Development of a multigenomic liquid biopsy (PROSTest) for prostate cancer in whole blood

INTRODUCTION

We describe the development of a molecular assay from publicly available tumor tissue mRNA databases using machine learning and present preliminary evidence of functionality as a diagnostic and monitoring tool for prostate cancer (PCa) in whole blood.

MATERIALS AND METHODS

We assessed 1055 PCas (public microarray data sets) to identify putative mRNA biomarkers. Specificity was confirmed against 32 different solid and hematological cancers from The Cancer Genome Atlas (n = 10,990). This defined a 27-gene panel which was validated by qPCR in 50 histologically confirmed PCa surgical specimens and matched blood. An ensemble classifier (Random Forest, Support Vector Machines, XGBoost) was trained in age-matched PCas (n = 294), and in 72 controls and 64 BPH. Classifier performance was validated in two independent sets (n = 263 PCas; n = 99 controls). We assessed the panel as a postoperative disease monitor in a radical prostatectomy cohort (RPC: n = 47).

RESULTS

A PCa-specific 27-gene panel was identified. Matched blood and tumor gene expression levels were concordant (r = 0.72, p < 0.0001). The ensemble classifier ("PROSTest") was scaled 0%-100% and the industry-standard operating point of ≥50% used to define a PCa. Using this, the PROSTest exhibited an 85% sensitivity and 95% specificity for PCa versus controls. In two independent sets, the metrics were 92%-95% sensitivity and 100% specificity. In the RPCs (n = 47), PROSTest scores decreased from 72% ± 7% to 33% ± 16% (p < 0.0001, Mann-Whitney test). PROSTest was 26% ± 8% in 37 with normal postoperative PSA levels (<0.1 ng/mL). In 10 with elevated postoperative PSA, PROSTest was 60% ± 4%.

CONCLUSION

A 27-gene whole blood signature for PCa is concordant with tissue mRNA levels. Measuring blood expression provides a minimally invasive genomic tool that may facilitate prostate cancer management.

Comparison of Joint and Landmark Modeling for Predicting Cancer Progression in Men With Castration-Resistant Prostate Cancer: A Secondary Post Hoc Analysis of the PREVAIL Randomized Clinical Trial

IMPORTANCE

Dynamic prediction models may help predict radiographic disease progression in advanced prostate cancer.

OBJECTIVE

To assess whether dynamic prediction models aid prognosis of radiographic progression risk, using ongoing longitudinal prostate-specific antigen (PSA) assessments.

DESIGN, SETTING, AND PARTICIPANTS

This prognostic study used data from the PREVAIL study to compare dynamic models for predicting disease progression. The PREVAIL study was a phase 3, multinational, double-blind, placebo-controlled randomized clinical trial of enzalutamide for prostate cancer conducted from September 2010 to September 2012. A total of 773 men with metastatic castration-resistant prostate cancer (CRPC) who had never received chemotherapy and had no baseline visceral disease were treated with enzalutamide. For illustration, 4 patients were selected based on PSA kinetics or PSA response in case studies. Data were analyzed from July 2018 to September 2019.

MAIN OUTCOMES AND MEASURES

Landmark and joint models were applied to dynamically predict radiographic progression-free survival (PFS) using longitudinal PSA profile, baseline PSA, lactate dehydrogenase, and hemoglobin levels. The main outcome was radiographic PFS as predicted using landmark and joint models. Current PSA and PSA change were considered longitudinal biomarkers possibly associated with radiographic PFS. Predictive performance was evaluated using Brier score for overall prediction errors (PEs) and area under the curve (AUC) for model discriminative capability. Case studies were illustrated using dynamic prediction plots.

RESULTS

A total of 763 men with metastatic CRPC treated with enzalutamide (mean [SD] age, 71.2 [8.5] years; mean [SD] body mass index [calculated as weight in kilograms divided by height in meters squared], 28.4 [4.6]) were included in the analysis. Current PSA and PSA change were associated with radiographic PFS in all models. Adding the PSA slope, compared with the landmark models using current PSA alone, improved the prediction of 5-month prospect of radiographic progression, with relative gains of 5.7% in prediction (PE [SE], 0.132 [0.008] vs 0.140 [0.008]) and 7.7% in discrimination (AUC [SE], 0.800 [0.018] vs 0.743 [0.018]) at month 10. In joint models with linear vs nonlinear PSA, prediction of 5-month risk of radiographic progression was improved when PSA trajectories were not assumed to be linear, with 8.0% relative gain in prediction (PE [SE], 0.150 [0.006] vs 0.138 [0.005]) and 19.4% relative gain in discrimination (AUC [SE], 0.653 [0.022] vs 0.780 [0.016]) at month 10. Predictions were affected by amount of marker information accumulated and prespecified assumptions. PSA changes affected progression risk more strongly at later vs earlier follow-up.

CONCLUSIONS AND RELEVANCE

This prognostic study found that prediction of radiographic PFS was improved when longitudinal PSA information was added to baseline variables. In a population of patients with metastatic CRPC, dynamic predictions using landmark or joint models may help identify patients at risk of progression.

Lutetium-177-PSMA-617 in Low-Volume Hormone-Sensitive Metastatic Prostate Cancer: A Prospective Pilot Study

PURPOSE

[¹⁷⁷Lu]Lu-PSMA-617 radioligand therapy (¹⁷⁷Lu-PSMA) is a novel treatment for metastatic castration-resistant prostate cancer (mCRPC), which could also be applied to patients with metastatic hormone-sensitive prostate cancer (mHSPC) with PSMA expression. In this prospective study (NCT03828838), we analyzed toxicity, radiation doses, and treatment effect of ¹⁷⁷Lu-PSMA in pateints with low-volume mHSPC.

PATIENTS AND METHODS

Ten progressive patients with mHSPC following local treatment, with a maximum of ten metastatic lesions on [⁶⁸Ga]Ga-PSMA-11 PET/diagnostic-CT imaging (PSMA-PET) and serum PSA doubling time <6 months received two cycles of ¹⁷⁷Lu-PSMA. Whole-body single-photon emission CT/CT (SPECT/CT) and blood dosimetry was performed to calculate doses to the tumors and organs at risk (OAR). Adverse events (AE), laboratory values (monitoring response and toxicity), and quality of life were monitored until week 24 after cycle 2, the end of study (EOS). All patients underwent PSMA-PET at screening, 8 weeks after cycle 1, 12 weeks after cycle 2, and at EOS.

RESULTS

All patients received two cycles of ¹⁷⁷Lu-PSMA without complications. No treatment-related grade III-IV adverse events were observed. According to dosimetry, none of the OAR reached threshold doses for radiation-related toxicity. Moreover, all target lesions received a higher radiation dose than the OAR. All 10 patients showed altered PSA kinetics, postponed androgen deprivation therapy, and maintained good quality of life. Half of the patients showed a PSA response of more than 50%. One patient had a complete response on PSMA-PET imaging until EOS and two others had only minimal residual disease.

