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Context: Various molecular mechanisms play a role in the development of resistance to androgen deprivation therapy in castration-resistant prostate cancer (CRPC)., Objective: To understand the mechanisms and biological pathways associated with the progression of prostate cancer (PCa) under systemic androgen depletion or administration of the novel antiandrogens abiraterone, enzalutamide, and ARN-509. This review also examines the introduction of novel combinational approaches for patients with CRPC., Evidence Acquisition: PubMed was the data source. Keywords for the search were castrate resistant prostate cancer, abiraterone, enzalutamide resistance mechanisms, resistance to androgen deprivation, AR mutations, amplifications, splice variants, and AR alterations. Papers published before 1990 were excluded from the review, and only English-language papers were included., Evidence Synthesis: This review summarizes the current literature regarding the mechanisms implicated in the development of CRPC and the acquisition of resistance to novel antiandrogen axis agents. The review focuses on androgen biosynthesis in the tumor microenvironment, androgen receptor (AR) alterations and post-transcriptional modifications, the role of glucocorticoid receptor, and alternative oncogenic signaling that is derepressed on maximum AR inhibition and thus promotes cancer survival and progression., Conclusions: The mechanisms implicated in the development of resistance to AR inhibition in PCa are multiple and complex, involving virtually all classes of genomic alteration and leading to a host of selective/adaptive responses. Combinational therapeutic approaches targeting both AR signaling and alternative oncogenic pathways may be reasonable for patients with CRPC., Patient Summary: We looked for mechanisms related to the progression of PCa in patients undergoing hormonal therapy and treatment with novel drugs targeting the AR. Based on recent data, combining maximal AR inhibition with novel agents targeting other tumor-compensatory, non-AR-related pathways may improve the survival and quality of life of patients with castration-resistant PCa., (Copyright © 2014 European Association of Urology. Published by Elsevier B.V. All rights reserved.)

Context: Androgen deprivation therapy (ADT) for prostate cancer (PCa) represents one of the most effective systemic palliative treatments known for solid tumors. Although clinical trials have assessed the role of ADT in patients with metastatic and advanced locoregional disease, the risk-benefit ratio, especially in earlier stages, remains poorly defined. Given the mounting evidence for potentially life-threatening adverse effects with short- and long-term ADT, it is important to redefine the role of ADT for this disease., Objective: Review the published experience with currently available ADT approaches in various contemporary clinical settings of PCa and reported serious treatment-related adverse events. This review addresses the level of evidence associated with the use of ADT in PCa, focusing upon survival outcome measures. Furthermore, this paper discusses evolving approaches targeting androgen receptor signaling pathways and emerging evidence from clinical trials with newer compounds., Evidence Acquisition: A comprehensive review of the literature was performed, focusing on data from the last 10 yr (January 2000 to July 2011) and using the terms androgen deprivation, hormone treatment, prostate cancer and adverse effects. Abstracts from trials reported at international conferences held in 2010 and 2011 were also evaluated., Evidence Synthesis: Data from randomized controlled trials and population-based studies were analyzed in different clinical paradigms. Specifically, the role of ADT was evaluated in patients with nonmetastatic disease as the primary and sole treatment, in combination with radiation therapy (RT) or after surgery, and in patients with metastatic disease. The data suggest that in men with nonmetastatic disease, the use of primary ADT as monotherapy has not shown a benefit and is not recommended, while ADT combined with conventional-dose RT (<72Gy) for patients with high-risk disease may delay progression and prolong survival. The postoperative use of ADT remains poorly evaluated in prospective studies. Likewise, there are no trials evaluating the role of ADT in patients with biochemical relapses after surgery or RT. In patients with metastatic disease, there is a clear benefit in terms of quality of life, reduction of disease-associated morbidity, and possibly survival. Treatment with bilateral orchiectomy, luteinizing hormone-releasing hormone agonist therapy, with and without antiandrogens has been associated with various serious adverse events, including cardiovascular disease, diabetes, and skeletal complications that may also affect mortality., Conclusions: Although ADT is an effective treatment of PCa, consistent long-term benefits in terms of quality and quantity of life are predominantly evident in patients with advanced/metastatic disease or when ADT is used in combination with RT (<72Gy) in patients with high-risk tumors. Implementation of ADT should be evidence based, with special consideration to adverse events and the risk-benefit ratio., (Copyright © 2011 European Association of Urology. Published by Elsevier B.V. All rights reserved.)

