Prostate Specific Antigen after Gonadal Androgen Withdrawal and Deferred Flutamide Treatment

Spatio-temporal analysis of prostate tumors in situ suggests pre-existence of treatment-resistant clones

The molecular mechanisms underlying lethal castration-resistant prostate cancer remain poorly understood, with intratumoral heterogeneity a likely contributing factor. To examine the temporal aspects of resistance, we analyze tumor heterogeneity in needle biopsies collected before and after treatment with androgen deprivation therapy. By doing so, we are able to couple clinical responsiveness and morphological information such as Gleason score to transcriptome-wide data. Our data-driven analysis of transcriptomes identifies several distinct intratumoral cell populations, characterized by their unique gene expression profiles. Certain cell populations present before treatment exhibit gene expression profiles that match those of resistant tumor cell clusters, present after treatment. We confirm that these clusters are resistant by the localization of active androgen receptors to the nuclei in cancer cells post-treatment. Our data also demonstrates that most stromal cells adjacent to resistant clusters do not express the androgen receptor, and we identify differentially expressed genes for these cells. Altogether, this study shows the potential to increase the power in predicting resistant tumors.

Treatment Options in Hormone-refractory Metastatic Prostate Carcinoma

Prostate cancer represents one of the most important health problems in industrialized countries. It is the second leading cause of cancer-related death in the United States. Therapeutic options are different according to the stage of the disease at the diagnosis. Patients with localized disease may be treated with surgery or radiation, whereas the treatment for patients with a metastatic disease is purely palliative. Hormonal treatment represents the standard therapy for stage IV prostate cancer, but patients ultimately become unresponsive to androgen ablation and are classified as hormone-refractory prostate cancer patients. The molecular mechanisms involved in progression in hormone resistance are characterized by mutations, down and up-regulation in the androgen receptor gene, mutations in p53 and over-expression of Bcl2 and other alterations in genes and in gene expression. The important thing is that we understand these mechanisms to define potential therapeutic agents for the treatment of hormone-refractory prostate cancer patients. Conventional options for patients with hormone-refractory prostate cancer include secondary hormone therapy, radiotherapy and cytotoxic chemotherapy. The commonest antineoplastic agents are mitoxantrone, estramustine and taxanes. Despite an improvement In the palliative benefit, none of these agents has demonstrated a beneficial impact on the overall survival of patients. Therefore, there is no standard therapy for these patients, thus we need new approaches which should be studied in clinical trials. The evaluation and incorporation of new agents into current treatment regimens could have a role in the treatment of hormone-refractory prostate cancer, but their efficacy has not yet been demonstrated.

Prospective study on the relationship between clinical efficacy of secondary hormone therapy with flutamide and neuroendocrine differentiation in patients with relapsed prostate cancer after first line hormone therapy

OBJECTIVE

The aim of this study was to prospectively verify the relationship between the clinical efficacies of secondary hormone therapy for castration-resistant prostate cancer (CRPC) following first line hormone therapy and neuroendocrine differentiation (NED).

MATERIAL AND METHODS

Forty-six consecutive patients with CRPC following first line hormone therapy who were treated with flutamide as secondary hormone therapy were prospectively assessed with a median follow-up of 21 months. Serum chromogranin A (CgA), as a marker of NED, was measured using an immunoradiometric assay.

RESULTS

Of the 46 patients, 22 (48%) responded to the secondary hormone therapy as a 50% or more reduction from baseline prostate-specific antigen (PSA) with a median response duration of 9.2 months. The PSA response group was correlated with significantly favorable cancer-specific survival (CSS) (92% vs 59% at 5 years, p = 0.0146) compared with the non-response group. Above-normal CgA levels at study entry were detected in 15 patients (33%), but no association with CSS was identified. Data on CgA kinetics were available in 35 patients. The CgA levels before and at 3 months during the treatment were similar. However, eight patients (23%) with an increase in CgA level of a quarter or more from baseline had a tendency for worse CSS (63% vs 84% at 5 years, p = 0.0507) compared with the remaining patients.

CONCLUSION

Within limitations, in this study secondary hormone therapy with flutamide was effective for CRPC following first line hormone therapy. The above-normal CgA level in the first hormone resistance phase is mostly unrelated to prognosis. However, some patients with a remarkable increase in CgA in a short duration may have an unfavorable prognosis caused by NED as well.

Metastatic castration resistant prostate cancer: current strategies of management in the Middle East

Although most patients with prostate cancer respond to initial androgen-deprivation therapy, progression to castration-resistant prostate cancer (CRPC) is almost inevitable. In 2004, the docetaxel/prednisone regimen was approved for the management of patients with metastatic CRPC, becoming the standard first-line therapy. Recent advances have also led to an unprecedented number of approved new drugs; thus, providing several treatment options for patients with metastatic CRPC. Five new drugs have received US Food and Drug Administration-approval between 2010 and 2012: sipuleucel-T, an immunotherapeutic agent; cabazitaxel, a novel microtubule inhibitor; abiraterone acetate, a new androgen biosynthesis inhibitor; enzalutamide, a novel androgen receptor inhibitor; and denosumab, a bone-targeting agent. Such drugs are either already marketed or about to be marketed in the Middle East. Data supporting the approval of each of these agents are described in this review, as are recent approaches to the treatment of metastatic CRPC.

