Long-term efficacy and safety of nilutamide plus castration in advanced prostate cancer, and the significance of early prostate specific antigen normalization. International Anandron Study Group

Targeting signaling pathways in prostate cancer: mechanisms and clinical trials

Prostate cancer (PCa) affects millions of men globally. Due to advances in understanding genomic landscapes and biological functions, the treatment of PCa continues to improve. Recently, various new classes of agents, which include next-generation androgen receptor (AR) signaling inhibitors (abiraterone, enzalutamide, apalutamide, and darolutamide), bone-targeting agents (radium-223 chloride, zoledronic acid), and poly(ADP-ribose) polymerase (PARP) inhibitors (olaparib, rucaparib, and talazoparib) have been developed to treat PCa. Agents targeting other signaling pathways, including cyclin-dependent kinase (CDK)4/6, Ak strain transforming (AKT), wingless-type protein (WNT), and epigenetic marks, have successively entered clinical trials. Furthermore, prostate-specific membrane antigen (PSMA) targeting agents such as ¹⁷⁷Lu-PSMA-617 are promising theranostics that could improve both diagnostic accuracy and therapeutic efficacy. Advanced clinical studies with immune checkpoint inhibitors (ICIs) have shown limited benefits in PCa, whereas subgroups of PCa with mismatch repair (MMR) or CDK12 inactivation may benefit from ICIs treatment. In this review, we summarized the targeted agents of PCa in clinical trials and their underlying mechanisms, and further discussed their limitations and future directions.

Efficacy and Safety of Non-Steroidal Anti-Androgens in Patients with Metastatic Prostate Cancer: Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Prostate cancer (PCa) is the sixth primary cause of cancer death. However, conflicts are present about the efficacy and safety of Non-steroidal anti-androgens (NSAA) for its treatment. The aim of this study was to assess the efficacy and safety of NSAAs versus any comparator for the treatment of advanced or metastatic PCa (mPCa).

METHODS

MEDLINE and the Cochrane Library were searched. References of included studies and clinicaltrials.gov were also searched for relevant studies. Only English language studies after 1990 were considered for review. Randomized controlled trials (RCTs) examining the efficacy and safety of NSAAs as compared with any other comparator including surgery or chemotherapy in mPCa patients were included. The outcomes include efficacy, safety and the tolerability of the treatment. The Cochrane Risk of Bias Assessment Tool was used for quality assessment. Two authors were independently involved in the selection, extraction and quality assessment of included studies and disagreements were resolved by discussion or by consulting a third reviewer.

RESULTS

Fifty-eight out of 1307 non-duplicate RCTs with 29154 patients were considered for the review. NSAA showed significantly better progression-free survival [PFS] (Hazard ratio [HR], 0.60; 95% confidence interval [CI], 0.46-0.78; P=0.0001), time to distant metastasis or death [TTD] (HR, 0.80; 95% CI 0.73-0.91; P<0.0001), objective response (Odds ratio [OR], 1.64; 95% CI 1.06-2.54; P=0.03) and clinical benefits (OR, 1.33; 95% CI 1.08-1.63; P=0.006) as compared to the control group. There was no significant difference observed between the groups in terms of overall survival (HR, 0.95; 95%CI, 0.87-1.03; P=0.18) and time to progression (HR, 0.93; 95% CI 0.77-1.11; P=0.43). Treatment-related adverse events were more with the NSAA group, but the discontinuation due to lack of efficacy reason was 43% significantly lesser than the control group in patients with mPCa. Rest of the outcomes were appeared to be non-significant.

CONCLUSION

Treatment with NSAA was appeared to be better efficacious with respect to PFS, TTD, and response rate with considerable adverse events when compared to the control group in patients with metastatic PCa.

Previous, Current, and Future Pharmacotherapy and Diagnosis of Prostate Cancer-A Comprehensive Review

Prostate cancer (PCa) is one of the most common cancers in men that usually develops slowly. Since diagnostic methods improved in the last decade and are highly precise, more cancers are diagnosed at an early stage. Active surveillance or watchful waiting are appealing approaches for men diagnosed with low-risk prostate cancer, and they are an antidote to the overtreatment problem and unnecessary biopsies. However, treatment depends on individual circumstances of a patient. Older hormonal therapies based on first generation antiandrogens and steroids were widely used in metastatic castration-resistant prostate cancer (mCRPC) patients prior to the implementation of docetaxel. Nowadays, accordingly to randomized clinical trials, abiraterone, enzalutamide, apalutamide. and docetaxel became first line agents administrated in the treatment of mCRPC. Furthermore, radium-223 is an optional therapy for bone-only metastasis patients. Sipuleucel-T demonstrated an overall survival benefit. However, other novel immunotherapeutics showed limitations in monotherapy. Possible combinations of new vaccines or immune checkpoint blockers with enzalutamide, abiraterone, radium-223, or docetaxel are the subject of ongoing rivalry regarding optimal therapy of prostate cancer.

Androgen Receptor Signaling in the Development of Castration-Resistant Prostate Cancer

Most prostate cancers are androgen-sensitive malignancies whose growths depend on the transcriptional activity of the androgen receptor (AR). In the 1940s, Charles Huggins demonstrated that the surgical removal of testes in men can result in a dramatic improvement in symptoms and can induce prostate cancer regression. Since then, androgen deprivation therapies have been the standard first-line treatment for advanced prostate cancer, including: surgical castration, medical castration, antiandrogens, and androgen biosynthesis inhibitors. These therapies relieve symptoms, reduce tumor burden, and prolong patient survival, while having relatively modest side effects. Unfortunately, hormone deprivation therapy rarely cures the cancer itself. Prostate cancer almost always recurs, resulting in deadly castration-resistant prostate cancer. The underlying escape mechanisms include androgen receptor gene/enhancer amplification, androgen receptor mutations, androgen receptor variants, coactivator overexpression, intratumoral de novo androgen synthesis, etc. Whereas, the majority of the castration-resistant prostate cancers continuously rely on the androgen axis, a subset of recurrent cancers have completely lost androgen receptor expression, undergone divergent clonal evolution or de-differentiation, and become truly androgen receptor-independent small-cell prostate cancers. There is an urgent need for the development of novel targeted and immune therapies for this subtype of prostate cancer, when more deadly small-cell prostate cancers are induced by thorough androgen deprivation and androgen receptor ablation.

Efficacy and safety of combined androgen blockade with antiandrogen for advanced prostate cancer

Background

Combined androgen blockade (cab) is a promising treatment modality for prostate cancer (pca). In the present meta-analysis, we compared the efficacy and safety of first-line cab using an antiandrogen (aa) with castration monotherapy in patients with advanced pca.

Methods

PubMed, embase, Cochrane, and Google Scholar were searched for randomized controlled trials (rcts) published through 12 December 2016. Hazard ratios (hrs) with 95% confidence intervals (cis) were determined for primary outcomes: overall survival (os) and progression-free survival (pfs). Subgroup analyses were performed for Western compared with Eastern patients and use of a nonsteroidal aa (nsaa) compared with a steroidal aa (saa).

