Redefining clinically significant castration levels in patients with prostate cancer receiving continuous androgen deprivation therapy

Effect of deep testosterone reduction on the prognosis of metastatic prostate cancer with high-volume disease

OBJECTIVE

This study aims to investigate the correlation between serum testosterone levels after one month of treatment and prognosis in patients with high-volume disease metastatic prostate cancer (mPCa) who are undergoing combined androgen blockade therapy (CAB).

METHODS

The clinical data of 199 patients with high-volume disease mPCa, diagnosed through biopsy pathology and imaging, were retrospectively analyzed from January 2010 to October 2022 in the Department of Urology at the First Affiliated Hospital of Xinjiang Medical University. Among these patients, 111 cases had a deep reduction in serum testosterone (< 0.7 nmol/l) after one month of treatment, while 88 cases did not achieve a deep reduction (≥ 0.7 nmol/l). The study utilized the Kaplan-Meier method to plot survival curves and employed the multifactor COX regression model to analyze independent risk factors. The risk factors with a significance level of P < 0.05 in the multivariate analysis were included in the nomogram prediction model. The accuracy of the model was assessed using the ROC curve and the calibration curve, while the net benefit for patients was evaluated through the decision curve analysis (DCA).

RESULTS

The group that achieved deep testosterone reduction(DTR) had a higher proportion of PSA < 0.2 ng/ml and a greater PSA decline rate after six months of treatment (P < 0.05). The group that achieved DTR and the group that did not achieve DTR had a progression to castration resistant prostate cancer(CRPC) time of 17.93 ± 6.68 months and 13.43 ± 6.12 months, respectively (P < 0.001). The median progression-free survival time for the 2 groups were 18 months and 12 months, respectively (P < 0.001). The median overall survival times were 57 months and 32 months, respectively (P < 0.001). The median progression-free survival times were 18, 15, and 10 months for the group that achieved DTR within 1 month, the group that achieved DTR beyond 1 month but within 1 year, and the group that did not achieve DTR within 1 year, respectively (P < 0.001), and the median survival times were 57, 45, and 26 months, respectively (P < 0.001). COX multivariate analysis revealed that a testosterone level of ≥ 0.7 nmol/l at 1 month of treatment is an independent risk factor for the progression to CRPC and prognosis in patients with high-volume disease mPCa (P < 0.05). The risk of death in patients with a testosterone level of ≥ 0.7 nmol/l at 1 month of treatment was 2.087 times higher than that of patients with a level of < 0.7 nmol/l (P < 0.05). A nomogram prediction model was developed using independent risk factors, with the area under the ROC curve (AUC) for progression-free survival (PFS) at 12, 15, 18, and 21 months being 0.788, 0.772, 0.760, and 0.739, respectively. For 3 and 5 years, the AUCs for overall survival (OS) were 0.691 and 0.624. The calibration curve demonstrated good consistency between the model's predicted values and the actual outcomes.

CONCLUSION

Patients with high-volume disease mPCa who receive CAB treatment may experience extended progression-free survival and overall survival if their serum testosterone levels are below 0.7 nmol/l after one month of treatment. The longer it takes to achieve DTR, the worse the patient's prognosis may be. The nomogram prediction model developed in this study demonstrates good predictive ability in assessing the progression and prognosis of high-volume disease mPCa.

Methods for Evaluating the Efficacy of Medical Castration: A Systematic Review

Measuring serum testosterone determination during medical castration is recommended by prostate cancer (PCa) guidelines to assess its efficacy and define castration resistance. It has been suggested that other biochemical compounds, such as free testosterone or luteinising hormone (LH), could also assess castration efficacy. We aimed to analyse the current evidence for serum biochemical compounds that could be appropriate candidates for evaluating medical castration efficacy. A systematic review was conducted after two investigators independently searched the literature in the PubMed, Cochrane Library, and EMBASE databases published between January 1980 and February 2023. Their searches used the medical subject headings 'prostatic neoplasms', 'testosterone and androgen antagonists', 'gonadotropin-releasing hormone/analogues and derivatives', 'free testosterone', and 'luteinising hormone'. Studies were selected according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria, and their eligibility was based on the Participants, Intervention, Comparator, and Outcome strategy. The search was limited to original articles published in English. Among the 6599 initially identified titles, 15 original studies analysing the clinical impact of serum testosterone levels in PCa patients undergoing androgen deprivation therapy (ADT) were selected for evidence acquisition. The risk of bias in individual studies was assessed using the Quality Assessment of Diagnostic Accuracy Studies 2 tool. All selected studies used immunoassays to measure serum testosterone, although only methods based on liquid or gas chromatography and mass spectrometry are recommended to measure low testosterone concentrations. The reported series were not uniform in clinical stage, ADT types, and the time or number of serum testosterone measurements. Only some studies found low serum testosterone levels (<20 or <32 ng/dL) associated with greater survival free of biochemical progression and castration resistance. We conclude that little current evidence justifies the measurement of serum testosterone during ADT using no appropriate methods. No reported longitudinal studies have examined the clinical impact of serum testosterone measured using liquid chromatography with tandem mass spectrometry (LC-MSMS), free testosterone, or LH in PCa patients undergoing medical castration. We conclude that well-designed longitudinal studies examining the clinical impact of serum testosterone measured with LC-MSMS, serum-free testosterone, and LH on biochemical progression and castration resistance in PCa patients undergoing neo-adjuvant castration in radiation therapy or continuous castration are needed.

Adherence to oral hormonal therapy in advanced prostate cancer: a scoping review

Background

Orally administrated agents play a key role in the management of prostate cancer, providing a convenient and cost-effective treatment option for patients. However, they are also associated with adherence issues which can compromise therapeutic outcomes. This scoping review identifies and summarizes data on adherence to oral hormonal therapy in advanced prostate cancer and discusses associated factors and strategies for improving adherence.

Methods

PubMed (inception to 27 January 2022) and conference databases (2020-2021) were searched to identify English language reports of real-world and clinical trial data on adherence to oral hormonal therapy in prostate cancer using the key search terms 'prostate cancer' AND 'adherence' AND 'oral therapy' OR respective aliases.

Results

Most adherence outcome data were based on the use of androgen receptor pathway inhibitors in metastatic castration-resistant prostate cancer (mCRPC). Self-reported and observer-reported adherence data were used. The most common observer-reported measure, medication possession ratio, showed that the vast majority of patients were in possession of their medication, although proportion of days covered and persistence rates were considerably lower, raising the question whether patients were consistently receiving their treatment. Study follow-up for adherence was generally around 6 months up to 1 year. Studies also indicate that persistence may drop further with longer follow-up, especially in the non-mCRPC setting, which may be a concern when years of therapy are required.

Conclusions

Oral hormonal therapy plays an important role in the treatment of advanced prostate cancer. Data on adherence to oral hormonal therapies in prostate cancer were generally of low quality, with high heterogeneity and inconsistent reporting across studies. Short study follow-up for adherence and focus on medication possession rates may further limit relevance of available data, especially in settings that require long-term treatment. Additional research is required to comprehensively assess adherence.

Mass spectrometry redefines optimal testosterone thresholds in prostate cancer patients undergoing androgen deprivation therapy

BACKGROUND

Androgen deprivation therapy (ADT) is the standard of care for prostate cancer treatment. Studies suggest that patients with testosterone levels below 0.7 nM have a longer time to castration resistance. Using the most accurate testosterone measurement method, namely mass spectrometry (MS), we sought to determine if a lower testosterone level under ADT could be associated with longer time to castration resistance.

METHODS

This retrospective study included 138 prostate cancer patients undergoing noncurative continuous ADT for which we had access to testosterone measurements assessed by MS. For 108 samples, paired immunoassays (IA) testosterone measurement was available. Primary outcome was time to castration-resistant prostate cancer (CRPC). The Contal and O'Quigley method was used to determine the optimal testosterone castration cut-off point considering the outcome and time-to-event variables. Relationship between testosterone levels assessed either by IA or MS and time to CRPC was evaluated using Cox regression.

RESULTS

Mean testosterone level was 0.370 nM by IA and 0.275 nM as assessed by MS. The optimal testosterone cut-off point identified to predict time to CRPC was of 0.705 nM for IA and of 0.270 nM for MS. While no significant difference for time to CRPC was found between patients showing IA testosterone level ≥0.705 nM versus <0.705 nM (hazard ratio [HR]: 1.579; 95% confidence interval [CI]: 0.908-2.745), patients with MS testosterone ≥0.270 nM had an increased risk of progression to CRPC compared to MS testosterone <0.270 nM in univariate (HR: 1.717; 95% CI: 1.160-2.541) and multivariate analysis (HR: 1.662; 95% CI: 1.043-2.648).

CONCLUSIONS

The higher sensitivity of MS testosterone measurement methods allows the identification of a lower castration threshold and leads to early identification of patients more likely to progress to CRPC. These patients would likely benefit from treatment intensification by androgen receptor axis-targeted therapies to delay disease progression.

