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

An Actionable Expert-System Algorithm to Support Nurse-Led Cancer Survivorship Care: Algorithm Development Study

BACKGROUND

Comprehensive models of survivorship care are necessary to improve access to and coordination of care. New models of care provide the opportunity to address the complexity of physical and psychosocial problems and long-term health needs experienced by patients following cancer treatment.

OBJECTIVE

This paper presents our expert-informed, rules-based survivorship algorithm to build a nurse-led model of survivorship care to support men living with prostate cancer (PCa). The algorithm is called No Evidence of Disease (Ned) and supports timelier decision-making, enhanced safety, and continuity of care.

METHODS

An initial rule set was developed and refined through working groups with clinical experts across Canada (eg, nurse experts, physician experts, and scientists; n=20), and patient partners (n=3). Algorithm priorities were defined through a multidisciplinary consensus meeting with clinical nurse specialists, nurse scientists, nurse practitioners, urologic oncologists, urologists, and radiation oncologists (n=17). The system was refined and validated using the nominal group technique.

RESULTS

Four levels of alert classification were established, initiated by responses on the Expanded Prostate Cancer Index Composite for Clinical Practice survey, and mediated by changes in minimal clinically important different alert thresholds, alert history, and clinical urgency with patient autonomy influencing clinical acuity. Patient autonomy was supported through tailored education as a first line of response, and alert escalation depending on a patient-initiated request for a nurse consultation.

CONCLUSIONS

The Ned algorithm is positioned to facilitate PCa nurse-led care models with a high nurse-to-patient ratio. This novel expert-informed PCa survivorship care algorithm contains a defined escalation pathway for clinically urgent symptoms while honoring patient preference. Though further validation is required through a pragmatic trial, we anticipate the Ned algorithm will support timelier decision-making and enhance continuity of care through the automation of more frequent automated checkpoints, while empowering patients to self-manage their symptoms more effectively than standard care.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

RR2-10.1136/bmjopen-2020-045806.

Preclinical models of prostate cancer - modelling androgen dependency and castration resistance in vitro, ex vivo and in vivo

Prostate cancer is well known to be dependent on the androgen receptor (AR) for growth and survival. Thus, AR is the main pharmacological target to treat this disease. However, after an initially positive response to AR-targeting therapies, prostate cancer will eventually evolve to castration-resistant prostate cancer, which is often lethal. Tumour growth was initially thought to become androgen-independent following treatments; however, results from molecular studies have shown that most resistance mechanisms involve the reactivation of AR. Consequently, tumour cells become resistant to castration - the blockade of testicular androgens - and not independent of AR per se. However, confusion still remains on how to properly define preclinical models of prostate cancer, including cell lines. Most cell lines were isolated from patients for cell culture after evolution of the tumour to castration-resistant prostate cancer, but not all of these cell lines are described as castration resistant. Moreover, castration refers to the blockade of testosterone production by the testes; thus, even the concept of "castration" in vitro is questionable. To ensure maximal transfer of knowledge from scientific research to the clinic, understanding the limitations and advantages of preclinical models, as well as how these models recapitulate cancer cell androgen dependency and can be used to study castration resistance mechanisms, is essential.

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.

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.

Testosterone Therapy in Advanced Prostate Cancer

Androgen deprivation therapy is a mainstay of advanced prostate cancer (PCa) but the resulting low testosterone levels leave men susceptible to a multitude of adverse effects. These can include vasomotor symptoms, reduced sexual desire and performance, and mood changes. Testosterone therapy (TTh) in advanced PCa has historically been contraindicated since Huggins and Hodges reported that testosterone activates PCa. Although TTh has been demonstrated to be safe in patients who have undergone treatment for localized PCa, there is extremely limited evidence on its safety in advanced PCa. Despite the lack of evidence, some men with advanced PCa still inquire about TTh, and recent publications have described its use. In this article, we review the potential implications of TTh in men with advanced PCa, defined here as biochemical recurrence after localized therapy or metastatic PCa that is either hormone sensitive or castration resistant.

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.

Androgen deprivation monotherapy usage in non-metastatic prostate cancer: results from eight European countries

Introduction

The aim of this study was to investigate the attitudes towards use of androgen deprivation therapy (ADT) as monotherapy for localized or locally advanced prostate cancer (PC).

Material and methods

A survey using a 28-item, structured, quantitative questionnaire about the management of patients with PC was conducted in eight European countries between February and May 2018. Survey recipients were selected from a private database of healthcare providers.

Results

Overall, 375 physicians completed the survey (response rate, 58%). Participants were urologists (71.2%) or medical oncologists (28.8%), with a mean practice duration of 19.9 years and with university hospital or cancer center (41.6%), non-teaching hospital (38.4%) or private-sector clinic (20.0%) affiliations. Median proportions of physicians considering ADT as monotherapy to treat patients with PC in different risk groups varied between countries, but overall were: high/very high-risk, 60%; intermediate-risk, 30%; low-risk, 7.5%. The use of ADT monotherapy in the different risk groups also varied by medical specialty and type of affiliation. Proportions of participants applying different target thresholds for testosterone (T) levels also varied by country, but overall were: <50 ng/dL, 29.9%; <32 ng/dL, 4.8%; <20 ng/dL, 54.3%; castration but no specific target, 11%. More than half of participants (58.7%) determined target T levels only when prostate-specific antigen level was increased.