Results

Compared with castration monotherapy, cab using an aa was associated with significantly improved os (n = 14; hr: 0.90; 95% ci: 0.84 to 0.97; p = 0.003) and pfs (n = 13; hr: 0.89; 95% ci: 0.80 to 1.00; p = 0.04). No significant difference in os (p = 0.71) and pfs (p = 0.49) was observed between the Western and Eastern patients. Compared with castration monotherapy, cab using a nsaa was associated with significantly improved os (hr: 0.88; 95% ci: 0.82 to 0.95; p = 0.0009) and pfs (hr: 0.85; 95% ci: 0.73 to 0.98; p = 0.007)-a result that was not achieved with cab using a saa. The safety profiles of cab and monotherapy were similar in terms of adverse events, including hot flushes, impotence, and grade 3 or 4 events, with the exception of risk of diarrhea and liver dysfunction or elevation in liver enzymes, which were statistically greater with cab using an aa.

Conclusions

Compared with castration monotherapy, first-line cab therapy with an aa, especially a nsaa, resulted in significantly improved os and pfs, and had an acceptable safety profile in patients with advanced pca.

Efficacy and Safety of Nilutamide in Patients with Metastatic Prostate Cancer who Underwent Orchiectomy: A Systematic Review and Metaanalysis

BACKGROUND

Prostate cancer is the sixth leading cause of death, among all cancer deaths By 2030, this burden is expected to increase with 1.7 million new cases and 499,000 new deaths. We aimed to evaluate the efficacy and safety of Nilutamide in metastatic prostate cancer (mPCa) patients who underwent orchiectomy.

METHODS

A comprehensive search was conducted in the Medline/PubMed and Cochrane Library. References from included studies and studies from clinicaltrials.gov were explored without language and date restrictions. We included only randomized controlled trials, comparing the safety and efficacy of Nilutamide in Metastatic Prostate Cancer (mPCa) patients who underwent orchiectomy with placebo. The outcomes of concerns were survival and the response of drug and safety.. Quality of the included studies was assessed using the Cochrane Risk of Bias Tool. Two authors were independently involved in the study selection, data extraction and quality assessment. Disagreements between the two reviewers were resolved by consulting a third reviewer.

RESULTS

A total of five out of 244 studies were included in meta-analysis involving1637 participants. Nilutamide group showed improved response rate (RR=1.77, 95%CI 1.46-2.14, p<0.00001), disease progression (RR=0.59, 95%CI 0.47-0.73, p<0.00001), complete response (RR=2.13, 95%CI 1.40-3.23, p=0.003) and clinical benefit (RR=1.23, 95%CI 1.13-1.34, p<0.00001) when compared to placebo; however, stable disease favored the control group (RR=0.80, 95%CI 0.68-0.94, p=0.007). In addition, patients on Nilutamide showed prolonged progression-free survival and overall survival. Nausea and vomiting were the most common adverse events reported in Nilutamide group.

CONCLUSION

Evidence suggests that patients with mPCa who underwent orchiectomy receiving Nilutamide showed significant improvement in progression-free survival and overall survival response rate and clinical benefits in comparison with the placebo group.

Precision medicine applications in prostate cancer

Aided by developments in diagnostics and therapeutics, healthcare is increasingly moving toward precision medicine, in which treatment is customized to each individual. We discuss the relevance of precision medicine in prostate cancer, including gene targets, therapeutics and resistance mechanisms. We foresee precision medicine becoming an integral component of prostate cancer management to increase response to therapy and prolong survival.

Usefulness of Prostate-Specific Antigen Nadir as Predictor of Androgen-Independent Progression of Metastatic Prostate Cancer

The objective of this study was to analyze the value of the nadir level of prostate-specific antigen (PSA) to predict androgen-independent progression (AIP) in metastatic prostate cancer patients after androgen deprivation therapy. In a group of 185 metastatic prostate cancer patients who received androgen deprivation therapy serum PSA was determined every three months until AIP occurred. Multiple regression analysis was performed to define independent clinical and PSA-related predictors of AIP. AIP was assumed to be present after two consecutive increases in serum PSA after the PSA nadir. Independent predictors of the duration of AIP-free survival (less than 12 months versus more than 12 months) were the extent of bone involvement (six or fewer hot spots versus more than six) with an odds ratio (O.R.) of 3.95, Gleason score (7 or less versus more than 7) with an O.R. of 3.47, and PSA nadir (2 μg/L or less versus more than 2 μg/L) with an O.R. of 14.63. AIP was independently predicted by the extent of bone involvement with an O.R. of 1.72, Gleason score with an O.R. of 1.74, PSA nadir with an O.R. of 3.22, and time to reach the PSA nadir (9 months or less versus more than 9 months) with an O.R. of 2.84. When patients were stratified according to these predictors, those with three good prognostic factors had a median AIP-free survival of 58 months while those with two, one or no good prognostic factors had a median AIP-free survival of 19 months, 12 months and 7 months, respectively. We conclude that the PSA nadir seems to be a good predictor of AIP in patients with metastatic prostate cancer after androgen deprivation therapy. Time to PSA nadir, extent of bone involvement and Gleason score are also independent predictors. The combination of these prognostic factors allows to stratify metastatic prostate cancer patients for the prediction of AIP.

Androgen receptor antagonism drives cytochrome P450 17A1 inhibitor efficacy in prostate cancer

The clinical utility of inhibiting cytochrome P450 17A1 (CYP17), a cytochrome p450 enzyme that is required for the production of androgens, has been exemplified by the approval of abiraterone for the treatment of castration-resistant prostate cancer (CRPC). Recently, however, it has been reported that CYP17 inhibitors can interact directly with the androgen receptor (AR). A phase I study recently reported that seviteronel, a CYP17 lyase-selective inhibitor, ædemonstrated a sustained reduction in prostate-specific antigen in a patient with CRPC, and another study showed seviteronel's direct effects on AR function. This suggested that seviteronel may have therapeutically relevant activities in addition to its ability to inhibit androgen production. Here, we have demonstrated that CYP17 inhibitors, with the exception of orteronel, can function as competitive AR antagonists. Conformational profiling revealed that the CYP17 inhibitor-bound AR adopted a conformation that resembled the unliganded AR (apo-AR), precluding nuclear localization and DNA binding. Further, we observed that seviteronel and abiraterone inhibited the growth of tumor xenografts expressing the clinically relevant mutation AR-F876L and that this activity could be attributed entirely to competitive AR antagonism. The results of this study suggest that the ability of CYP17 inhibitors to directly antagonize the AR may contribute to their clinical efficacy in CRPC.

The Change of Semen Superoxide Dismutase and Acrosin Activity in the Sterility of Male Patients with Positive Antisperm Antibody

In this study, we report the change of semen superoxide dismutase (SOD) and acrosin activities in the male sterility patients with positive antisperm antibody (AsAb). The activity of SOD was measured by xanthine oxidase assay and sperm acrosin activity was calculated by BAEE/ADH. Our data show that compared with the normal fertility group, the semen SOD activity in AsAb-positive patients was significantly lower. Similarly, the sperm acrosin activity in AsAb-positive patients was also significantly lower. Our results suggest that the sterility resulting from positive AsAb may be related with the changes of semen SOD and sperm acrosin activities.