Serum testosterone measured by liquid chromatography-tandem mass spectrometry is an independent predictor of response to castration in metastatic hormone-sensitive prostate cancer

BACKGROUND

Although testosterone levels have been associated with progression-free survival (PFS) in metastatic hormone-sensitive prostate cancer (mHSPC) patients, this has primarily been investigated using inaccurate immunoassays (IA). Here, we investigated whether castrate testosterone levels determined by a liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay is an independent risk factor for treatment response in mHSPC.

METHODS

In total, 106 mHSPC patients treated with luteinizing-hormone releasing-hormone (LHRH) agonists were retrospectively analyzed between March 2018 and August 2021. Testosterone levels in serum samples were quantitated using an LC-MS/MS assay. In a subset of patients, IA (Roche Cobas Pro) values were compared with LC-MS/MS results. Survival analysis was performed using Kaplan-Meier curves and Cox proportional hazard models.

RESULTS

Median PFS was shorter for high testosterone levels (>0.231 nmol/L, 18.4 v. 42.6 months, HR 1.7, p = 0.018). Low testosterone levels and a PSA response below 4 ng/mL was associated with longer median PFS (46.2 months) than the remaining combinations (13.8-19.3 months, 3.4-5.8, overall p < 0.01). In 67 patients, testosterone levels below the median remained associated with longer PFS, whereas IA measurements did not show a similar difference.

CONCLUSION

Our results suggest that high castration testosterone levels measured by LC-MS/MS is an independent response predictor for mHSPC patients.

Testosterone analysis in prostate cancer patients

Testosterone is an essential steroid hormone associated with a wide variety of biological processes in humans. In prostate cancer, androgen signaling is an important driver of tumor cell growth. Depletion of gonadal testosterone, achieved by surgical or chemical castration, prevents androgenic signaling and temporally reduces, stops or reverses tumor growth before inevitable progression to castration-resistant prostate cancer occurs. Additional treatment strategies targeting androgenic signaling have become available, although these are without curative intent. While circulating testosterone is also associated with disease risk and potential clinical utility, the main use in the clinical lab is monitoring adequate castration and subsequent resistance to therapy. Adequate castrate testosterone concentrations are currently based on over 50 year-old double-isotope derivative assays that are disputed in automated immunoassay (IA) analysis. The debate has been further fueled with the introduction of mass spectrometry-based assays for testosterone, offering a substantial increase in sensitivity and specificity. In this review, we discuss testosterone regulation and androgen deprivation therapy in prostate cancer. We provide an overview of the developments in testosterone analysis for monitoring adequate castration and resistance to therapy. Current clinical practice and future clinical utility will be discussed. Finally, clinical and research recommendations will be presented.

Comparison of Testosterone and Prostate-Specific Antigen Nadir Value between Castration Resistant Prostate Cancer and Non-Castration Resistant Prostate Cancer Patients after Androgen Deprivation Therapy - A Single Center Study in Indonesia

BACKGROUND: Prostate cancer is the second most commonly occurring cancer in adult males worldwide. Androgen deprivation therapy (ADT) is the mainstay treatment for patients with advanced prostate cancer. However, despite the low testosterone level (indicative of ADT success), most advanced prostate cancers progress into an androgen unresponsive or castrate resistant state; such cases are defined as castrate-resistant prostate cancer (CRPC) and were associated with worse outcomes and more rapid prostate cancer progression. This study aimed to compare the value of nadir testosterone level and nadir PSA in CRPC and non-CRPC patients who received ADT. AIM: This study was aimed to compare value of nadir testosterone level and nadir PSA in CRPC and non-CRPC patients who received ADT. METHODS: Prostate cancer patients receiving ADT in dr. Hasan Sadikin Bandung General Hospital in September 2018–September 2020 without previous history of CRPC and surgical castration, and prostate cancer with histopathological confirmation were included to the study. The patients prior had received complete blockade ADT with luteinizing hormone agonist (LHRH) goserelin acetate 10.8 mg injected subcutaneously per 3 months and oral anti-androgen bicalutamide 50 mg orally daily. Testosterone and PSA levels were assessed on 1st, 3rd, 6th, and 12th month. Patients then were grouped into CRPC group and non-CRPC group and further subdivided according testosterone levels (<20 and 20–500 ng/dL). Paired t-test and Chi-square test were used to analyze statistical difference (p < 0.05 deemed significant). RESULTS: Significantly higher baseline PSA (p = 0.002) and nadir PSA (p = 0.013) were found on the CRPC group. Nadir testosterone in CRPC group was higher than non-CRPC group but statistically insignificant (p = 0.849). Time to CRPC is faster in nadir testosterone 20–50 ng/dl group than in <20 ng/dl group but statistically insignificant (p = 0.837). CONCLUSION: Prostate cancer patients who had high baseline PSA and nadir PSA after ADT need a longer follow-up time and more frequent testing of the testosterone and PSA values. It can predict the incidence of CRPC and to ensure that prostate cancer patients receive adequate therapy.

Definition of Castrate Resistant Prostate Cancer: New Insights

The term castrate resistant prostate cancer (CRPC) was initially proposed by the Prostate Cancer Working Group 2 in 2008 to define the state of clinical and/or biochemical progression of prostate cancer (PCa) in an environment with very low serum testosterone concentration. Clinical progression is based on the radiological imaging proposed by the Response Evaluation Criteria in Solid Tumors (RECIST) adapted to PCa. Biochemical progression is defined as an over 25% increase in serum prostate-specific antigen within two consecutive measurements separated by at least one week, and an absolute value above 2.0 ng/mL. Finally, the castrate environment is usually defined as a serum testosterone concentration maintained below 50 ng/dL or 1.7 nmol/dL. This definition does not incorporate the new and more accurate imaging modalities to assess clinical progression and the capability of the new biochemical measurements to assess the true castration environment. Ga-68-PSMA-11 PET CT/MRI and whole-body MRI are the new imaging modalities that should replace the classic thoracic CT scan, abdomino-pelvic CT scan, and technetium 99-m bone scintigraphy. In addition, Ga-68-PSMA-11 PET is the current basis for the new therapies targeting metastatic sites. Moreover, the current methods for measuring the very low serum testosterone concentrations in clinical laboratories are the widespread chemiluminescent assays, which are inappropriate, while LC-MSMS is the only method recommended to assess the castrate environment. In addition, recent research shows that serum luteinising hormone concentration associates better than serum testosterone with the castration environment, even when it is measured with LC-MSMS. In summary, the current definition of CRPC seems outdated. An extensive update to diagnose true CRPC is also needed to differentiate CRPC men with M0 (non-metastatic) from those with M1 (metastatic) CRPC. WC: 277.

Evolution of Androgen Deprivation Therapy (ADT) and Its New Emerging Modalities in Prostate Cancer: An Update for Practicing Urologists, Clinicians and Medical Providers

Androgen deprivation therapy (ADT) has been the main management strategy for prostate cancer for more than eight decades, nowadays achieved commonly by administration of luteinizing hormone-releasing hormone agonists. ADT markedly suppresses androgen hormones with the long-term risks of adverse events such as muscle weakness, impairment of glucose and lipid metabolism, impotence, osteoporosis, and secondary fractures. Extensive research has provided significantly better insight into the dynamics of ADT including identification of the benefits of sequential and combination therapies. This has led to the development of new pharmaceutical ADT modalities. This review provides a general overview of the evolution of ADT in the context of the new emerging pharmaceutical ADT modalities so that clinicians and medical providers have a better understanding of personalizing the available ADT options with their different risk-benefit profiles.

[Management of testosterone in advanced hormone-sensitive prostate cancer: still up to date?]

Androgen-deprivation therapy (ADT) is the standard therapy used for advanced or metastatic prostate cancer, either alone or in association with additional procedures and substances. The optimum value of testosterone postulated more than 40 years ago was arbitrarily set to be < 50 ng/dL or < 1.7 nmol/L and, from today's perspective, was defined by more insensitive measurement methods. Since then, more and more data has been generated, suggesting that a value of < 20 ng/dL would be prognostically relevant. Yet no guideline has been changed so far despite the call for lowering the target value. Measuring testosterone to evaluate the response to androgen suppression is not yet established in clinical routine. There are no specific recommendations in national and international guidelines. Based on the evolving evidence, the question about testosterone management during ADT is gaining importance. The current data is summarised in this paper.

Relugolix, an oral gonadotropin-releasing hormone antagonist for the treatment of prostate cancer

Androgen deprivation therapy using gonadotropin-releasing hormone (GnRH) analogues is standard treatment for intermediate and advanced prostate cancer. GnRH agonist therapy results in an initial testosterone flare, and increased metabolic and cardiovascular risks. The GnRH antagonist relugolix is able to reduce serum testosterone levels in men with prostate cancer without inducing testosterone flare. In the HERO Phase III trial, relugolix was superior to leuprolide acetate at rapidly reducing testosterone and continuously suppressing testosterone, with faster post-treatment recovery of testosterone levels. Relugolix was associated with a 54% lower incidence of major adverse cardiovascular events than leuprolide acetate. As the first oral GnRH antagonist approved for the treatment of advanced prostate cancer, relugolix offers a new treatment option.

