2019 Canadian Urological Association (CUA)-Canadian Uro Oncology Group (CUOG) guideline: Management of castration-resistant prostate cancer (CRPC)

From conventional therapy to novel nano-based approaches. A focus on prostate cancer

The currently available clinical anticancer approaches pertaining to the treatment of prostate cancer are summarized here. After providing an overview of the main features of this highly impactful global disease, the currently available clinical treatments are briefly reviewed. Then, alternative and innovative nano-based therapeutic options that have been proposed or are currently being explored to significantly improve prostate cancer management (i.e. anti-prostate cancer polymeric nanoparticles loaded with drugs to promote their release and biological activity, including non-targeted and functionalized PLGA-PEG NPs and AuNPs), are introduced. Furthermore, the problem of gathering insights into the mechanistic aspects related to the fate of the nanoformulation in complex matrices, such as blood plasma, is addressed.

Surgical Management of Genitourinary Cancer Liver Metastases

Genitourinary cancers are common. Liver metastases from genitourinary cancers are uncommon; isolated liver metastasis is rare. Liver resection in select patients with metastatic renal cell carcinoma can lead to prolonged survival. Patients with metachronous and low-burden disease are most likely to benefit. Chemotherapy is first-line treatment of metastatic germ cell tumors. Liver resection is dependent on germ cell lineage and initial response to chemotherapy. Prognosis with liver metastases from prostate cancer is poor; liver-only lesions are rare. Liver resection generally is not indicated. Cumulative experience with liver resection for metastatic bladder cancer is limited. Liver metastases are poor prognostic indicators for metastasectomy.

Cost-effectiveness and budget impact analysis of enzalutamide in comparison to abiraterone in treatment of metastatic prostate cancer resistant to castration in Iran

INTRODUCTION

In recent years, enzalutamide and abiraterone have been widely used as treatments for metastatic castration-resistant prostate cancer (mCRPC). However, the cost-effectiveness of these drugs in Iran is unknown. This study evaluated the cost-effectiveness of enzalutamide for the treatment of metastatic prostate cancer resistant to castration in Iran.

METHODS

A 3-state Markov model was developed to evaluate the cost-effectiveness of enzalutamide and abiraterone from a social perspective over 10 years. The clinical inputs were obtained from the meta-analysis studies. The direct medical costs were obtained from the tariffs of the healthcare system, while the direct non-medical and indirect costs were collected from the patients. The data of utilities were derived from the literature. In addition, sensitivity analyses were conducted to assess the uncertainties.

RESULTS

Compared with Abiraterone, enzalutamide was associated with a high incremental cost-effectiveness ratio (ICER) of $6,260 per QALY gained. According to the one-way sensitivity analysis, ICER was most heavily influenced by the prices of enzalutamide and Abiraterone, non-medical costs, and indirect costs. Regardless of the variation, enzalutamide remained cost-effective. The budget impact analysis of enzalutamide in the health system during 5 years was estimated at $6,362,127.

CONCLUSIONS

At current prices, adding enzalutamide to pharmaceutical lists represents the cost-effective use of the healthcare resources in Iran for the treatment of metastatic castration-resistant prostate cancer.

Utilization Trends of Novel Hormonal Agents in Metastatic Castration-Resistant Prostate Cancer in Quebec

BACKGROUND

The introduction of novel hormonal agents (NHAs) such as abiraterone acetate (ABI) and enzalutamide (ENZ) for metastatic castration-resistant prostate cancer (mCRPC) was an important milestone given their survival benefits, tolerability, and ease of administration relative to taxane chemotherapies. This descriptive study sought to describe the utilization trends of ABI and ENZ in patients with mCRPC in the early years after their approval in the province of Quebec in Canada.

METHODS

A retrospective population-based cohort was extracted from Quebec public healthcare administrative databases. The cohort included first-time users of NHAs (ABI or ENZ) from 2011 to 2016. The primary analyses aimed to describe the overall temporal trends (2011-2016) of NHA initiators by chemotherapy status (chemotherapy-naïve versus post-chemotherapy), and prescribing specialty (medical oncology versus urology versus others).