[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.

The long-term results with delayed-combined androgen blockade therapy in local or locally advanced prostate cancer

OBJECTIVE

To evaluate long-term clinical outcomes in cT1c-T3a prostate cancer patients following delayed-combined androgen blockade therapy.

METHODS

From January 2001 to December 2004, 92 cT1c-T3a prostate cancer cases were enrolled. Medical castration and anti-androgen treatment were used sequentially as delayed-combined androgen blockade therapy. Time to prostate-specific antigen biochemical failure was estimated, and risk factors for prostate-specific antigen biochemical failure were evaluated.

RESULTS

The average patient age was 76.4 years (range, 59-91 years), the median observation period was 52.8 months (range, 26-106.6 months) and the median pre-treatment prostate-specific antigen level was 14 ng/ml (range, 3.68-492 ng/ml). The TNM classification distribution was as follows: T1c, n= 27; T2a, n = 39; T2b, n = 20; and T3a, n = 6. In the multivariate analysis, Gleason's score ≥8 (P < 0.05; hazard ratio, 3.02), prostate-specific antigen nadir >1.4 ng/ml (P = 0.001; hazard ratio, 8.76) and a half-life of the prostate-specific antigen level >1.2 months (P < 0.005; hazard ratio, 6.3) during the initial 6 months of luteinizing hormone-releasing hormone agonist monotherapy were significant independent risk factors for prostate-specific antigen biochemical failure with luteinizing hormone-releasing hormone agonist monotherapy. The high-risk group, which had at least one of these three risk factors, had a shorter time to prostate-specific antigen biochemical failure than the low-risk group, during luteinizing hormone-releasing hormone agonist monotherapy (P < 0.0001). For the total delayed-combined androgen blockade therapy observation period, the free-prostate-specific antigen biochemical failure rate was 88.3% at 5 years. Only a maintenance period following luteinizing hormone-releasing hormone agonist monotherapy (P < 0.005; hazard ratio, 16.8) was revealed to be a significant independent risk factor for prostate-specific antigen biochemical failure with total delayed-combined androgen blockade.

CONCLUSIONS

The free-prostate-specific antigen biochemical failure rate of delayed-combined androgen blockade therapy in our study was as valuable as those in other androgen deprivation therapy of previous reports.

[How should hormone therapy for castration-resistant prostate cancer be continued?]

After an average of 18-36 months under androgen suppression therapy by surgical castration, LHRH, and steroidal or non-steroidal antiandrogens, almost all patients with metastatic prostate cancer show PSA progression as a sign of androgen-independent but still androgen-sensitive tumor growth. Our understanding and the treatment of such castration-resistant prostate cancer has changed markedly. The introduction of new drugs like abiraterone and MDV3100 has shown that prostate cancer progression even in the"hormone-refractory" stage is driven by androgen receptor signaling. Based on this information the question of whether androgen deprivation therapy in castration-resistant prostate cancer should be continued or not is still of relevance. This review gives a critical overview of the literature and current guideline recommendations.

Mechanisms mediating androgen receptor reactivation after castration

Androgen deprivation is still the standard systemic therapy for metastatic prostate cancer (PCa), but patients invariably relapse with a more aggressive form of PCa termed hormone refractory, androgen independent, or castration resistant PCa (CRPC). Significantly, the androgen receptor (AR) is expressed at high levels in most cases of CRPC, and these tumors resume their expression of multiple AR-regulated genes, indicating that AR transcriptional activity becomes reactivated at this stage of the disease. The molecular basis for this AR reactivation remains unclear, but possible mechanisms include increased AR expression, AR mutations that enhance activation by weak androgens and AR antagonists, increased expression of transcriptional coactivator proteins, and activation of signal transduction pathways that can enhance AR responses to low levels of androgens. Recent data indicate that CRPC cells may also carry out intracellular synthesis of testosterone and DHT from weak adrenal androgens and may be able to synthesize androgens from cholesterol. These mechanisms that appear to contribute to AR reactivation after castration are further outlined in this review.

[Natural history of metastasic prostate cancer treated with androgen deprivation therapy and secondary hormonal therapy efficiency]

OBJECTIVE

to analyze metastatic prostate cancer progression in patients treated with hormonal blockade as well as second line hormonal treatments outcomes.

PATIENTS AND METHODS

199 metastatic patients were selected from a 455 hormonal treated patients pool. Time to biochemical progression was studied with Kaplan Meier analysis and patients were stratified according to pathological differentiation. Second line treatment lasting and efficacy were also assessed.