Objective: To evaluate the effect of bicalutamide ('Casodex') 150mg (in addition to standard care), on the risk of prostate-specific antigen (PSA) progression, in patients with early prostate cancer., Methods: The bicalutamide 150mg Early Prostate Cancer (EPC) programme is the largest clinical trial programme in the treatment of prostate cancer to date. This paper reports the PSA progression data from the EPC programme at a median of 3years' follow-up, for the overall study population, and across the radical prostatectomy and radiotherapy primary therapy strategies. PSA progression was predefined as the earliest occurrence of PSA doubling from baseline, objective progression, or death from any cause., Result: Overall, bicalutamide 150 mg in addition to standard care significantly reduced the risk of PSA progression by 59% compared with standard care alone (HR 0.41; 95% CI 0.38, 0.45; p<<0.0001). Significant reductions were observed following radical prostatectomy (51%; HR 0.49; 95% CI 0.43, 0.56; p<<0.0001) and radiotherapy (58%; HR 0.42; 95% CI 0.33, 0.53; p<<0.0001). Further exploration of the data by disease stage, nodal status, Gleason score and pre-treatment PSA level revealed significant reductions in the risk of PSA progression across most prognostic risk factor subgroups., Conclusions: Bicalutamide 150mg significantly reduces the risk of PSA progression, irrespective of whether patients received radical prostatectomy or radiotherapy as standard care. The EPC programme is ongoing and further progression and survival data are awaited.

Cancer of the prostate continues to be one of the most common malignancies in men in Europe, with a large number of patients presenting with advanced disease. The current standard treatment for metastatic cancer of the prostate, permanent androgen withdrawal, is palliative. Patients treated with permanent androgen blockade usually relapse and die secondary to prostate cancer's ability to progress to an androgen-independent state of growth. Based on experimental and preclinical studies, intermittent androgen blockade appears to be a potential alternative to permanent androgen blockade. Through the cycling of reversible androgen suppression, there appears to be recovery of apoptosis and subsequent slower progression to an androgen-independent state. In this paper experimental and preclinical studies concerning intermittent androgen blockade are reviewed. At present several prospective randomized trials are under way to test intermittent androgen blockade as an alternative treatment in various stages of cancer of the prostate. However, until the results of these trials are available, this approach remains experimental.

Objectives: In patients with progressive prostate cancer who have been treated with surgical or medical castration plus an antiandrogen, antiandrogen withdrawal can result in a significant decline in serum prostate-specific antigen (PSA). Although the incidence of antiandrogen withdrawal syndrome after combination treatment with the nonsteroidal antiandrogen flutamide has been thoroughly documented, the phenomenon clearly occurs in many other combination therapies and is presently being widely investigated. This paper would like to contribute to this effort by describing the endocrine withdrawal phenomenon in patients treated with combinations of castration plus chlormadinone acetate, ethynylestradiol or estramustine phosphate., Materials and Methods: Clinical records of 68 prostate cancer patients who had been treated with surgical castration plus the administration of chlormadinone acetate, ethynylestradiol or estramustine phosphate, and who had shown clinical progression associated with a steady increase in serum PSA, were investigated. Forty-one cases were evaluable for changes in PSA after discontinuation of the hormonal agents., Results: Of 28 patients who had been treated with chlormadinone acetate, 12 (42.9%) revealed 50% or more decline in PSA level following withdrawal of the agent. Among these, 5 cases (17.9%) showed subjective and/or objective improvements. There was no significant difference in histological grade of the tumor at diagnosis, mode of progression, time interval from the start of endocrine therapy to discontinuation of the hormonal agents, or PSA level at withdrawal of the agents between patients who did develop antiandrogen withdrawal syndrome and those who did not., Conclusion: When a steady increase in serum PSA is noted in a prostate cancer patient who has been treated with castration plus a steroidal antiandrogen, discontinuation of the antiandrogen may benefit the patient.

This trial compares Casodex (ICI 176,334) monotherapy with the combination of castration (medical or surgical) plus nilutamide. The trial is now closed to entry, 270 patients having been recruited from 32 French centres. As it is too early to present efficacy data, only patient characteristics and interim tolerability data appear in this paper. In the combined treatment group, interstitial pneumonitis (4.5%) was observed, leading to withdrawal from the trial. Other adverse events leading to withdrawal included dyspnoea and ocular problems. There was also 1 case of hepatitis in this treatment group. In the Casodex treatment group, only 6 patients (as compared with 13 in the combined treatment group) withdrew from the trial because of adverse events. As expected with this group, the adverse events were mainly pharmacological effects of an anti-androgen as monotherapy. In the majority of patients, the effects of gynaecomastia and breast tenderness did not result in withdrawal.