RESULTS

The cohort comprised 2183 patients, with 1562 (72%) in the chemotherapy-naïve group and 621 (28%) in the post-chemotherapy group. While the majority of patients were post-chemotherapy NHA initiators in 2012, this proportion decreased over time and accounted for only 13% of NHA initiators by the end of 2016. Medical oncologists were the most frequent prescribers of NHAs (upwards of 60%) throughout 2012 but fell to 45% by the end of 2016. Conversely, the proportion of prescriptions by urologists increased from 22% in 2012 to 42% in 2016.

CONCLUSION

Over time, there was an increasing proportion of (1) patients who initiated NHAs without prior chemotherapy treatment, (2) NHA prescribing by urologists, and (3) ENZ users. Taken together, this implies that the introduction of NHAs has altered the management of mCRPC and urologists quickly adopted NHAs into their practice.

Incidence of dural metastases in castrate-resistant prostate cancer

Purpose:

The natural history and clinical manifestations of dural metastases (DM) in castrate-resistant prostate cancer (CRPC) will change with advances in new hormonal therapy. Here, we characterised the incidence, clinical presentation, and outcomes of patients with DM in a contemporary patient cohort with CRPC.

Methods:

We retrospectively reviewed our CRPC database from 2012 to 2020. The primary outcome was the diagnosis of DM, defined as metastasis to the dura mater in the brain or spine. We describe the presenting symptoms, biochemistry, radiologic findings, and therapy sequence for all DM patients. Multivariable logistic regression was performed to identify predictors of DM.

Results:

Six of the 275 patients (2.2%) with CRPC developed DM. The average age of CRPC diagnosis for patients with DM was 65.6 years. Mean patient survival was 4.5 months after the diagnosis of DM. At the time of CRPC diagnosis, patients who developed DM were significantly younger, had lower baseline haemoglobin, higher lactate dehydrogenase (LDH), and elevated alkaline phosphatase (ALP) compared to those without DM. On multivariable analysis, younger age of CRPC diagnosis was found to be a predictor for DM.

Conclusion:

The presence of neurological symptoms in the context of younger age, anaemia, and elevated baseline LDH and ALP are associated with DM in CRPC.

Level of Evidence:

4

CRPC Membrane-Camouflaged, Biomimetic Nanosystem for Overcoming Castration-Resistant Prostate Cancer by Cellular Vehicle-Aided Tumor Targeting

Castration-resistant prostate cancer (CRPC) is the most common malignant tumor of the male urinary system. Nanodrug delivery systems (NDDS) have been widely applied in drug delivery for tumor therapy; however, nanotherapeutics encounter various biological barriers that prevent successful accumulation of drugs, specifically at diseased sites. Therefore, there is an urgent need to develop a CRPC-targeting nanocomposite with fine biocompatibility for penetrating various biological barriers, delivering sufficient drugs to the targeting site and improving therapeutic efficiency. In this work, CRPC cell membranes were firstly adapted as biomimetic vectors for the encapsulating PEG-PLGA polymer containing the chemotherapy drug docetaxel (DTX). The CRPC membrane-camouflaged nanoparticles can easily escape early recognition by the immune system, penetrate the extracellular barrier, and evade clearance by the circulatory system. In addition to the characteristics of traditional nanoparticles, the CRPC cell membrane contains an arsenal of highly specific homotypic moieties that can be used to recognize the same cancer cell types and increase the targeted drug delivery of DTX. In vivo fluorescence and radionuclide dual-model imaging were fulfilled by decorating the biomimetic nanosystem with near-infrared dye and isotope, which validated the homotypic targeting property offered by the CRPC cell membrane coating. Importantly, remarkably improved therapeutic efficacy was achieved in a mice model bearing CRPC tumors. This homologous cell membrane enabled an efficient drug delivery strategy and enlightened a new pathway for the clinical application of tumor chemotherapy drugs in the future.