Conclusions

Our multinational survey provides evidence that PC management varies across European countries and with clinical context, and frequently diverges from European Association of Urology (EAU) - European Society for Radiotherapy and Oncology (ESTRO) - European Society of Urogenital Radiology (ESUR) - International Society of Geriatric Oncology (SIOG) guidelines. Strategies for effective implementation of evidence-based recommendations in clinical practice may be needed to optimize patient outcomes.

A population K-PD model analysis of long-term testosterone inhibition in prostate cancer patients undergoing intermittent androgen deprivation therapy

Intermittent androgen deprivation therapy with gonadotropin-releasing-hormone (GnRH) agonists can prevent or delay disease progression and development of castration resistant prostate cancer for subpopulations of prostate cancer patients. It may also reduce risk and severity of side effects associated with chemical castration in prostate cancer (PCa) patients. One of the earliest comprehensively documented clinical trials on this was reported in a Canadian patient population treated with leuprorelin preceded by a lead-in with cyproterone acetate. A systems-based mixed effect analysis of testosterone response in active and recovery phases allows inference of new information from this patient population. Efficacy of androgen deprivation therapy is presumed to depend on a treshold value for testosterone at the nadir, below which no additional beneficial effects on PSA reponse can be expected, and occurance of testosterone breakthroughs during active therapy. The present analysis results in a mixed effect model, incorporating GnRH receptor activation, testosterone turnover and feedback mechanisms, describing and predicting testosterone inhibition under intermittent androgen deprivation therapy on the individual and population level, during multiple years of therapy. Testosterone levels in these patients decline over time with an estimated first order rate constant of 0.083 year^-1(T_1/2 = 8.4 y), with a substantial distribution among this patient population, compared to the general population. PCa patients leaving the trial due to unmanageble PSA relapse appear to have slightly higher testosterone levels at the nadir than sustained responders. These findings are expected to contribute to an increased understanding of the role of testosterone in long term disease progression of prostate cancer.

Prevalence and predictors of cannabis use among men receiving androgen-deprivation therapy for advanced prostate cancer

INTRODUCTION

Prostate cancer patients receiving androgen-deprivation therapy (ADT) often experience a combination of disease symptoms and treatment side effects. The therapeutic use of cannabis to alleviate these side effects has not been studied, despite increasing patient interest. With the increasing availability of cannabis, it is important for clinicians to understand the prevalence, predictors, and perceived benefits of cannabis use among patients with prostate cancer.

METHODS

A total of 222 men undergoing ADT were assessed in this two-part study. In part one, the cannabis-use questionnaire was administered to 56 men, probing demographics, usage habits, perspectives, and degrees of symptom relief related to cannabis use. In part two, 191 cryopreserved urine samples were retrieved and analyzed for the presence of tetrahydrocannabidiol (THC) metabolite 11-nor-Δ9-THC-COOH. The respondents were then stratified into two groups, users vs. non-users, and statistical analyses were conducted.

RESULTS

Questionnaire data revealed that 23.2% of surveyed men had recently used cannabis. In contrast, 5.8% of men had detectable levels of THC metabolite in their urine. Combined questionnaire and urine data revealed that cannabis users were significantly younger (p=0.003) and had lower testosterone levels (p=0.003) than non-users. The majority of men experiencing common ADT side effects reported some degree of relief following cannabis use.

CONCLUSIONS

Cannabis use among men with advanced prostate cancer receiving ADT is more prevalent than in the general population and the majority of other oncological cohorts. Lower testosterone levels and reported therapeutic benefit among cannabis users warrants confirmation in appropriate clinical trials.

Management algorithms for prostate-specific antigen progression in prostate cancer: Biochemical recurrence after definitive therapy and progression to non-metastatic castrate-resistant prostate cancer

INTRODUCTION

Current prostate cancer (PCa) guidelines primarily focus on localized or metastatic PCa. A multidisciplinary genitourinary oncology panel determined that additional guidance focusing on monitoring and management of biochemical recurrence (BCR) following radical therapy and non-metastatic castration-resistant prostate cancer (nmCRPC) was warranted.

METHODS

The most up-to-date national and international guidelines, consensus statements, and emerging phase 3 trials were identified and used to inform development of algorithms by a multidisciplinary genitourinary oncology panel outlining optimal monitoring and treatment for patients with non-metastatic PCa.

RESULTS

A total of eight major national and international guidelines/consensus statements published since 2015 and three phase 3 trials were identified. Working group discussions among the multidisciplinary genitourinary oncology panel led to the development of two algorithms: the first addressing management of patients with BCR following radical therapy (post-BCR), and the second addressing management of nmCRPC. The post-BCR algorithm suggests consideration of early salvage treatment in select patients and provides guidance regarding observation vs. intermittent or continuous androgen-deprivation therapy (ADT). The nmCRPC algorithm suggests continued ADT and monitoring for all patients, with consideration of treatment with apalutamide or enzalutamide for patients with high-risk disease (prostate-specific antigen [PSA] doubling time of ≤ 10 months).

CONCLUSIONS

Two treatment algorithms have been developed to guide the management of non-metastatic PCa and should be considered in the context of local guidelines and practice patterns.

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.