RESULTS

74 patients out of 192 metastatic patients (56.1%) progressed in terms of PSA. Median time to biochemical progression was 1.7 years (1.2-2.3, CI 95%). We did not find stadistical differences on pathological differentiation (p = 0.238). Second line treatment's efficacy, applied to 41 patients was 34.1%, without any stadistical differences among these treatments. Response treatment median time was 6.8 months without stadistical differences among different treatments (p = 0.220).

CONCLUSIONS

hormonal blockade efficacy in metastatic prostate cancer has a limited value in time in our experience. One third of these patients have a limited response to a second line treatment although this response is even shorter in duration.

Rising prostate-specific antigen after primary treatment of prostate cancer: sequential hormone manipulation

OBJECTIVE

To evaluate systematically the current endocrine treatment options for patients with biochemical recurrence after radical prostatectomy or radiation therapy for localized prostate cancer.

METHODS

Literature search of PubMed documented publications and abstracts from international meetings. Key items included timing and type of salvage hormone therapy, length of its application and handling of side effects.

RESULTS

The majority of patients with isolated prostate-specific antigen (PSA) relapse are not candidates for salvage treatment with curative intent. The PSA threshold that triggers initiation of hormonal therapy is debatable and should be based also on pretreatment risk assessment. Intermittent androgen suppression is an emerging concept to circumvent the unresolved controversy of early versus deferred endocrine therapy. Since the tumor load at time of recurrence is low, peripheral androgen blockade with an antiandrogen and a 5alpha-reductase inhibitor is an acceptable first choice. In case of progression, addition of a LHRH analogue would be the next step. Antiandrogen withdrawal and second-line antiandrogens are clinically of limited value.

CONCLUSIONS

Biochemical-only progression after definitive treatment in curative intent is different from objective or even symptomatic relapse and allows for sequential hormonal therapy with a variety of compounds.

Prostate-specific antigen half-life and pretreatment prostate-specific antigen: Crucial predictors for prostate-specific antigen trend in delayed-combined androgen blockade therapy

PURPOSE

To elucidate the crucial predictors for prostate-specific antigen (PSA) trends and determine the usage of anti-androgen treatment during delayed-combined androgen blockade (CAB) leading to a PSA level below 0.2 ng/mL.

MATERIALS AND METHODS

From January 2001 to December 2004, 105 prostate cancer patients were enrolled. Medical castration and anti-androgen treatment were used sequentially and termed delayed-CAB. The first goal was to maintain an undetectable PSA level. The nadir PSA was determined after medical castration only. Anti-androgen was given if a PSA level of more than 0.2 ng/mL was observed and the subsequent PSA response was assessed. All cases were divided into two groups based on whether the PSA was lower (n = 59) or higher (n = 46) than 0.2 ng/mL. An analysis of the difference between the two groups was calculated.

RESULTS

The median of the initial PSA level in the lower group was lower than in the higher group with a 95% cut-off level of 40 ng/mL. The median PSA half-life in the lower group was also reduced with a 95% cut-off of 3.6 months. In a multivariate analysis, the pretreatment PSA level and the PSA half-life exhibited a significant correlation between the two groups. Anti-androgen treatment was given to 26 cases in the higher group. The PSA increased in one case, decreased to less than 0.2 ng/mL in 17 cases and remained over 0.2 ng/mL in eight cases.

CONCLUSION

Both the PSA half-life and the pretreatment PSA level were useful markers for predicting the PSA trends to determine the optimal use of anti-androgen treatment during delayed-CAB.

Adjuvant and salvage treatment options for patients with high-risk prostate cancer treated with radical prostatectomy

The management of high-risk prostate cancer following radical prostatectomy remains a treatment dilemma. Multimodality approaches incorporating surgery, radiation therapy and systemic agents offer the hope of improved cure rates; however, most randomized studies to date are either immature or negative. The systemic treatment options best studied is androgen deprivation, which has been shown to demonstrate a survival advantage in patients with lymph node-positive disease. Systemic chemotherapy has demonstrated a modest survival advantage in androgen-independent disease. Current studies are exploring its role in the adjuvant and neo-adjuvant setting. Lastly, recent randomized trials have demonstrated a biochemical advantage to adjuvant radiation therapy, but it remains to be seen if this will translate to an improvement is survival end points or if salvage radiation therapy would be just as effective. In this update article, we review the use of external beam radiation therapy and systemic agents in combination with surgery for high-risk prostate cancer patients.