CONCLUSIONS

¹⁷⁷Lu-PSMA appeared to be a feasible and safe treatment modality in patients with low-volume mHSPC.

Interim and end-treatment 18F-Fluorocholine PET/CT and bone scan in prostate cancer patients treated with Radium 223 dichloride

To assess the predictive and prognostic aim of interim and end-treatment 18F-fluorocholine PET/CT (FCH-PET/CT) and 99mTc-methilen diphosphonate bone scintigraphy (BS) in patients with castration-resistant prostate cancer and bone metastases (CRPC-BM) treated with Radium 223 dichloride (223Ra). Prospective and multicentre ChoPET-Rad study including 82 patients with CRPC-BM. Baseline, after 3 (interim) and 6 doses (end-treatment) BS and FCH PET/CT were performed in patients who meet the study criteria. Clinical variables, imaging and clinical progression were obtained and their association with progression free survival (PFS), and overall survival (OS) was studied. Agreement between BS and FCH PET/CT response was assessed using Kappa (K) analysis. Median of PFS and OS was 3 and 16 months, respectively. Agreement between interim BS and FCH PET/CT was weak (K: 0.28; p = 0.004). No agreement was observed between end-treatment diagnostic studies. Interim and end-treatment FCH PET/CT were related to PFS (p = 0.011 and p < 0.001, respectively). Therapeutic failure and interim BS and FCH PET/CT showed association with OS (p < 0.001, p = 0.037 and p = 0.008, respectively). Interim and end-treatment FCH PET/CT were good predictors of biochemical progression in patients treated with 223Ra. Therapeutic failure and progression in interim BS or FCH PET/CT were adverse factors for OS.

Radium-223 as an Approved Modality for Treatment of Bone Metastases

Radium-223 dichloride (²²³Ra) is an α-emitter radionuclide approved for treatment of osteoblastic metastases in castrate-resistant prostate cancer (mCRPC) patients. ²²³Ra increases overall survival, improves bone pain, increases the median time to the first skeletal-related event, reduces the use of external beam radiation therapy for bone pain palliation, reduces the rates of spinal cord compression, and hospitalization. ²²³Ra therapy has minimal side effects; the most common hematological side effects are anemia, thrombocytopenia and neutropenia while the nonhematological side effects that may occur are bone pain flare, nausea, fatigue, and diarrhea. Alongside ²²³Ra therapy there are currently a variety of first-line therapeutic options available to treat mCRPC patients and much debate regarding the appropriate treatment algorithm for these patients and the possible combination of therapies among the ones available. In this article, we review the rationale behind ²²³Ra therapy as well as ²²³Ra mechanisms of action, biodistribution and dosimetry, optimal timing possibilities to initiate ²²³Ra in contrast to other treatments available, the association of ²²³Ra with other therapies and the means of evaluating patients in order to properly deliver to ²²³Ra therapy. Furthermore, we will discuss ²²³Ra dose administration possibilities, patient and dose preparation and the challenges of treatment response evaluation during and after ²²³Ra.

Prostate-specific antigen response patterns during cabazitaxel therapy in patients with metastatic castration-resistant prostate cancer

Background

The objective of this study was to categorize prostate-specific antigen (PSA) response during cabazitaxel therapy in patients with metastatic castration-resistant prostate cancer (mCRPC) into different patterns and to investigate the prognostic impact of the PSA response patterns.

Methods

We reviewed data from patients with mCRPC who had been treated with cabazitaxel therapy at four institutions belonging to Tokai Urologic Oncology Research Seminar. Patients eligible for this study had received at least three cycles of cabazitaxel treatment at three- or four-week intervals. The PSA response patterns were categorized as primary resistance (PR), response (RE), stabilization (ST), and fluctuating (FL). The overall survival (OS) was compared among the patterns.

Results

Data from a total of 50 patients were analyzed in this study. The number of patients exhibiting PR, RE, ST and FL patterns were 18 (36%), 14 (28%), 12 (24%) and 6 (12%), respectively. The median (95% CI) OS of patients with PR and RE patterns was 10.7 (5.6–15.9) and 14.9 (6.8–23.0) months, respectively, and was not reached for patients with ST and FL patterns. The OS of patients with the FL pattern was significantly better than that of patients with PR (P = 0.012) and RE (P = 0.010) patterns.

Conclusion

There were some patients whose PSA were fluctuating during cabazitaxel therapy in patients with mCRPC. Because the prognosis of such patients was relatively good, the judgment to discontinue the cabazitaxel therapy after PSA rise followed by decrease should be made prudently.

Consensus on management of castration-resistant prostate cancer on behalf of the Urological Tumours Working Group (URONCOR) of the Spanish Society of Radiation Oncology

BACKGROUND

The knowledge in the field of castration-resistant prostate cancer (CRPC) is developing rapidly, with emerging new therapies and advances in imaging. Nonetheless, in multiple areas there is still a lack of or very limited evidence, and clear guidance from clinicians regarding optimal strategy is required.

METHODS

A modified Delphi method, with 116 relevant questions divided into 7 different CRPC management topics, was used to develop a consensus statement by the URONCOR group.

RESULTS

A strong consensus or unanimity was reached on 93% of the proposed questions. The seven topics addressed were: CRPC definition, symptomatic patients, diagnosis of metastasis, CRPC progression, M0 management, M1 management and sequencing therapy, and treatment monitoring.

CONCLUSIONS

The recommendations based on the radiation oncology experts' opinions are intended to provide cancer specialists with expert guidance and to standardise CRPC patient management in Spain, facilitating decision-making in different clinically relevant issues regarding CRPC patients.

The Contemporary Use of Radium-223 in Metastatic Castration-resistant Prostate Cancer

Radium-223 dichloride (radium-223) was approved for the treatment of patients with castration-resistant prostate cancer (CRPC) and symptomatic bone metastases in the United States and Europe in 2013. This followed a reported overall survival benefit for patients treated with radium-223 and best standard of care (BSoC) when compared with placebo and BSoC in the ALpharadin in SYMptomatic Prostate CAncer (ALSYMPCA) trial. At that time, docetaxel was the standard first-line choice for patients with metastatic CRPC (mCRPC). Since then, the treatment landscape has changed dramatically with new hormonal agents (abiraterone and enzalutamide) considered to be the first-line choice for many patients. The optimal patient profile for radium-223 in the modern setting, and its best use either in sequence or in combination with other approved agents are unclear, with few definitive guidelines available. This article reports on the views of a group of urologists and medical oncologists experienced in treating patients with mCRPC with radium-223 in routine clinical practice. The aim is to provide an overview of the current use of radium-223 in the treatment of patients with mCRPC, and to discuss best practices for patient selection and on-treatment monitoring. Where agreement was reached, guidance on the optimal use of radium-223 is provided.

Clinical Correlates of Benefit From Radium-223 Therapy in Metastatic Castration Resistant Prostate Cancer

BACKGROUND

We sought to identify potential clinical variables associated with outcomes after radium-223 therapy in routine practice.