Androgen-deprivation therapy alone versus combined with radiation therapy or chemotherapy for nonlocalized prostate cancer: a systematic review and meta-analysis

In this paper, we reviewed the long-term survival outcomes, safety, and quality-of-life of androgen-deprivation therapy (ADT) alone versus combined with radiation therapy (RT) or chemotherapy for locally advanced and metastatic prostate cancer (PCa). A literature search was performed using OvidSP. Randomized controlled trials (RCTs) that met the following criteria were included: including locally advanced or metastatic PCa, comparing ADT alone versus combined with any treatment method and reporting quantitative data of disease control or survival outcomes. Finally, eight RCTs met the inclusion criteria. Among these, three compared ADT versus ADT plus RT (n = 2344) and one compared ADT versus ADT plus docetaxel–estramustine (n = 413) in locally advanced PCa; two compared ADT versus ADT plus docetaxel (n = 1175) and two compared ADT versus ADT plus estramustine (n = 114) in metastatic PCa. For locally advanced PCa, the addition of RT to long-term ADT can improve the outcomes of survival and tumor control with fully acceptable adverse effects. Specially, the pooled odds ratio (OR) of overall survival (OS) was 1.43 (95% confidence interval 1.20–1.71) when compared ADT plus RT with ADT alone (P < 0.0001). For metastatic hormonally sensitive PCa, the concurrent use of docetaxel plus ADT was effective and safe (pooled OR of OS: 1.29 [1.01–1.65]: P = 0.04). In all, long-term ADT plus RT and long-term ADT plus docetaxel should be considered as proper treatment option in locally advanced and metastatic hormonally sensitive PCa, respectively. The major limitation for the paper was that only eight RCTs were available.

Combined blockade of testicular and locally made androgens in prostate cancer: a highly significant medical progress based upon intracrinology

Recently two drugs, namely the antiandrogen MDV-3100 and the inhibitor of 17α-hydroxylase abiraterone have been accepted by the FDA for the treatment of castration-resistant prostate cancer (CRPC) with or without previous chemotherapy, with a prolongation of overall survival of 2.2-4.8 months. While medical (GnRH agonist) or surgical castration reduces the serum levels of testosterone by about 97%, an important concentration of testosterone and dihydrotestosterone remains in the prostate and activates the androgen receptor (AR), thus offering an explanation for the positive data obtained in CRPC. In fact, explanation of the response observed with MDV-3100 or enzalutamide in CRPC is essentially a blockade of the action or formation of intraprostatic androgens. In addition to the inhibition of the action or formation of androgens made locally by the mechanisms of intracrinology, increased AR levels and AR mutations can be involved, especially in very advanced disease. Future developments look at more efficient inhibitors of the action or formation of intraprostatic androgens and starting treatment earlier when blockade of androgens can exert long-term control and even cure prostate cancer treated at a stage before the appearance of metastases. This article is part of a Special Issue entitled 'Essential role of DHEA'.

Targeted prodrug approaches for hormone refractory prostate cancer

Due to the propensity of relapse and resistance with prolonged androgen deprivation therapy (ADT), there is a growing interest in developing non-hormonal therapeutic approaches as alternative treatment modalities for hormone refractory prostate cancer (HRPC). Although the standard treatment for HRPC consists of a combination of ADT with taxanes and anthracyclines, the clinical use of chemotherapeutics is limited by systemic toxicity stemming from nondiscriminatory drug exposure to normal tissues. In order to improve the tumor selectivity of chemotherapeutics, various targeted prodrug approaches have been explored. Antibody-directed enzyme prodrug therapy (ADEPT) and gene-directed enzyme prodrug therapy (GDEPT) strategies leverage tumor-specific antigens and transcription factors for the specific delivery of cytotoxic anticancer agents using various prodrug-activating enzymes. In prostate cancer, overexpression of tumor-specific proteases such as prostate-specific antigen (PSA) and prostate-specific membrane antigen (PSMA) is being exploited for selective activation of anticancer prodrugs designed to be activated through proteolysis by these prostate cancer-specific enzymes. PSMA- and PSA-activated prodrugs typically comprise an engineered high-specificity protease peptide substrate coupled to a potent cytotoxic agent via a linker for rapid release of cytotoxic species in the vicinity of prostate cancer cells following proteolytic cleavage. Over the past two decades, various such prodrugs have been developed and they were effective at inhibiting prostate tumor growth in rodent models; several of these prodrug approaches have been advanced to clinical trials and may be developed into effective therapies for HRPC.

Safety of antiandrogen therapy for treating prostate cancer

INTRODUCTION

Antiandrogens are a treatment option in patients with prostate cancer, given either in combination with androgen deprivation or, in selected cases, as monotherapy. New-generation antiandrogens have been recently introduced in clinical practice (enzalutamide) or are under evaluation in clinical trials (ARN-509).

AREAS COVERED

This review elucidates the safety profile of antiandrogens, in particular focusing on the tolerability profile of each drug either when employed in combination with castration or as monotherapy, in hormone-naive or in castration-resistant patients.

EXPERT OPINION

Non-steroidal antiandrogens are widely used in the management of hormone-sensitive disease in combination with luteinizing hormone-releasing hormone agonists or in patients failing front-line treatment with androgen-deprivative maneuvers. In selected patients, non-steroidal antiandrogen monotherapy appears to yield comparable results as castration. Novel non-steroidal antiandrogens have been investigated with promising results in castration-resistant prostate cancer. Beyond the safety profile specific to any individual compound, increased testosterone and 17β-estradiol levels are commonly observed during antiandrogen monotherapy, leading to gynecomastia and breast pain. The safety profile of old and novel antiandrogens should be taken into account by clinicians in decision making and in selecting the most suitable patients. Beyond patient selection, full clinical evaluation of patient co-morbidities that might affect the drug tolerability and clinical monitoring are anyway required.

Optimal pharmacotherapeutic management of hormone-sensitive metastatic prostate cancer

The mainstay of initial therapy of metastatic prostate cancer has not changed since 1941 when Huggins and Hodges described the efficacy of castration. The benefit of combining an androgen receptor blocker with medical castration has been debatable despite several large randomized trials and meta-analyses intended to answer the question. Recent phase III trial data with continuous versus intermittent androgen deprivation in newly diagnosed metastatic prostate cancer have established continuous therapy as the preferred approach at the present time. Novel and more potent inhibitors of androgen signaling have been developed in the past 5 years and have been validated in castration-resistant disease. Their role in management of hormone-sensitive metastatic prostate cancer is under evaluation in ongoing studies. As androgen deprivation therapy carries significant long-term toxicities including fatigue and loss of bone and muscle mass, an important element of clinical management is prevention and amelioration of these toxicities.

