Real-World Use of Androgen-Deprivation Therapy: Intensification Among Older Canadian Men With de Novo Metastatic Prostate Cancer

Emerging racial disparities among Medicare beneficiaries and Veterans with metastatic castration-sensitive prostate cancer

BACKGROUND

Previous studies have shown that Black men receive worse prostate cancer care than White men. This has not been explored in metastatic castration-sensitive prostate cancer (mCSPC) in the current treatment era.

METHODS

We evaluated treatment intensification (TI) and overall survival (OS) in Medicare (2015-2018) and Veterans Health Administration (VHA; 2015-2019) patients with mCSPC, classifying first-line mCSPC treatment as androgen deprivation therapy (ADT) + novel hormonal therapy; ADT + docetaxel; ADT + first-generation nonsteroidal antiandrogen; or ADT alone.

RESULTS

We analyzed 2226 Black and 16,071 White Medicare, and 1020 Black and 2364 White VHA patients. TI was significantly lower for Black vs White Medicare patients overall (adjusted odds ratio [OR] 0.68; 95% confidence interval [CI] 0.58-0.81) and without Medicaid (adjusted OR 0.70; 95% CI 0.57-0.87). Medicaid patients had less TI irrespective of race. OS was worse for Black vs White Medicare patients overall (adjusted hazard ratio [HR] 1.20; 95% CI 1.09-1.31) and without Medicaid (adjusted HR 1.13; 95% CI 1.01-1.27). OS was worse in Medicaid vs without Medicaid, with no significant OS difference between races. TI was significantly lower for Black vs White VHA patients (adjusted OR 0.75; 95% CI 0.61-0.92), with no significant OS difference between races.

CONCLUSIONS

Guideline-recommended TI was low for all patients with mCSPC, with less TI in Black patients in both Medicare and the VHA. Black race was associated with worse OS in Medicare but not the VHA. Medicaid patients had less TI and worse OS than those without Medicaid, suggesting poverty and race are associated with care and outcomes.

Prostate Radiotherapy in Low-volume Metastatic Hormone-sensitive Prostate Cancer: A Network Meta-analysis

BACKGROUND AND OBJECTIVE

The utility of prostate radiotherapy (RT) is unclear in men with metastatic hormone-sensitive prostate cancer (mHSPC) receiving intensified systemic therapy with androgen deprivation therapy (ADT) and androgen receptor pathway inhibitors (ARPIs). We performed a network meta-analysis of randomized controlled trials (RCTs) to investigate the role of prostate RT in low-volume mHSPC.

METHODS

Bibliographic databases and conference proceedings were searched through July 2023 for RCTs evaluating the addition of ARPIs or prostate RT to standard of care (SOC) systemic therapy, defined as ADT or ADT plus docetaxel, for the initial treatment of mHSPC. We focused exclusively on aggregate data from the low-volume mHSPC subpopulation in these trials. We pooled the treatment arms into four groups: SOC, SOC plus ARPI, SOC plus RT, and SOC plus ARPI plus RT. The primary outcome was overall survival (OS). To compare treatment strategies, a fixed-effects Bayesian network meta-analysis was undertaken, while a Bayesian network meta-regression was performed to account for across-trial differences in docetaxel use as part of SOC and in proportions of patients with de novo presentation.

KEY FINDINGS AND LIMITATIONS

Ten RCTs comprising 4423 patients were eligible. The Surface Under the Cumulative Ranking Curve scores were 0.0006, 0.45, 0.62, and 0.94 for SOC, SOC plus RT, SOC plus ARPI, and SOC plus ARPI plus RT, respectively. On a meta-regression, in a population with de novo mHSPC and no docetaxel use, we did not find sufficient evidence of a difference in OS between SOC plus ARPI plus RT versus SOC plus ARPI (hazard ratio [HR]: 0.76; 95% credible interval: 0.51-1.16) and SOC plus RT versus SOC plus ARPI (HR: 1.10; 95% credible interval: 0.92-1.42).