METHODS

Consecutive non-trial mCRPC patients who received ≥1 dose of radium dichloride-223 at four academic and one community urology-specific cancer centers from May 2013 to June 2014 were retrospectively identified. Association of baseline and on-therapy clinical variables with number of radium doses received and clinical outcomes including overall survival were analyzed using chi-square statistics, cox proportional hazards, and Kaplan-Meier methods. Bone Scan Index (BSI) was derived from available bone scans using EXINI software.

RESULTS

One hundred and forty-five patients were included. Radium-223 was administered for six cycles in 74 patients (51%). One-year survival in this heavily pre-treated population was 64% (95%CI: 54-73%). In univariate and multivariate analysis, survival was highly associated with receiving all six doses of Radium-223. Receipt of six doses was associated with ECOG PS of 0-1, lower baseline PSA & pain level, no prior abiraterone/enzalutamide, <5 BSI value, and normal alkaline phosphatase. In patients who reported baseline pain (n = 72), pain declined in 51% after one dose and increased in 7%. PSA declined ≥50% in 16% (18/110). Alkaline phosphatase declined ≥25% in 48% (33/69) and ≥50% in 16/69 patients. BSI declined in 17 (68%) of the 25 patients who had bone scan available at treatment follow-up. Grade ≥3 neutropenia, anemia, and thrombocytopenia occurred in 4% (n = 114), 4% (n = 125), and 5% (n = 123), respectively.

CONCLUSIONS

Patients earlier in their disease course with <5 BSI, low pain score, and good ECOG performance status are optimal candidates for radium-223. Radium-223 therapy is well tolerated with most patients reporting declines in pain scores and BSI. Prostate 77:479-488, 2017. © 2016 Wiley Periodicals, Inc.

Clinical outcomes and survival surrogacy studies of prostate-specific antigen declines following enzalutamide in men with metastatic castration-resistant prostate cancer previously treated with docetaxel

BACKGROUND

In the AFFIRM trial, enzalutamide significantly increased overall survival (OS) for men with metastatic castration‐resistant prostate cancer (mCRPC) after chemotherapy versus placebo and significantly decreased prostate‐specific antigen (PSA) levels. The goal of this post hoc analysis was to associate levels of PSA decline from baseline after enzalutamide with clinical outcomes in the postchemotherapy mCRPC setting.

METHODS

Men in the AFFIRM trial (n = 1199) were grouped by maximal PSA decline in the first 90 days of treatment. Kaplan‐Meier estimates evaluated the association of defined PSA changes from baseline with OS, progression‐free survival (PFS), radiographic PFS (rPFS), and pain response. Each PSA decline category was assessed for OS surrogacy using Prentice criteria, proportion of treatment effect explained (PTE), and proportion of variation explained.

RESULTS

Men treated with enzalutamide had improved OS (hazard ratio, 0.63; P < .001) and higher rates of PSA decline (odds ratio, >19.0; P < .001) versus placebo. PSA declines of any, ≥30%, ≥50%, and ≥90% with enzalutamide were strongly associated with greater OS, PSA PFS, rPFS (P < .001), and pain response (P < .026) versus PSA increase/no decline. Any, ≥30%, and ≥50% declines in PSA resulted in the PTE range of 1.07‐1.29, where treatment was no longer significant after adjustment for decline measures (P > .20).

CONCLUSIONS

PSA declines of any, ≥30%, and ≥50% following enzalutamide were associated with greater clinical and pain response and improvements in PFS and OS. Surrogacy of PSA decline for OS was not fully established, possibly due to lack of PSA declines with placebo, and discordant results between PSA and imaging responses over time, and because some declines were not durable due to rapid resistance development. However, a lack of PSA decline by 90 days following enzalutamide treatment was a poor prognosis indicator in this setting. Conclusions from sensitivity analyses of maximal PSA decline from baseline over the entire treatment period are consistent with PSA declines restricted to the first 90 days. Cancer 2017;123:2303–2311. © 2017 American Cancer Society.

A post hoc analysis of the randomized, double‐blind AFFIRM trial revealed that postenzalutamide prostate‐specific antigen declines of any, ≥30%, and ≥50% are associated with greater clinical and pain response. The decline criteria explain a large proportion of treatment effect on survival improvements but do not fulfill the criteria for surrogacy.

Prostate-specific Antigen Decline After 4 Weeks of Treatment with Abiraterone Acetate and Overall Survival in Patients with Metastatic Castration-resistant Prostate Cancer

BACKGROUND

The availability of multiple new treatments for metastatic castration-resistant prostate cancer (mCRPC) mandates earlier treatment switches in the absence of a response. A decline in prostate-specific antigen (PSA) is widely used to monitor treatment response, but is not validated as an intermediate endpoint for overall survival (OS).

OBJECTIVE

To evaluate the association between early PSA decline and OS following abiraterone acetate (AA) treatment.

DESIGN, SETTING, AND PARTICIPANTS

We identified mCRPC patients treated with AA before or after docetaxel at the Royal Marsden NHS Foundation Trust between 2006 and 2014. Early PSA decline was defined as a 30% decrease in PSA at 4 wk relative to baseline, and early PSA rise as a 25% increase.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Association with OS was analyzed using multivariate Cox regression and log-rank analyses. Spearman's rho correlation coefficient (r) was calculated to evaluate the association between PSA changes at 4 wk and 12 wk.

RESULTS AND LIMITATIONS

There were 274 patients eligible for this analysis. A 30% PSA decline at 4 wk was associated with longer OS (25.8 vs 15.1 mo; hazard ratio [HR] 0.47, p<0.001), and a 25% PSA rise at 4 wk with shorter OS (15.1 vs 23.8 mo; HR 1.7, p=0.001) in both univariate and multivariable models. The percentage PSA decline at 4 wk was significantly correlated with the percentage PSA change at 12 wk (r=0.82; p<0.001). Patients achieving a 30% PSA decline at 4 wk were 11.7 times more likely to achieve a 50% PSA decrease at 12 wk (sensitivity 90.9%, specificity 79.4%). Limitations include the retrospective design of this analysis.

CONCLUSIONS

Patients not achieving 30% PSA decline after 4 wk of AA have a lower likelihood of achieving PSA response at 12 wk and significantly inferior OS. Prospective multicentre validation studies are needed to confirm these findings.

PATIENT SUMMARY

Prostate-specific antigen (PSA) is commonly used to evaluate response to treatment in metastatic castration-resistant prostate cancer. Expert recommendations discourage reliance on PSA changes earlier than 12 wk after treatment initiation. Our data suggest that early PSA changes are associated with survival in patients receiving abiraterone acetate.

Survival Outcomes of Concurrent Treatment with Docetaxel and Androgen Deprivation Therapy in Metastatic Castration-Resistant Prostate Cancer

PURPOSE

Docetaxel-based chemotherapy (DTX) improves overall survival (OS) of men with metastatic castration-resistant prostate cancer (mCRPC). Considering the potential existence of androgen receptors that remain active at this stage, we aimed to assess the impact of the combined use of androgen deprivation therapy (ADT) with DTX for mCRPC.