[Hormone-refractory prostate cancer. Modifications of the therapeutic strategies since chemotherapy proved its usefulness]

Back in the 90's it was difficult to have access to the conclusions of publications on HRPC. Homogeneity was very scarce regarding issues as significant as the definition of HRPC itself, patient selection, or evaluation of the responses to therapy. Consensus has currently been reached on such matters, and it is described in this text. Two works were published in late 2004 showing that docetaxel-based chemotherapy improved metastatic HRPC survival. Until then, the different treatments used could only provide symptomatic relief. But probably not all of the HRPC patients are eligible for primary docetaxel chemotherapy. The current debate focuses on determinating to which patients should chemotherapy be administered and at which time should it start, in order to exclude those patients at risk of experiencing its adverse effects without benefitting from its clinical advantages. Non-metastatic HRPC patients may be candidates to receiving secondary hormone manoeuvres before starting with chemotherapy. We will analyse in this review the changes occurred in the therapeutic strategies ever since chemotherapy showed its value, and we shall also disclose our attitude regarding treatment of these patients in daily practice.

Secondary Hormonal Manipulations in Prostate Cancer

Targeting AIPC with therapies that affect the mechanisms of androgen receptor signaling despite a castrate testosterone milieu is an active and growing area of clinical research. At present, for patients with AIPC, the data support the maintenance of the castrate state, recognition of the AAWD phenomenon,the sequential use of oral antiandrogens, and a trial of estrogens or adrenal androgen-targeted therapies. Novel agents are being developed that seek to prolong the duration of clinical responses and the overall response rate.

Synthesis and biological evaluation of a nonsteroidal bromine-76-labeled androgen receptor ligand 3-[76Br]bromo-hydroxyflutamide

INTRODUCTION

Androgen receptors (ARs) are overexpressed in normal tissues and in most primary and metastatic prostate cancers. In our efforts to develop a nonsteroidal AR-specific imaging agent, we synthesized (+/-)-3-[(76)Br]bromo-hydroxyflutamide ((76)Br-), an analog of hydroxyflutamide, the active metabolite of the AR antagonist ligand flutamide.

MATERIALS AND METHODS

(76)Br- was synthesized in three steps, starting with commercially available compounds. Labeling of (76)Br- was achieved through the nucleophilic opening of an epoxide intermediate, and a labeled compound was obtained in high specific activity and good radiochemical yield.

RESULTS AND DISCUSSION

(+/-)-3-Bromo-hydroxyflutamide has a significantly higher affinity for ARs compared to hydroxyflutamide, its parent compound. The androgen target-tissue uptake of (76)Br- in diethylstilbestrol-treated male rats was examined; however, AR-mediated uptake was minimal due most likely to the rapid metabolic debromination of the radiolabeled ligand.

CONCLUSIONS

This study is part of our first look at a novel class of nonsteroidal AR antagonists as positron emission tomography (PET) imaging agents, which are alternatives to steroidal AR agonist-based imaging agents. Although (76)Br- has a significant affinity for ARs, it showed limited promise as a PET imaging agent because of its poor target-tissue distribution properties.

New approaches in hormone refractory prostate cancer

Effective therapeutic options have not existed for prostate cancer progressing after androgen deprivation therapy until very recently. Docetaxel based chemotherapy has been demonstrated to extend survival in 2 large randomized trials. These studies have provided the impetus to combine docetaxel with novel biologic agents to further consolidate the gains in long-term outcome. With the arrival of exciting agents including vaccines, monoclonal antibodies, bone-targeted drugs, antisense oligonucleotides, antiangiogenic drugs, and small molecule receptor tyrosine kinase inhibitors, the future of prostate cancer therapy appears promising.

[Treatment options for hormone-refractory prostate cancer]

Surgical or medical androgen deprivation therapy in its multiple variants represents the standard therapeutic approach in the management of metastatic prostate cancer resulting in a primary response rate of about 90%. However, about 90% of the men treated will develop PSA progression within 3-4 years resulting in androgen-independent and later on hormone-refractory prostate cancer. Management of AIPCA and HRPCA still represents a therapeutic challenge despite the development of new and effective treatment options. PSA progression following primary ADT defines an androgen-refractory but still hormone-sensitive PCA which might respond to secondary hormonal manipulations such as antiandrogen withdrawal, addition of nonsteroidal antiandrogens, and administration of estrogens, ketoconazole and hydrocortisone, and somatostatin analogues. Secondary hormonal manipulations will result in a PSA decline >50% in about 60-80% of the patients with a mean duration of 7-17 months depending on the type of treatment. PSA progression following secondary endocrine treatment defines hormone-refractory prostate cancer (HRPCA) which might be treated by systemic chemotherapy. Based on the results of two prospective, randomized clinical phase III trials comparing docetaxel and mitoxantrone, docetaxel results in a statistically significant survival benefit of 2.5 months, a significantly higher PSA and pain response, and represents the treatment of choice in the management of HRPCA. Bisphosphonates such as zoledronate represent another cornerstone in the management of PSA-progressive PCA demonstrating a significant benefit with regard to the prevention of skeletal-related events. Furthermore, bisphosphonates might be indicated in the treatment of symptomatic bone pain as has been demonstrated for ibandronate and zoledronate. The current article critically reflects on the various therapeutic options in the management of PSA progression following primary androgen deprivation for advanced prostate cancer. The development, rationale, and results of systemic chemotherapy are discussed critically and a therapeutic algorithm is demonstrated.