Nadir PSA level and time to nadir PSA are prognostic factors in patients with metastatic prostate cancer

Background

Primary androgen deprivation therapy (PADT) is the most effective systemic therapy for patients with metastatic prostate cancer. Nevertheless, once PSA progression develops, the prognosis is serious and mortal. We sought to identify factors that predicted the prognosis in a series of patients with metastatic prostate cancer.

Methods

Two-hundred eighty-six metastatic prostate cancer patients who received PADT from 1998 to 2005 in Nara Uro-Oncology Research Group were enrolled. The log-rank test and Cox’s proportional hazards model were used to determine the predictive factors for prognosis; rate of castration-resistant prostate cancer (CRPC) and overall survival.

Results

The median age, follow-up period and PSA level at diagnosis were 73 years, 47 months and 174 ng/mL, respectively. The 5-year overall survival rate was 63.0%. The multivariable analysis showed that Gleason score (Hazard ratio [HR]:1.362; 95% confidence interval [C.I.], 1.023-1.813), nadir PSA (HR:6.332; 95% C.I., 4.006-9.861) and time from PADT to nadir (HR:4.408; 95% C.I., 3.099-6.271) were independent prognostic factors of the incidence of CRPC. The independent parameters in the multivariate analysis that predicted overall survival were nadir PSA (HR:5.221; 95% C.I., 2.757-9.889) and time from PADT to nadir (HR:4.008; 95% C.I., 2.137-7.517).

Conclusions

Nadir PSA and time from PADT to nadir were factors that affect both CRPC and overall survival in a cohort of patients with metastatic prostate cancer. Lower nadir PSA level and longer time from PADT to nadir were good for survival and progression.

Serum testosterone levels after medical or surgical androgen deprivation: a comprehensive review of the literature

Androgens and the androgen receptor play a role in the progression of prostate cancer. Androgen deprivation therapy (ADT) is a mainstay in the treatment of metastatic prostate cancer. ADT is expected to reduce serum testosterone levels from a normal level of about 500 to 600 ng/dl (17.3-20.8 nmol) down to castration levels. Traditionally, castration was considered to be achieved if testosterone levels were lowered to a threshold of 50 ng/dl (1.73 nmol/l), a definition determined more by measurement methods derived from the use of old assay methods than by evidence. Serum testosterone levels in three-quarter patients after surgical castration drop to less than 20 ng/dl (0.69 nmol/l). Ineffective suppression of testosterone is currently poorly recognized and may possibly have an effect of prostate cancer mortality. Persistent levels of serum testosterone after castration are mainly derived from adrenal androgens. Furthermore, the arrival of new therapies targeting androgen synthesis and androgen receptor activity has renewed interest on serum testosterone. This review discusses the biosynthetic pathway for androgen synthesis in humans and provides a comprehensive review of serum testosterone levels after surgical or medical castration. This review assesses serum testosterone levels after surgical castration and different pharmacologic castration in patients with prostate cancer under ADT, and ineffective testosterone suppression. The author proposes methods to better lower serum testosterone levels during ADT.

Safety and efficacy of cabazitaxel in the docetaxel-treated patients with hormone-refractory prostate cancer

Prostate cancer (PC) is one of the most common cancers and is a leading cause of death. Its initial growth is dependent on androgens; most patients show an initial response to hormonal therapy but will experience disease progression when PC becomes resistant to castration. In 2004, two key randomized controlled trials demonstrated a benefit for docetaxel-based regimens in the treatment of men with castration-resistant prostate cancer (CRPC). Cabazitaxel (XRP6258, TXD258, and RPR116258A), a tubulin-binding taxane drug as potent as docetaxel in cell lines, was the first treatment able to prolong survival for metastatic CRPC in the post-docetaxel setting. This review describes pharmacologic parameters of this agent followed by a review of clinical trials involving cabazitaxel. Other available treatments and the place of cabazitaxel in metastatic CRPC setting are discussed.

Contemporary role of androgen deprivation therapy for prostate cancer

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.

Role of maximum androgen blockade in advanced prostate cancer

Androgen ablation is the mainstay treatment for advanced prostate cancer (PC). Researchers proposed that maximum androgen blockade (MAB) therapy with antiandrogen agent in combination with castration might result in a better outcome among patients with advanced PC. In the last two decades, numerous trials and pooled data analyses were conducted to optimize the role of MAB in the treatment of metastatic PC. Non-steroidal antiandrogens administered as part of MAB proved to have a small (3%) survival benefit, however, the magnitude of this difference is of questionable clinical significance. Available evidence suggests that MAB should not be routinely offered to patients with metastatic PC, however, it should remain a reasonable option when discussing management. The standard first line treatment should be a monotherapy, consisting of orchiectomy or LHRH agonist. MAB still has a role as a short-term therapy (2-4 weeks). The ongoing large sample population based prospective studies may add new dimensions in the use of MAB in treatment of the prostate cancer in future.

Efficacy of maximal androgen blockade versus castration alone in the treatment of advanced prostate cancer: a retrospective clinical experience from a Chinese medical centre

In this retrospective study, we evaluated and compared the efficacy and toxicities of maximal androgen blockade (MAB) versus castration alone in Chinese patients with advanced prostate cancer. From 1996 to 2004, 608 patients with advanced prostate cancer were included in the study. Patients were retrospectively divided into two groups according to different therapeutic regimens. Of the 608 patients, 300 patients were treated with MAB (castration plus nonsteroidal antiandrogens) and the remaining 308 were treated with castration alone. The 2- and 5-year overall survival rates of these patients were 73.7% and 56%, respectively. Multivariate analysis showed that, in patients with metastatic prostate cancer, MAB was associated with not only the improvement of progression-free survival (PFS) (increased by 10 months) but also a 20.6% reduction in mortality risk compared with castration alone. In contrast, the efficacy of MAB was not superior to castration alone for patients with nonmetastatic prostate cancer. Interestingly, among patients with MAB, those using bicalutamide had a longer PFS than those using flutamide; this was especially so in patients with metastatic prostate cancer. Almost all of the toxicities due to the hormone therapy were mild to moderate and manageable. To conclude, in China, hormone therapies, including MAB and castration alone, have been standard treatments for advanced prostate cancer. For patients with nonmetastatic prostate cancer, castration alone might be adequately practical and efficient. In patients with metastatic prostate cancer, however, MAB has superior efficacy over castration alone. It is clear that MAB should be considered the first-line standard treatment for patients with metastatic prostate cancer.

Should we follow-up serum testosterone in patients with advanced prostate cancer?

Agonistic analogs of luteinizing hormone-releasing hormones are indicated for the palliative treatment of metastatic prostate cancer. While the prognostic role of prostate-specific antigen in patients submitted to androgen-deprivation therapy has been extensively investigated in these patients, there is no consensus about the utility of serum testosterone measurements during follow-up and about their possible prognostic value. Recent reports have shown that testosterone levels might be directly related to survival and risk of death. These results need to be confirmed by further prospective studies. Given this concept, lowering testosterone as much as possible should be the goal of androgen-deprivation therapy in patients with metastatic prostate cancer, as this may have an impact on patient survival.

