Prostate-specific antigen doubling time before onset of chemotherapy as a predictor of survival for hormone-refractory prostate cancer patients

The prognostic value of Eastern Cooperative Oncology Group performance status on overall survival among patients with metastatic prostate cancer: a systematic review and meta-analysis

Background

There is heterogeneity in the literature regarding the strength of association between Eastern Cooperative Oncology Group performance status (ECOG PS) and mortality. We conducted a systematic review and meta-analysis of studies reporting the prognostic value of ECOG PS on overall survival (OS) in metastatic prostate cancer (mPC).

Methods

PubMed was searched from inception to March 21, 2022. A meta-analysis pooling the effect of ECOG PS categories (≥2 vs. <2, 2 vs. <2, and ≥1 vs. <1) on OS was performed separately for studies including patients with metastatic castration-resistant prostate cancer (mCRPC) and metastatic castration-sensitive prostate cancer (mCSPC) using a random-effects model. Analyses were stratified by prior chemotherapy and study type.

Results

Overall, 75 studies, comprising 32,298 patients, were included. Most studies (72/75) included patients with mCRPC. Higher ECOG PS was associated with a significant increase in mortality risk, with the highest estimate observed among patients with mCRPC with an ECOG PS of ≥2 versus <2 (hazard ratio [HR]: 2.10, 95% confidence interval [CI]: 1.87-2.37). When stratifying by study type, there was a higher risk estimate of mortality among patients with mCRPC with an ECOG PS of ≥1 versus <1 in real-world data studies (HR: 1.98, 95% CI: 1.72-2.26) compared with clinical trials (HR: 1.32, 95% CI: 1.13-1.54; p < 0.001). There were no significant differences in the HR of OS stratified by previous chemotherapy.

Conclusion

ECOG PS was a significant predictor of OS regardless of category, previous chemotherapy, and mPC population. Additional studies are needed to better characterize the effect of ECOG PS on OS in mCSPC.

Investigation into the Optimal Strategy of Radium-223 Therapy for Metastatic Castration-Resistant Prostate Cancer

The optimal sequence and combination of radium-223 therapy (Ra-223) for castration-resistant prostate cancer with bone metastasis (mCRPC) remain unclear. This study aimed to explore the prognostic factors after Ra-223 administration and to determine the optimal treatment strategy. We enrolled 64 patients with mCRPC who underwent Ra-223 therapy from June 2016 to July 2022 at a single institution in Japan. Overall survival (OS) and pain progression-free survival (p-PFS), which was proposed as a measure of quality of life (QOL), were analyzed using Cox proportional hazards models and log-rank tests, and between-factor analysis was performed with the Mann–Whitney U (MWU) test. Univariable and multivariable analyses revealed prognostic factors; specifically, early treatment (≤third line), completion of six treatment cycles, low bone scan index (BSI) (<0.61), alkaline phosphatase (ALP) (<140 U/L), prostate-specific antigen (PSA; <22.9 ng/mL), lactate dehydrogenase (LDH; <240 U/L), high hemoglobin (Hb) (≥11.4 g/dL), and prior denosumab use significantly prolonged OS. Low BSI, low ALP, and early Ra-223 treatment also prolonged p-PFS in the log-rank tests. The MWU test showed that high BSI (≥0.61) was associated with high PSA and high ALP and a tendency for Hb to decrease. Late Ra-223 treatment (≥fourth line) was significantly associated with low Hb and high PSA. Early Ra-223 treatment was significantly associated with improved OS, and administering Ra-223 before novel hormonal or anticancer agents may be meaningful.

Clinical indicators for predicting prognosis after radium-223 administration in castration-resistant prostate cancer with bone metastases

BACKGROUND

Radium-223 (Ra-223) is a targeted alpha therapy that has been shown to prolong overall survival (OS) in patients with metastatic castration-resistant prostate cancer (mCRPC) with bone metastases. However, prognosis after Ra-223 administration varies among patients. The aim of the present study was to assess risk factors associated with the poor prognosis of patients treated with Ra-223.

METHODS

We retrospectively reviewed patients' records of treatment with Ra-223 between October 2016 and December 2019. All patients had mCRPC, bone metastasis, and no known visceral metastases, and received up to six cycles of Ra-223 (55 kBq/kg). Prognostic factors for OS were analyzed by Cox proportional hazards model and log-rank test.

RESULTS

We identified 42 patients who received at least one cycle of Ra-223 (median six cycles, range 1-6). Approximately two-thirds of patients had received at least two lines of therapy for mCRPC. The median age was 74 years, and the median follow-up duration was 13.6 months. The median OS time was 16.6 months. On multivariate analysis, PSA doubling time (PSADT) (0-3 months) at baseline, number of bone metastases (≥ 20), and treatment line of Ra-223 (4th-5th line) remained significantly correlated with the poor OS (HR 4.354, P = 0.003; HR 2.855, P = 0.020; and HR 4.871, P = 0.001, respectively).

CONCLUSIONS

Our study demonstrated that a shorter PSADT, a heavier volume of bone metastases, and a later treatment line before Ra-223 are poor prognostic factors for mCRPC patients. These newly discovered risk factors may help select patients who potentially have long-term OS after Ra-223 treatment.

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.

[Metastatic castration-resistant prostate cancer : Use of cabazitaxel taking into consideration current data]

BACKGROUND

At the 2016 ASCO annual meeting, new data from two randomized phase III studies concerning taxane-based chemotherapy as a treatment option for patients with metastatic castration-resistant prostate cancer (mCRPC) were presented.

OBJECTIVES

The focus is on the clinical impact of these data.