CONCLUSIONS AND CLINICAL IMPLICATIONS

There was some evidence that SOC plus ARPI plus RT reduced mortality compared with the next best strategy of SOC plus ARPI in patients with low-volume de novo mHSPC. A meta-analysis with individual patient data or an RCT is needed to confirm these findings.

Costs to Medicare of Nonrecommended Bone-Modifying Agent Use for Castration-Sensitive Prostate Cancer

PURPOSE

Bone-modifying agents (BMAs) do not prevent skeletal-related events among patients with castration-sensitive prostate cancer (CSPC), but many patients receive BMAs unnecessarily. The costs to Medicare from overuse have not been assessed.

METHODS

We used linked SEER-Medicare data 2011-2015 to measure the frequency and number of doses of zoledronic acid (ZA) and denosumab received during CSPC (between diagnosis and initiation of metastatic, castration resistant prostate cancer therapy). We estimated excess BMA among patients who received BMA therapy for CSPC and did not have an indication for osteoporosis fracture prevention. We used the Medicare fee schedule for drug prices and peer-reviewed sources to estimate adverse event frequencies and costs.

RESULTS

Median CSPC duration was 387 days (IQR, 253-573), during which time 42% of patients received ≥one dose of denosumab (mean doses, 7) and 18% received ≥one dose of ZA (mean doses, 7). Thirty-eight percent of those receiving denosumab and 47% of those receiving ZA had a history of osteoporosis, osteopenia, spine or hip fracture, or hypercalcemia. The estimated, annual excess BMA cost to Medicare was $44,105,041 in US dollars (USD), composed of $43,303,078 USD and $45,512 USD in drug costs for denosumab and ZA, respectively, and $682,865 USD and $75,585 USD in adverse event costs, respectively. In one-way sensitivity analysis, the estimate was most sensitive to denosumab dosing frequency (estimate range, $28,469,237 USD-$98,830,351 USD) and duration of CSPC (estimate range, $36,823,311 USD-$99,015,908 USD).

CONCLUSION

BMA overuse in CSPC incurs substantial cost to Medicare, largely because of denosumab drug costs. Excess costs may be reduced by greater adherence to guideline-concordant BMA use.

Lower baseline testosterone level is related to earlier development of castration resistance in metastatic prostate cancer: a multi-center cohort study

Purpose

In the era of concurrent combination therapy in metastatic hormone sensitive prostate cancer, the impact of the testosterone level before initiating androgen deprivation therapy on treatment outcome is still uncertain. We aimed to investigate its effect on time-to-castration-resistance in a metastatic hormone sensitive prostate cancer cohort.

Methods

This is a multi-center retrospective study of 5 databases from China, Japan, Austria and Spain including 258 metastatic hormone sensitive prostate cancer patients with androgen deprivation therapy initiated between 2002 and 2021. Baseline testosterone was divided into high and low groups using 12 nmol/L as cutoff level. Primary outcome was time-to-castration-resistance. Secondary outcomes were survival functions. Kaplan-Meier method was employed to evaluate the correlation between baseline testosterone and time-to-castration-resistance. Subgroup analysis was performed to elucidate the effect of upfront combination-therapy and metastatic volume.

Results

Median age was 72 years. Median follow-up time was 31 months. Median pre-treatment prostate-specific-antigen level was 161 ng/mL. Majority of case were graded as International-Society-of-Urological-Pathology grade 5 (63.6%). 57.8% patients had high volume disease and 69.0% received upfront combination treatment. 44.6% of the cohort developed castration-resistance. The low testosterone group demonstrated shorter mean-time-to-castration-resistance (19.0 vs 22.4 months, p=0.031). The variance was more significant in patients without combination therapy (13.2 vs 26.3 months, p=0.015). Cancer-specific and overall survival were inferior in the low baseline testosterone level group without receiving combination therapy (p=0.001).

Conclusions

Lower pre-treatment testosterone level is correlated to shorter time-to-castration resistance and worse survival in metastatic prostate cancer patients without upfront combination therapy. Those with low baseline testosterone should be encouraged to adopt combination therapy to delay progression.