Duration of first off-treatment interval is prognostic for time to castration resistance and death in men with biochemical relapse of prostate cancer treated on a prospective trial of intermittent androgen deprivation

PURPOSE

This was an exploratory analysis of a trial of intermittent androgen deprivation (IAD) in men with biochemical relapse (BR) to establish first cycle characteristics prognostic for progression to castration-resistant prostate cancer (CRPC) and death.

PATIENTS AND METHODS

Men with BR of prostate cancer after radical prostatectomy (RP) or radiation (RT) were treated with androgen deprivation therapy (ADT) comprised of leuprolide and flutamide. After 9 months on treatment, ADT was stopped, and monthly prostate-specific antigen (PSA) levels were observed during the off-treatment interval. When the PSA reached a threshold value (1 ng/mL for RP, 4 ng/mL for RT), ADT was resumed in a new cycle. Patients were treated intermittently in this manner until CRPC, which was defined as > or = two consecutive increasing PSA values while on ADT with castrate testosterone levels.

RESULTS

Seventy-two of 100 patients enrolled onto the study met criteria for this analysis. The duration of the first off-treatment interval (< or = v > 40 weeks) was associated with shorter time to CRPC (hazard ratio = 2.9; 95% CI, 1.1 to 7.7; P = .03) and death (hazard ratio = 3.8; 95% CI, 1.1 to 13.6; P = .04) after adjusting for age, stage, grade, and PSA at diagnosis.

CONCLUSION

In patients who completed the first cycle of IAD, a duration of the first off-treatment interval of < or = 40 weeks defines a subset of patients at higher risk of CRPC and death. Conversely, patients with an off-treatment interval of more than 40 weeks have a significantly better long-term prognosis.

Maximal androgen blockade for advanced prostate cancer

Prostate cancer has now become one of the leading types of cancer in urban India. It is now the third most common cancer in Delhi. As we advance in health care with the resultant increase in longevity, we will be seeing more of advanced carcinoma prostate. Since the early 1980.s, there have been many trials on MAB. However, the question remains whether these agents actually make a difference? The role of MAB is probably limited to the prevention of the beta are reaction in patients on LHRH agonists. The non steroidal antiandrogens have a marginal benefit of increased overall survival by approximately 3% to 5% at 5 ve years. There may be a role for MAB in patients with metastatic carcinoma of prostate, low volume metastases, patients with M 1 disease with absence of metastases in the skull, ribs, long bones, and soft tissues excluding lymph nodes.

Hormonal therapy of prostate cancer

Of all cancers, prostate cancer is the most sensitive to hormones: it is thus very important to take advantage of this unique property and to always use optimal androgen blockade when hormone therapy is the appropriate treatment. A fundamental observation is that the serum testosterone concentration only reflects the amount of testosterone of testicular origin which is released in the blood from which it reaches all tissues. Recent data show, however, that an approximately equal amount of testosterone is made from dehydroepiandrosterone (DHEA) directly in the peripheral tissues, including the prostate, and does not appear in the blood. Consequently, after castration, the 95-97% fall in serum testosterone does not reflect the 40-50% testosterone (testo) and dihydrotestosterone (DHT) made locally in the prostate from DHEA of adrenal origin. In fact, while elimination of testicular androgens by castration alone has never been shown to prolong life in metastatic prostate cancer, combination of castration (surgical or medical with a gonadotropin-releasing hormone (GnRH) agonist) with a pure anti-androgen has been the first treatment shown to prolong life. Most importantly, when applied at the localized stage, the same combined androgen blockade (CAB) can provide long-term control or cure of the disease in more than 90% of cases. Obviously, since prostate cancer usually grows and metastasizes without signs or symptoms, screening with prostate-specific antigen (PSA) is absolutely needed to diagnose prostate cancer at an 'early' stage before metastasis occurs and the cancer becomes non-curable. While the role of androgens was believed to have become non-significant in cancer progressing under any form of androgen blockade, recent data have shown increased expression of the androgen receptor (AR) in treatment-resistant disease with a benefit of further androgen blockade. Since the available anti-androgens have low affinity for AR and cannot block androgen action completely, especially in the presence of increased AR levels, it becomes important to discover more potent and purely antagonistic blockers of AR. The data obtained with compounds under development are promising. While waiting for this (these) new anti-androgen(s), combined treatment with castration and a pure anti-androgen (bicalutamide, flutamide or nilutamide) is the only available and the best scientifically based means of treating prostate cancer by hormone therapy at any stage of the disease with the optimal chance of success and even cure in localized disease.

Anti-androgens and androgen-depleting therapies in prostate cancer: new agents for an established target

Activation of the androgen receptor is crucial for prostate cancer growth at all points of the illness. Current therapies targeting the androgen receptor, including androgen-depletion approaches and anti-androgens, do not completely inhibit the receptor activity. Prostate cancer cells develop resistance to castration by acquiring changes that include androgen-receptor overexpression and overexpression of enzymes involved in androgen biosynthesis, which result in reactivation of the receptor. Based on an understanding of these resistance mechanisms and androgen biosynthesis pathways, new anti-androgens and androgen-depleting agents have been developed. Notably, promising activity has been shown in early phase trials by MDV3100, a new anti-androgen designed for activity in prostate cancer model systems with overexpressed androgen receptor, and by abiraterone acetate, a CYP17A inhibitor that blocks steroid biosynthesis in the adrenal gland and possibly within the tumour. Both agents are undergoing phase 3 testing. Here, we review the basic science and clinical development of these and other agents.

Testosterone levels in patients with metastatic prostate cancer treated with luteinizing hormone-releasing hormone therapy: prognostic significance?

OBJECTIVE

To determine if the testosterone level achieved with androgen-deprivation therapy (ADT) is directly related to survival and risk of death in men with metastatic prostate cancer, as agonistic analogues of luteinizing hormone-releasing hormones (LHRH) are indicated for palliative treatment of these patients, but there is no consensus about the utility of serum testosterone measurements during the follow-up, and their possible prognostic value.

PATIENTS AND METHODS

We retrospectively reviewed 129 consecutive patients with a histological diagnosis of metastatic bony-only prostate cancer and previously untreated with ADT. They were treated with 3 months of goserelin. Testosterone and prostate-specific antigen (PSA) levels were measured in all patients every 3 months for the duration of the follow-up. The following variables were recorded: age, stage, Gleason score, basal PSA level, basal testosterone level, PSA nadir, time to PSA nadir, testosterone after 6 months, testosterone nadir and time to testosterone nadir. Data were analysed using Cox's proportional hazards models, with the primary endpoint being cancer-specific survival.