MATERIALS AND METHODS

We performed a single-institutional retrospective analysis of patients with mCRPC who received either DTX alone (DTX group, n=21) or concurrent DTX and ADT (DTX+ADT group, n=26) between August 2006 and February 2014. All patients received DTX doses of 75 mg/m² every three weeks for at least three cycles. In the DTX+ADT group, all patients used luteinizing hormone releasing hormone agonist continuously as a concurrent ADT.

RESULTS

The median follow-up period was 24.0 months (interquartile range 12.0-37.0) for the entire cohort. The median radiographic progression-free survival (rPFS) was 9.0 months and 6.0 months in the DTX+ADT and DTX groups, respectively (log-rank p=0.036). On multivariable Cox regression analysis, concurrent administration of ADT was the only significant predictor of rPFS [hazard ratio (HR)=0.525, 95% confidence intervals (CI) 0.284-0.970, p=0.040]. The median OS was 42.0 and 38.0 months in the DTX+ADT and DTX groups, respectively (log-rank p=0.796). On multivariable analysis, hemoglobin level at the time of DTX initiation was associated with OS (HR=0.532, 95% CI 0.381-0.744, p<0.001).

CONCLUSION

In chemotherapy-naive patients with mCRPC, the combined use of ADT with DTX improved rPFS. Our result suggests that the concurrent administration of ADT and DTX is superior to DTX alone.

Determine of the optimal number of cycles of docetaxel in the treatment of metastatic castration-resistant prostate cancer

To determine the optimal number of cycles of docetaxel for metastatic castration-resistant prostate cancer, we retrospectively collected 73 patients receiving varying numbers of docetaxel plus prednisolone and analyzed the clinical outcomes including overall survival, prostate-specific antigen (PSA) response, and adverse events. The study included 33 patients receiving ≤ 10 cycles of docetaxel and 40 patients receiving > 10 cycles. Patients receiving > 10 cycles were younger than those who received ≤ 10 cycles. There was no statistical significant difference in overall survival between the two groups (log-rank test, p = 0.75). Adverse effects were more common among patients receiving ≥ 10 cycles of treatment. A PSA flare-up was observed among six patients (8.2%); the median duration of the PSA surge was 3 weeks (range, 3-12 weeks). The overall survival rates in patients with PSA flare-up were comparable with the patients having PSA response. We concluded that at least four cycles of docetaxel should be administered in metastatic castration-resistant prostate cancer patients in order not to cease treatment prematurely from potentially beneficial chemotherapy. However, administering > 10 cycles does not result in any further improvement in survival and is associated with more adverse effects.

Diagnostic imaging to detect and evaluate response to therapy in bone metastases from prostate cancer: current modalities and new horizons

Different therapeutic options for the management of prostate cancer (PC) have been developed, and some are successful in providing crucial improvement in both survival and quality of life, especially in patients with metastatic castration-resistant PC. In this scenario, diverse combinations of radiopharmaceuticals (for targeting bone, cancer cells and receptors) and nuclear medicine modalities (e.g. bone scan, SPECT, SPECT/CT, PET and PET/CT) are now available for imaging bone metastases. Some radiopharmaceuticals are approved, currently available and used in the routine clinical setting, while others are not registered and are still under evaluation, and should therefore be considered experimental. On the other hand, radiologists have other tools, in addition to CT, that can better visualize bone localization and medullary involvement, such as multimodal MRI. In this review, the authors provide an overview of current management of advanced PC and discuss the choice of diagnostic modality for the detection of metastatic skeletal lesions in different phases of the disease. In addition to detection of bone metastases, the evaluation of response to therapy is another critical issue, since it remains one of the most important open questions that a multidisciplinary team faces when optimizing the management of PC. The authors emphasize the role of nuclear modalities that can presently be used in clinical practice, and also look at future perspectives based on relevant clinical data with novel radiopharmaceuticals.

Biomarker detection technologies and future directions

Biomarkers play a vital role in disease detection and treatment follow-up. It is important to note that diseases in the early stage are typically treated with the greatest probability of success. However, due to various technical difficulties in current technologies for the detection of biomarkers, the potential of biomarkers is not explored completely. Therefore, the developments of technologies, which can enable the accurate detection of prostate cancer at an early stage with simple, experimental protocols are highly inevitable. This critical review evaluates the current methods and technologies used in the detection of biomarkers. The aim of this article is to provide a comprehensive review covering the advantages and disadvantages of the biomarker detection methods. Future directions for the development of technologies to achieve highly selective and sensitive detection of biomarkers for point-of-care applications are also commented on.

Management of patients with advanced prostate cancer: recommendations of the St Gallen Advanced Prostate Cancer Consensus Conference (APCCC) 2015

The first St Gallen Advanced Prostate Cancer Consensus Conference (APCCC) Expert Panel identified and reviewed the available evidence for the ten most important areas of controversy in advanced prostate cancer (APC) management. The successful registration of several drugs for castration-resistant prostate cancer and the recent studies of chemo-hormonal therapy in men with castration-naïve prostate cancer have led to considerable uncertainty as to the best treatment choices, sequence of treatment options and appropriate patient selection. Management recommendations based on expert opinion, and not based on a critical review of the available evidence, are presented. The various recommendations carried differing degrees of support, as reflected in the wording of the article text and in the detailed voting results recorded in supplementary Material, available at Annals of Oncology online. Detailed decisions on treatment as always will involve consideration of disease extent and location, prior treatments, host factors, patient preferences as well as logistical and economic constraints. Inclusion of men with APC in clinical trials should be encouraged.

Efficacy and safety of docetaxel and prednisolone for castration-resistant prostate cancer: a multi-institutional retrospective study in Japan

OBJECTIVE

Although some new drugs for castration-resistant prostate cancer are available, docetaxel still plays an important role in castration-resistant prostate cancer treatment. In this study, we evaluated the efficacy and safety of docetaxel and prednisolone in patients with castration-resistant prostate cancer.

METHODS

We conducted a retrospective chart review of castration-resistant prostate cancer patients who received docetaxel and prednisolone at 14 hospitals in the Sapporo Medical University Urologic Oncology Consortium from August 2004 to December 2011.

RESULTS

A total of 140 patients with castration-resistant prostate cancer received docetaxel and prednisolone (median age, 73.8 years; median prostate specific antigen, 54.7 ng/ml). A median of six cycles (range: 1-43) of docetaxel and prednisolone was administered per patient. Median follow-up was 13.7 months. Median overall survival was 22.0 months. The log-rank test revealed that prostate specific antigen before docetaxel and prednisolone (<50 ng/ml) and the prostate specific antigen reduction rate (≥30%) were associated with overall survival (P < 0.001 and P < 0.001, respectively). Eighty patients (57.1%) achieved a prostate specific antigen reduction rate of over 30%. All except two (97.5%) reached 30% prostate specific antigen reduction within five cycles of docetaxel and prednisolone. There were two (1.4%) treatment-related deaths due to adverse events, which were interstitial lung disease, and febrile neutropenia and bacterial pneumonia. Interstitial lung disease occurred in 14 (10.0%) patients within a median of 2.5 cycles of docetaxel and prednisolone. Grade 5 interstitial lung disease was seen after three cycles of docetaxel and prednisolone.