Retrospective analysis of serum testosterone levels by LC-MS/MS in chemically castrated prostate cancer patients: Biological variation and analytical performance specifications

BACKGROUND

A sensitive liquid chromatography tandem-mass spectrometry (LC-MS/MS) method was used to monitor serum testosterone levels in castrated prostate cancer patients. We subsequently performed an observational and retrospective study to estimate the within- and between-subject biological variation of these patients.

METHODS

In total, 474 samples from 72 prostate cancer patients in the Netherlands receiving either chemical castration (CAS) or castration plus enzalutamide (ENZA) treatment were selected for data analysis. ANOVA was performed to estimate analytical variation (CV_A) and within-patient variation (CV_I). A nested ANOVA was applied to estimate between-patient variation (CV_G). From these data, the reference change value (RCV) and analytical performance specifications (APS) were calculated.

RESULTS

Testosterone levels were significantly higher in the ENZA group (0.318 vs. 0.191 nmol/L, p < 0.005) than the CAS group. Overall, variation components were estimated at 6.1%, 24.6% and 60.3% for CV_A, CV_I and CV_G, respectively. Both groups showed high individuality (<0.6). The RCV was 70.3% for all patients. Desirable APS were 12.3% for imprecision, 16.3% for bias and 26.4% for total error.

CONCLUSION

The generated APS are valuable for sensitive testosterone assays and the high individuality indicates that castrated testosterone levels can be studied as a predictive or prognostic biomarker in prostate cancer patients.

Bilateral Orchidectomy Revisited in Management of Metastatic Hormone-Sensitive Prostate Cancer

INTRODUCTION

Androgen deprivation therapy (ADT) is a well-established treatment for metastatic hormone-sensitive prostate cancer (mHSPC). It includes either bilateral orchiectomy or medical castration in form of luteinizing hormone-releasing hormone (LHRH) agonist or antagonist. We conducted this study to compare surgical and medical castration in terms of time to progression (TTP) to castration resistant prostate cancer.

METHODS

Patients with mHSPC underwent either bilateral orchidectomy or medical castration by either LHRH agonist or by antagonist from November 2016 to May 2018 in our institution. Initial PSA and baseline imaging either magnetic resonance imaging (MRI) or positron emission tomography-computed tomography (PET CT) finding were recorded. Serum PSA, testosterone, and FSH were repeated every 3 months till 1 year. All enrolled patients were followed up with a bone scan/MRI/ PET CT at 6 months and 12 months. End point of study was progression of disease and death of patient.

RESULTS

Mean nadir PSA (ng/ml) after treatment was 4.7 and 9.8 in surgical and medical group respectively, whereas mean time to the nadir PSA was 8.7 and 8.8 respectively with no statistically significant difference. Mean TTP was 13.9 months in bilateral orchidectomy group and 13.8 months in medical castration group (chi-square 0.003, p value 0.958).

CONCLUSION

There was no significant difference in time to progression between bilateral orchidectomy and medical castration. Considering nadir PSA level, better quality of life, patient compliance, reduced hospital visit, and decrease in cost of treatment, bilateral orchidectomy may be a better treatment option especially in developing countries.

Hormonal manipulation in androgen signaling: a narrative review on using novel androgen therapy agents to optimize clinical outcomes and minimize side effects for prostate cancer patients

Prostate cancer is a significant public health burden and one of the most common cancers globally and in the United States. The current cornerstone of prostate cancer systemic treatment involves the suppression of androgen receptor (AR) signaling, either by reducing the body's testosterone production or inhibiting its binding to AR and its subsequent gene regulatory network driving carcinogenesis. This signaling pathway plays a central role in both hormone sensitive and castration resistant prostate cancer (CRPC), as evidenced by survival benefit when AR-targeted therapies are applied in the setting of CRPC. With the development of increasingly potent central and peripherally acting androgen targeting agents physicians treating prostate cancer can expect to treat their patients for a longer duration with a larger selection of effective agents. In this setting clinicians are now faced with questions of how to best tailor treatments for the prostate cancer patient to not only maximize overall survival but also optimize the quality of life and mitigate toxicity. In this manuscript we discuss the newer hormone therapy agents for prostate cancer and highlight what they indicate about optimizing medical castration, and the potential value of peripheral blockade.

Gonadorelins adherence in prostate cancer: A time-series analysis of England's national prescriptions during the COVID-19 pandemic (from Jan 2019 to Oct 2020)

Objective

To examine the effect of the COVID‐19 pandemic on gonadorelin analogue prescription for community patients in England.

Materials and methods

We included data from all primary‐care patients who had relevant prescriptions dispensed in the community in England. Descriptive statistics and interrupted time series analysis over 22 months (15 months before and 7 months after lockdown) was evaluated.

Results

A total of 22 months’ worth of data were analyzed (or 1 041 638 total items, monthly average 47 347 items). Goserelin; leuprorelin, and triptorelin are the medicines most used by total quantity in the study period. Simple descriptive statistics show that mean values have declined during the pandemic. The Interrupted Time Series (ARIMA Modeling) shows declining trends.

After the pandemic's onset, we observe a statistically significant downward trend for goserelin (P = .017) and leuprorelin (P = .014). As these are the major constituents of the model, we interpret this overall data as showing a significant downward category trend. Aside from linearity, a significant step change was noted for leuprorelin (P = .029) showing an increase in prescription items with a similar effect that is close to being statistically significant for goserelin (P = .051).

The actual cost of medicines shows minimal variation suggesting that prices of individual medicines have remained stable. The regional data showed variation but this was not statistically significant. In all cases, the Oct‐20 figures are lower “year on year.” This novel work reports the impact of a global pandemic on prescription volumes of prostate cancer (PCa) medicines.

Conclusions

A worrying decrease in prescription medicines raises concerns for the care of PCa patients. We encourage diagnosed patients to discuss their planned care with their doctor.

Characterization of Novel Progression Factors in Castration-Resistant Prostate Cancer Based on Global Comparative Proteome Analysis

Simple Summary

Here, we investigated prostate cancer (PCa) tissues at each stage of progression, from benign prostatic hyperplasia to castration-resistant prostate cancer (CRPC), based on quantitative proteomic technology, including tissues after androgen deprivation therapy (ADT). In total, we identified 4768 proteins, and 4069 of them were quantified. We performed a systematic bioinformatics analysis of 865 differentially expressed proteins (DEPs) in the combined PCa tissues. We found 15 DEPs, including FOXA1 and HMGN1–3, as novel factors were significantly involved in the progression to CRPC after ADT in T3G3. All targets were verified to have increased levels of FOXA1 and HMGN1–3 in CRPC by immunoblotting and indirect enzyme-linked immunosorbent assay. The FOXA1 and HMGN1–3 proteins could be used as CRPC-related factors in clinical therapeutic agents.

Abstract

Identifying the biological change from hormone-naïve prostate cancer to castration-resistant prostate cancer (CRPC) is a major clinical challenge for developing therapeutic agents. Although the pathways that lead to CRPC are not fully completely understood, recent evidence demonstrates that androgen signaling is often maintained through varied mechanisms. Androgen deprivation therapy (ADT) is used as a primary treatment for preventing the progression of prostate cancer (PCa). Here we investigated PCa tissues at each stage of progression, from benign prostatic hyperplasia (BPH) to CRPC, based on quantitative proteomic technology, including tissues after ADT. In total, 4768 proteins were identified in this study, of which 4069 were quantified in the combined PCa tissues. Among the quantified proteins, 865 were differentially expressed proteins (21.2%). Based on the quantitative protein results, we performed systematic bioinformatics analysis and found that the levels of 15 proteins, including FOXA1 and HMGN1–3, increased among T3G3, T3GX, and CRPC, despite the ADT. Among all targets, we verified the increased levels of FOXA1 and HMGN1–3 in CRPC by immunoblotting and indirect enzyme-linked immunosorbent assay. In summary, we discuss the changes in intracellular factors involved in the progression of CRPC PCa despite ADT. Moreover, we suggest that FOXA1 and HMGN1–3 proteins could be used as potential CRPC-related factors in clinical therapeutic agents.

Beetroot and leaf extracts present protective effects against prostate cancer cells, inhibiting cell proliferation, migration, and growth signaling pathways

Beet (Beta vulgaris L.) has high nutritional value, containing bioactive compounds such as betalains and flavonoids. Scientific evidence points to the use of these natural compounds in the treatment of several types of cancer, such as prostate cancer, one of the main causes of morbidity and mortality in men. Here, we compared beet roots and leaves extracts, and their main compounds, apigenin, and betanin, respectively, in DU-145 and PC-3 prostate cancer cell lines. Both cells presented the proliferation decreased for beetroot and beet leaves extracts. The apigenin treatment also reduced the proliferation of both cell lines. Regarding cell migration, beet leaves extract was able to decrease the scratch area in both cell lines, whereas apigenin affected only PC-3 cells' migration. In colony formation assay, both extracts were effective in reducing the number of colonies formed. Besides, the beet leaves extracts and apigenin presented strong inhibition of growth-related signaling pathways in both cell lines, and the beetroot extract and betanin presented effects only in DU-145 cells. Furthermore, the extracts and isolated compounds were able to reduce the levels of apoptotic and cell cycle proteins. This study reveals that beet extracts have important anti-cancer effects against prostate cancer cells.