RESULTS

The mean (SD) basal PSA level was 185.8 (344.1) ng/mL, and the mean nadir PSA level 2.7 (8.6) ng/mL. The mean testosterone levels at baseline, 6 months and the nadir were 440 (200), 40 (40) and 21 (15) ng/dL. With a mean follow-up of 47.5 (29.7) months, 71 patients were dead (55%) and 78 were alive (45%) at the time of analysis. Statistical analysis using Cox's model showed that in these patients the risk of death was directly correlated not only to Gleason score (P < 0.01) and to the 6-month PSA level (P < 0.01), but also to the 6-month serum testosterone level (hazard ratio 1.32, P < 0.05).

CONCLUSION

These results suggest a direct correlation between the risk of death and testosterone levels achieved during ADT. Based on the present results, lowering the testosterone level as much as possible should be the goal of ADT in patients with metastatic prostate cancer, as this might affect patient survival.

Chemical synthesis and biological activities of 16α-derivatives of 5α-androstane-3α,17β-diol as antiandrogens

In our efforts to develop compounds with therapeutic potential as antiandrogens, we synthesized a series of 5alpha-androstane-3alpha,17beta-diol derivatives with a fixed side-chain length of 3-methylenes at C-16alpha, but bearing a diversity of functional groups at the end. Among these, the chloride induced the best antiproliferative activity on androgen-sensitive Shionogi cells. Substituting the OH at C-3 by a methoxy group showed the importance of the OH. Moreover, its transformation into a ketone increased the androgen receptor (AR) binding but decreased the antiproliferative activity and induced a proliferative effect on Shionogi cells. These results confirm the importance of keeping a 5alpha-androstane-3alpha,17beta-diol nucleus instead of a dihydrotestosterone nucleus. Variable side-chain lengths of 2-, 3-, 4-, and 6-methylenes at C-16alpha were investigated and the optimal length was found to be 3-methylenes. Although exhibiting a weak AR binding affinity, 16alpha-(3'-chloropropyl)-5alpha-androstane-3alpha,17beta-diol (15) provided an antiproliferative activity on Shionogi cells similar to that of pure non-steroidal antiandrogen hydroxy-flutamide (77% and 67%, respectively, at 0.1 microM). The new steroidal compound, 15, thus constitutes a good starting point for development of future antiandrogens with a therapeutic potential against prostate cancer.

Long-term effectiveness of luteinizing hormone-releasing hormone agonist or antiandrogen monotherapy in elderly men with localized prostate cancer (T1-2) : a retrospective study

AIM

To evaluate the long-term effectiveness, side effects and compliance rates of two types of drugs (luteinizing hormone-releasing hormone [LHRH] agonist and antiandrogen) that were used individually to treat patients with localized prostate cancer (T1-2) at our institution.

METHODS

Ninety-seven patients who were diagnosed in the period from April 1997 to January 2000 as having clinically localized prostate cancer (T1-2) received either LHRH agonist (leuprolide acetate 7.5 mg/month) monotherapy (group 1, n = 62) or antiandrogen monotherapy (group 2, n = 35; 18 received bicalutamide 50 mg q.d., 13 received nilutamide 150 mg t.i.d. and 4 received flutamide 250 mg t.i.d.). The mean age in both groups was 76 years.

RESULTS

The mean follow-up time was (50.8 +/- 8.5) months in group 1 and (43.1 +/- 2.2) months in group 2. Prostate-specific antigen (PSA) levels rose in only 1 of the 62 patients (1.6%) in group 1, and in 20 of the 35 patients (57.1%) in group 2. In group 2, 10 of the 20 patients (50%) with increasing PSA levels were treated with LHRH salvage therapy, and eight (80%) responded. Hot flashes (54.8%) and lethargy (41.9%) were the most common side effects in group 1. In contrast, nipple-tenderness (40%) and light-dark adaptation (17.1%) were more often seen in group 2. Only 1 of the 62 patients (1.6%) in group 1 switched to another medication because of adverse side effects; whereas 8 of the 35 patients (22.9%) in group 2 did so.

CONCLUSION

Unlike antiandrogen monotherapy, LHRH agonist monotherapy provided long-term durable control of localized prostate cancer (T1-2). It can also be an effective treatment option for patients whose disease failed to respond to antiandrogen monotherapy. The limitations of our study are the lack of health outcomes analysis and a small sample size.

Absolute Prostate-Specific Antigen Value After Androgen Deprivation Is a Strong Independent Predictor of Survival in New Metastatic Prostate Cancer: Data From Southwest Oncology Group Trial 9346 (INT-0162)

Purpose

To establish whether absolute prostate-specific antigen (PSA) value after androgen deprivation (AD) is prognostic in metastatic (D2) prostate cancer (PCa).

Patients and Methods

D2 PCa patients with baseline PSA of at least 5 ng/mL received 7 months induction AD. Patients achieving PSA of 4.0 ng/mL or less on months 6 and 7 are randomly assigned to continuous versus intermittent AD on month 8. Eligibility for this analysis required a prestudy PSA with at least two subsequent PSAs and that patients be registered at least 1 year before analysis date. Survival was defined as time to death after 7 months of AD. Associations were evaluated by proportional hazards regression models.

Results

One thousand one hundred thirty four of 1,345 eligible patients achieved a PSA of 4 ng/mL or less. At end of induction, 965 patients maintained PSA of 4 or less and 604 had a PSA of 0.2 ng/mL or less. After controlling for prognostic factors, patients with a PSA of 4 or less to more than 0.2 ng/mL had less than one third the risk of death (ROD) as those with a PSA of more than 4 ng/mL (P < .001). Patients with PSA of 0.2 ng/mL or less had less than one fifth the ROD as patients with a PSA of more than 4 ng/mL (P < .001) and had significantly better survival than those with PSA of more than 0.2 to 4 ng/mL or less (P < .001). Median survival was 13 months for patients with a PSA of more than 4 ng/mL, 44 months for patients with PSA of more than 0.2 to 4 ng/mL or less, and 75 months for patients with PSA of 0.2 ng/mL or less.

Conclusion

A PSA of 4 ng/mL or less after 7 months of AD is a strong predictor of survival. This data should be used to tailor future trial design for D2 prostate cancer.

Efficacy of nilutamide as secondary hormonal therapy in androgen-independent prostate cancer

OBJECTIVE

To evaluate the activity of nilutamide as secondary hormonal therapy in patients with androgen-independent prostate cancer (AIPC), as treatment options are limited for these patients and secondary hormonal therapy with antiandrogens has advantages, including low toxicity, oral administration and high patient acceptance.

PATIENTS AND METHODS

We retrospectively identified 45 patients with AIPC who were treated with nilutamide as secondary hormonal therapy in two institutions. The decrease in prostate-specific antigen (PSA) levels, side-effects of treatment, and the relationship between baseline characteristics, type and duration of previous therapy and response to nilutamide were assessed. Most patients received oral nilutamide at 150 mg/day.