Hormone refractory prostate cancer: Management and advances

Effective therapeutic options have not existed for prostate cancer progressing after androgen deprivation therapy until very recently. Secondary hormonal manipulations offer marginal benefits. Docetaxel based chemotherapy has been demonstrated to extend survival and change the natural history of the disease in two large randomized trials. These studies have provided the impetus to combine docetaxel with novel biologic agents to further consolidate the gains in long-term outcome. With the arrival of exciting agents including vaccines, monoclonal antibodies, bone-targeted drugs, antisense oligonucleotides, anti-angiogenic drugs and small molecule receptor tyrosine kinase inhibitors, the future treatment of prostate cancer appears promising.

Secondary Hormonal Therapy for Advanced Prostate Cancer

PURPOSE

Androgen ablation remains the cornerstone of management for advanced prostate cancer. Therapeutic options in patients with progressive disease following androgen deprivation include antiandrogen withdrawal, secondary hormonal agents and chemotherapy. Multiple secondary hormonal agents have clinical activity and the sequential use of these agents may lead to prolonged periods of clinical response. We provide a state-of-the-art review of the various agents currently used for secondary hormonal manipulation and discusses their role in the systemic treatment of patients with prostate cancer.

MATERIALS AND METHODS

A comprehensive review of the peer reviewed literature was performed on the topic of secondary hormonal therapies, including oral antiandrogens, adrenal androgen inhibitors, corticosteroids, estrogenic compounds, gonadotropin-releasing hormone antagonists and alternative hormonal therapies for advanced prostate cancer.

RESULTS

Secondary hormonal therapies can provide a safe and effective treatment option in patients with AIPC. The use of steroids and adrenolytics, such as ketoconazole and aminoglutethimide, has resulted in symptomatic improvement and a greater than 50% prostate specific antigen decrease in a substantial percent of patients with AIPC. A similar clinical benefit has been demonstrated with estrogen based therapies. Furthermore, these therapies have demonstrated a decrease in metastatic disease burden. Other novel hormonal therapies are currently under investigation and they may also show promise as secondary hormonal therapies. Finally, guidelines from the United States Food and Drug Administration Prostate Cancer Endpoints Workshop were reviewed in the context of developing new agents.

CONCLUSIONS

Secondary hormonal therapy serves as an excellent therapeutic option in patients with AIPC in whom primary hormonal therapy has failed. Practicing urologists should familiarize themselves with these oral medications, their indications and their potential side effects.

Therapie des hormonrefraktären Prostatakarzinoms

PSA-progression following primary ADT defines an androgen-refractory but still hormone sensitive PCA which might respond to secondary hormonal manipulations. Secondary hormonal manipulations will result in a PSA decline >50% in about 60-80% of the patients with a mean duration of 7-17 months depending on the type of treatment. PSA-progression following secondary endocrine treatment defines hormone-refractory prostate cancer (HRPCA) which might be treated by systemic chemotherapy. Based on the results of 2 prospective, randomized clinical phase-III trials comparing docetaxel and mitoxantrone, docetaxel results in a statistically significant survival benefit of 2.5 months, a significantly higher PSA- and pain response and represents the treatment of choice in the management of HRPCA. Bisphosphonates such as zoledronate represent another cornerstone in the management of PSA-progressive PCA demonstrating a significant benefit with regard to the prevention of skeletal related events. Furthermore, bisphosphonates might be indicated in the treatment of symptomatic bone pain. The current article critically reflects the various therapeutic options in the management of PSA progression following primary androgen deprivation for advanced prostate cancer.

Managing metastatic prostate cancer

Prostate cancer is one of the most commonly diagnosed malignancies in the west. Most patients with metastatic or recurrent prostate cancer initially respond to androgen deprivation therapy, but almost all eventually progress. This review will focus on current treatment options for metastatic prostate cancer, with a focus on hormonal therapies, chemotherapy and treatment of bony disease, along with biological and targeted therapy.

Luteinizing hormone-releasing hormone agonist monotherapy for prostate cancer: outcome and prognostic factors

BACKGROUND

We assessed the outcome and prognostic factors in men with prostate cancer after luteinizing hormone-releasing hormone agonist monotherapy.

METHODS

Between April 1998 and August 2002, 62 men with prostate cancer who were treated with monotherapy at our institution were included in this analysis. Prostate-specific antigen (PSA) failure-free (bNED) survival was calculated using Kaplan-Meier methods. Prognostic factors were evaluated using Cox proportional hazards regression model.