Serum testosterone levels and testosterone 'bounce' phenomenon predict response to novel anti-androgen therapies in castration-resistant prostate cancer

BACKGROUND

The relevance of continuous testosterone (TT) monitoring in castration-resistant prostate cancer (CRPC) remains in question.

OBJECTIVE

To determine if TT levels before and during novel anti-androgen therapies (NAAT), and the TT 'bounce' phenomenon may predict treatment response in CRPC.

MATERIALS AND METHODS

From 2014 through 2018, we identified 92 CRPC patients treated with either Abiraterone or Enzalutamide from a prospectively maintained cancer registry. The TT levels measured before and during NAAT were correlated with the oncological outcomes, determined by PSA response (% change), PSA progression-free survival (PFS) and overall survival (OS).

RESULTS AND LIMITATIONS

At CRPC, 58 (63.0%) and 34 (37.0%) patients opted for Abiraterone and Enzalutamide respectively. Median TT levels at CRPC status before and during NAAT were 10.37 ng/dl and 20.46 ng/dl respectively. PSA response was superior in patients with a higher TT before NAAT (P:0.048, median difference: 18.22%, 95% CI 0.70 - 40.37) and longer time to CRPC (P: 0.041, median difference: 15.31%, 95% CI 1.84 -34.84), with a trend towards lower TT during NAAT (P: 0.062). Over a follow up of 33.0 months, 65 patients (70.7%) developed PSA progression. PSA PFS was longer in patients with higher TT before NAAT (16.3 vs. 10.8 months; P: 0.023), lower TT during NAAT (17.0 vs. 9.1 months; P: 0.001), and longer time to CRPC (13.4 vs. 8.0 months; P: 0.032). Importantly, better OS was observed in lower TT during NAAT (45.0 vs. 33.0 months; P:0.029) and longer time to CRPC (43.0 vs. 31.0 months; P: 0.025). The TT 'bounce' phenomenon was observed in 28 patients (33.3%), and was associated with a poorer PSA response (P: 0.029, median difference: 18.90%, 95% CI 3.83 - 41.45), shorter PSA PFS (8.6 vs 15.2 months, P: 0.002) and shorter OS (29.0 vs. 45.0 months, P: 0.012).

CONCLUSION

In CRPC patients, TT behaviors before and during NAAT, and the 'bounce' phenomenon continue to predict treatment response and could guide clinical decisions.

A prospective study of the effect of testosterone escape on preradiotherapy prostate-specific antigen kinetics in prostate cancer patients undergoing neoadjuvant androgen deprivation therapy

Introduction

Prostate-specific antigen (PSA) kinetic patterns during neoadjuvant androgen deprivation therapy have been shown to predict unfavorable long-term outcomes.

Objective

To investigate the effect of testosterone escape (TE) on these kinetic patterns, as this had not been previously reported.

Methods

There were 50 consecutive prostate cancer patients who received 6 months of triptorelin prior to definitive radiotherapy (RT). Testosterone and PSA levels were measured at baseline and every 6 weeks. Clinical factors were tested for their ability to predict for TE and unfavorable PSA kinetic patterns. The effects of TE, at both 1.7 and 0.7 nmol/L levels, were analyzed.

Results

TE occurred in at least one reading for 14% and 34% of the patients at the 1.7 and 0.7 nmol/L levels, respectively. No baseline factors predicted TE. The median PSA halving time was 25 days and the median pre-RT PSA level was 0.55 ng/mL. The only factor significantly associated with a higher pre-RT PSA level was a higher baseline PSA level. The only factor that significantly predicted a longer PSA halving time was TE at the 1.7 nmol/L level.

Conclusions

TE and higher baseline PSA levels may adversely affect PSA kinetics and other outcomes for patients undergoing neoadjuvant hormone therapy prior to radiotherapy. Studies investigating the tailoring of neoadjuvant therapy by extending the duration in those patients with a higher baseline PSA level or by the addition of anti-androgens in those demonstrating TE, should be considered.

Volume matters and intensification is needed: emerging trends in the management of advanced prostate cancer

Significant changes in the management of patients with de novo metastatic prostate cancer have led to the use of novel oral agents and docetaxel-based chemotherapy earlier in the natural history of their disease. Our main challenge is the lack of prospective randomized data comparing these regimens. It is clear that treatment intensification is needed. Yet, the heterogeneity of this patient population coupled with the lack of understanding of the specific biology for a given individual makes treatment selection challenging. The aim of this narrative review is to discuss the importance of defining advanced disease by volume, the necessity for treatment intensification, and the current and future landscape of metastatic hormone-sensitive prostate cancer management.

Effectiveness and Distribution of Testosterone Levels within First Year of Androgen Deprivation Therapy in a Real-World Setting: Results from the Non-Interventional German Cohort LEAN Study

BACKGROUND

Observational studies generate information on real-world therapy and complement data from prospective randomized trials. LEAN is an open-label, non-interventional, multi-centre, German cohort study on leuprorelin in routine clinical practice.

OBJECTIVES

To extend knowledge on the use, effectiveness, and tolerability of HEXAL/Sandoz leuprorelin (in this article, the term Leuprone® HEXAL® covers Leuprorelin Sandoz® as well) solid implant in patients with prostate cancer (PCa) in a real-world setting.

METHODS

959 PCa patients scheduled for androgen deprivation therapy (ADT) received leuprorelin acetate implant. Metabolism, serum prostate-specific antigen (PSA), and testosterone data, if available, were collected at baseline and follow-up visits for ≥12 months.

RESULTS

Of 694 patients in the modified full analysis set, 26.4% received GnRH analogues ≤6 months before enrolment. Fifty-one percent of patients were treated for locally advanced or metastatic PCa. In 19.6% of patients, ADT was used in neoadjuvant or adjuvant settings and in 28.5% with rising PSA after definite therapy. Testosterone levels <0.5 ng/mL were achieved in >90% of patients. Safety profile was in line with the summary of product characteristics. Therapy was well tolerated, with patient-triggered therapy discontinuation in 3.6%.

CONCLUSIONS

This interim analysis confirmed previous efficacy findings for leuprorelin implant in a real-world setting. This contemporary cohort showed a shift in the use of ADT to non-metastatic PCa stages.

Polymorphisms in androgen metabolism genes with serum testosterone levels and prognosis in androgen-deprivation therapy

OBJECTIVE

Androgen metabolism is a key component in therapeutic resistance to androgen deprivation therapy (ADT). This study aimed to reveal the significance of genetic polymorphisms in genes involved in androgen metabolism, including CYP17A1, AKR1C3, and HSD17B, on serum testosterone levels during ADT, as well as the prognosis of men undergoing ADT for metastatic prostate cancer (CaP).

MATERIALS AND METHODS

This study included 104 Japanese patients with metastatic CaP, for whom serum testosterone data during ADT were available for 80 patients. The association of CYP17A1 (rs743572), AKR1C3 (rs12529), HSD17B1 (rs605059), HSD17B3 (rs2066479), and HSD17B4 (rs7737181) with serum testosterone levels during ADT and prognosis (progression-free survival and overall survival) was examined. Enzymatic activity in AKR1C3 H5Q was examined using recombinant protein.

RESULTS

Homozygous wild-type (GG allele; median [interquartile range], 12.0 ng/ml [8.0-19.0 ng/ml]) AKR1C3 rs12529 was associated with higher serum testosterone levels during ADT compared with variant-type (GC/CC alleles; median [interquartile range], 9.0 ng/ml [6.4-10.8 ng/ml]). Consistently, variant-type (GC/CC alleles) AKR1C3 rs12529 showed significantly lower risk of progression (hazard ratio [95% confidence interval], 0.47 [0.24-0.96], P = 0.039) compared with homozygous wild-type (GG allele) on multivariate analysis. Meanwhile, other genetic variations were associated with neither serum testosterone during ADT nor prognosis. Enzyme activity of wild-type AKR1C3 was comparable to the H5Q mutant.

CONCLUSIONS

Taken together, this study demonstrated that AKR1C3 polymorphism, which was associated with serum testosterone levels during ADT, may be a prognostic factor of the progression to castration-resistant prostate cancer in Japanese men with metastatic CaP.