CONCLUSIONS

If a prostate specific antigen reduction rate of over 30% is not obtained within five cycles of docetaxel and prednisolone, other treatment options should be considered. Although most patients safely received docetaxel and prednisolone, we must always keep interstitial lung disease in mind as a possible lethal adverse event.

Exponential rise in prostate-specific antigen (PSA) during anti-androgen withdrawal predicts PSA flare after docetaxel chemotherapy in patients with castration-resistant prostate cancer

PURPOSE

To investigate the relationship between rising patterns of prostate-specific antigen (PSA) before chemotherapy and PSA flare during the early phase of chemotherapy in patients with castration-resistant prostate cancer (CRPC).

MATERIALS AND METHODS

This study included 55 patients with CRPC who received chemotherapy and in whom pre-treatment or post-treatment PSA levels could be serially obtained. The baseline parameters included age, performance, Gleason score, PSA level, and disease extent. PSA doubling time was calculated using the different intervals: the conventional interval from the second hormone manipulation following the nadir until anti-androgen withdrawal (PSADT1), the interval from the initial rise after anti-androgen withdrawal to the start of chemotherapy (PSADT2), and the interval from the nadir until the start of chemotherapy (PSADT3). The PSA growth patterns were analyzed using the ratio of PSADT2 to PSADT1.

RESULTS

There were two growth patterns of PSA doubling time: 22 patients (40.0%) had a steady pattern with a more prolonged PSADT2 than PSADT1, while 33 (60.0%) had an accelerating pattern with a shorter PSADT2 than PSADT1. During three cycles of chemotherapy, PSA flare occurred in 11 patients (20.0%); of these patients, 3 were among 33 (9.1%) patients with an accelerating PSA growth pattern and 8 were among 22 patients (36.4%) with a steady PSA growth pattern (p=0.019). Multivariate analysis showed that only PSA growth pattern was an independent predictor of PSA flare (p=0.034).

CONCLUSION

An exponential rise in PSA during anti-androgen withdrawal is a significant predictor for PSA flare during chemotherapy in CRPC patients.

Clinical predictor of survival following docetaxel-based chemotherapy

Prostate cancer (PCa) is the most common type of cancer in males in the USA and the incidence is increasing. For castration-resistant PCa (CRPC), previous studies have identified docetaxel-based chemotherapy as the first-line therapy. In the present study, the efficacy of docetaxel-based chemotherapy was investigated in a population of patients with CRPC. This study included 26 individuals (mean age, 73 years) with CRPC who were patients between July 2007 and October 2012 at the Kaohsiung Medical University Hospital (Kaohsiung, Taiwan). The regimen consisted of intravenous docetaxel (70 mg/m²) once every four weeks plus oral prednisolone (5 mg) twice daily for five days. Prostate-specific antigen (PSA) response (defined as a PSA decrease of >50% over four weeks), time to PSA progression, PCa-specific survival and overall survival (OS) were evaluated. For these 26 patients, the mean PSA level prior to chemotherapy treatment was 335.58 ng/ml. During follow-up, the average number of cycles of chemotherapy was approximately seven and 15 patients (58%) achieved a PSA response. PSA response was found to significantly correlate with OS and PCa-specific survival (P=0.014 and P=0.028, respectively). The mean value of the PSA nadir level was 89.97 ng/ml and time to PSA nadir was five months. The most common adverse event was leucopenia, which affected 88% of the patients. The results indicated that the length of time to PSA nadir and the occurrence of leucopenia may impact the PSA response. The docetaxel-based chemotherapy was a feasible and effective treatment regimen in patients with CRPC. However, the occurrence of adverse events, particularly the high incidence of leucopenia, may be cause for concern.

PSA flare with abiraterone in patients with metastatic castration-resistant prostate cancer

BACKGROUND

The aim of this study was to assess early serum prostate-specific antigen (PSA) changes in patients treated with abiraterone and to correlate those changes with clinical outcome.

PATIENTS AND METHODS

We retrospectively evaluated 103 patients with castrate-resistant prostate cancer (CRPC) treated with compassionate use of abiraterone in Romagna, Italy. In these patients, serum PSA levels were monitored every 4 weeks, and a time course of serum PSA levels was obtained. The PSA flare phenomenon was evaluated. The log-rank test was applied to compare survival between groups of patients according to early PSA level changes.

RESULTS

Of 103 patients, 43 (41.7%) had an immediate PSA response, whereas 9 (8.7%) had an initial PSA flare. Of the 9 patients with PSA flare, 5 attained a subsequent PSA response. The temporary PSA flare exceeded baseline values by a median of 19.7% (range, 5%-62.9%). The median PFS of the 9 patients in the PSA-flare group was higher compared with patients without the PSA flare (10.5 vs. 6.4 months; P = .0999) but was similar to the subgroup of patients with immediate PSA response (10.5 vs. 10.7 months; P = .7019). In the multivariate analysis, only the PSA response remained as a predictor of progression-free survival (PFS) (P < .0001) and overall survival (OS) (P = .0003), respectively.

CONCLUSION

PSA flare occurs not infrequently in patients with CRPC who respond to abiraterone. Patients should be informed of this possible PSA flare phenomenon.

Serum alkaline phosphatase differentiates prostate-specific antigen flare from early disease progression after docetaxel chemotherapy in castration-resistant prostate cancer with bone metastasis

PURPOSE

A transient rise in prostate-specific antigen (PSA) after the initiation of chemotherapy, called as PSA flare, has been frequently reported in patients with castration-resistant prostate cancer (CRPC) but there has been no way to differentiate PSA rises in CRPC. We investigated whether bone-related serum markers differentiate PSA flare from progression in CRPC patients with bone metastasis.

METHODS

We reviewed CRPC patients with bone metastasis who received systemic chemotherapy from 2002 to 2008. Pretreatment baseline and follow-up data including age, performance score, PSA, Gleason score, alkaline phosphatase (ALP), calcium level, and hemoglobin were evaluated. Pretreatment parameters and follow-up serum parameters after the first cycle of chemotherapy were included in statistical analyses.

RESULTS

PSA increased in 38 patients (45.8 %) at the first evaluation after chemotherapy. Among the PSA rises, PSA increased continuously or did not decrease to the stabilization level by the third evaluation in 22 (26.5 %) patients, while PSA decreased to the stabilization or response level by the third evaluation in 16 (19.3 %). PSA flare occurred in 17 (20.5 %). The univariate analyses showed that no baseline parameters were associated with PSA flare, but the initial ALP decrease, changed ALP ratio, and median calcium level were significantly associated with PSA flare (p = 0.001, p = 0.008 and p = 0.012, respectively). Multivariate logistic regression analysis showed that a change in the ALP level is an independent predictive factor for PSA flare (p = 0.017).