RESULTS

We reviewed the data of patients, with a median follow-up from the commencement of monotherapy of 26 months. The overall survival rate at 3 years was 89.9%. The bNED survival rate was 63.7% at 3 years. Of the 20 patients with clinical stage B, 2 progressed to PSA failure, whereas PSA failure was seen in 8 of 30 patients with stage C and 8 of 12 patients with stage D. The significant factors for bNED status were an initial PSA level of <30 ng/ml (p=0.0044), achievement of PSA nadir level of <2.0 ng/ml (p<0.001), and Gleason score of <or=6 (p<0.001).

CONCLUSIONS

Patients with high clinical stage, a high initial PSA level of >or=30 ng/ml, and high Gleason score of >or=7 are at increased risk for PSA failure. Failure to achieve PSA nadir level of <2.0 ng/ml is an important predictor of the progression. The use of PSA nadir can provide useful guidelines for the reconsideration of treatment in patients who have received monotherapy.

An interdisciplinary approach to treating prostate cancer

Urologists often are faced with challenges in treating men with metastatic prostate cancer. Although historically chemotherapy has had limited utility in treating this disease, therapeutic nihilism surrounding its use is no longer warranted, as demonstrated by results of 2 recent randomized clinical trials showing that docetaxel-based chemotherapy improves survival in patients with hormone-refractory prostate cancer (HRPC). Although the survival benefit was a modest 2 months, the results hold the promise that docetaxel-based treatment in earlier-stage disease may provide a longer survival advantage. The Cancer and Leukemia Group B (CALGB) 90203 and TAX 3501 studies are phase 3 neoadjuvant and adjuvant radical prostatectomy trials designed to assess the role of docetaxel in patients with high-risk localized disease. These 2 trials, along with the Southwest Oncology Group (SWOG) 9921 trial, which will assess the potential for adjuvant mitoxantrone, are paving the way for earlier systemic treatment. The need for better therapies for patients routinely seen in the urology clinic and the potential for improvements with chemotherapy necessitate an increasing collaboration between urologists and oncologists. Referral to a medical oncologist for a full discussion of treatment options is in the best interest of patients with HRPC, and patients at high-risk for treatment failure should be encouraged to consider clinical trial enrollment.

Secondary hormonal manipulations in prostate cancer

Virtually all patients treated with androgen deprivation eventually develop progressive clinical or biochemical disease despite this therapy. Despite low levels of androgen, the androgen receptor remains active, making secondary hormonal therapies a reasonable clinical approach. Considerations for such patients include antiandrogen withdrawal, sequential use of antiandrogens, adrenal cortex inhibitors, and estrogenic compounds. Collectively, the modest activity of these therapies challenges the notion that advancing prostate cancer will uniformly become "hormone refractory."

Antiandrogen withdrawal alone or in combination with ketoconazole in androgen-independent prostate cancer patients: a phase III trial (CALGB 9583)

PURPOSE

Antiandrogen withdrawal (AAWD) results in a prostate-specific antigen (PSA) response (decline in PSA level of > or =50%) in 15% to 30% of androgen-independent prostate cancer (AiPCa) patients. Thereafter, adrenal androgen ablation with agents such as ketoconazole (K) is commonly utilized. The therapeutic effect of AAWD alone was compared with simultaneous AAWD and K therapy.

PATIENTS AND METHODS

AiPCa patients were randomized to undergo AAWD alone (n=132), or together with K (400 mg orally [p.o.] tid) and hydrocortisone (30 mg p.o. each morning, 10 mg p.o. each evening; n=128). Patients who developed progressive disease after AAWD alone were eligible for deferred treatment with K.

RESULTS

Eleven percent of patients undergoing AAWD alone had a PSA response, compared to 27% of patients who underwent AAWD and simultaneous K (P=.0002). Objective responses were observed in 2% of patients treated with AAWD alone compared to 20% in patients treated with AAWD/K (P=.02). There was no difference in survival. PSA and objective responses were observed in 32% and 7%, respectively, of patients receiving deferred K, and were more common in patients with prior AAWD response. Treatment with K was well tolerated, and resulted in a decline in adrenal androgen levels, which rose at the time of disease progression.

CONCLUSION

K has modest activity in AiPCa patients, while AAWD alone has minimal activity. Adrenal androgen levels fall with treatment with K and then climb at the time of progression, suggesting that progressive disease while on K may be due to tachyphylaxis to the adrenolytic properties of K.

Prostate-specific antigen doubling time predicts response to deferred antiandrogen therapy in men with androgen-independent prostate cancer

OBJECTIVES

To identify the pretreatment variables that are predictive of response and the duration of response to deferred antiandrogen therapy in men with androgen-independent prostate cancer (AIPC).

METHODS

A total of 375 patients receiving androgen deprivation therapy for advanced prostate cancer between 1977 and 2002 had medical records available for retrospective review. Of these 375 patients, 163 were diagnosed with AIPC. The inclusion criteria included (1) diagnosis of AIPC and (2) treatment with deferred antiandrogen therapy. AIPC was biochemically defined as two consecutive rises in the prostate-specific antigen (PSA) level during androgen deprivation therapy. The treatment response to deferred antiandrogen therapy was defined as a 50% or greater decline in the pretreatment PSA level. The prognostic value of various pretreatment parameters was determined with the appropriate statistical methods and tested with a Cox proportional hazards model.