Subcutaneous in situ gel delivered leuprolide acetate's consistent and prolonged drug delivery maintains effective testosterone suppression independent of age and weight in men with prostate cancer

Objectives

To assess the impact of patient age and weight on the pharmacokinetics (PK), testosterone (T) suppression and safety from four fixed dosing regimens (7.5, 22.5, 30, or 45 mg for 1‐, 3‐, 4‐, or 6‐months, respectively) of subcutaneous in situ gel delivered leuprolide acetate (Gel‐LA) injected via the ATRIGEL Delivery System in patients with prostate cancer (PCa).

Patients and methods

Two patient populations were specified for analysis: a small cohort of surgically castrated PCa patients and a large, pooled population of PCa patients from four pivotal trials of Gel‐LA. Two separate analyses of the impact of age and weight on study endpoints were conducted: (1) PK and safety of a single monthly dose of Gel‐LA in a Phase 1 study with PCa patients who had undergone bilateral surgical orchiectomy (“Bilaterally orchiectomized male study”); (2) PK/pharmacodynamic (PD) effects and safety using pooled data from four pivotal trials assessing 1‐, 3‐, 4‐, and 6‐month dosing of Gel‐LA in patients with advanced PCa, stratified by age and body weight (pivotal trials).

Results

Eight orchiectomized patients from the “Bilaterally orchiectomized male study” and 438 patients from the pivotal trials were included in the analyses. Age and body weight did not appear to affect the PK results in the orchiectomized patient population. Pooled pivotal trial data showed that serum T levels did not appear to be influenced by age or weight; ≥90% of patients across all age groups and ≥92% of patients across all weight groups achieved T ≤ 50 ng/dL by week 4. Median T levels for castration (T ≤ 50 ng/dL) were maintained from week 3 until the end of the study and all subgroups achieved median T ≤ 20 ng/dL by week 4. Patients from the orchiectomized patient study did not report any serious treatment‐related adverse events (AEs) and there were no AE‐related withdrawals from the study. The most common AEs were hot flashes and injection site events. The safety profiles from pivotal trials have been previously described and, as expected, were consistent with known effects of LHRH agonist therapy and suppression of T levels.

Conclusion

PK and PD of Gel‐LA appear to be unaffected by age and body weight, as demonstrated by persistence of effective drug levels through the dosing period and consistent T suppression across different ages and body weights.

Is there still a role for bilateral orchidectomy in androgen-deprivation therapy for metastatic prostate cancer?

Objective: To compare bilateral orchidectomy, as the classical ‘gold standard’ androgen-deprivation therapy (ADT), and ADT using a luteinising hormone-releasing hormone (LHRH) antagonist (degarelix) for the treatment of metastatic prostate cancer regarding their short-term biochemical efficacy, testosterone castrate level, tolerability, and effect on health-related quality of life (HRQoL).

Patients and methods: A total of 60 patients with newly diagnosed metastatic prostate cancer were managed by either bilateral orchidectomy or degarelix injection as ADT. Both groups were compared according to their prostate-specific antigen (PSA) nadir and testosterone level at the 6-month follow-up. HRQoL was assessed using the European Organisation for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire-Core 30 (QLQ-C30) after 12 months.

Results: Bilateral orchidectomy and degarelix showed comparable results for PSA reduction, but there was a statistically significantly lower castrate level of testosterone in the bilateral orchidectomy group. Using the EROTC QLQC-30, bilateral orchidectomy was associated with better HRQoL, better global health status, and better functional status.

Conclusion: Bilateral orchidectomy resulted in lower castrate levels of testosterone, which may be associated with better disease control, together with better HRQoL and general health status compared to LHRH antagonist (degarelix). These results indicate that we should consider revisiting bilateral orchidectomy as a valuable and effective treatment option for ADT.

Abbreviations: ADT: androgen-deprivation therapy; EORTC (QLQ-C30): European Organisation for Research and Treatment of Cancer (Quality of Life Questionnaire-Core 30); HRQoL: health-related quality of life

Measuring testosterone and testosterone replacement therapy in men receiving androgen deprivation therapy for prostate cancer: A survey of UK uro-oncologists' opinions and practice

AIM

To explore the practice and attitudes of uro-oncologists in the UK regarding monitoring testosterone levels and the use of testosterone replacement therapy (TRT) in their prostate cancer patients treated with androgen deprivation therapy (ADT).

METHODS

An expert-devised online questionnaire was completed by the members of the British Uro-oncology Group (BUG).

RESULTS

Of 160 uro-oncologists invited, 84 completed the questionnaire. Before initiating ADT in patients with non-metastatic prostate cancer, only 45% of respondents measured testosterone levels and 61% did not measure testosterone at all during ADT in the adjuvant or neoadjuvant setting. However, in men with metastatic prostate cancer, 71% of the uro-oncologists measured testosterone before starting ADT and the majority continued testing during treatment. Approximately two-thirds of respondents did not prescribe TRT for their patients who were in remission following neo(adjuvant) ADT and who had castration levels of testosterone.

DISCUSSION

Among UK uro-oncologists, the measurement of testosterone levels before and during ADT was not typically part of routine practice in the management of patients with prostate cancer. However, testosterone levels were checked more frequently for patients with metastatic disease than disease at an earlier stage. Testing could be conducted in parallel with PSA measurement as testosterone levels are linked to biochemical failure. The majority of specialists participating in the survey did not prescribe TRT for their patients in remission following ADT.

CONCLUSION

Uro-oncologists in the UK do not generally measure testosterone as part of their patient management and they remain cautious about the possible benefits of TRT in men with prostate cancer.

Clinical studies investigating the use of leuprorelin for prostate cancer in Asia

Background

Leuprorelin is a well-established treatment for prostate cancer (PCa); however, there is limited information on its use in Asian males. This review of English language publications between January 2000 and 2016 describes the outcomes of clinical trials on leuprorelin in Asian males with PCa of any grade, stage, or histopathology.

Methods

The literature search was undertaken using PubMed, Cochrane Library, and ClinicalTrials.gov databases.

Results

We identified nine studies from Japan, two studies from South Korea, and one international, multisite study which included Asian sites, with a total of 1,652 males previously diagnosed with PCa. All studies included subcutaneous or depot administration of leuprorelin at varying dose levels including 3.75 mg four weekly, 11.25 mg 12 weekly, or 22.5 mg every 12 or 24 weeks. Leuprorelin was administered as monotherapy or in combination with chemotherapy or hormonal therapy. Leuprorelin appears well tolerated in Asian males and is effective in reducing serum testosterone to castration levels (<50 ng/dL (<1.7 nmol/L)) and prostate-specific antigen levels. Common adverse events included hot flushes and mild hepatic dysfunction. Leuprorelin was shown to provide reasonable survival rates in PCa (T1b-T3N0M0) and in metastatic disease; another reasonable option for these patients is radiation therapy. Leuprorelin treatment also improved the quality of life.

Conclusion

Leuprorelin may be an appropriate and efficacious treatment for males with PCa (T1b-T3N0M0). Leuprorelin treatment was well tolerated and associated with improvement in the quality of life.

Effectiveness of three different luteinizing hormone-releasing hormone agonists in the chemical castration of patients with prostate cancer: Goserelin versus triptorelin versus leuprolide

Purpose

To investigate the changes in testosterone levels and rates of chemical castration following androgen-deprivation therapy (ADT) with goserelin, triptorelin, and leuprolide.

Materials and Methods

We retrospectively reviewed the medical records of 125 patients with prostate cancer treated with luteinizing hormone-releasing hormone (LHRH) agonists between January 2009 and December 2015. Changes in testosterone concentration during 9 months of ADT with goserelin 11.34 mg, triptorelin 11.25 mg, and leuprolide 11.25 mg were analyzed using a mixed model. The number of patients with serum testosterone below castration levels defined as various values (<50 ng/dL, <20 ng/dL, or <10 ng/dL) at 3, 6, and 9 months were also evaluated.

Results

Of the 125 patients, 59 received goserelin, 44 received triptorelin, and 22 received leuprolide, respectively. The lowest mean testosterone levels during 9 months of treatment were achieved in patients treated with triptorelin, followed by those treated with leuprolide, and then by those treated with goserelin (p=0.001). Significant differences in chemical castration levels were observed only at <10 ng/dL, with 54.2% of goserelin, 93.2% of triptorelin, and 86.4% of leuprolide treated patients (p<0.001).

Conclusions

Three LHRH agonists showed comparable efficacy for achieving castration when the castration threshold was 50 or 20 ng/dL. However, triptorelin was the most potent LHRH agonist, achieving the lowest mean testosterone levels and the highest rate of chemical castration at <10 ng/dL testosterone.