CONCLUSIONS

ALP is a useful biomarker to differentiate PSA flare from early PSA progression during docetaxel chemotherapy in CRPC patients with bone metastasis.

Optimal management of metastatic castration-resistant prostate cancer: highlights from a European Expert Consensus Panel

The exponential growth of novel therapies for the treatment of metastatic castration-resistant prostate cancer (mCRPC) over the last decade has created an acute need for education and guidance of clinicians regarding optimal strategies for patient management. A multidisciplinary panel of 21 European experts in mCRPC assembled for comprehensive discussion and consensus development, seeking to move the field forward and provide guidance and perspectives on optimal selection and sequencing of therapeutic agents and monitoring of response to treatment and disease progression. A total of 110 clinically-relevant questions were addressed and a modified Delphi method was utilised to obtain a consensus. The panel reached a consensus on several important issues, providing recommendations on appropriate phase III clinical trial end-points and optimal strategies for imaging and monitoring of bone metastases. Guidance regarding selection and sequencing of therapy in patients with newly diagnosed or progressive mCRPC is emphasised, including the use of novel bone-targeted agents, chemotherapy, androgen receptor pathway-targeted agents and immunotherapy. The impact of drug resistance and prostate-specific antigen flare on treatment decisions was also addressed. Ultimately, individualised therapy for patients with mCRPC is dependent on continued refinement of clinical decision-making based on patient and disease characteristics. This consensus statement offers clinicians expert guidance on the implementation of recent advances to improve patient outcome, focusing on the future of prostate cancer care.

Transient therapy-related surge in serum tumor biomarkers: characterizing behavior and postulating its biologic role

A phenomenon of serum tumor biomarker surge or flare that ensues shortly after initiating cancer therapy and that may precede the actual therapeutic response-related decline is poorly understood and remains under-appreciated. However, it may have a significant clinical implication as it could be misinterpreted in clinical practice as therapeutic failure and lead to a premature discontinuation of potentially effective therapy. Therefore, in the present study, attempts have been made to understand the behavior of this phenomenon with respect to a reported median incidence, duration, and its relationship to clinical response. The results of these analyses suggest a significantly lower incidence of this phenomenon with carcinoembryonic antigen (CEA) as determined in colorectal cancer and prostate specific antigen (PSA) in prostate cancer as compared to the other biomarkers studied (p=0.006). Furthermore, regardless of the type of biomarker or the extent of its incidence, a therapy-related initial surge appears to correlate with eventual response to therapy. Although, the biologic significance of this phenomenon is currently elusive, two distinct hypothesis-generating cases with CEA and alpha-fetoprotein (AFP) are presented that, if supported by further research, would provide insights into the role of a biomarker surge in overall tumor growth control by cancer therapy.

Abiraterone acetate for treatment of metastatic castration-resistant prostate cancer: final overall survival analysis of the COU-AA-301 randomised, double-blind, placebo-controlled phase 3 study

BACKGROUND

Abiraterone acetate improved overall survival in metastatic castration-resistant prostate cancer at a preplanned interim analysis of the COU-AA-301 double-blind, placebo-controlled phase 3 study. Here, we present the final analysis of the study before crossover from placebo to abiraterone acetate (after 775 of the prespecified 797 death events).

METHODS

Between May 8, 2008, and July 28, 2009, this study enrolled 1195 patients at 147 sites in 13 countries. Patients were eligible if they had metastatic castration-resistant prostate cancer progressing after docetaxel. Patients were stratified according to baseline Eastern Cooperative Oncology Group (ECOG) performance status, worst pain over the past 24 h on the Brief Pain Inventory-Short Form, number of previous chemotherapy regimens, and type of progression. Patients were randomly assigned (ratio 2:1) to receive either abiraterone acetate (1000 mg, once daily and orally) plus prednisone (5 mg, orally twice daily) or placebo plus prednisone with a permuted block method via an interactive web response system. The primary endpoint was overall survival, analysed in the intention-to-treat population. This study is registered with ClinicalTrials.gov, number NCT00091442.

FINDINGS

Of the 1195 eligible patients, 797 were randomly assigned to receive abiraterone acetate plus prednisone (abiraterone group) and 398 to receive placebo plus prednisone (placebo group). At median follow-up of 20·2 months (IQR 18·4-22·1), median overall survival for the abiraterone group was longer than in the placebo group (15·8 months [95% CI 14·8-17·0] vs 11·2 months [10·4-13·1]; hazard ratio [HR] 0·74, 95% CI 0·64-0·86; p<0·0001). Median time to PSA progression (8·5 months, 95% CI 8·3-11·1, in the abiraterone group vs 6·6 months, 5·6-8·3, in the placebo group; HR 0·63, 0·52-0·78; p<0·0001), median radiologic progression-free survival (5·6 months, 5·6-6·5, vs 3·6 months, 2·9-5·5; HR 0·66, 0·58-0·76; p<0·0001), and proportion of patients who had a PSA response (235 [29·5%] of 797 patients vs 22 [5·5%] of 398; p<0·0001) were all improved in the abiraterone group compared with the placebo group. The most common grade 3-4 adverse events were fatigue (72 [9%] of 791 patients in the abiraterone group vs 41 [10%] of 394 in the placebo group), anaemia (62 [8%] vs 32 [8%]), back pain (56 [7%] vs 40 [10%]), and bone pain (51 [6%] vs 31 [8%]).

INTERPRETATION

This final analysis confirms that abiraterone acetate significantly prolongs overall survival in patients with metastatic castration-resistant prostate cancer who have progressed after docetaxel treatment. No new safety signals were identified with increased follow-up.

Reduced-dose docetaxel for castration-resistant prostate cancer has no inferior impact on overall survival in Japanese patients

BACKGROUND

In clinical practice, an adapted regimen with dose reduction is applied to castration-resistant prostate cancer (CRPC) treated with docetaxel because of its toxicity. However, there are few reports on the impact of dose reduction on survival.

METHODS

Fifty-seven patients with CRPC treated with first-line docetaxel in a single institution from 2005 to 2008 were evaluated retrospectively.

RESULTS

The median follow-up period was 20.5 months. Twenty-eight patients (49 %) received a standard 60 mg/m(2) regimen (SR), and 29 patients (51 %) received an adapted regimen (AR) with dose reduction. There was no difference in their baseline characteristics. The prostate-specific antigen response rates were not significantly different between the SR and AR groups (50 vs. 62 %, p = 0.36). Progression-free survival (PFS) and overall survival (OS) were also not significantly different between the groups (PFS 5.3 vs. 7.3 months, p = 0.39; OS 26.4 vs. 27.1 months, p = 0.53, respectively). No significant difference in the incidence of grade 3 or 4 adverse events was noted between the groups (89 vs. 83 %, p = 0.70). In multivariate analysis, hemoglobin and alkaline phosphatase were significant predictive factors for OS (hazard ratios 2.81 and 2.39, p = 0.012 and 0.024, respectively).