MATERIALS AND METHODS

A group of German experts in the field of urogenital-oncologic expertise discussed the clinical impact with respect to the current data.

RESULTS

The study results support the current clinical data. They confirm the efficacy and safety of cabazitaxel beyond first-line therapy with docetaxel for patients with mCRPC.

CONCLUSIONS

Cabazitaxel is an important treatment option after docetaxel progression. With respect to the performance status of a patient, it is adequate to reduce the dosage to 20 mg/m² cabazitaxel.

An integrative model of prostate cancer interaction with the bone microenvironment

Despite advanced efforts in early diagnosis, aggressive surgical treatment, and use of targeted chemotherapies, the prognosis for many cancers is still dismal. This emphasizes the necessity to develop new strategies for understanding tumor growth and metastasis. Here we use a systems approach that combines mathematical modeling and numerical simulation to develop a predictive computational model for prostate cancer and its subversion of the bone microenvironment. This model simulates metastatic prostate cancer evolution, progressing from normal bone and hormone levels to quantifiable diseased states. The simulations clearly demonstrate phenomena similar to those found clinically in prostate cancer patients. In addition, the major prediction of this model is the existence of low and high osteogenic states that are markedly different from one another. The existence and potential realization of these steady states appear to be mediated by the Wnt signaling pathway and by the effects of PSA on TGF-β, which encourages the bone microenvironment to evolve. The model is used to explore several potential therapeutic strategies, with some potential drug targets showing more promise than others: in particular, completely blocking Wnt and greatly increasing DKK-1 had significant positive effects, while blocking RANKL did not improve the outcome.

Predictors for progression of metastatic prostate cancer to castration-resistant prostate cancer in Indians

Background & objectives:

There is lack of data on natural history and progression of prostate cancer (PC) which have implications in the management of the disease. We undertook this retrospective study to analyze factors predicting progression of metastatic PC to castration-resistant prostate cancer (CRPC) in Indian men.

Methods:

Complete records of 223 of the 489 patients with metastatic PC were obtained from computerized data based system in a tertiary care hospital in north India between January 2000 to June 2012. Patients with follow up of < 6 months were excluded. Age (≤ and > 65 yr), baseline PSA (< and ≥ 50 ng/ml), bone scan and Gleason score (≤7 and >7) were recorded. Extent of bone disease (EOD) was stratified according to the number of bone lesions i.e., < 5, 5-10, > 10. CRPC was defined as two consecutive PSA rise of > 50 per cent from nadir or an absolute value of > 5 ng/ml.

Results:

Mean age of patients was 61.5 ± 12.45 yr and their PSA level was 325.6 ± 631.35 ng/dl. Of the 223 patients, 193 (86%) progressed to CRPC at median time of 10.7 (4-124) months. Median follow up was 24 (6-137) months. On univariate and multivariate analyses EOD on bone scan was found to be a significant predictor (P=0.006) for time to CRPC. Median time to CRPC was 10 months (CI 95%, 7.5-12.48) with >10 lesions or super scan versus 16 months (CI 95%, 10.3-21.6) with <10 bone lesion (P=0.01). Ninety (46.6 %) patients of CRPC died with median time to death from time of CRPC 21 (10-120) months.

Interpretation & conclusions:

Median time for progression of metastatic PC to CRPC ranged from 10-16 months depending on the extent of the bone involvement. In Indians, the aggressive course of advanced prostate cancer warrants further clinical trials to explore the need for additional treatment along with initial castration.

Thresholds for PSA doubling time in men with non-metastatic castration-resistant prostate cancer

OBJECTIVES

To examine whether prostate-specific antigen doubling time (PSADT) correlates with metastases, all-cause mortality (ACM), and prostate cancer-specific mortality (PCSM) and to identify PSADT thresholds that can be used clinically for risk stratification in men with M0 castration-resistant prostate cancer (CRPC).

MATERIALS AND METHODS

We collected data on 441 men with M0 CRPC in 2000-2015 at five Veterans Affairs hospitals. Cox models were used to test the association between log-transformed PSADT and the development of metastasis, ACM and PCSM. To identify thresholds, we categorized PSADT into 3-month groups and then combined groups with similar hazard ratios (HRs).

RESULTS

The median (interquartile range) follow-up was 28.3 (14.7-49.1) months. As a continuous variable, PSADT was associated with metastases, ACM and PCSM (HR 1.40-1.68, all P < 0.001). We identified the following PSADT thresholds: <3 months; 3-8.9 months; 9-14. months; and ≥15 months. As a categorical variable, PSADT was associated with metastases, ACM and PCSM (all P < 0.001). Specifically, PSADT <3 months was associated with an approximately ninefold increased risk of metastases (HR 8.63, 95% CI 5.07-14.7) and PCSM (HR 9.29, 95% CI 5.38-16.0), and a 4.7-fold increased risk of ACM (HR 4.71, 95% CI 2.98-7.43) on multivariable analysis compared with PSADT ≥15 months. The median times to metastasis for patients with PSADT <3, 3-8.9, 9-14.9 and ≥15 months were 9, 19, 40 and 50 months, respectively.

CONCLUSION

Prostate-specific antigen doubling time was a strong predictor of metastases, ACM and PCSM in patients with M0 CRPC. As with patients at earlier disease stages, <3, 3-8.9, 9-14.9 and ≥15 months are reasonable PSADT thresholds for risk stratification in men with M0 CRPC. These thresholds can be used for selecting high-risk men for clinical trials.

Feasibility of classical secondary hormonal therapies prior to docetaxel therapy in Japanese patients with castration-resistant prostate cancer: Multicenter retrospective study

BACKGROUND

We retrospectively analyzed castration-resistant prostate cancer (CRPC) patients treated with secondary hormonal therapies (SHTs) prior to docetaxel therapy.

