI 0.21 to 0.76) compared to CP, while no significant differences between the treatments were found regarding biochemical progression-free survival (PFS; HR 0.78 [95% CI 0.49 to 1.24]). However, in a post-hoc Cox regression analysis adjusted for potential confounders there were not differences between AAP and CP in any of the time-to-event outcomes, including overall survival. We observed no new safety signals related to either regimen.

CONCLUSION

Second-line AAP for patients with mCRPC is the most common treatment strategy after progression with a docetaxel-based regimen. When controlling for potential confounders, patients receiving this treatment showed no differences in PFS and OS in comparison to those receiving CP, although these latter results should be confirmed in randomized controlled trials.

Radium-223 for the treatment of metastatic castration-resistant prostate cancer: A window of opportunity

CONTEXT

The elimination of bone metastases, restoration and/or preservation of bone morphology and prevention and/or delay of skeletal events are a fundamental objective in the management of metastatic castration-resistant prostate cancer (mCRPC). Radium-223 is the first targeted alpha therapy with effects on bone that has been shown to increase survival in these patients, besides providing other bone-related benefits.

OBJECTIVE

To analyze the impact of bone metastasis on mCRPC, and the benefits and the window of opportunity provided by radium-223 in the treatment of patients with mCRPC in the current treatment era.

EVIDENCE ACQUISITION

A bibliographic search of PubMed and Spanish and international congresses on radium-223 and other first-line treatments for mCRPC was performed. Recent guidelines and recommendations by experts were also consulted.

SUMMARY OF THE EVIDENCE

Evidence for the mechanism of action of radium-223 widen its effects to the tumor bone environment. Survival of patients treated with radium-223 is higher in those with mild symptoms as opposed to those with moderate-severe symptoms. The presence of visceral metastases even in the early stages of mCRPC supports starting radium-223 therapy before the symptoms become clinically relevant. A 3-year study has confirmed its good safety profile. Changes in tALP and LDH may be useful markers for monitoring the treatment with radium-223, but they are not predictors of overall survival.

CONCLUSION

Radium-223 is a valuable therapeutic alternative in the treatment of patients with mCRPC in early stages of the disease, with a good safety profile. Its benefits extend to the bone environment.

Optimizing the treatment of metastatic castration-resistant prostate cancer: a Latin America perspective

Prostate cancer is a significant burden and cause of mortality in Latin America. This article reviews the treatment options for patients with metastatic castration-resistant prostate cancer (mCRPC) and provides consensus recommendations to assist Latin American prostate cancer specialists with clinical decision making. A multidisciplinary expert panel from Latin America reviewed the available data and their individual experience to develop clinical consensus opinions for the use of life-prolonging agents in mCRPC, with consideration given to factors influencing patient selection and treatment monitoring. There is a lack of level 1 evidence for the best treatment sequence or combinations in mCRPC. In this context, consensus recommendations were provided for the use of taxane-based chemotherapies, androgen receptor axis-targeted agents and targeted alpha therapy, for patients in Latin America. Prostate-specific antigen (PSA) changes alone, during treatment, should be treated with caution; PSA may not be a suitable biomarker for radium-223. Bone scans and computed tomography are the standard imaging modalities in Latin America. Imaging should be prompted during treatment where symptomatic decline and/or significant worsening of laboratory evaluations are reported, or where a course of therapy has been completed and another antineoplastic agent is under consideration. Recommendations and guidance for treatment options in Latin America are provided in the context of country-level variable access to approved agents and technologies for treatment monitoring. Patients should be treated with the purpose of prolonging overall survival and preserving quality of life through increasing the opportunity to administer all available life-prolonging therapies when appropriate.

EANM guideline for radionuclide therapy with radium-223 of metastatic castration-resistant prostate cancer

Radium Ra-223 dichloride (radium-223, Xofigo®) is a targeted alpha therapy approved for the treatment of castration-resistant prostate cancer (CRPC) with symptomatic bone metastases and no known visceral metastatic disease. Radium-223 is the first targeted alpha therapy in this indication providing a new treatment option, with evidence of a significant survival benefit, both in overall survival and in the time to the first symptomatic skeletal-related event. The skeleton is the most common metastatic site in patients with advanced prostate cancer. Bone metastases are a clinically significant cause of morbidity and mortality, often resulting in bone pain, pathologic fracture, or spinal cord compression necessitating treatment. Radium-223 is selectively accumulated in the bone, specifically in areas of high bone turnover, by forming complexes with the mineral hydroxyapatite (the inorganic matrix of the bone). The alpha radiation generated during the radioactive decay of radium-223 produces a palliative anti-tumour effect on the bone metastases. The purpose of this guideline is to assist nuclear medicine specialists in evaluating patients who might be candidates for treatment using radium-223, planning and performing this treatment, understanding and evaluating its consequences, and improving patient management during therapy and follow-up.

The Contemporary Use of Radium-223 in Metastatic Castration-resistant Prostate Cancer

Radium-223 dichloride (radium-223) was approved for the treatment of patients with castration-resistant prostate cancer (CRPC) and symptomatic bone metastases in the United States and Europe in 2013. This followed a reported overall survival benefit for patients treated with radium-223 and best standard of care (BSoC) when compared with placebo and BSoC in the ALpharadin in SYMptomatic Prostate CAncer (ALSYMPCA) trial. At that time, docetaxel was the standard first-line choice for patients with metastatic CRPC (mCRPC). Since then, the treatment landscape has changed dramatically with new hormonal agents (abiraterone and enzalutamide) considered to be the first-line choice for many patients. The optimal patient profile for radium-223 in the modern setting, and its best use either in sequence or in combination with other approved agents are unclear, with few definitive guidelines available. This article reports on the views of a group of urologists and medical oncologists experienced in treating patients with mCRPC with radium-223 in routine clinical practice. The aim is to provide an overview of the current use of radium-223 in the treatment of patients with mCRPC, and to discuss best practices for patient selection and on-treatment monitoring. Where agreement was reached, guidance on the optimal use of radium-223 is provided.