CONCLUSIONS

A reduced-dose regimen of docetaxel has no inferior impact on OS. Further studies on the optimal dose of docetaxel for Japanese patients are required.

[Strategy in advanced castration-resistant prostate cancer]

If androgen deprivation, chemical with LH-RH analogs or surgical with bilateral orchiectomy, still remains the stone edge of treatment of prostate cancer, in the metastatic setting, this hormonosensitivity, most of the time long, finally move on in hormonal-failure. If rare changes in the therapeutic strategy have been achieved in this setting since 2004 and the arrival of docetaxel, it is the global perception of the disease that has been modified and the definition of one specific entity: the castrate-resistant prostate cancer. This new definition and the changes of design and end-points of clinical trials testing new agents with strong recruitment during the past years have conducted to a real revolution in the management of castrate-refractory prostate cancer. The place of secondary hormonal manipulations, such as withdrawal of the anti-androgen, oestrogen or ketoconazole, still exists for a selected group of patients. In case of aggressive disease and symptoms, chemotherapy should be selected, docetaxel, in a three weeks schedule, and may be combined with Estracyt. It is time to consider the revolution of the post-chemotherapy setting with the arrival of two new drugs ; a cytotoxic one, the cabazitaxel and hormonal for the second one, the abiraterone acetate. The place of the immunotherapy with the sipuleucel-T may be more difficult to precise, especially in Europe, even if it has been finally indicated in the United States in the metastatic setting. Concerning bone metastasis, zoledronic acid was during a long time the only bone-targeted agent, effective in reducing the incidence of skeletal related events, and was recently exceeded by the denosumab, an anti-RANK ligand. Finally, let us hope that other changes will be achieved in the near future, with the cabazitaxel-docetaxel confrontation in the first-line setting, and the introduction of the abiraterone acetate before chemotherapy with docetaxel, already tested in ongoing trials.

Prognostic, predictive, and surrogate factors for individualizing treatment for men with castration-resistant prostate cancer

With the surge in therapeutic options for castration-resistant prostate cancer (CRPC) comes increasingly complicated treatment decision making, highlighting the need for biomarkers that can identify appropriate patients for specific treatments and accurately assess disease response. Here we discuss existing and potential prognostic, predictive, and surrogate biomarkers in CRPC.

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.

Bevacizumab and weekly docetaxel in patients with metastatic castrate-resistant prostate cancer previously exposed to docetaxel

Background. The aim of this paper was to evaluate the activity and tolerability of docetaxel (D) and bevacizumab (Bev) in patients with metastatic castrate-resistant prostate cancer (CRPC) previously exposed to D. Methods. Treatment consisted of D 30 mg/m(2) i.v. for four consecutive weekly administrations followed by a 2-week rest interval, in addition to Bev 5 mg/kg i.v. every 2 weeks. Results. Forty-three patients were enrolled: a PSA response was observed in 27 patients (62.7%, 95% CI: 0.41 to 0.91), and a palliative response was achieved in 31 patients (72.1%, 95%CI: 0.48 to 1.02). After a median followup of 11.3 months, only five patients had died. The regimen was generally well tolerated. Conclusion. Weekly D + biweekly Bev seems to be an effective and well-tolerated treatment option for patients with metastatic CRPC previously exposed to D-based chemotherapy.

Contemporary management of metastatic castration-resistant prostate cancer

PURPOSE OF REVIEW

This review will describe the contemporary management of castration-resistant prostate cancer in the context of multiple recent advances.

RECENT FINDINGS

Two novel agents have been added to the therapeutic armamentarium including cabazitaxel and sipuleucel-T. Cabazitaxel, a novel taxane extended survival in men with progressive metastatic CRPC following conventional docetaxel-based chemotherapy. Sipuleucel-T, an autologous dendritic cell based vaccine extended survival in men with relatively asymptomatic metastatic CRPC without visceral metastasis. A third agent, abiraterone acetate, an orally administered CYP17 inhibitor, which suppresses androgen synthesis has been preliminarily reported to significantly prolong survival following prior docetaxel and approval by regulatory agencies is anticipated. Baseline and early changes in circulating tumor cells appear useful as a prognostic factor. Additionally, data demonstrated the superiority of denosumab, a RANK-ligand antagonist, compared to zoledronic acid in the prevention of skeletal related events in men with bone metastases.

SUMMARY

Cabazitaxel, sipuleucel-T and denosumab were approved in 2010 by regulatory agencies in the USA for men with metastatic CRPC, and approval of abiraterone acetate is anticipated based on the results of a phase III trial. The evaluation of circulating tumor cells assists in determining prognosis, although its utility for clinical decision-making entails validation.

The interval from the last cycle of docetaxel-based chemotherapy to progression is associated with the efficacy of subsequent docetaxel in patients with prostate cancer

There is currently no standard treatment after first-line docetaxel-based chemotherapy for patients with castration-refractory prostate cancer (CRPC). Some patients are likely to discontinue first-line docetaxel-based chemotherapy because of either completed treatment or the occurrence of manageable side-effects. The aim of this study was to determine whether a rechallenge with docetaxel might be appropriate in patients with CRPC previously treated with docetaxel. Between December 2004 and July 2009, 39 patients diagnosed with metastatic cancer prostate at the Institut Gustave Roussy were administered subsequent docetaxel after front-line docetaxel-based chemotherapy. The medical records of these patients were extracted from the database. The PSA response rate (PSA decline > or =30% and > or =50%), progression-free survival (PFS) and overall survival (OS) of patients receiving docetaxel as a subsequent line of therapy were evaluated using consensus criteria. The effect of pre-treatment variables on efficacy was studied. A PSA decline > or =30% and > or =50% was observed in 64% and 38% of patients, respectively, median PFS was 4.3 months [confidence interval (CI) 95%: 3.6-4.9] and median OS was 15.8 months (CI 95%: 11.7-20.3) in 39 patients who received subsequent docetaxel. The interval between the last cycle of first-line docetaxel and progression [median: 3.0 months; range: 1-30 months] was associated with PFS: median PFS was 3.4 months (CI 95%: 2.6-4.1) and 6.3 months (CI 95%: 3.0-5.6), respectively, in patients with an interval <3.0 months and an interval > or =3.0 months, (p=0.04). Tolerance of re-treatment with docetaxel was acceptable with no toxicity-related death. Re-treatment with subsequent docetaxel in patients with CRPC pretreated with first-line docetaxel is safe and demonstrates some activity. The interval from the last cycle of first-line docetaxel-based chemotherapy to progression is associated with the efficacy of subsequent docetaxel.