METHODS

The cases of 73 CRPC patients who underwent docetaxel therapy in 2005-2011 at four hospitals in Ibaraki, Japan were analyzed. We determined the cause-specific survival (CSS) from the start of docetaxel therapy and the time point of CRPC diagnosis, and we compared the CSS achieved with/without prior classical SHTs, which were defined as low-dose steroid and estramustine phosphate.

RESULTS

Of the 73 enrolled patients, 26 underwent docetaxel therapy (DOC group), and 47 underwent SHTs (SHTs-DOC group) as the initial treatment for CRPC. In the docetaxel therapy, the rate of prostate-specific antigen responses were higher in the DOC group compared with the SHTs-DOC group (76.9% vs. 44.7%, P = 0.0066). The median CSS from the docetaxel therapy initiation was not significant but longer in the DOC group than in the SHTs-DOC group (23.4 months vs. 16.6 months, P = 0.0969). However, the median CSS from the time of CRPC diagnosis did not significantly differ between the DOC and SHTs-DOC groups (23.4 months vs. 24.7 months, P = 0.9233). In a univariate analysis, pain and visceral metastasis appeared to be risk factors for the CSS in the SHTs-DOC group. The patients with pain and/or visceral metastasis had significantly poorer survival than those without these factors in the SHTs-DOC group (31.5 months vs. 16.8 months, P = 0.0053).

CONCLUSION

The induction of SHTs prior to docetaxel therapy is an acceptable treatment option with some survival benefits for CRPC patients without pain and visceral metastases.

[Chemotherapy of prostate cancer]

The prognosis of patients with advanced prostate cancer has improved over the last few years. In addition to the new antihormonal treatment, chemotherapy with agents such as docetaxel and cabazitaxel has contributed to the improved prognosis. After the introduction of abiraterone and enzalutamide, conventional chemotherapy seemed to become less important but the discussion about the use of chemotherapy for hormone-sensitive prostate cancer has gained attention again. Combining docetaxel with conventional androgen deprivation therapy (ADT) improves survival compared to ADT alone. In addition, docetaxel and cabazitaxel now represent the standard for first and second line therapy in patients with castration-resistant prostate cancer.

The Present and Future of Biomarkers in Prostate Cancer: Proteomics, Genomics, and Immunology Advancements

Prostate cancer (PC) is the second most common form of cancer in men worldwide. Biomarkers have emerged as essential tools for treatment and assessment since the variability of disease behavior, the cost and diversity of treatments, and the related impairment of quality of life have given rise to a need for a personalized approach. High-throughput technology platforms in proteomics and genomics have accelerated the development of biomarkers. Furthermore, recent successes of several new agents in PC, including immunotherapy, have stimulated the search for predictors of response and resistance and have improved the understanding of the biological mechanisms at work. This review provides an overview of currently established biomarkers in PC, as well as a selection of the most promising biomarkers within these particular fields of development.

[Metastasized prostate cancer. Position paper on the use of chemotherapy]

BACKGROUND

Antihormonal and cytotoxic therapy options are available for the therapy of metastasized prostate cancer (mPC). Because no comparative studies are available, especially for castration-resistant prostate cancer (mCRCP), it remains unclear which patients will profit best from which therapy.

OBJECTIVES

Previous data on the sequence of the various therapy options show that correct selection of the first line therapy for mCRPC can have an influence on the prognosis of the patient. In this position paper the various therapy options are critically illustrated and the clinical and pathohistological criteria for selection of the first line therapy of mCRPC are discussed.

RESULTS

Molecular markers are an important aid for future patient selection and individualized therapy for optimal use of the available forms of therapy.

Expert opinion on first-line therapy in the treatment of castration-resistant prostate cancer

Treatment of metastatic castration-resistant prostate cancer (mCRPC) has been revolutionized in recent years. It is well known that androgen receptor is still active in most patients with disease progression and serum testosterone levels <50 ng/dL. Moreover, further hormonal maneuvers, either through decreasing androgen levels (abiraterone) or by targeting the androgen receptor (AR) pathway (enzalutamide), prolong survival. In addition, a new cytostatic able to overcome docetaxel resistance, cabazitaxel, and the radioisotope radium 223 have been incorporated to the armamentarium of mCRPC. mCRPC is not only a heterogeneous tumor, it changes over time developing neuroendocrine features or selection of clones resistant to hormonal maneuvers. In addition, the multiplicity of current treatments, make it necessary to design algorithms that help the specialist to choose the most appropriate treatment for a particular patient. The lack of randomized trials comparing face to face the different available options limit the scope of this review. In this article, the authors describe the prognostic factors for first line therapy in patients with mCRPC, and propose a treatment algorithm for mCRPC based on the levels of scientific evidence available and, if not available, on the consensus between medical professionals. Finally, the panel discuss how to define progressive disease in the setting of mCRPC and treatment with targeted therapies.

Bone-related Parameters are the Main Prognostic Factors for Overall Survival in Men with Bone Metastases from Castration-resistant Prostate Cancer

BACKGROUND

Previous studies have reported on prognostic factors for castration-resistant prostate cancer (CRPC); however, most of these studies were conducted before docetaxel chemotherapy was approved for CRPC.

OBJECTIVE

To evaluate the prognostic value of multiple parameters in men with bone metastases due to CRPC using a contemporary dataset.

DESIGN, SETTING, AND PARTICIPANTS

The analysis included 1901 patients with metastatic CRPC enrolled in an international, multicenter, randomized, double-blind phase 3 trial conducted between May 2006 and October 2009.