Does Research from Clinical Trials in Metastatic Hormone-sensitive Prostate Cancer Treatment Translate into Access to Treatments for Patients in the "Real World"? A Systematic Review

CONTEXT

Since 2015 there have been major advances in the management of primary metastatic hormone-sensitive prostate cancer (mHSPC) following the publication of key clinical trials that demonstrated significant clinical benefits with docetaxel chemotherapy or novel hormone therapy (NHT) in addition to androgen deprivation therapy (ADT). Despite these advances, there is evidence to show that these treatments are not being utilised for mHSPC in clinical practice.

OBJECTIVE

To determine the utilisation of docetaxel and NHT in mHSPC in routine practice and the determinants of variation in their use.

EVIDENCE ACQUISITION

MEDLINE and Embase were searched systematically for studies on utilisation of treatments for primary mHSPC that were based on regional or national data sets and published after January 2005. Study results were summarised using a narrative synthesis.

EVIDENCE SYNTHESIS

Thirteen papers were included in the analysis, six full-text articles and seven abstracts, on studies that included a total of 166 876 patients. The utilisation rate of treatment intensification with either docetaxel or NHT (enzalutamide, apalutamide, or abiraterone) in addition to ADT ranged from 9.3% to 38.1% across the studies. Younger, White patients with fewer comorbidities and living in more urban settings were more likely to be prescribed treatment intensification. Patients treated in private academic institutions by oncologists were more likely to receive docetaxel or NHT. Socioeconomic status did not impact receipt of systemic therapy. NHT utilisation rates appear to have increased over time.

CONCLUSIONS

These results highlight the need to change the approach to the treatment of primary mHSPC in the real world by harnessing the practice-changing results from recent trials in this setting to optimise upfront systemic therapy for this patient population.

PATIENT SUMMARY

We reviewed the use of treatments for primary metastatic hormone-sensitive prostate cancer that showed a benefit in key clinical trials. We found that these treatments are underused, particularly among certain patient groups.

Real-World Treatment Trends Among Patients with Metastatic Castration-Sensitive Prostate Cancer: Results from an International Study

BACKGROUND

Continuous androgen deprivation therapy ± first-generation non-steroidal antiandrogen was previously the standard-of-care for patients with metastatic castration-sensitive prostate cancer (mCSPC). Treatment intensification with novel hormonal therapy (NHT) or taxane chemotherapy is now approved and guideline-recommended for these patients.

METHODS

Physician-reported data on adult patients with mCSPC from the Adelphi Prostate Cancer Disease Specific Programme were analyzed descriptively. We evaluated real-world treatment trends for patients with mCSPC in 5 European countries (United Kingdom, France, Germany, Spain, and Italy) and the United States (US), looking at differences between patients initiating treatment in 2016-2018 and in 2019-2020. We also investigated treatment trends by ethnicity and insurance status in the US.

RESULTS

This study found that most patients with mCSPC do not receive treatment intensification. However, greater use of treatment intensification with NHT and taxane chemotherapy was observed in 2019-2020 than in 2016-2018 across 5 European countries. In the US, greater use of treatment intensification with NHT in 2019-2020 than in 2016-2018 was observed for all ethnicity groups and those with Medicare and commercial insurance status.

CONCLUSIONS

As the number of patients with mCSPC who receive treatment intensification increases, more patients who progress to metastatic castration-resistant prostate cancer (mCRPC) will have been exposed to intensified treatments. Treatment options for patients with mCSPC and mCRPC overlap, suggesting that an unmet need will emerge for new therapies. Further studies are needed to understand optimal treatment sequencing in mCSPC and mCRPC.

Real-World Treatment Patterns Among Patients With Metastatic Castration-Resistant Prostate Cancer: Results From an International Study

BACKGROUND

There is limited real-world evidence on how increasing use of treatment intensification in metastatic castration-sensitive prostate cancer (mCSPC) has influenced treatment decisions in metastatic castration-resistant prostate cancer (mCRPC). The study objective was to evaluate the impact of novel hormonal therapy (NHT) and docetaxel use in mCSPC on first-line treatment patterns among patients with mCRPC in 5 European countries and the United States (US).