Higher Serum Testosterone Levels Associated with Favorable Prognosis in Enzalutamide- and Abiraterone-Treated Castration-Resistant Prostate Cancer

Testosterone plays a significant role in maintaining the tumor microenvironment. The role of the target serum testosterone (TST) level in enzalutamide- (Enza) and abiraterone (Abi)-treated castration-resistant prostate cancer (CRPC) patients was studied. In total, 107 patients treated with Enza and/or Abi at Chiba University Hospital and affiliated hospitals were studied. The relationships between progression-free survival (PFS), overall survival (OS), and clinical factors were studied by Cox proportional hazard and Kaplan–Meier models. In the Abi and Enza groups overall, TST ≥ 13 ng/dL (median) (Hazard Ratio (HR) 0.43, p = 0.0032) remained an independent prognostic factor for PFS. In the Enza group, TST ≥ 13 ng/dL (median) was found to be a significant prognostic factor (HR 0.28, p = 0.0044), while, in the Abi group, TST ≥ 12 ng/dL (median) was not significant (HR 0.40, p = 0.0891). TST showed significant correlation with PFS periods (r = 0. 32, p = 0.0067), whereas, for OS, TST ≥ 13 ng/dL (median) showed no significant difference in the Abi and Enza groups overall. According to Kaplan–Meier analysis, a longer PFS at first-line therapy showed a favorable prognosis in the Enza group (p = 0.0429), while no difference was observed in the Abi group (p = 0.6051). The TST level and PFS of first-line therapy may be considered when determining the treatment strategy for CRPC patients.

Population pharmacokinetic-pharmacodynamic modelling of the relationship between testosterone and prostate specific antigen in patients with prostate cancer during treatment with leuprorelin

AIMS

This investigation aimed to quantitatively characterize the relationship between the gonadotropin-releasing hormone agonist leuprorelin, testosterone (T) and prostate specific antigen (PSA) concentrations over time, to aid identification of a target T concentration that optimises the balance of the benefits of T suppression whilst reducing the risk of side effects related to futile over-suppression.

METHODS

Data from a single dose study to investigate the effect of leuprorelin in a 6-month depot formulation on T and PSA in prostate cancer patients were analysed using a population pharmacokinetic-pharmacodynamic modelling approach. The developed model was qualified using external data from 3 studies, in which the effect of different formulations of leuprorelin on T and PSA was evaluated in prostate cancer patients.

RESULTS

The effect of leuprorelin on the relationship between T and PSA was adequately characterized by the Romero model with minor modifications, combined with a turnover model to describe the delay in response between T and PSA. The data were significantly better described when assuming a minimum PSA level that is independent on the treatment-related reduction in T, as compared to a model with a proportional reduction in PSA and T.

CONCLUSIONS

The model-based analysis suggests that on a population level, reducing T concentrations below 35 ng/dL does not result in a further decrease in PSA levels (>95% of the minimal PSA level is reached). More data are required to support this relationship in the lower T and PSA range.

Discordance between testosterone measurement methods in castrated prostate cancer patients

Failure to suppress testosterone below 0.7 nM in castrated prostate cancer patients is associated with poor clinical outcomes. Testosterone levels in castrated patients are therefore routinely measured. Although mass spectrometry is the gold standard used to measure testosterone, most hospitals use an immunoassay method. In this study, we sought to evaluate the accuracy of an immunoassay method to measure castrate testosterone levels, with mass spectrometry as the reference standard. We retrospectively evaluated a cohort of 435 serum samples retrieved from castrated prostate cancer patients from April to September 2017. No follow-up of clinical outcomes was performed. Serum testosterone levels were measured in the same sample using liquid chromatography coupled with tandem mass spectrometry and electrochemiluminescent immunoassay methods. The mean testosterone levels were significantly higher with immunoassay than with mass spectrometry (0.672 ± 0.359 vs 0.461 ± 0.541 nM; P < 0.0001). Half of the samples with testosterone ≥0.7 nM assessed by immunoassay were measured <0.7 nM using mass spectrometry. However, we observed that only 2.95% of the samples with testosterone <0.7 nM measured by immunoassay were quantified ≥0.7 nM using mass spectrometry. The percentage of serum samples experiencing testosterone breakthrough at >0.7 nM was significantly higher with immunoassay (22.1%) than with mass spectrometry (13.1%; P < 0.0001). Quantitative measurement of serum testosterone levels >0.7 nM by immunoassay can result in an inaccurately identified castration status. Suboptimal testosterone levels in castrated patients should be confirmed by either mass spectrometry or an immunoassay method validated at low testosterone levels and interpreted with caution before any changes are made to treatment management.

Subcastrate Testosterone Nadir and Clinical Outcomes in Intermediate- or High-Risk Localized Prostate Cancer

PURPOSE

It is unclear if additional serum testosterone suppression below the castrate threshold of 50 ng/dL improves clinical outcomes in patients with localized prostate cancer undergoing definitive therapy.

METHODS AND MATERIALS

We examined the association of subcastrate testosterone nadir with prostate-specific antigen (PSA) response and long-term clinical outcomes in 764 U.S. veterans with intermediate- or high-risk localized prostate cancer treated with androgen deprivation therapy and definitive radiation therapy from 2000 to 2015. Patients were categorized into testosterone nadir groups based on the minimum testosterone measurement during continuous gonadotropic-releasing hormone agonist therapy (<20 ng/dL vs 20-49 ng/dL). Outcomes included PSA response (3-month post-radiation therapy PSA and 2-year PSA nadir; multivariable linear regression) and long-term clinical outcomes (biochemical recurrence, metastasis, and prostate cancer-specific mortality; Fine-Gray competing risk regression).

RESULTS

A testosterone nadir of 20 to 49 ng/dL was associated with higher 3-month post-radiation therapy PSA compared to <20 ng/dL (ß = 0.16, 95% confidence interval [CI], 0.06-0.26, P = .001) and higher 2-year PSA nadir (ß = 0.12, 95% CI, 0.04-0.21, P = .005). Compared to the <20-ng/dL group, the 20 to 49-ng/dL group showed higher 10-year biochemical recurrence rates (28.1% vs 18.3%) and metastasis rates (12.9% vs 7.8%) persisting on multivariable analyses (biochemical recurrence: sub-distribution hazard ratio [SDHR], 1.62 for 20-49 ng/dL, 95% CI, 1.07-2.45, P = .02; metastasis: SDHR, 2.19, 95% CI, 1.21-3.94, P = .009). There was a trend toward inferior prostate cancer-specific mortality for the 20 to 49-ng/dL group (SDHR, 1.95, 95% CI, 0.90-4.22, P = .09).

CONCLUSIONS

Additional serum testosterone suppression below 50 ng/dL was associated with improved PSA responses and lower rates of biochemical recurrence and metastasis in this cohort of patients with localized prostate cancer.

Importance of androgen-deprivation therapy during enzalutamide treatment in men with metastatic castration-resistant prostate cancer following chemotherapy: results from retrospective, multicenter data

BACKGROUND

Enzalutamide can significantly prolong the survival of patients with metastatic castration-resistant prostate cancer (mCRPC). However, there is a paucity of evidence on continuing androgen-deprivation therapy (ADT) for mCRPC. Here, we analyzed the effect of concomitant ADT during enzalutamide treatment in men with mCRPC following chemotherapy.

METHODS

We retrospectively reviewed the medical records of 232 patients with mCRPC who received oral enzalutamide (160 mg per day) following chemotherapy at 9 tertiary centers in Korea between 2014 and 2016. The primary endpoint was overall survival, while secondary endpoints included time to prostate-specific antigen (PSA) progression and radiographic progression-free survival.

RESULTS

The median age of the patients was 71 years (interquartile range, 64-75 years). The proportion of patients in a grade group ≥4 was 77.6%. The rate of concomitant ADT was 29.3%, and the all-cause mortality rate was 27.1% (n = 63). Median overall survival, time to PSA progression, and radiographic progression-free survival were 24.0, 8.0, and 10.0 months, respectively. Notably, concomitant ADT showed a significant association with longer overall survival (median duration not reached vs. 18.2 months; p = 0.008). After adjusting for confounding factors, concomitant ADT was still associated with longer overall survival (hazard ratio, 0.35; 95% confidence interval, 0.17-0.72).

CONCLUSION

Concomitant ADT during enzalutamide treatment may improve the survival of patients with mCRPC following chemotherapy.

Androgen-targeted therapy in men with prostate cancer: evolving practice and future considerations

Background

Androgen deprivation therapy (ADT) is foundational in the management of advanced prostate cancer (PCa) and has benefitted from a recent explosion in scientific advances. These include approval of new therapies that suppress testosterone (T) levels or inactivate its function, improvements in diagnostic and assay technologies, identification of lower therapeutic targets for T, discovery of the relevance of germline genetic mutations and identification of the benefits of sequential and combination therapies.

Methods

This review discusses the clinical profiles of the most up-to-date options for ADT, best practices for managing patients with advanced PCa and future directions in therapy.

Results and conclusions

Modern assay technologies reveal that bilateral orchiectomy results in a serum T level of approximately 15 ng/dL as compared to the historical definition of castration of T < 50 ng/dL. Evidence shows that lowering T levels to <20 ng/dL improves patient survival and delays disease progression. Routine monitoring of T in addition to prostate-specific antigen throughout treatment is important to ensure continuing efficacy of T suppression. New drugs that inhibit androgen signaling in combination with traditional ADT suppress T activity to near zero and have significantly improved patient survival. When personalizing ADT regimens physicians should consider a number of factors including initiation and duration of ADT, monitoring of T levels and PSA, the possibility of switching monotherapies if a patient does not achieve adequate T suppression, and consideration of intermittent vs. continuous ADT according to patients’ lifestyles, comorbidities, risk factors and tolerance to treatment.