OUTCOME MEASURES AND STATISTICAL ANALYSIS

We developed multivariate validated Cox proportional hazards models and nomograms to estimate 12-mo and 24-mo survival probabilities and median survival time.

RESULTS AND LIMITATIONS

The median (95% confidence interval) overall survival was 20 (18, 21) mo. The final model included 12 of the 15 potential prognostic variables evaluated (concordance index 0.72). Seven bone-related variables were associated with longer survival in the final model: alkaline phosphatase ≤143 U/l (p<0.0001); bone-specific alkaline phosphatase (BSAP) <146 U/l (p<0.0001); corrected urinary N-telopeptide (uNTx) ≤50 nmol/mmol (p=0.0008); mild or no pain (Brief Pain Inventory-Short Form [BPI-SF] score ≤4) (p<0.0001); no previous skeletal-related event (SRE; p=0.0002); longer time from initial diagnosis to first bone metastasis (p<0.0001); and longer time from first bone metastasis to randomization (p<0.0001). Other significant predictors of improved survival included prostate-specific antigen (PSA) level <10 ng/ml (p<0.0001), hemoglobin >128g/l (p<0.0001), absence of visceral metastases (p<0.0001), Eastern Co-operative Oncology Group (ECOG) score ≤1 (p=0.017), and younger age (p=0.008). Nomograms were generated based on the parameters included in the final validated models (with/without uNTx and BSAP). One limitation was that lactate dehydrogenase (LDH) levels, a known prognostic factor, were not available in this study.

CONCLUSIONS

Bone-related parameters are strong prognostic variables for overall survival in patients with bone metastases from CRPC.

PATIENT SUMMARY

Survival time is variable in patients with bone metastases from prostate cancer. We found that factors related to bone help to predict how long a patient will live.

KLK3, PCA3, and TMPRSS2-ERG expression in the peripheral blood mononuclear cell fraction from castration-resistant prostate cancer patients and response to docetaxel treatment

BACKGROUND

To monitor systemic disease activity, the potential of circulating tumor cells (CTCs) bears great promise. As surrogate for CTCs we measured KLK3, PCA3, and TMPRSS2-ERG messenger RNA (mRNA) in the peripheral blood mononuclear cell (PBMC) fraction from a castration-resistant prostate cancer (CRPC) patient cohort and three control groups. Moreover, biomarker response to docetaxel treatment was evaluated in the patient group.

METHODS

Blood samples from 20 CRPC patients were analyzed at four different time points (prior to docetaxel treatment, at 9 weeks, 27 weeks, and 2 months after treatment). Blood was drawn once from three control groups (10 age-matched men, 10 men under 35 years of age, 12 women). All samples were analyzed for KLK3, PCA3, and TMPRSS2-ERG mRNA by using a quantitative nucleic acid amplification assay with gene-specific primers in the complementary DNA synthesis.

RESULTS

At baseline, mRNA for KLK3 was detected in 17 (89%, 95% CI 76-100%), PCA3 in 10 (53%, 95% CI 30-75%), and TMPRSS2-ERG in seven of 19 evaluable patients (37%, 95% CI 15-59%). In contrast, the blood samples from all 32 healthy volunteers were reproducible negative for all markers. In response to docetaxel treatment, KLK3 levels decreased in 80% (95% CI 60-100%), PCA3 in 89% (95% CI 68-100%), and TMPRSS2-ERG in 86% (95% CI 60-100%) of patients.

CONCLUSIONS

The feasibility of a highly sensitive modified nucleic acid amplification assay to assess KLK3, PCA3, and TMPRSS2-ERG mRNA in the PBMC fraction from CRPC patients was demonstrated. Moreover, response of these markers to systemic treatment was shown.

Potential value of rapid prostate-specific antigen decline in identifying primary resistance to abiraterone acetate and enzalutamide

ABSTRACT: 

Aim: To identify factors predicting primary resistance to new-generation hormonal agents (NHAs), abiraterone acetate and enzalutamide in patients with castration-resistant prostate cancer (CRPC). Patients & methods: Our hospital has conducted two successive named patient NHA programs. A total of 57 patients with progressive CRPC previously treated with first-line docetaxel-based chemotherapy received standard NHA doses: abiraterone acetate 1000 mg once-daily combined with prednisone (5 mg twice daily) or enzalutamide 160 mg once-daily. Patients, who were assessed monthly to check their hematological parameters and prostate-specific antigen (PSA) levels, also underwent imaging investigations every 3–4 months. In total, 24 variables were assessed as potential predictors of primary NHA resistance. Results: Univariate analysis indicated that baseline pain and lactate dehydrogenase levels, and PSA levels after 1 month’s treatment were predictive of primary NHA resistance. Only the predictive value of PSA levels after 1 month of treatment was confirmed at multivariate analysis. This factor strongly predicted progression-free and overall survival. Conclusion: Results suggest the use of a simple and rapid method of identifying patients with primary resistance to NHAs: patients not achieving a ≥50% reduction in PSA levels within the first treatment month should undergo intensive investigations to verify whether they have primary resistance to NHAs.