METHODS

Physician-reported data on patients with mCRPC from the Adelphi Prostate Cancer Disease Specific Program were descriptively analyzed.

RESULTS

A total of 215 physicians provided data on 722 patients with mCRPC. Across 5 European countries and the US, 65% and 75% of patients, respectively, received NHT, and 28% and 9% of patients, respectively, received taxane chemotherapy as first-line mCRPC treatment. In Europe, patients who had received NHT in mCSPC (n = 76) mostly received taxane chemotherapy in mCRPC (55%). Patients who had received taxane chemotherapy, or who did not receive taxane chemotherapy or NHT in mCSPC (n = 98 and 434, respectively) mostly received NHT in mCRPC (62% and 73%, respectively). In the US, patients who had received NHT, taxane chemotherapy, or neither in mCSPC (n = 32, 12, and 72, respectively) mostly received NHT in mCRPC (53%, 83%, and 83%, respectively). Two patients in Europe were rechallenged with the same NHT.

CONCLUSIONS

These findings suggest that physicians consider mCSPC treatment history when making first-line treatment decisions in mCRPC. Further studies are needed to better understand optimal treatment sequencing, especially as new treatments emerge.

A Real-World Evidence Study Using Alberta-Population-Based Data to Describe Treatment Patterns for Metastatic Castration-Sensitive Prostate Cancer Patients (AWARENESS)

INTRODUCTION

Over the past decade, the treatment of metastatic castration-sensitive prostate cancer (mCSPC) has changed significantly. Current guidelines suggest the use of androgen deprivation therapy (ADT) plus an additional systemic therapy, regardless of disease burden and risk, based on phase 1 evidence showing improved overall survival. We sought to describe treatment patterns of patients with mCSPC in the province of Alberta.

METHODS

This was a retrospective, population-based, cohort study of male patients aged ≥18 with mCSPC at the time of diagnosis and who initiated ADT between 1 January 2016 and 31 December 2020. Data were obtained from the Alberta Cancer Registry. Patients were assigned to an ADT-alone cohort or a treatment intensification cohort (cohorts 2-5). The primary objectives of this study were to describe baseline characteristics and the treatment of mCSPC patients who initiated ADT with or without treatment intensification. Overall survival between cohorts was a secondary objective. Descriptive statistics were used to describe differences in baseline characteristics of each cohort. Overall survival was calculated using the Kaplan-Meier method. All statistical tests were two-sided and are used to call out likely cohort differences descriptively.

RESULTS

Between 1 January 2016 and 31 December 2020, we identified a total of 960 patients with mCSPC (median age 74 years, IQR 66-82). Most patients received ADT alone (67%), followed by ADT plus abiraterone (18%), ADT plus docetaxel (12%), and ADT plus enzalutamide or apalutamide (3%). Over the study period, we observed an increase in the utilization of treatment intensification over time, in particular, the increased use of androgen-receptor-axis-targeted (ARAT) therapies. Patients who received ADT alone were older, were more likely to have more than one comorbid condition, had fewer sites of metastatic disease, and were less likely to be on opioid medications.

CONCLUSIONS

In this study, we show that patients who received ADT alone as treatment for mCSPC are older, have more comorbidities, and have less extensive disease. While there has been a decline over time in the number of patients treated with ADT alone, over 50% of all patients with mCSPC continue to receive ADT alone. Further work is needed to understand barriers to treatment intensification and for knowledge translation initiatives to improve the treatment of patients with mCSPC.