RESULTS

Of the 163 patients with AIPC, 36 were treated with deferred antiandrogen therapy. Of these 36 patients, 12 (33.3%) experienced a PSA response. The median PSA failure-free survival was 9.0 months (95% confidence interval 5.2 to 12.9). The only pretreatment variable predictive of a PSA response was the PSA doubling time (PSADT). The mean PSADT in responders was 12.7 months versus 7.5 months in nonresponders (P = 0.037). Moreover, PSADT was the only statistically significant variable on univariate analysis of PSA failure-free survival in responders (hazard ratio 0.202, 95% confidence interval 0.041 to 0.990, P = 0.049). No statistically significant difference was found in cancer-specific survival between responders and nonresponders (P = 0.1501).

CONCLUSIONS

The PSADT predicted both the response and the duration of the response to deferred antiandrogen therapy in patients diagnosed with AIPC.

Role of secondary hormonal therapy in the management of recurrent prostate cancer

Androgen ablation remains the cornerstone of the systemic management of prostate cancer. After initial androgen deprivation, clinical outcomes vary considerably. For the patient with progressive disease after androgen deprivation, multiple therapeutic options are available and include antiandrogen withdrawal, chemotherapy, and secondary hormonal agents. Multiple secondary hormonal agents have clinical activity and the sequential use of these agents may lead to prolonged periods of clinical response. In addition to the use of oral antiandrogens, active secondary hormonal therapies include adrenolytic agents such as ketoconazole and aminoglutethimide, corticosteroids and estrogenic compounds. This article reviews the clinical trial data for these various agents and discusses their role in the management of patients with advanced prostate cancer.

Current strategies in the management of hormone refractory prostate cancer

Prostate cancer is the most common cancer diagnosed in American males, and is the second leading cause of cancer-related deaths. Most patients who develop metastatic disease will initially respond to androgen deprivation, but response is invariably temporary. Most patients will develop androgen-independent ("hormone-refractory") disease that results in progressive clinical deterioration and ultimately death. This progression to androgen independence is accompanied by increasingly evident DNA instability and alterations in genes and gene expression, including mutations in p53, over-expression of Bcl2, and mutations in the androgen receptor gene, among others. Treatment options for hormone refractory disease include intensive supportive care, radiotherapy, bisphosphonates, second-line hormonal manipulations, cytotoxic chemotherapy and investigational agents. A post-treatment reduction in the level of prostate specific antigen (PSA) by 50% has been shown to correlate with survival and has been accepted by consensus as a valid endpoint in clinical trials. Chemotherapeutic agents such as mitoxantrone, estramustine, and the taxanes have yielded improved response rates and palliative benefit, but not improved survival. Therefore, current efforts must be focused on enrolling patients onto clinical trials of investigational agents with novel mechanisms of action, and on using survival, time to progression, and quality of life as end points in routine clinical practice.

Secondary hormonal manipulation of prostate cancer

Prostate cancer is the second leading cause of cancer mortality among men in Western countries. The initial treatment of advanced prostate cancer is suppression of testicular androgen production by medical or surgical castration, but nearly all men with metastases develop disease progression. Patients with hormone-resistant prostate cancer (HRPC) have a median survival of approximately 18 months, and no therapy has yet demonstrated a definitive survival advantage. However, in the past several years, a number of promising new treatment strategies have emerged. One of the most important new treatment strategies involves secondary hormonal manipulation after the failure of primary androgen deprivation. This approach is predicated on the recognition that HRPC is a heterogeneous disease, and some patients may respond to alternative hormonal interventions despite the presence of castrate levels of testosterone.

Hormonal treatment for prostate cancer

For nearly six decades the preferred primary treatment for advanced prostate cancer has been continuous suppression of testicular androgen production by medical or surgical castration. While androgen deprivation is effective in inducing tumour regression in the large majority of cases, essentially all patients will develop progressive disease. In addition androgen deprivation may be associated with a variety of side effects. Thus, strategies that minimise the use of these agents could potentially lower the morbidity and cost associated with the treatment of advanced prostate cancer. In the era of prostate-specific antigen (PSA) testing, hormonal therapy is being used earlier in the course of the disease when the only evidence of recurrent disease is an elevated PSA. These men may survive for many years and thus have the potential for long periods of exposure to hormonal therapy and its side effects. It has been hoped that the development of alternative hormonal interventions might lead to both enhanced antitumour efficacy as well as improvements in side effect profile.

New treatment strategies in advanced prostate cancer

The treatment of advanced prostate cancer has evolved rapidly in the last 5 years. Therapeutic options for patients with advanced disease, once essentially limited to the use of androgen deprivation, have expanded to include a number of interventions, including secondary hormonal manipulations, chemotherapy, and a variety of investigational approaches. Novel therapeutic approaches in prostate cancer patients are likely to be undertaken in patients with disease that is at or below the limits of detection by current imaging technology, so novel methods will be essential to the successful evaluation and use of these agents.