RESULTS

Eighteen of 45 evaluable patients (40%) had a PSA level decrease of > or = 50%. Responders (PSA decline > or = 50%) had a median (range) time to progression of 4.4 (0.31-44.7) months. There were responses to nilutamide whether used as the second to fifth line of hormonal therapy. There were no differences in response to nilutamide based on clinical stage, type of local therapy, PSA level at diagnosis or initiation of nilutamide, or type of previous antiandrogen therapy. Responders were more likely to have received monotherapy with luteinizing hormone-releasing hormone analogues or orchidectomy as first-line hormonal treatment (P = 0.02). The most common reversible adverse effects were mild to moderate visual adaptation effects, reported in 20% of patients.

CONCLUSIONS

Nilutamide appears to be an effective secondary hormonal therapy in patients with AIPC and is associated with a mild toxicity profile.

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.

Gonadotropin-releasing hormone agonists in the treatment of prostate cancer

In 1979, the first prostate cancer patient was treated with a GnRH agonist at the Laval University Medical Center in Quebec City, Canada, thus rapidly leading to the worldwide replacement of surgical castration and high doses of estrogens. The discovery of medical castration with GnRH agonists was soon followed by fundamental changes in the endocrine therapy of prostate cancer. Most importantly, the excellent tolerance accompanying the treatment with GnRH agonists has been a key factor that permitted a series of studies demonstrating a major reduction in the death rate from prostate cancer ranging from 31 to 87% at 5 yr of follow-up in patients with localized or locally advanced prostate cancer. In fact, a one third reduction in prostate cancer deaths has been calculated in the metaanalysis of all available studies. The general acceptance of this discovery by patients and physicians is illustrated by world sales above 3.0 billion U.S. dollars in 2003. Although extremely efficient in achieving complete medical castration and well tolerated, with no other side effects than the expected hypoandrogenicity, GnRH agonists should not be administered alone. In fact, shortly after discovery of the castration effects of GnRH agonists, we observed that approximately 50% of androgens remain in the prostate after castration, thus leading to the recognition of the role of adrenal dehydroepiandrosterone as an important source of the androgens synthesized locally in the prostate and in many peripheral target tissues. We therefore developed combined androgen blockade (CAB), whereby the androgens of both testicular and adrenal origins are blocked simultaneously at start of treatment with the combination of a GnRH agonist to block the testis and a pure antiandrogen to block the action of the androgens produced locally. CAB, first used in advanced metastatic disease, has been the first treatment shown to prolong life in prostate cancer. Most interestingly, in 2002, we made the observation that CAB alone given continuously for 6.5 yr or more leads to cure of the disease in at least 90% of cases, thus suggesting that androgen blockade combining a GnRH agonist and a pure antiandrogen could well be the most efficient treatment of localized prostate cancer, and thus offering the possibility of practically eliminating death from prostate cancer.

Current status of endocrine therapy in localized prostate cancer: cure has become a strong possibility

It is clear that all available means should be taken to diagnose prostate cancer early and to use efficient therapy immediately in order to prevent prostate cancer from migrating to the bones where treatment becomes extremely difficult and cure or even long-term control of the disease is an exception. The only means of preventing prostate cancer from migrating to the bones and becoming incurable is efficient treatment at the localized stage of the disease. In fact, since radical prostatectomy, radiotherapy and brachytherapy can achieve cure in about 50% of cases, these approaches are all equally valid choices as first treatment of localized prostate cancer. However, in view of the current knowledge and available data, nowadays, androgen blockade should also be considered as first line treatment. While showing the high efficacy of hormonal therapy in localized prostate cancer, present knowledge clearly indicate that long-term treatment with the best available hormonal drugs, somewhat similar to the 5 years of Tamoxifen in breast cancer, is required for optimal control of prostate cancer. It is also clear from the data analyzed that combined androgen blockage alone could well be an efficient therapy of localized prostate cancer while it has already been recognized as the best therapy for metastatic disease. This paper presents and discusses the current knowledge available on the use and results of endocrine therapy in localized prostate cancer.

Combined androgen blockade in the management of advanced prostate cancer: a sensible or ostensible approach

BACKGROUND

To compare the efficacy of orchiectomy alone and orchiectomy plus flutamide in treating patients with advanced carcinoma prostate.

MATERIALS AND METHODS

The study was initiated on 1 July 1997 and closed after enrolling 100 patients on 30 June 2000. Patients were prospectively randomized to orchiectomy alone (O) and orchiectomy plus flutamide (OF). A complete response (CR) was defined as the normalization of bone scans and serum prostate-specific antigen (PSA) levels returning to normal (< 4 ng/mL). A partial response (PR) was defined as a 50% reduction in metastasis mass compared to the initial study or a decrease in the PSA level of 50% of the initial value. Progressive disease (PD) was defined as the development of any new hot spot on bone scan or any increase in previously existing PSA level by 25%.

RESULTS

A total of 100 patients were entered in the study. The maximum percentage change in PSA levels in both groups was found in the first 3 months after orchiectomy, that is, 95% and 97% for the O and OF groups, respectively. In more than 80% of the patients this decrease in PSA was maintained for 3 years. The mean percentage change at 3 years in the O and OF groups was 70% and 75% (P = 0.95), respectively, and the overall response rate (CR + PR) was 88.50% and 86.53% in the two groups, respectively (P = 0.85). The follow-up period ranged between 3 and 5 years (mean, 3.5 years). The mean time to progression was 27 and 29 months in the O and OF groups, respectively. The overall survival rate at 3 and 5 years in two treatment groups was 45.83% and 48.07%, 20.83% and 23.07% in the O and OF groups, respectively (P = 0.75).

CONCLUSIONS

Maximum percentage decrease in PSA is seen within the first 3 months of therapy. Orchiectomy alone is as effective as combination therapy in decreasing serum PSA. Overall survival at 3 and 5 years in the orchiectomy only group was as good as that of combination therapy. These data suggest that the routine addition of flutamide to orchiectomy is not advisable.

Gleason score and pretreatment prostate-specific antigen in survival among patients with stage D2 prostate cancer

Although multiple studies have addressed the prognostic importance of tumor differentiation in patients with clinically localized prostate cancer, few data are available in patients with metastatic disease. We evaluated and compared survival data in two groups of men with Whitmore stage D2 metastatic prostate cancer initially treated with hormonal therapy. A series of 76 patients with D2 metastatic disease were evaluated and treated at the National Cancer Institute (NCI) in conjunction with an additional cohort of 141 patients from the Louisiana State University School of Medicine (LSU). Pathological specimens were classified according to the Gleason score. Fifty-two (25%) of the combined NCI/LSU specimens had a Gleason score of 6 or less, 71 (34%) had a value of 7, and remaining 87 (41%) had scores between 8 and 10. The median PSA at the time of diagnosis for the NCI patients was 294.2 ng/ml. Time to treatment failure was defined as the time that a greater than 50% increase above nadir PSA was noted. In neither group was Gleason score correlated with overall survival. There was no association between the time to progression following hormone therapy and primary tumor Gleason score. The PSA concentration at the time of diagnosis was not correlated with the Gleason score for the NCI patients; however, there was an inverse correlation between pretreatment PSA level and time to progression following hormonal ablation. Gleason score does not appear to impact survival in metastatic prostate cancer. PSA as a marker of the biological behavior in metastatic disease may also be limited. These findings should be reevaluated in larger, better matched cohorts. Novel techniques such as serum proteomics, microarrays, and metastatic cell isolation methods may better predict outcome in advanced prostate cancer.