Receptor for Hyaluronic Acid-mediated Motility (RHAMM) Is Associated With Prostate Cancer Migration and Poor Prognosis

BACKGROUND/AIM

Hyaluronic acid (HA) is a large glycosaminoglycan composed of an extracellular matrix. The HA-rich microenvironment and receptors of HA have been suggested to play roles in cancer progression. The biological and clinical significance of receptor for HA-mediated motility (RHAMM), known as CD168 in prostate cancer (PC) remains unknown. This study aimed to investigate the expression of RHAMM, as well as its functional and clinical relevance in PC.

MATERIALS AND METHODS

HA concentration and RHAMM mRNA expression were examined in 3 PC cell lines (LNCaP, PC3 and DU145). We investigated the effect of HA and RHAMM on the migratory ability of PC cells using a transwell migration assay. Immunohistochemistry was also used to evaluate the RHAMM expression pattern in pre-treatment tissue samples from 99 patients with metastatic hormone-sensitive PC (HSPC) who received androgen deprivation therapy (ADT).

RESULTS

HA was secreted in all cultured PC cell lines. Among the total HA, low-molecular-weight HA (LMW-HA) (<100 kDa) was detected all examined cell lines. The number of migration cells was significantly increased by adding LMW-HA. RHAMM mRNA expression was increased in DU145 cells. Knockdown of RHAMM using small-interfering RNA resulted in decreased cell migration. Immunohistochemical analysis revealed strong RHAMM expression in 31 (31.3%) patients with metastatic HSPC. A strong RHAMM expression was significantly associated with short ADT duration and poor survival in univariate and multivariate analyses.

CONCLUSION

The size of HA is important in terms of PC progression. LMW-HA and RHAMM enhanced PC cell migration. RHAMM could be used as a novel prognostic marker in patients with metastatic HSPC.

Real-world utilization and outcomes of docetaxel among older men with metastatic prostate cancer: a retrospective population-based cohort study in Canada

BACKGROUND

The adoption of docetaxel for systemic treatment of metastatic prostate cancer (PCa), in both castration-sensitive (mCSPC) and castration-resistant (mCRPC) settings, is poorly understood. This study examined the real-world utilization of docetaxel in these patients and their outcomes.

METHODS

A retrospective population-based study used administrative data from Ontario, Canada, to identify men aged ≥66 years who were diagnosed with de novo mCSPC or mCRPC between 2014 and 2019 and received docetaxel. The study assessed treatment tolerability and toxicity, and survival in both cohorts. Descriptive and comparative statistical analysis were conducted.

RESULTS

The study identified 11.2% (399/3556) and 13.2% (203/1534) patients diagnosed with de novo mCSPC and with mCRPC who received docetaxel respectively. The median age in both cohorts was 72 years (IQR: 68-76). Overall, 43.9% (n = 175) patients with de novo mCSPC and 52.1% (n = 85) with mCRPC completed ≥6 cycles of docetaxel. Over two-fifth also needed dose adjustments in both cohorts. Hospitalization or emergency department visit for febrile neutropenia were noted in 15.8% (n = 63) of de novo mCSPC patients and similarly in 19% (n = 31) of mCRPC cohort. The median survival of PCa patients who completed ≥6 cycles of docetaxel was significantly longer relative to those who completed <4 cycles: 32.7 vs. 23.5 months (p < 0.001) for mCSPC and 20.5 vs. 10.7 (p = 0.012) for mCRPC respectively.

CONCLUSIONS

In this population-based study of elderly patients with metastatic PCa, treatment with docetaxel was associated with poor tolerability and higher toxicity compared with clinical trials. Receipt of limited cycles and reduced overall dose of docetaxel were associated with inferior overall survival.

Combination treatment in metastatic prostate cancer: is the bar too high or have we fallen short?

Androgen deprivation therapy (ADT) alone has been the cornerstone of treatment for patients with newly diagnosed metastatic prostate cancer for the past century. Based on results from landmark trials in the past decade, combination approaches of ADT with chemotherapy or novel hormonal agents have established a new standard of care for these patients. This paradigm shift in treatment has been reflected in the updates to guideline recommendations of major professional associations. However, real-world data from around the world have highlighted the dismal adoption of combination therapy, despite evidence-based recommendations. The disparity between evidence and practice is concerning, especially with emerging evidence of survival benefit with further treatment intensification using triplet combinations (ADT, docetaxel and novel hormonal agents). Thus, a pressing need to raise awareness and call the uro-oncology community to action exists to deliver evidence-based care for these patients.