The utility of prostate-specific antigen in the management of advanced prostate cancer

To review current prostate-specific antigen (PSA) metrics used in monitoring treatment of advanced prostate cancer, with a specific focus on castration-resistant prostate cancer (CRPC) therapies. Explore what is known about the correlation between PSA and androgen levels as well as underlying reasons for persistent PSA expression and serum elevation in CRPC, and outline suggestions for use of PSA in managing patients with advanced prostate cancer. A comprehensive search of the PubMed database for English language articles through April 2012 was performed using the following Medical Subject Headings (MeSH) keywords or terms, alone or in combination: 'prostate cancer'; 'prostate cancer treatment'; 'prostate cancer outcomes'; 'prostate-specific antigen'; 'androgen receptor'; 'advanced prostate cancer'; 'castration-resistant prostate cancer'; 'biomarkers'. Bibliographies of relevant articles were searched for additional references. Relevant medical society and regulatory agency web sites from the USA and Europe were accessed for issued guidance on PSA use. PSA doubling time (PSADT) is a useful metric for determining which patients should be considered for androgen-deprivation therapy (ADT) after failing local treatment or for second-line therapies after failing ADT. However, it is not a validated surrogate for survival and no therapy has received regulatory approval based upon PSADT characteristics. PSA nadir and time-to-nadir have been identified as possible prognostic markers for patients receiving ADT. There is no universally accepted definition for PSA progression, nor is PSA progression a regulatory-approved surrogate for clinical progression in drug approval trials. PSA responses to second-line therapies can vary and are not considered by regulatory agencies as valid surrogates for clinical endpoints, so they must be assessed in the context of each individual therapy and trial design. PSA expression in CRPC is often a reflection of persistent androgen receptor activity. While we can provide guidance for use of PSA monitoring in managing patients with advanced prostate cancer based on the data at hand, there is an urgent need for prospective analyses of refined PSA metrics in conjunction with newer prostate cancer biomarkers in clinical trials to provide stronger evidence for their roles as surrogate endpoints.

Perspectives on treatment of metastatic castration-resistant prostate cancer

The arrival of several new agents--cabazitaxel, abiraterone acetate, enzalutamide, and radium-223--is changing the treatment options and management of patients with metastatic castration-resistant prostate cancer (mCRPC). Many other novel agents are also being investigated. As new drugs become approved, new treatment strategies and markers to best select which patients will best respond to which drug are needed. This review article is a summary of a European Treatment Practices Meeting, which was convened to discuss these latest data on novel agents and current treatment strategies in the mCRPC setting.

[Recomendations on the management of controversies in advanced castrate-resistant prostate cancer]

CONTEXT

Controversies and uncertainties among integral management of advanced castration resistant prostate cancer continue to exist despite the number of evidence based clinical practice guidelines published with high international consensus.

OBJECTIVE

To develop a document that reviews the management of controversies in advanced castration resistant prostate cancer, with recommendations from the definition, to the management in hormonal maneuvers, first-line treatment and second-line with new treatments as cabazitaxel or abirarerone and the multidisciplinary approach of the pathology with the goal of finding the most efficient, best time to act and safety.

EVIDENCE ACQUISITION

Two meetings of a multidisciplinary group of experts involved in the management of this disease (Oncologist and Urologist) where pooled analysis of original literature and reached consensus document of recommendations on castration resistant prostate cancer, reviewing and attempting to address the current controversies of the disease.

EVIDENCE SYNTHESIS

This document is endorsed by the corresponding Scientific Associations and Working Groups involved in the current management of Genitourinary Tumours: the Spanish Association of Urology (AEU) with the Uro-Oncoloy Group (GUO) and the Spanish Oncology of Genitourinary Group (SOGUG).

CONCLUSIONS

With the adaptation and implementation of this Document of Recommendations for clinical practice are available for the first time, a real road map for quality, efficiency and safety in the management of patients with CRPC.

PSA Velocity and Doubling Time in Diagnosis and Prognosis of Prostate Cancer

Cancer is a growth process and it is natural that we should be concerned with how the routinely used marker of prostate cancer tumour burden - PSA - changes over time. Such change is measured by PSA velocity or PSA doubling time, described in general as "PSA kinetics". However, it turns out that calculation of PSA velocity and doubling time is far from straightforward. More than 20 different methods have been proposed, and many of these give quite divergent results. There is clear evidence that PSA kinetics are critical for understanding prognosis in advanced or relapsed prostate cancer. However, PSA kinetics have no value for men with an untreated prostate: neither PSA velocity nor doubling time have any role in diagnosing prostate cancer or providing a prognosis for men before treatment.

Prostate-specific antigen kinetics as a surrogate endpoint in clinical trials of metastatic castration-resistant prostate cancer: a review

Prostate cancer is the most common cancer in men. Overall survival is considered the best endpoint for clinical trials, but it is difficult to use in phase-2 studies. Although the reduction of PSA after cytotoxic chemotherapy has been identified as a valid surrogate for overall survival, it has not proven reliable for the evaluation of many biologics. Moreover, the PSA progression-free survival at 3 months was validated only for cytotoxic drugs, and the various measures of progression/delay have not been confirmed by large studies. Ultimately, outside of overall survival, no measure has been validated as a surrogate endpoint after treatment with targeted therapies and vaccine therapy. The PSA levels have a great variability and, theoretically, the use of measures of cell kinetics and PSA may be the most reliable approach to estimate the behavior of metastatic disease. Some measures of PSA kinetics have been well developed in the clinical castration-resistant prostate cancer, the PSA doubling time and the growth rate constant. The studies about the kinetics of PSA measures are reviewed and discussed. To date, studies that consider the measures of PSA kinetics as surrogate endpoints are still very few. However in the near future, the drug evaluation can not proceed separately, with distinct endpoints between cytotoxic and non-cytotoxic agents. Therefore, extensive analysis and validation of measures of kinetics derived from PSA, and candidates for a role for surrogate endpoint, will be needed in phase-3 studies, in order to test their effectiveness in different disease scenarios.