Secondary hormonal manipulations in hormone refractory prostate cancer

Hormone refractory prostate cancer is clinically heterogeneous, and many patients retain sensitivity to subsequent hormonal manipulations, even after combined androgen blockage. Antiandrogen withdrawal is a mandatory first step. Subsequent treatment with an alternate antiandrogen, adrenal androgen inhibitor (such as ketoconazole), or glucocorticoid may provide both subjective and objective clinical benefit in up to 65% of patients.

Biochemical response to testicular androgen ablation among patients with prostate cancer for whom flutamide and/or finasteride therapy failed

OBJECTIVES

To evaluate the response of testicular androgen ablation in patients with advanced prostate cancer with a biochemical recurrence after finasteride or combined finasteride and flutamide therapy.

METHODS

Eighteen hormone naïve men with advanced prostate cancer (10 with detectable prostate-specific antigen [PSA] levels after radical prostatectomy, 4 with rising PSA levels after definitive radiation therapy, and 4 with Stage D2 disease) were treated with finasteride (5 mg/day) alone or in combination with flutamide (250 mg three times a day). All men experienced an initial reduction in serum PSA, but later had treatment failure with two consecutive rising PSA measurements. All men were then treated with testicular androgen ablation (bilateral orchiectomy in 15 and luteinizing hormone-releasing hormone analogue in 3).

RESULTS

Overall, serum PSA declined by more than 80% in 15 (83%) of 18 and to undetectable levels in 14 (78%) of 18. With a median+/-semi-interquartile range follow-up of 22+/-14.5 months from the initiation of hormone therapy, 12 (67%) of 18 currently have undetectable PSA levels. Two men having rising serum PSA levels above 100 ng/mL and 1 man has died from complications of metastatic prostate cancer.

CONCLUSIONS

Testicular androgen ablation effectively lowers serum PSA levels in most men with advanced prostate cancer who have experienced a biochemical recurrence despite initial response and subsequent relapse on finasteride or combined finasteride and flutamide therapy.

Management of Hormone-Sensitive and Hormone-Refractory Metastatic Prostate Cancer

BACKGROUND: Prostate cancer is a significant health problem in the United States and is the focus of increasing attention in our society. With the aging of the US population, it is likely that prostate cancer will continue to grow in importance. The options for systemic therapy of metastatic prostate cancer should be familiar to physicians, including nonspecialists, whose patients seek their advice and counsel. METHODS: Past and recent literature was surveyed to provide an understanding of the systemic treatment of advanced prostate cancer. The author presents a review of the systemic treatment of metastatic prostate cancer in different clinical circumstances and addresses the current status of chemotherapy in the management of advanced prostate cancer. RESULTS: Early androgen deprivation used over prolonged periods appears to be modestly superior to delayed androgen deprivation with a small potential survival advantage and an advantage in delaying disease progression in advanced prostate cancer. Patients with hormone-refractory prostate cancer may benefit from secondary hormonal therapy (eg, adrenal enzyme inhibitors, antiandrogens, glucocorticoids) and chemotherapy. CONCLUSIONS: The choices of therapy for metastatic prostate cancer depend on individual patient preference. Patients and physicians should be aware of the possible side effects associated with the therapeutics options for treatment of metastatic prostate cancer.

Prostate specific antigen in black and white men after hormonal therapies for prostate cancer

PURPOSE

Prostate cancer deaths usually result from proliferation of the androgen independent malignant phenotype, and in the United States the survival of black men with metastatic cancer is less favorable than that of white men. We compared prostate specific antigen (PSA) functions after hormonal therapies in men of both races to investigate potential differences in the biology of androgen independent cancer.

MATERIALS AND METHODS

The PSA nadir after gonadal androgen withdrawal was determined in 217 black and 188 white men with localized or metastatic cancer. The time to PSA elevation and PSA doubling time were determined in 62 black and 27 white men with biochemical relapse. Biochemical response to deferred flutamide treatment and flutamide withdrawal was assessed in 87 and 11 black and 30 and 10 white men, respectively.

RESULTS

There were no significant racial differences in the PSA nadir when controlled for clinical stage and pretreatment PSA, or in PSA doubling time when controlled for clinical stage, PSA nadir and month of PSA elevation. The biochemical response to deferred flutamide therapy and flutamide withdrawal was the same in black and white men.

CONCLUSIONS

The burden and growth rate of androgen independent cancer estimated from PSA functions after gonadal androgen withdrawal, and the impact of deferred antiandrogen therapy on the serum PSA are similar in black and white men. These findings suggest that racial differences in the biology of androgen independent carcinoma do not contribute to the inferior survival of black men with metastatic prostate cancer.