2022 UPDATE: Canadian Urological Association-Canadian Urologic Oncology Group guideline: Metastatic castration-naive and castration-sensitive prostate cancer Summary of changes

The most recent Canadian Urological Association-Canadian Urologic Oncology Group guideline on metastatic castration- naive and castration-sensitive prostate cancer (mCNPC/ mCSPC) was published in 2020.1 New data in this patient population have prompted an update to the guideline in order to add treatment options that have proven to improve disease progression and overall survival (OS). This brief review summarizes the changes in the guideline, as well as the importance of ensuring proper treatment intensification in addition to androgen deprivation therapy (ADT) in patients with metastatic hormone-naive or castration-sensitive prostate cancer.

Systemic therapy in metastatic hormone-sensitive prostate cancer

PURPOSE OF REVIEW

The landscape of metastatic hormone sensitive prostate cancer (mHSPC) has evolved rapidly in recent years with new data from landmark trials supporting upfront treatment intensification. The developments come not only on the fronts of systemic agents but also in area of therapy to primary tumour and metastases.

RECENT FINDINGS

More recently, the ARASENS and PEACE trials have taken the concept of treatment intensification further by demonstrating survival benefit from combination of chemotherapy (docetaxel) and androgen receptor pathway inhibitors (abiraterone and darolutamide) in addition to backbone therapy of androgen deprivation therapy (ADT). Intensification of treatment has also seen evidence supporting local therapy to the primary tumour with overall survival and biochemical recurrence-free survival although only evident in low volume synchronous metastases. There is emerging evidence for metastases-directed therapy as well with pooled data suggesting improved biochemical-free and ADT-free survival.

SUMMARY

Robust clinical data has demonstrated survival benefits with treatment intensification and this should be the new standard of care. Subgroup analysis has highlighted the importance of tailoring mHSPC treatment for patients with high- and low-volume metastatic disease. However, defining the volume of disease is becoming increasingly controversial due to heterogeneity of trial patient populations and next generation molecular imaging.

Combination therapy in metastatic hormone-sensitive prostate cancer: is three a crowd?

The mainstay of treatment for metastatic prostate cancer is androgen deprivation therapy (ADT). Outcomes with ADT are variable but control of hormone-sensitive prostate cancer (HSPC) can often be achieved for many years. Death from prostate cancer is usually due to the development of escape variants able to survive and proliferate in the setting of castrate levels of serum androgens (metastatic castration-resistant prostate cancer, mCRPC). Several agents can improve survival for patients with mCRPC, including chemotherapy, agents to reduce androgen receptor signalling, the radioisotope radium-223 dichloride, and cellular immunotherapy with sipuleucel-T. Some of these agents have been moved earlier in the disease course and have shown to improve survival in metastatic HSPC also, often to a much greater degree than when the same agents are used in mCRPC. Specifically, survival of metastatic HSPC can be improved with the addition to ADT of any one of docetaxel, abiraterone acetate/prednisone combination, apalutamide, enzalutamide, or darolutamide in combination with docetaxel. Factors affecting outcomes include the volume or burden of disease, timing of metastases relative to the original diagnosis, and patient factors determining the appropriateness of therapy. Unfortunately, uptake of this information by the clinical community remains suboptimal, with many men potentially suitable for combination therapy still receiving only ADT. Some trials have examined the effects of ‘triplet’ therapies although few were designed specifically to address this question. The best evidence to date suggests that triplet therapy with ADT + abiraterone + docetaxel or ADT + darolutamide + docetaxel, can improve overall survival in metastatic HSPC. Clear opportunities exist to improve survival outcomes for men with metastatic HSPC but need to be balanced against cost, accessibility, toxicity, and patient-specific factors.