Biomarkers in the management and treatment of men with metastatic castration-resistant prostate cancer

CONTEXT

We have recently witnessed a rapid increase in the number of effective systemic agents for men with metastatic castration-resistant prostate cancer (CRPC), including novel hormonal therapies (abiraterone acetate and MDV3100), immunotherapies (sipuleucel-T), chemotherapies (cabazitaxel), and bone microenvironment targeting agents (denosumab, radium 223). Given the increasing complexity of treatment decisions for this disease, major research and clinical priorities are (1) finding biomarkers that enable an understanding of the natural history and complex biology of this heterogeneous malignancy, (2) defining predictive biomarkers that identify men most likely to benefit from a given therapy, and (3) identifying biomarkers of early response or progression to optimize outcomes.

OBJECTIVE

In this review, we discuss existing and potential biomarkers in CRPC and how they may currently inform prognosis, aid in treatment selection (predictive value), and relate to survival outcomes (surrogacy).

EVIDENCE ACQUISITION

PubMed-based literature searches and abstracts through September 2011 provided the basis for this literature review as well as expert opinion.

EVIDENCE SYNTHESIS

We address blood and urine-based biomarkers such as prostate-specific antigen, lactate dehydrogenase, total and bone alkaline phosphatase and other bone turnover markers, hemoglobin, and circulating tumor cells in the context of prognosis, prediction, and patient selection for therapy. Given the inherent problems associated with defining progression-free survival in CRPC, the importance of biomarker development and the needed steps are highlighted. We place the discussion of biomarkers within the context of the design/intent of a trial and mechanism of action of a given systemic therapy. We discuss novel biomarker development and the pathway for surrogate or predictive biomarkers to become credentialed as useful tests that inform therapeutic decisions.

CONCLUSIONS

A greater understanding of biomarkers in CRPC permits a more personalized approach to care that maximizes benefit and minimizes harm and can inform clinical trials tailored to men most likely to derive benefit.

TROPIC: Phase III trial of cabazitaxel for the treatment of metastatic castration-resistant prostate cancer

For patients with metastatic castration-resistant prostate cancer (mCRPC), the current standard of care is chemotherapy involving the tubulin-binding taxane docetaxel. However, as the tumor cells become resistant to docetaxel-based therapy, disease progression is inevitable, and until recently there was no further available treatment beyond palliative care. In June 2010, cabazitaxel, a next-generation taxane, was approved by the US FDA for the treatment of mCRPC that has progressed after docetaxel therapy. This article describes the background and rationale of cabazitaxel’s development and the clinical study program that led to its FDA approval, focusing on the Phase III TROPIC trial that demonstrated the efficacy of cabazitaxel plus prednisone in the treatment of mCRPC. Future development of this therapy and others under investigation is discussed.

Serum miRNA-21: elevated levels in patients with metastatic hormone-refractory prostate cancer and potential predictive factor for the efficacy of docetaxel-based chemotherapy

BACKGROUND

miR-21 has been recognized as an "onco-microRNA" with the activity of negatively modulating the expression of tumor-suppressor genes. However, its role in prostate cancer (CaP) has not been well-documented. We designed this study to assess the potential function of serum miR-21 in the progression of CaP.

METHODS

Serum samples of 56 patients, including 20 patients with localized CaP, 20 with androgen-dependent prostate cancer (ADPC), 10 with hormone-refractory prostate cancer (HRPC), and 6 with benign prostatic hyperplasia (BPH), were collected for the measurement of miR-21. The 10 HRPC patients were administered docetaxel-based chemotherapy. Quantification of miR-21 was assayed by specific TaqMan qRT-PCR.

RESULTS

Serum miR-21 level was found to correlate to serum PSA level in patients with ADPC and HRPC, P = 0.012 and 0.049, respectively. There was no significant difference in serum miR-21 level between BPH, localized CaP and ADPC with PSA level <4 ng/ml. Higher levels of miR-21 were detected in patients with HRPC and ADPC with PSA level >4 ng/ml. Six of the 10 HRPC patients reached partial remission with a decreased PSA level of >50% after chemotherapy. Serum miR-21 levels were higher in patients who were resistant to docetaxel-based chemotherapy when compared to those sensitive to chemotherapy, P = 0.032.

CONCLUSIONS

Serum miR-21 levels are elevated in HRPC patients, especially in those resistant to docetaxel-based chemotherapy. It may be applicable as a marker to indicate the transformation to hormone refractory disease, and a potential predictor for the efficacy of docetaxel-based chemotherapy.

PSA doubling time for prediction of [(11)C]choline PET/CT findings in prostate cancer patients with biochemical failure after radical prostatectomy

PURPOSE

Previous studies have shown that the positive detection rate of [(11)C]choline positron emission tomography/computed tomography (PET/CT) depends on prostate-specific antigen (PSA) plasma levels. This study compared PSA levels and PSA doubling time (PSADT) to predict [(11)C]choline PET/CT findings.

METHODS

PSADT was retrospectively calculated in 170 prostate cancer (PCa) patients with biochemical failure after radical prostatectomy who underwent [(11)C]choline PET/CT. PSADT was calculated as PSADT = ln2/m, where m is the slope of the linear regression line of the natural log of PSA values. At least three PSA measurements were used (median: 4; range: 3-16), separated by at least 3 months, each with a minimum increase of 0.20 ng/ml. PET/CT findings were validated using criteria based on histological analysis and clinical and imaging data. Statistical analysis was performed using the t test, chi-square test, analysis of variance and binary logistic regression. Regression-based coefficients were used to develop a nomogram predicting the probability of positive [(11)C]choline PET/CT and 200 bootstrap resamples were used for internal validation.