Are all gonadotrophin-releasing hormone agonists equivalent for the treatment of prostate cancer? A systematic review

To review direct comparative studies of the gonadotrophin-releasing hormone (GnRH) agonists goserelin, triptorelin, and leuprorelin for the treatment of prostate cancer, and identify whether there are meaningful clinical differences between these agents. In June 2017, the following searches were performed independently by two reviewers in PubMed: (i) 'prostate cancer' and 'triptorelin' and 'leuprorelin', (ii) 'prostate cancer' and 'triptorelin' and 'goserelin', and (iii) 'prostate cancer' and 'goserelin' and 'leuprorelin', without time restriction. Duplicates were deleted. Relevant conference abstracts were also screened. A total of 16 direct comparative trials were identified: 12 reported on efficacy outcomes, four on safety/tolerability, and five on the convenience of administration/user perceptions. These studies are restricted in terms of patient numbers, formulations assessed, and endpoints measured; none were adequately powered for survival outcome measures. Studies reporting on efficacy endpoints did not show major differences in the ability of these GnRH agonists to reduce levels of testosterone or prostate-specific antigen. Some studies suggest differences in short- or long-term testosterone control, the rate of injection site adverse events, and patient/healthcare professional perceptions, but definitive conclusions cannot be drawn from the existing evidence. Few direct comparative trials of GnRH agonists have been conducted. Whilst GnRH agonists provide a similar castration effect, there is not enough evidence to show that GnRH agonists are equivalent.

A systematic review of methods for quantifying serum testosterone in patients with prostate cancer who underwent castration

BACKGROUND

The clinical practice guidelines recommend measuring serum testosterone in patients with prostate cancer (PC) who undergo castration. The serum testosterone concentration should be <50ng/dL, a level established by using a radioimmunoassay method. The use of chemiluminescent immunoassays (IA) has become widespread, although their metrological characteristics do not seem appropriate for quantifying low testosterone concentrations. The objective of this review is to analyse the methods for quantifying testosterone and to establish whether there is scientific evidence that justifies measuring it in patients with PC who undergo castration, through liquid chromatography attached to a mass spectrometry in tandem (LC-MSMS).

MATERIAL AND METHODS

We performed a search in PubMed with the following MeSH terms: measurement, testosterone, androgen suppression and prostate cancer. We selected 12 studies that compared the metrological characteristics of various methods for quantifying serum testosterone compared with MS detection methods.

RESULTS

IAs are standard tools for measuring testosterone levels; however, there is evidence that IAs lack accuracy and precision for quantifying low concentrations. Most chemiluminescent IAs overestimate their concentration, especially below 100ng/dL. The procedures that use LC-MSMS have an adequate lower quantification limit and proper accuracy and precision. We found no specific evidence in patients with PC who underwent castration.

CONCLUSIONS

LC-MSMS is the appropriate method for quantifying low serum testosterone concentrations. We need to define the level of castration with this method and the optimal level related to better progression of the disease.

Sex steroids in the tumor microenvironment and prostate cancer progression

Prostate cancer is uniquely dependent on androgens. Despite years of research on the relationship between androgens and prostate cancer, many questions remain as to the biological effects of androgens and other sex steroids during prostate cancer progression. This article reviews the clinical and basic research on the influence of sex steroids such as androgens, estrogens and progesterone within the prostate tumor microenvironment on the progression of prostate cancer. We review clinical studies to date evaluating serum sex steroids as prognostic biomarkers and discuss their respective biological effects within the prostate tumor microenvironment. We also review the link between genomic alterations and sex steroid levels within prostate tumors. Finally, we highlight the links between sex steroid levels and the function of the immune system within the tumor microenvironment. As the context of treatment of lethal prostate cancer evolves over time, an understanding of this underlying biology remains central to developing optimal treatment approaches.

Pharmacokinetic and pharmacodynamic comparison of subcutaneous versus intramuscular leuprolide acetate formulations in male subjects

BACKGROUND

The aim of this study was to compare the pharmacokinetics (PK) and pharmacodynamics (PD) of two distinct formulations of leuprolide acetate (LA); subcutaneous (SC) injection and intramuscular (IM) injection.

METHODS

A total of 32 healthy men were randomized to receive a single 7.5 mg injection of SC-LA (n = 16) or IM-LA (n = 16) in this phase I, open-label, parallel-group study. PK was assessed via LA concentrations, and PD via serum luteinizing hormone (LH) and testosterone (T) concentrations.

RESULTS

The initial surge of LA was higher for IM-LA than SC-LA (Cmax 27 ± 4.9 versus 19 ± 8.0 ng/ml, respectively), with a shorter tmax (1.0 ± 0.4 versus 2.1 ± 0.8 h). The duration of quantifiable LA concentration was longer for SC-LA (up to 56 versus 42 days for SC-LA and IM-LA, respectively). Median LH concentrations in both groups rapidly increased, followed by gradual decrease. However, SC-LA demonstrated a longer duration of LH suppression, with median levels remaining below 1.0 IU/l through Day 56 compared with IM-LA where LH started to rise by Day 35. Consequently, serum T began to increase by Day 42 in the IM-LA group, with only four subjects maintaining levels ⩽50 ng/dl, compared with 14 subjects in the SC-LA group. By Day 56, 13 SC-LA subjects maintained serum T levels ⩽50 ng/dl. Both SC-LA and IM-LA were well tolerated.

CONCLUSIONS

Both formulations demonstrated consistent delivery of drug over 1 month; however, SC-LA provided a longer duration of action than expected based on the dosing interval. This profile suggests that SC-LA will provide effective suppression of T over a longer period of time, permitting greater injection scheduling flexibility.

Testosterone suppression in the treatment of recurrent or metastatic prostate cancer - A Canadian consensus statement

Testosterone suppression, achieved through orchiectomy or medically induced androgen-deprivation therapy (ADT), is a standard treatment for men with recurrent and metastatic prostate cancer. Current assay methods demonstrate the capacity for testosterone suppression to <0.7 nmol/l, and clinical data support improved outcomes from ADT when lower levels are achieved. Practical clinical guidelines are warranted to facilitate adoption of 0.7 nmol/l as the new standard castrate testosterone level.A pan-Canadian group of experts, representing diverse clinical specialties, identified key clinical issues, searched and reviewed relevant literature, and developed consensus statements on testosterone suppression for the treatment of prostate cancer. The expert panel found that current evidence supports the clinical benefit of achieving low testosterone levels during ADT, and encourage adoption of ≤0.7 nmol/l as a new castrate level threshold. The panel recommends regular monitoring of testosterone (e.g., every 3-6 months) and prostate-specific antigen (PSA) levels as clinically appropriate (e.g., every 3-6 months) during ADT, with reassessment of therapeutic strategy if testosterone is not suppressed or if PSA rises regardless of adequate testosterone suppression. The panel also emphasizes the need for greater awareness and education regarding testosterone assay specifications, and strongly promotes the use of mass spectrometry-based assays to ensure accurate measurement of testosterone at castrate levels.

Accuracy of serum luteinizing hormone and serum testosterone measurements to assess the efficacy of medical castration in prostate cancer patients

Background

Luteinizing hormone-releasing hormone (LH-RH) agonists are the standard for androgen deprivation therapy (ADT) in prostate cancer (PCa) patients. Current guidelines recommend serum testosterone measurement to assess the efficacy of ADT and to define castration resistance. However, serum testosterone does not reflect the exclusive effect of castration due to its extratesticular production. The aim of this study is to analyze if serum LH reflects better than serum testosterone the activity of LH-RH agonists.

Methods

Serum LH and serum testosterone were measured with chemiluminescent immunoassay (CLIA) in a cohort study of 1091 participants: 488 PCa patients “on LH-RH agonists”, 303 “off LH-RH agonist” in whom LH-RH agonists were withdrawn, and 350 men with PCa suspicion “no LH-RH agonist” who never received LH-RH agonists. In a validation cohort of 147 PCa patients, 124 on “LH-RH agonists” and 19 “off LH-RH agonists”, serum testosterone was also measured with liquid chromatography and tandem mass spectrometry (LC MSMS).

Results

The area under the curve (AUC) to distinguish patients “on versus off LH-RH agonists” was 0.997 for serum LH and 0.740 for serum testosterone, P < 0.001. The 97.5 percentile of serum LH in patients “on LH-RH agonists” was 0.97 U/L, been the most efficient threshold 1.1 U/L. The AUCs for serum LH, testosterone measured with CLIA and with LC MSMS, in the validation cohort, were respectively 1.000, 0.646 and 0.814, P < 0.001. The efficacy to distinguish patients “on versus off LH-RH agonists” was 98.6%, 78.3%, and 89.5% respectively, using 1.1 U/L as threshold for serum LH and 50 ng/dL for serum testosterone regardless the method.