Major impact of hormonal therapy in localized prostate cancer--death can already be an exception

For about 50 years, androgen blockade in prostate cancer has been limited to monotherapy (surgical castration) or high doses of estrogens in patients with advanced disease and bone metastases. The discovery of medical castration with LHRH agonists has led to fundamental changes in the endocrine therapy of prostate cancer. In 1979, the first prostate cancer patient treated with an LHRH agonist received such treatment at the Laval University Medical Center. A long series of studies have clearly demonstrated that medical castration with an LHRH agonist has inhibitory effects on prostate cancer equivalent to those of surgical castration. The much higher acceptability of LHRH agonists has been essential to permit a series of studies in localized disease. Based upon the finding that the testicles and adrenals contribute approximately equal amounts of androgens in the human prostate, the combination of medical (LHRH agonist) or surgical castration associated with a pure antiandrogen (flutamide, nilutamide or bicalutamide) has led to the first demonstration of a prolongation of life in prostate cancer, namely a 10-20% decreased risk of death according to the various metaanalyses of all the studies performed in advanced disease. In analogy with the other types of advanced cancers, the success of combined androgen blockade in metastatic disease is limited by the development of resistance to treatment. To avoid the problem of resistance to treatment while taking advantage of the relative ease of diagnosis of prostate cancer at an "early" stage, the much higher acceptability of LHRH agonists has permitted a series of studies which have demonstrated a major reduction in deaths from prostate cancer ranging from 31% to 87% at 5 years of follow-up in patients with localized or locally advanced prostate cancer. Most importantly, recent data show that the addition of a pure antiandrogen to an LHRH agonist in order to block the androgens made locally in the prostate leads to a 90% long-term control or probable cure of prostate cancer.

Intermittent androgen deprivation therapy for prostate cancer

Androgen deprivation therapy for prostate cancer is associated with several complications, including loss of libido, hot flashes, night sweats, psychological stress, osteoporosis, anemia, fatigue, loss of muscle mass, glucose intolerance, and changes in lipid profile. The natural history of prostate cancer while on such therapy is the attainment of an incurable androgen-independent state. Early diagnosis by prostate-specific antigen screening, longer life expectancies, and a penchant for immediate therapy pose a problem where clinicians have to balance the potential benefits of early hormonal therapy with the risks of development of these metabolic and psychological complications. Intermittent androgen deprivation offers clinicians a prospect to improve quality of life in patients with prostate cancer by harmonizing the benefits of androgen ablation with a reduction in treatment-related side effects and expenditure. In this review we discuss the challenges and opportunities of this mode of therapy and shed light on some of the underlying molecular mechanisms.

Nadir prostate-specific antigen best predicts the progression to androgen-independent prostate cancer

The objective of our study was to analyze the value of prostate-specific antigen (PSA) levels before and after androgen suppression to predict the time to androgen-independent progression (AIP) in patients with advanced and metastatic prostate cancer. A series of 283 prostate cancer patients under androgen suppression as a single treatment was studied. The disease was locally advanced in 98 patients and metastatic in the remainder 185. AIP was defined after 2 consecutive increases of serum PSA after the nadir value. The mean follow-up before AIP was 29.2 months (3-198). AIP was detected in 205 patients (72.4%). In 152 patients (74.1%), the event was detected within 24 months, while in 53 patients (25.9%), it was observed beyond 24 months. The multivariate analysis showed that the nadir PSA and the time to reach the nadir PSA were the most significant predictors of the time to AIP. The odds ratio of having a biochemical response greater than 24 months was 20 times higher in patients that achieved an undetectable PSA level of 0.2 ng/mL or less. Moreover in those patients whose nadir PSA reached beyond 12 months after androgen suppression the odds ratio was 18 times higher. These results show that the ability to achieve an undetectable nadir PSA and the time to reach it are the most significant predictors of the time to AIP in patients with locally advanced and metastatic prostate cancer under androgen suppression as a single therapy.

De la biologie à la clinique : le décès dû au cancer de la prostate peut-il maintenant être une exception ?

The most significant discovery of the second half of the XXth century in the field of prostate cancer therapy is probably the observation that the human prostate, as well as many other peripheral human tissues, synthesize locally an important amount of androgens from the inactive steroid precursors dehydroepiandrosterone (DHEA) and its sulfate DHEA-S. In parallel with these observations, two important discoveries also made by our group are applied in the clinic worldwide, namely the use of LHRH (luteininizing hormone-releasing hormone) agonists to completely block testicular androgens, while, simultaneously, the androgens made locally in the prostate from DHEA are blocked in their access to the androgen receptor by a pure antiandrogen of the class of flutamide. This treatment, called combined androgen blockade, has been the first treatment demonstrated to prolong life in prostate cancer. While the first studies were performed in patients with advanced and metastatic disease, our recent data indicate a remarkable level of efficacy of the same treatment applied to localized prostate cancer, namely a 90% possibility of cure. However, in order to be able to treat localized prostate cancer, early diagnosis must be achieved. In the first large-scale randomized study of prostate cancer screening, we have demonstrated that 99% of prostate cancers can be diagnosed at the localized or potentially curable stage, using simple annual measurement of PSA (prostatic specific antigen). Today's data show that with the simple application of the available diagnostic and therapeutic tools, death from prostate cancer should be an exception.

Prostate specific antigen: a prognostic marker of survival in good prognosis metastatic prostate cancer? (EORTC 30892)

PURPOSE

We study the value of PSA response and PSA progression as prognostic factors for survival in good prognosis metastatic prostate cancer.

METHODS

Data from 257 patients treated with Flutamide or Cyproterone acetate within the EORTC GU Group protocol 30892 have been used and analysis by Cox models.

RESULTS

A PSA response defined as a decrease to < or = 1 ng/ml and to between 1 and 10 ng/ml was associated with a hazard ratio of 0.30 and 0.61 for overall survival, respectively, as compared to the non-responders (PSA> 10 ng/ml). Five definitions of PSA progression were considered: (1) a confirmed or (2) a repeated doubling of the PSA over nadir and unconfirmed (3) 100%, (4) 50% and (5) 20% increase of the PSA over nadir, each to a value > 4 ng/ml. Definition (5) was the most sensitive with sensitivity 76.20% and specificity 32.08%. With this definition, 70.0% of the patients had a PSA progression, which occurred in median 1.98 years before death.

CONCLUSIONS

For good prognosis metastatic prostate cancer patients under anti-androgen treatment, PSA response at 6 months with cut-off levels of < or = 1 ng/ml and < or = 10 ng/ml is prognostic for survival. A 20% increase over nadir to a value > 4 ng/ml is prognostic for a poor survival with a 76.20% sensitivity. In this study, confirmation of the increase by a second observation did not seem necessary. Genuine surrogacy is not established in this study.