RESULTS

The median PSA was 1.25 ng/ml (range: 0.23-48.6 ng/ml), and the median PSADT was 7.0 months (range: 0.97-45.3 months). [(11)C]choline PET/CT was positive in 75 of 170 patients (44%). PET/CT findings were validated using histological criteria (11%) and clinical and imaging criteria (89%). The overall accuracy of [(11)C]choline PET/CT was 88%. Multivariate logistic regression showed that high PSA and short PSADT were significant (p < 0.05) predictors of positive [(11)C]choline PET/CT [PSA: odds ratio (OR) = 1.43; 95% confidence interval (CI): 1.15-1.78; PSADT: OR = 1.12; 95% CI: 1.04-1.21]. The percentage of patients with positive [(11)C]choline PET/CT was 27% for PSADT >6 months, 61% for PSADT between 3 and 6 months and 81% for PSADT <3 months. The percentage of patients who displayed pathological [(11)C]choline uptake in the skeleton significantly increased (p < 0.05) from 3% for PSADT >6 months to 52% for PSADT <3 months. Conversely, patients who displayed pathological [(11)C]choline uptake in the prostatectomy bed were 0% for PSADT <3 months and 17% for PSADT >6 months (p < 0.05). A nomogram based on age, PSA, PSADT, time to trigger PSA, Gleason score, pathological stage and androgen deprivation therapy demonstrated bootstrap-corrected predictive accuracy of 81%.

CONCLUSION

Like PSA, PSADT is an independent predictor of [(11)C]choline PET/CT. [(11)C]choline PET/CT is very sensitive to PCa tumour growth, as reflected by PSA kinetics. PSADT should be taken into account by physicians when referring PCa patients for [(11)C]choline PET/CT.

Predictors of clinical metastasis in prostate cancer patients receiving androgen deprivation therapy: results from CaPSURE

BACKGROUND

Virtually all patients with prostate cancer who receive androgen deprivation therapy (ADT) will ultimately develop evidence of resistance to treatment. The prognosis for patients who develop metastatic castrate-resistant disease is reported to be poor, with overall survival historically estimated to be 24 to 36 months. The goal of the current study was to identify predictors of clinical disease progression in patients with prostate cancer who were receiving ADT.

METHODS

Of the 13,740 men with biopsy-proven prostate cancer who were enrolled in the Cancer of the Prostate Strategic Urological Research Endeavor (CaPSURE) database from 1995 to 2007, 4003 men treated with ADT after diagnosis without evidence of metastases at treatment initiation were identified. The primary endpoint was the development of bone metastasis. Clinical and pathologic characteristics were compared between patients who developed metastasis and those who did not using chi-square tests in a Cox proportional hazards regression model.

RESULTS

The mean age of the men in the cohort was 70 years (range, 39-94 years). One hundred ninety-one men (4.8%) progressed to metastatic disease at a median of 18 months from the initiation of ADT (range, 1-139 months). On multivariate analyses, risk category (hazards ratio [HR], 2.58; P < .0001), percent of biopsies positive >33% (HR, 3.36; P = .003), age </=65 years at diagnosis (HR, 2.11; P = .001, and prostate-specific antigen velocity on ADT (HR, 1.04; P < .001) were found to be significantly associated with the development of metastatic disease after ADT.

CONCLUSIONS

Younger men with high-risk disease appear to have worse prognosis than older men with similar disease. This, along with the other prognostic variables established in the current study, may help identify candidates for clinical trials evaluating secondary treatments for patients with castrate-resistant disease.

Early prostate-specific antigen changes and the diagnosis and prognosis of prostate cancer

PURPOSE OF REVIEW

To delineate how recent findings on prostate-specific antigen (PSA) can improve prediction of risk, detection, and prediction of clinical endpoints of prostate cancer (PCa).

RECENT FINDINGS

The widely used PSA cut-point of 4.0 ng/ml increasingly appears arbitrary, but no cut-point achieves both high sensitivity and high specificity. The accuracy of detecting PCa can be increased by additional predictive factors and a combinations of markers. Evidence implies that a panel of kallikrein markers improves the specificity and reduces costs by eliminating unnecessary biopsies. Large, population-based studies have provided evidence that PSA can be used to predict PCa risk many years in advance, improve treatment selection and patient care, and predict the risk of complications and disease recurrence. However, definitive evidence is currently lacking as to whether PSA screening lowers PCa -specific mortality.

SUMMARY

PSA is still the main tool for early detection, risk stratification, and monitoring of PCa. However, PSA values are affected by many technical and biological factors. Instead of using a fixed PSA cut-point, using statistical prediction models and considering the integration additional markers may be able to improve and individualize PCa diagnostics. A single PSA measurement at early middle age can predict risk of advanced PCa decades in advance and stratify patients for intensity of subsequent screening.

What is the real impact of bone pain on survival in patients with metastatic hormone-refractory prostate cancer treated with docetaxel?

OBJECTIVES

To determine the benefit of starting early chemotherapy with docetaxel (the recommended first-line treatment) for patients with asymptomatic metastatic hormone-refractory prostate cancer (HRPC).

PATIENTS AND METHODS

Data were analysed from 145 patients with HRPC treated with chemotherapy between February 2000 and June 2002 in one French centre. Eligible patients were categorized into three groups according to the bone pain at baseline, i.e. minimal/no pain, mild, and moderate/severe pain. The primary endpoint was the effect of bone pain on overall survival (OS).

