A controlled trial of bicalutamide versus castration in patients with advanced prostate cancer

Toward Bicalutamide Analogues with High Structural Diversity Using Catalytic Asymmetric Oxohydroxylation

A catalytic enantioselective synthesis of bicalutamide derivatives with promising potentials in prostate cancer treatment has been disclosed. The key intermediates, α-hydroxy-β-keto esters, were efficiently constructed through cinchoninium-mediated asymmetric oxohydroxylation of easily accessible alkenes with potassium permanganate. Good yields and high levels of asymmetric induction are achieved. This method provides a new synthetic route to bicalutamide analogues with high structural diversity, which will beneficially support subsequent structure-activity relationship studies and boost prostate cancer drug development.

Emerging hormonal agents for the treatment of prostate cancer

INTRODUCTION

Prostate cancer is the most common solid organ malignancy in men in the United States. Until recently, treatment options for men with metastatic disease were limited and patients faced poor outcomes with minimal alternatives. The landscape of prostate cancer treatment has transformed and taken shape over the last 20 years with novel hormonal and non-hormonal therapeutics that have demonstrated significant improvement in survival. However, patients with advanced disease still face imminent progression on hormone blockade therapy.

AREAS COVERED

There is a significant market opportunity to devise novel, more potent agents for patients with hormone-resistant disease. Here we review the existing treatment options in men with advanced prostate cancer, the market opportunity within this field, goals of current research, and the novel agents under investigation, including androgen receptor degraders, testosterone synthesis pathway inhibitors, DNA-binding domain and N-terminal domain antagonists, and the combination of hormonal and non-hormonal agents.

EXPERT OPINION

Combination therapy regimens and novel agents targeting alternative binding domains of the androgen receptor are of great interest, as they may overcome resistance mechanisms and hold promise as the future of advanced prostate cancer treatment.

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.

Androgen deprivation therapy during and after post-prostatectomy radiotherapy in patients with prostate cancer: a case control study

Background

Here we assessed the influence of androgen deprivation therapy (ADT) during and/or after post-prostatectomy radiotherapy (RT) on biochemical recurrence (BCR) and radiographic progression in patients with prostate cancer.

Methods

Patients with prostate cancer who underwent post-prostatectomy RT were analyzed. BCR and radiographic progression after RT were compared according to the concurrent or salvage ADT. Cox regression analyses were used to identify risk factors for BCR and radiographic progression.

Results

Of the 227 patients who underwent post-prostatectomy RT, 95 (41.9%) received concurrent ADT for a median of 17.0 months. Despite more aggressive disease characteristics in the concurrent ADT group than in the RT-only group, the former had a better 5-year BCR-free survival rate than the latter (66.1 vs. 53.9%; p = 0.016), whereas the radiographic progression rate was not significantly different between two groups. On the other hand, salvage ADT after post-RT BCR significantly delayed radiographic progression (5-year radiographic progression-free survival; 75.2 vs. 44.5%; p = 0.002).

Conclusions

Concurrent ADT improved BCR-free survival, and salvage ADT after post-RT BCR improved radiographic progression-free survival. To maximize the oncological benefit, ADT of sufficient duration should be implemented.

Androgen receptor targeting drugs in castration-resistant prostate cancer and mechanisms of resistance

Reactivated androgen receptor (AR) signaling drives castration-resistant prostate cancer (CRPC). The novel AR targeting drugs abiraterone and enzalutamide have improved survival of CRPC patients. However, resistance to these agents develops and patients ultimately succumb to CRPC. Potential mechanisms of resistance include the following: 1) Expression of AR splice variants, such as the AR-V7 isoform, which lacks the ligand-binding domain; 2) AR missense mutations in the ligand-binding domain, such as F876L and T877A; and 3) Mutation or overexpression of androgen biosynthetic enzymes or glucocorticoid receptor. Several novel agents may overcome resistance mechanisms. Galeterone acts through multiple mechanisms that include degradation of AR protein and is being evaluated in CRPC patients positive for AR-V7. EPI-001 and related compounds inhibit AR splice variants by targeting the N-terminal transactivation domain of AR. Promising therapies and novel biomarkers, such as AR-V7, may lead to improved outcomes for CRPC patients.