Salvage lymph node dissection for prostate-specific membrane antigen (PSMA) positron emission tomography (PET)-identified oligometastatic disease

INTRODUCTION

The availability of prostate-specific membrane antigen (PSMA) positron emission tomography (PET)/computed tomography (CT) imaging, particularly in the setting of rising prostate-specific antigen (PSA) after definitive treatment, has led to oligometastatic prostate cancer being increasingly identified. Despite the enthusiasm surrounding treating oligometastatic disease, it has been relatively understudied. We sought to review our salvage lymphadenectomy experience in the PSMA PET/CT era.

METHODS

We retrospectively reviewed patients undergoing lymphadenectomy following curative-intent primary therapy with rising PSA who had undergone a PSMA PET/CT identifying oligometastatic disease (defined as ≤5 PSMA-avid lesions) between January 2016 and April 2020. The primary endpoint was complete response, defined as achieving a PSA <0.2 ng/ml without concomitant androgen deprivation therapy (ADT).

RESULTS

Twenty-two patients were included. Primary curative therapy included radical prostatectomy (86.4%) and brachytherapy (13.6%). Median PSA at salvage surgery was 1.72 ng/ml. Pelvic lymph node dissection was the most performed procedure (72.7%). Median node yield was 10.5, with a median of 1.5 positive nodes on pathology. Eight patients (36.4%) achieved PSA <0.2, with six (27.3%) remaining with PSA <0.2 after a median followup of 23.1 months. Nine (40.9%) had an initial PSA decline, but nadired ≥0.2, and in five (22.7%) the PSA rose immediately after surgery. Overall, ADT was started in seven patients (31.8%) at a median of 10.1 months post-salvage surgery.

CONCLUSIONS

In our series of salvage dissection for PSMA-PET-detected nodal oligometastases, approximately a third achieved PSA <0.2; yet, it was only durable in 27%. Prospective trials of salvage nodal radiation are ongoing, however, more prospective trials of salvage node dissection are needed.

Evaluation of the reporting quality of clinical practice guidelines on prostate cancer using the RIGHT checklist

Background

The International Reporting Items for Practice Guidelines in Healthcare (RIGHT) statement is a set of recommendations for reporting in clinical practice guidelines (CPGs). We aimed to use RIGHT to evaluate the reporting quality of CPGs on prostate cancer.

Methods

We systematically searched literature databases and websites from January 1, 2018 to December 1, 2020 to identify CPGs on prostate cancer. Two investigators reviewed the identified articles and assessed the reporting quality independently by using the RIGHT checklist. We reported the proportions of guidelines that complied with each of the 35 RIGHT checklist item and the mean reporting compliance percentages for each of the seven domains of RIGHT.

Results

A total of 38 CPGs were included. The mean overall reporting rate over the included CPGs was 51.6%. Eighteen items were reported by more than half of the guidelines four items (1a 3, 7a and 13a) were reported by all guidelines. Items 7b (10.5%), 13b (10.5%), 14c (13.2%), and 18b (7.9%) had the lowest reporting proportions. The mean reporting rates in each RIGHT domain were 74.6% for “Basic Information”, 26.3% for “Review and quality assurance”, 59.9% for “Background”, 43.7% for “Evidence”, 43.2% for “Recommendations”, 43.4% for “Funding and declaration and management of interests”, and 43.0% for “Other information”.

Conclusions

The overall adherence of CPGs on prostate cancer to RIGHT checklist is poor. Following the RIGHT checklist during the development of the guideline could improve the quality of reporting in the future.

Distinct DNA methylation patterns associated with treatment resistance in metastatic castration resistant prostate cancer

Androgens are a major driver of prostate cancer (PCa) and continue to be a critical treatment target for advanced disease, which includes castration therapy and antiandrogens. However, resistance to these therapies leading to metastatic castration-resistant prostate cancer (mCRPC), and the emergence of treatment-induced neuroendocrine disease (tNEPC) remains an ongoing challenge. Instability of the DNA methylome is well established as a major hallmark of PCa development and progression. Therefore, investigating the dynamics of the methylation changes going from the castration sensitive to the tNEPC state would provide insights into novel mechanisms of resistance. Using an established xenograft model of CRPC, genome-wide methylation analysis was performed on cell lines representing various stages of PCa progression. We confirmed extensive methylation changes with the development of CRPC and tNEPC using this model. This included key genes and pathways associated with cellular differentiation and neurodevelopment. Combined analysis of methylation and gene expression changes further highlighted genes that could potentially serve as therapeutic targets. Furthermore, tNEPC-related methylation signals from this model were detectable in circulating cell free DNA (cfDNA) from mCRPC patients undergoing androgen-targeting therapies and were associated with a faster time to clinical progression. These potential biomarkers could help with identifying patients with aggressive disease.