Conclusions

Serum LH is more accurate than serum testosterone regardless the method, to distinguish patients “on versus off LH-RH agonists”. The castrate level of serum LH is 1.1 U/l. These findings suggest that assessment of LH-RH agonist efficacy and castration resistance definition should be reviewed.

Testosterone Responders to Continuous Androgen Deprivation Therapy Show Considerable Variations in Testosterone Levels on Followup: Implications for Clinical Practice

PURPOSE

We determined whether men on continuous androgen deprivation therapy who achieve testosterone less than 0.7 nmol/l demonstrate subsequent testosterone elevations during followup and whether such events predict worse oncologic outcomes.

MATERIALS AND METHODS

We evaluated a random, retrospective sample of 514 patients with prostate cancer treated with continuous androgen deprivation therapy in whom serum testosterone was less than 0.7 nmol/l at University Health Network between 2007 and 2016. Patients were followed from the date of the first testosterone measurement of less than 0.7 nmol/l to progression to castrate resistance, death or study period end. Study outcomes were the development of testosterone elevations greater than 0.7, greater than 1.1 and greater than 1.7 nmol/l, and progression to a castrate resistant state. Survival curves were constructed to determine the rate of testosterone elevations. Multivariate Cox regression analysis was done to assess whether elevations predicted progression to castrate resistance.

RESULTS

Median patient age was 74 years and median followup was 20.3 months. Within 5 years of followup 82%, 45% and 18% of patients had subsequent testosterone levels greater than 0.7, greater than 1.1 and greater than 1.7 nmol/l, respectively. In 96% to 100% of these patients levels less than 0.7 nmol/l were subsequently reestablished within 5 years. No patient baseline characteristic was associated with elevations and elevations were not a significant predictor of progression to a castrate resistant state.

CONCLUSIONS

Men on continuous androgen deprivation therapy in whom initial testosterone is less than 0.7 nmol/l frequently show subsequent elevations in serum testosterone. Such a development should not trigger an immediate response from physicians as these events are prognostically insignificant with regard to oncologic outcomes. Levels are eventually reestablished at less than 0.7 nmol/l.

Prognosis of prostate cancer with initial prostate-specific antigen >1,000 ng/mL at diagnosis

PURPOSE

Prostate cancer patients with surprisingly high prostate-specific antigen (PSA) are encountered clinically. However, descriptions of this group of patients are extremely rare in the published literature. This study reports treatment outcome and long-term prognosis for this group of patients.

PATIENTS AND METHODS

Between January 2007 and December 2012, 2,064 patients with PCa diagnosed at a tertiary medical center were retrospectively reviewed. A total of 90 PCa cases were identified with initial PSA (iPSA) >1,000 ng/mL at diagnosis. A retrospective study was conducted in this cohort, with comparison among stratified patient age groups, PSA, treatment options, and overall survival.

RESULTS

The mean PSA at PCa diagnosis in this cohort was 3,323 ng/mL (1,003-23,126, median: 2,050 ng/mL). Most patients were in the age group 65-79 years (55/90, 61%). Males older than 80 years had a poor prognosis (P<0.001). Forty-six patients (51%) underwent orchiectomy with a median follow-up period of 16.2 (1.3-72.7) months, compared to 44 patients treated with medical castration and a median follow-up of 9.1 (0.3-70.5) months. Kaplan-Meier analysis revealed survival benefit from treatment with orchiectomy (P<0.001). PSA reduction >90% of iPSA following primary androgen deprivation therapy (reaching true nadir) could be a predictor of longer survival (P<0.001). Cox regression revealed the hazard ratio (HR) of variables were age (HR: 4.57, 95% confidence interval [CI]: 1.45-14.37, P=0.009), reaching true nadir (HR: 0.12, 95% CI: 0.03-0.58, P=0.008), and the treatment option with orchiectomy (HR: 0.22, 95% CI: 0.65-0.76, P=0.016).

CONCLUSION

Age ≥80 years indicated poor overall survival in PCa patients with iPSA >1,000 ng/mL. Reaching a true nadir of PSA following primary androgen deprivation therapy could be a predictor of longer survival. Bilateral orchiectomy is recommended for this group of patients.

Testosterone monitoring for men with advanced prostate cancer: Review of current practices and a survey of Canadian physicians

Androgen-deprivation therapy (ADT) is a standard of care in the treatment of advanced prostate cancer; however, testosterone monitoring practices for men undergoing ADT vary across Canada. Although a testosterone level of 1.7 nmol/L or lower has historically been defined as the accepted castrate level, newer assays with improved sensitivity have shown that both medical and surgical castration can suppress testosterone levels to below 0.7 nmol/L. This review explores the evidence supporting a redefinition of the castrate testosterone level as 0.7 nmol/L or lower, and presents results of a survey of testosterone monitoring practices among 153 Canadian urologists, uro-oncologists, and radiation oncologists who manage the treatment of men with hormone-sensitive prostate cancer.

Clinical Outcomes and Testosterone Levels Following Continuous Androgen Deprivation in Patients with Relapsing or Locally Advanced Prostate Cancer: A Post Hoc Analysis of the ICELAND Study

PURPOSE

Lower serum testosterone levels correlate with improved cause specific survival and longer time to progression in year 1 of continuous androgen deprivation in men with prostate cancer. ICELAND was a large European study demonstrating the efficacy of leuprorelin (Eligard®) during continuous androgen deprivation. In this post hoc analysis we investigated serum testosterone levels within year 1 of continuous androgen deprivation to determine survival and time to progression.

MATERIALS AND METHODS

In ICELAND (ClinicalTrials.gov NCT00378690) patients with locally advanced or relapsing nonmetastatic prostate cancer and with prostate specific antigen 1 ng/ml or less following 6-month induction with leuprorelin 3-month depot 22.5 mg (plus bicalutamide 50 mg per day for 1 month) were randomized 1:1 to continuous androgen deprivation (361) or intermittent androgen deprivation (340) with leuprorelin for 36 months. Patients receiving continuous androgen deprivation were stratified by minimum, median and maximum testosterone levels during year 1 of therapy into 20 or less, greater than 20 to 50 and greater than 50 ng/dl subgroups. Cause specific survival and time to prostate specific antigen (castrate resistant prostate cancer) progression were analyzed.

RESULTS

A total of 90.1%, 83.5% and 74.5% of patients receiving continuous androgen deprivation achieved minimum, median and maximum serum testosterone levels of 20 ng/dl or less, respectively. Cause specific survival rates and time to prostate specific antigen progression did not differ among the testosterone subgroups.

CONCLUSIONS

In patients receiving continuous androgen deprivation cause specific survival and time to prostate specific antigen progression did not differ according to testosterone levels in year 1 of therapy. This finding may in part be due to the induction period and the effectiveness of leuprorelin in lowering testosterone.

Testosterone suppression with a unique form of leuprorelin acetate as a solid biodegradable implant in patients with advanced prostate cancer: results from four trials and comparison with the traditional leuprorelin acetate microspheres formulation

BACKGROUND

There are two slow-release ready-to-use forms of leuprorelin acetate (1-month and 3-month) that are available as solid, biodegradable implants for the treatment of advanced, hormone-sensitive prostate cancer. These implants have been shown to be as effective as traditional leuprorelin acetate microspheres for achieving successful testosterone suppression (⩽0.5 ng/ml) and lowering prostate-specific antigen (PSA) levels. Here we further evaluate testosterone suppression levels from four clinical trials evaluating the 3-month leuprorelin implant, including analysis below the European Association of Urology (EAU) castration level (<0.2 ng/ml).

METHODS

Studies were conducted in patients with locally advanced/metastatic prostate cancer: (1) a randomised, controlled single-dose study comparing the leuprorelin implant with leuprorelin microspheres; (2) a single-arm, single-dose study of the leuprorelin implant; (3 and 4) two long-term studies with the leuprorelin implant administered twice, 12 or 16 weeks apart. Patients received 3-month leuprorelin (5 mg) implant or 3-month leuprorelin (10.72 mg) microspheres. Testosterone levels were analysed using radioimmunoassay or ultrasensitive liquid chromatography tandem mass spectrometry.

RESULTS

Both the leuprorelin implant and the leuprorelin microspheres achieved mean testosterone suppression (⩽0.5 ng/ml) within 4 weeks for >3 months. In both long-term, single-arm studies with the leuprorelin implant, median values of testosterone ⩽0.2 ng/ml were achieved at Week 4 and maintained until study completion (6 and 8 months); PSA decrease was also observed versus baseline.

CONCLUSIONS

Long-lasting steady serum levels of testosterone, comparable with orchiectomy and consistent with the EAU-recommended castration level (<0.2 ng/ml), were achieved at Week 4 and maintained up to 8 months in men with advanced prostate cancer who received the leuprorelin implant.