Surgical stress delays prostate involution in mice

Androgens control growth of prostate epithelial cells and androgen deprivation induces apoptosis, leading to prostate involution. We investigated the effects of surgical stress on prostate involution induced by androgen ablation and determined the underlying mechanisms. Androgen ablation in mice was induced by surgical castration and administration of the anti-androgenic drugs bicalutamide and MDV3100. Surgical stress was induced by sham castration under isoflurane anesthesia. Surgical stress delayed apoptosis and prostate involution induced by anti-androgenic drugs. These effects of stress were prevented by administering the selective beta2-adrenoreceptor antagonist ICI118,551 and were also blocked in BAD^3SA/WT mice expressing phosphorylation-deficient mutant BAD3SA. These results indicate that apoptosis and prostate involution in response to androgen ablation therapy could be delayed by surgical stress via the beta2-adrenoreceptor/BAD signaling pathway. Thus, surgery could interfere with androgen ablation therapy, whereas administration of beta2-adrenoreceptor antagonists may enhance its efficacy.

[Hormonal treatment in prostate cancer]

AIM

To describe drugs used in the hormonal treatment (hormonotherapy) of prostate cancer.

MATERIAL

Bibliographical search was performed from the database Medline (National Library of Medicine, PubMed) and websites of the HAS and the ANSM. The search was focused on the characteristics, the mode of action, the efficiency and the side effects of the various drugs concerned.

RESULTS

LHRH analogs and the antiandrogens remain the cornerstone in the treatment of locally advanced and metastatic prostate cancer. New therapeutic classes emerged recently (inhibitor of the synthesis of the androgen, the new antiandrogens) and allowed to grow again the limits of the hormone resistance and define the concept castration-resistant prostate cancer.

CONCLUSION

The hormonal treatment of the prostate cancer grew rich of new therapeutic classes which are going to change the medical care of the prostate cancer in the coming years and the urologist must play its full part.

Estrogens in men: clinical implications for sexual function and the treatment of testosterone deficiency

INTRODUCTION

The role of estrogens in male sexual function and the pathogenesis of testosterone deficiency remain controversial and poorly understood.

AIMS

To review the distribution of estrogens in normal and testosterone deficient men, their potential role in sexual function, and the clinical implications of elevated estrogens during testosterone therapy.

METHODS

A comprehensive, broad-based literature review was conducted on the role of estrogens in male sexual function and testosterone deficiency.

RESULTS

Estrogens elicit a variety of physiological responses in men and may contribute to modulation of sexual function. In the absence of testosterone deficiency, elevations in estrogens do not appear to be harmful and estrogens may help maintain some, but not all, sexual function in castrated men. While the therapeutic use of estrogens at pharmacologic doses has been used to suppress serum testosterone, naturally occurring elevations of estrogens do not appear to be a cause of low testosterone. During testosterone replacement, estrogens may rise and occasionally reach elevated levels. There is a lack of evidence that treatment of elevated estrogen levels during testosterone replacement has benefit in terms of male sexuality.

CONCLUSION

Further research on the importance of estrogens in male sexual function is needed. Current evidence does not support a role of naturally occurring estrogen elevations in testosterone deficiency or the treatment of elevated estrogens during testosterone therapy.

Treating prostate cancer in elderly men: how does aging affect the outcome?

OPINION STATEMENT

Prostate Cancer (PCa) is the second most common cancer in United States and remains the second leading cause of death in the Western world. Because the median age of diagnosis for men with prostate cancer is greater than 75 years, PCa can be considered a disease of the elderly. Several disease-specific factors (e.g., stage, tumor grade, prostate-specific antigen (PSA) level) and patient-specific factors (e.g., age, co-morbidity, and functional status) need to be considered in the decision-making process. In an attempt to incorporate these important factors to select optimal treatment for older individuals, several decision models have been published, yet their utility in clinical practice remains poorly understood. Current guidelines for the management of patients with PCa do not make specific recommendations for the elderly. Clearly there is a need to improve our understanding of the complex interrelationships between old age, co-morbidities, and their impact on expected outcomes.