RESULTS

Docetaxel was administered to 67% of patients. The risk of death was 1.56 and 2.11 times higher for patients with mild or moderate/severe pain than for those with minimal/no pain (P = 0.027). The median (95% confidence interval (CI)) OS was 23.1 (18.5-27.6) and 14.1 (8.9-19.2) months (P = 0.001, log-rank-test) for patients with minimal pain or no pain treated with docetaxel-based chemotherapy compared with mitoxantrone, respectively. The prostate-specific antigen doubling time (PSA-DT) had a significant effect on OS in patients with minimal/no pain, with a median of 32.4 and 16.5 months for a PSA-DT of >or=45 and <45 days, respectively (P < 0.001).

CONCLUSIONS

Our results suggest that patients with HRPC and minimal or no bone pain could have better survival than those with mild pain or moderate to severe pain, independent of the treatment administered. In addition, patients with HRPC and minimal or no bone pain treated with docetaxel-based chemotherapy have a significantly better OS than those treated with mitoxantrone. The PSA-DT can be useful to identify asymptomatic patients who are candidates for early treatment.

Systematic review of pretreatment prostate-specific antigen velocity and doubling time as predictors for prostate cancer

PURPOSE

Pretreatment prostate-specific antigen (PSA) dynamics (PSA velocity and PSA doubling time) are widely advocated as useful prognostic markers in prostate cancer. We aimed to assess the published evidence for the clinical utility of PSA dynamics in this population.

METHODS

We conducted a systematic review of studies published before March 2007 in which a PSA dynamic (velocity or doubling time) was calculated in patients before definitive treatment, a subsequent event (such as biopsy or recurrence) was ascertained, and the association between the two was analyzed. Our principal end point was the type of analysis reported, particularly whether the predictive accuracy of a statistical model that included both absolute PSA level and a PSA dynamic was compared with that of a model that included only PSA.

RESULTS

Eighty-seven articles were eligible for analysis. The most common end points were biopsy (42 articles), and either recurrence (14 articles) or metastases or death (14 articles) after definitive therapy. Although PSA dynamics were generally found to be associated with outcome, only one article compared predictive accuracy of models with and without a PSA dynamic: this reported that PSA velocity improved prediction slightly (from 0.81 to 0.83), but was subject to verification bias. No article used decision analytic methods to examine the clinical impact of PSA dynamics.

CONCLUSION

There is little evidence that calculation of PSA velocity or doubling time in untreated patients provides predictive information beyond that provided by absolute PSA level alone. We see no justification for the use of PSA dynamics in clinical decision making before treatment in early-stage prostate cancer.

When to start cytotoxic therapy in asymptomatic patients with hormone refractory prostate cancer?

Until the publication of two pivotal trials, there were no treatment options available that did prolong the overall survival in men with hormone refractory prostate cancer (HRPC). Currently, docetaxel-based cytotoxic treatment is considered as a standard of care in all the patients with progressive metastatic HRPC. The use of this treatment regimen renders an equal survival benefit in all the subgroups of patients; however, there is a substantial difference in the overall survival between the subgroups. This review addresses the optimal timing of the cytotoxic treatment in asymptomatic patients with HRPC.

Advantages of prostate-specific antigen (PSA) clearance model over simple PSA half-life computation to describe PSA decrease after prostate adenomectomy

OBJECTIVES

A population kinetic approach based on PSA clearance (CL(PSA)) may be a more rational strategy to characterize prostate-specific antigen (PSA) decrease profile after prostate surgery than the commonly used method (half-life from mono/bi-exponential models).

METHODS

We used 182 post-adenomectomy PSA concentrations from 56 benign prostatic hyperplasia patients to build, with NONMEM software, a multi-exponential and a CL(PSA) model for comparison.

RESULTS

The best multi-exponential model was PSA(t)=4.96e(-)(0.269t)+3.10e(-)(0.16t)+0.746e(+)(0.0002t) with a stable median residual PSA at 0.64 ng/mL. The best model parametrized with clearance was CL(PSA)=0.0229()(AGE/69)(3.78). Akaike information criteria and standard errors favored the CL(PSA) model. Median peripheral zone and transitional zone productions were 0.034 ng/mL/cm(3) and 0.136 ng/mL/g. A threshold at 2 ng/mL on day 90 allowed for a diagnostic of biochemical relapse diagnostic.

CONCLUSIONS

The population CL(PSA) model was superior to the multi-exponential approach for investigating individual post-adenomectomy PSA decreases.

Current applications for prostate-specific antigen doubling time

OBJECTIVE

To review the current status of prostate-specific antigen doubling time (PSADT) as it pertains to the evolution of prostate cancer (PCa), specifically assessing its role in the following four stages: before diagnosis, prior to definitive treatment, following treatment including salvage therapy after recurrence, and lastly, after onset of androgen-insensitive PCa.

METHODS

We searched PubMed literature for current articles on PSADT using the key words listed for this review and, where possible, selected those with significant levels of evidence that were deemed relevant, seminal, or controversial. We summarized the data regarding PSADT as a marker for diagnosis and disease characterization, as well as a predictor of progression, response to treatment, and mortality.

RESULTS

PSADT may offer an advantage in providing a more dynamic picture of tumor behavior, providing clues regarding the relative aggressiveness of the underlying pathology. Evidence points toward a role for PSADT in the management of PCa, specifically in active surveillance, disease recurrence after treatment, and in androgen-independent PCa. PSADT is an important prognostic factor that may serve as an auxiliary end point for cancer-specific survival; however, optimal cut-off points denoting risk remain debatable.

CONCLUSIONS

PCa management requires risk stratification with a combination of variables, PSADT being one of the most reliable predictors. It is now a parameter included in many predictive nomograms and in treatment guidelines for expectant management and salvage therapy.