Treatment of nonmetastatic castration-resistant prostate cancer: focus on second-generation androgen receptor inhibitors

BACKGROUND

Nonmetastatic castration-resistant prostate cancer (nmCRPC) is defined as a rising prostate-specific antigen concentration, despite castrate levels of testosterone with ongoing androgen-deprivation therapy or orchiectomy, and no detectable metastases by conventional imaging. Patients with nmCRPC progress to metastatic disease and are at risk of developing cancer-related symptoms and morbidity, eventually dying of their disease. While patients with nmCRPC are generally asymptomatic from their disease, they are often older and have chronic comorbidities that require long-term concomitant medication. Therefore, careful consideration of the benefit-risk profile of potential treatments is required.

METHODS

In this review, we will discuss the rationale for early treatment of patients with nmCRPC to delay metastatic progression and prolong survival, as well as the factors influencing this treatment decision. We will focus on oral pharmacotherapy with the second-generation androgen receptor inhibitors, apalutamide, enzalutamide, and darolutamide, and the importance of balancing the clinical benefit they offer with potential adverse events and the consequential impact on quality of life, physical capacity, and cognitive function.

RESULTS AND CONCLUSIONS

While the definition of nmCRPC is well established, the advent of next-generation imaging techniques capable of detecting hitherto undetectable oligometastatic disease in patients with nmCRPC has fostered debate on the criteria that inform the management of these patients. However, despite these developments, published consensus statements have maintained that the absence of metastases on conventional imaging suffices to guide such therapeutic decisions. In addition, the prolonged metastasis-free survival and recently reported positive overall survival outcomes of the three second-generation androgen receptor inhibitors have provided further evidence for the early use of these agents in patients with nmCRPC in order to delay metastases and prolong survival. Here, we discuss the benefit-risk profiles of apalutamide, enzalutamide, and darolutamide based on the data available from their pivotal clinical trials in patients with nmCRPC.

Surgical Management of Genitourinary Cancer Liver Metastases

Genitourinary cancers are common. Liver metastases from genitourinary cancers are uncommon; isolated liver metastasis is rare. Liver resection in select patients with metastatic renal cell carcinoma can lead to prolonged survival. Patients with metachronous and low-burden disease are most likely to benefit. Chemotherapy is first-line treatment of metastatic germ cell tumors. Liver resection is dependent on germ cell lineage and initial response to chemotherapy. Prognosis with liver metastases from prostate cancer is poor; liver-only lesions are rare. Liver resection generally is not indicated. Cumulative experience with liver resection for metastatic bladder cancer is limited. Liver metastases are poor prognostic indicators for metastasectomy.

Bone scan use in the management of metastatic castration-resistant prostate cancer: Survey of practice patterns among Canadian radiation oncologists, medical oncologists, and urologists

The use of skeletal scintigraphy with technetium-99 methylene diphosphonate (hereafter referred to as a bone scan) for evaluating response to systemic treatment in men with metastatic castration-resistant prostate cancer (mCRPC) is an evolving paradigm in this era of advancing therapies and imaging techniques. Indeed, the interpretation of bone scans can be challenging, and there is a growing expectation that advanced imaging techniques such as prostate-specific membrane antigen positron emission tomography/computer tomography (PSMA PET/CT) may play a complementary role.1 The Prostate Cancer Working Group (PCWG) has outlined specific criteria to define disease progression with respect to bone scans performed as part of clinical trials.2 However, there is no high-level evidence for the scheduling and interpretation of bone scans during routine therapeutic interventions for mCRPC. Thus, patterns of bone scan use are variable and practice-dependent outside of clinical trials.