Androgens as therapy for androgen receptor-positive castration-resistant prostate cancer

Prostate cancer is the most frequently diagnosed non-cutaneous tumor of men in Western countries. While surgery is often successful for organ-confined prostate cancer, androgen ablation therapy is the primary treatment for metastatic prostate cancer. However, this therapy is associated with several undesired side-effects, including increased risk of cardiovascular diseases. Shortening the period of androgen ablation therapy may benefit prostate cancer patients. Intermittent Androgen Deprivation therapy improves quality of life, reduces toxicity and medical costs, and delays disease progression in some patients. Cell culture and xenograft studies using androgen receptor (AR)-positive castration-resistant human prostate cancers cells (LNCaP, ARCaP, and PC-3 cells over-expressing AR) suggest that androgens may suppress the growth of AR-rich prostate cancer cells. Androgens cause growth inhibition and G1 cell cycle arrest in these cells by regulating c-Myc, Skp2, and p27Kip via AR. Higher dosages of testosterone cause greater growth inhibition of relapsed tumors. Manipulating androgen/AR signaling may therefore be a potential therapy for AR-positive advanced prostate cancer.

Sipuleucel-T for therapy of asymptomatic or minimally symptomatic, castrate-refractory prostate cancer: an update and perspective among other treatments

Sipuleucel-T is an autologous cell immunotherapy for castrate-refractory prostate cancer, with US Food and Drug Administration (FDA) approval in asymptomatic or minimally symptomatic prostate cancer. In this review we address the background of prostate cancer incidence and other available therapy onto which sipuleucel-T treatment has been added, with discussion of hormone-therapy, chemotherapy, and other investigational immunotherapies. The sipuleucel-T manufacturing process, toxicity and clinical benefit are reviewed, along with an examination of the issue of clinical benefit to survival, independent of apparent changes of prostate-specific antigen (PSA) levels. Sipuleucel-T therapy is appraised from clinician, patient and immunotherapeutic perspectives, with reference to the clinical data from the pivotal trial, the mechanism of action, and the treatment process.

Overcoming persistent dependency on androgen signaling after progression to castration-resistant prostate cancer

Prostate cancer is the most common form of cancer in males in the United States, and the second leading cause of cancer death. Initially, most cases of prostate cancer respond well to hormone therapy; however, resistance often develops rapidly, leading to castration-resistant prostate cancer (CRPC). Several mechanisms for castration resistance have been proposed, of which the most significant seems to be the "intracrine" production of androgens from adrenal androgen or intratumorally via the de novo route. This mechanism stimulates disease progression through reactivation of androgen receptor signaling in patients who have previously undergone castration therapy. 17,20-lyase is essential for androgen synthesis in both the adrenal glands and CRPC tissue, and some 17,20-lyase inhibitors and second-generation anti-androgens that were developed to treat CRPC are currently under clinical investigation, with encouraging preliminary data reported so far. However, resistance to some of these therapies has already been noted. The study of circulating tumor cells will likely be important not only to identify patients likely to receive benefit from this therapeutic approach, but also to further understand the molecular mechanisms of resistance.

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.

Management of complications of androgen deprivation therapy in the older man

Prostate cancer is the most common malignancy in older men. With the aging of the population, the number of older men with prostate cancer will grow rapidly. Androgen deprivation therapy (ADT) is the mainstay of treatment for men with systemic disease and is increasingly utilized as primary therapy or in combination with other therapies for localized disease. Side effects of therapy are multifold and include hot flashes, osteoporosis, and adverse psychological and metabolic effects. Recent research has illustrated that ADT can negatively impact the functional, cognitive, and physical performance of older men. Patients with prostate cancer, despite recurrence of the disease, have a long life expectancy and may be subjected to the side effects of ADT for many years. This review highlights the complications of ADT and approaches to management. We also provide recommendations for assessment and management of ADT complications among the most vulnerable and frail older male patients.