The development of risk groups in men with metastatic castration-resistant prostate cancer based on risk factors for PSA decline and survival

AIMS OF THE STUDY

There are no known predictive factors of response in men receiving chemotherapy for metastatic castration-resistant prostate cancer (mCRPC). We investigated pre-treatment factors that predicted a 30% PSA decline (30% PSAD) within 3 months of starting chemotherapy, and assessed performance of a risk group classification in predicting PSA declines and overall survival (OS) in men with mCRPC.

METHODS

In TAX327, 1006 men with mCRPC were randomized to receive docetaxel (D) in two schedules, or mitoxantrone (M), each with prednisone: 989 provided data on PSA decline within 3 months. Predictive factors for a 30% PSAD were identified using multivariable regression in D-treated men (n=656) and validated in M-treated men (n=333).

RESULTS

Four independent risk factors predicted 30% PSAD: pain, visceral metastases, anaemia and bone scan progression. Risk groups (good: 0-1 factors, intermediate: 2 factors and poor: 3-4 factors) were developed with median OS of 25.7, 18.7 and 12.8 months (p<0.0001); 30% PSAD in 78%, 66% and 58% of men (p<0.001); and measurable disease response in 19%, 9% and 5% of men (p=0.018), respectively. In the validation cohort, similar predictive ability was noted for 30% PSAD, tumour response and OS. PCWG2 subtypes were also predictive but resulted in unequal grouping. C-indices were 0.59 and 0.62 for 30% PSAD and OS in the validation dataset, respectively.

CONCLUSIONS

Risk groups have been identified and validated that predict PSAD and OS in men with mCRPC and may facilitate evaluation of new systemic regimens warranting definitive testing in comparison with docetaxel and prednisone. Prospective validation of this classification system is needed.

PSA surge/flare-up in patients with castration-refractory prostate cancer during the initial phase of chemotherapy

BACKGROUND

Docetaxel-based chemotherapy has shown great promise for the treatment of CRPC and is considered the current standard of care. PSA is mainly used as marker to monitor the treatment response. Several articles were published reporting an initial PSA surge/flare-up after starting chemotherapy. The cause and the impact of this phenomenon are discussed controversially. The intention of this review is to define the significance of initial PSA surge/flare-up and to increase awareness to this phenomenon in the urological community.

MATERIALS AND METHODS

A comprehensive literature search was performed in different data bases using various key words. Relevant articles and references between 1999 and 2009 were reviewed and analyzed for data on the association between chemotherapy and initial PSA surge/flare.

RESULTS

The incidence of a PSA surge/flare-up ranges according to the reported studies between 7.6% and 13.6%. A PSA surge/flare-up was reported up to 404% from baseline PSA level followed by PSA response. The median duration of a PSA surge/flare-up is 2-3 weeks and can last up to 6-8 weeks. However, the occurrence of a PSA surge/flare-up did not impact outcome and survival negatively compared to patients with an immediate PSA response.

CONCLUSIONS

A considerable portion of CRPC patients experience an initial PSA surge/flare-up under systemic chemotherapy. The definitions used for PSA surge/flare-up differ slightly in the literature. This issue needs to be solved since it might impact defining treatment response. As a PSA surge/flare-up did not impact outcome and survival negatively, chemotherapy should be continued according to the literature addressing specifically the phenomenon of a PSA surge/flare-up for a minimum of 8 weeks or 3 rounds of a 3-weekly cycle chemotherapy regimen before further decisions are made about efficacy. However, Scher et al. recommended a 12-week period drug exposure based on their results on PSA progression-free survival and overall survival. This dilemma needs to be addressed in further data analysis in order to establish a general rule regarding when to stop chemotherapy. Physicians should be aware of this effect to avoid inadequate early discontinuation of chemotherapy. The underlying mechanisms of a PSA surge/flare-up are still elusive and need further clarification.

Docetaxel in combination with prednisolone for hormone refractory prostate cancer

OBJECTIVE

The objective of this study was to evaluate the efficacy and toxicity of docetaxel in combination with prednisolone in Japanese patients with hormone refractory prostate cancer.

METHODS

Twenty patients with hormone refractory prostate cancer (HRPC) were administered a treatment regimen consisting of docetaxel 75 mg/m(2) once every 3 or 4 weeks and prednisolone 5 mg twice daily at our institution between 2006 and 2008.

RESULTS

The patients received a median of 5.5 cycles of treatment (range, 2-12 cycles). Nine of the 20 patients (45%) had a >or=50% decrease in serum prostate-specific antigen (PSA). The median duration of response was 4 months (range, 1-11 months). The number of cycles performed, the presence of bone metastasis and the extent of disease had statistically significant associations with the response. Three patients had a transient PSA rise among the patients who ultimately had a response. Grade 3/4 leukopenia and neutropenia occurred in 80.0% and 85.0% of the patients, respectively. Interstitial pneumonia occurred in only one patient; however, the patient recovered. Finally, no treatment-related deaths were seen during the observation period.

CONCLUSIONS

The combination of docetaxel 75 mg/m(2) every 3 weeks and prednisolone 10 mg daily was effective and well tolerated in Japanese patients with HRPC. The results of this study suggest that a decision concerning discontinuation of this treatment should be carefully considered because a transient PSA rise was observed. Although interstitial pneumonia was rare, the potential risk of its development should be taken into consideration.

Phase II Trial of Consolidation Docetaxel and Samarium-153 in Patients With Bone Metastases From Castration-Resistant Prostate Cancer

Purpose

To assess docetaxel combined with samarium-153–ethylene diamine tetramethylene phosphonic acid (EDTMP), a radiopharmaceutical with a high affinity for bone, in patients with castration-resistant prostate cancer (CRPC).

Patients and Methods

Patients with bone metastases from CRPC who achieved a response or stabilization after four cycles of docetaxel and estramustine were given consolidation docetaxel 20 mg/m2/wk for 6 weeks and samarium-153-EDTMP (37 MBq/kg) during week 1. Prostate-specific antigen (PSA) response was assessed by using consensus criteria, and pain was assessed by using a visual analog scale (VAS). This study used a Simon two-step design with PSA–progression-free survival (PFS) as the primary end point.

Results

Forty-three patients were included in the trial. A PSA response was obtained in 77% (95% CI, 61% to 82%). The pain response rate was 69% (95% CI, 49% to 85%). At least five of the six planned weekly injections of docetaxel were administered to 34 patients (81%). The consolidation docetaxel–samarium-153–EDTMP regimen was well tolerated; there was no febrile neutropenia, and only two episodes (5%) of rapidly reversible grade 3 thrombocytopenia occurred. Although a serum PSA relapse eventually occurred in all patient cases, this regimen resulted in pain control in the long-term. The median PSA-PFS was 6.4 months (95% CI, 6 to 7 months). The median survival was 29 months (95% CI, 22 to 31); the 1-year survival rate was 77% (62% to 87%); and the 2-year survival rate was 56% (41% to 70%).

Conclusion

Combining docetaxel and samarium-153–EDTMP in patients with bone metastases from CRPC is well tolerated, and it yields major pain relief that persists long after treatment. Overall survival compares favorably with that expected in this population of patients, most of whom exhibit symptoms.