Hormonal approaches in prostate cancer: application in the contemporary prostate cancer patient

Early studies beginning in the 1940s confirmed the importance of the androgen receptor and benefits of androgen depletion in metastatic prostate cancer. These studies helped to establish management strategies with an excellent response rate. Despite this, there remains some controversy as to the optimal approach for patients. Fueling this controversy is the fact that routine PSA testing did not come into practice until the early 1990s, while the majority of the large trials evaluating the use of hormonal therapy were conducted in the pre-PSA era and in patients who had metastatic disease identifiable with radiographic imaging. With the onset of routine PSA testing and the subsequent stage migration that has occurred in men presenting with prostate cancer, the question of when to initiate hormonal therapy has become ever more controversial.

Management of asymptomatic rise in prostatic-specific antigen in patients with prostate cancer

Biochemical failure after curative-intent therapies is an increasingly common dilemma confronting patients and physicians. No definition of biochemical failure exists that can be applied to all forms of treatment and that is not to some degree affected by the follow-up interval, pretreatment prognostic factors, or the frequency of prostatic-specific antigen (PSA) testing. Available imaging techniques lack sensitivity in detection of occult micrometastases. Prognostic factors such as tumor characteristics and PSA kinetics should be considered when recommending second-line therapies. For those patients with suspected localized recurrence, second-line treatment with salvage therapies may provide long-term disease control. Hormonal therapy, although most commonly employed for PSA recurrence, is of palliative benefit only. Currently, the most appropriate therapeutic intervention for asymptomatic patients with evidence of biochemical failure remains undefined.

The role of hormonal treatment in prostate cancer

In 1941 Huggins and Hodges published for the first time the favorable effects of surgical castration and estrogen treatment on the progression of metastatic prostate cancer. However, this hormonal therapy is not without side effects. Since this pioneering milestone in history of prostate cancer, a further tremendous innovation did not take place. Today, due to intensive clinical, biochemical, nuclear-biological and molecular-biological research, many hormone active treatment variations are available. Besides traditional hormonal therapy, surgical or chemical castration, maximal androgen blockade, nontraditional forms of hormonal therapy, intermittent hormonal therapy, antiandrogens, 5-alpha-reductase inhibitors, and their combinations, we discuss options toward creating an increased number of side effect-oriented offers of hormonal treatment options, guaranteeing a longer and more comfortable exhaustion of the individual hormonal period of response and probably a longer survival. The prerequisite is a closer-than-ever monitoring by tumor marker and an early observation of symptomatic changes.

Population Based Study of Hormonal Therapy and Survival in Men With Metastatic Prostate Cancer

PURPOSE

Although the palliative benefits of hormonal therapy for metastatic prostate cancer are widely recognized, little information is available regarding the effect of hormonal therapy on cancer specific and overall survival, and the types of patients who might benefit the most or least from hormonal therapy.

MATERIALS AND METHODS

Prostate cancer specific and overall survival according to hormonal therapy use was determined by the Kaplan-Meier method in 6,098 men 65 years or older diagnosed with metastatic prostate cancer in 1991 to 1999 who were identified through the population based Surveillance, Epidemiology, and End Results, and Medicare linked database. Cox proportional hazards and propensity score methods were used to adjust for potential confounders, such as disease status and patient comorbidity.

RESULTS

Propensity score adjusted median overall survival was 26 months in men who received hormonal therapy compared with 13 months in those who did not (HR 0.66, 95% CI 0.17-0.70, p <0.0001). The benefit of hormonal therapy was observed across all comorbidity strata and races. Effects were most evident in patients with poorly differentiated cancer (cancer specific mortality in favor of treatment HR 0.60, 95% CI 0.53-0.69, p <0.001). Benefit was not found in patients with well differentiated cancer (cancer specific mortality in favor of no treatment HR 1.92, 95% CI 0.90-4.10, p = 0.09).

CONCLUSIONS

Hormonal therapy is associated with improved prostate cancer specific and overall survival in men with poorly differentiated cancer. Improved survival does not appear evident in men with well differentiated disease.

Management of the Patient with a Rising PSA Alone

PSA-only recurrence after definitive RP or RT for PCA is an increasingly com-mon scenario. The very definition of advanced prostate cancer is changing. Multimodal therapy improves cancer-specific outcomes especially in men with high-risk disease. After RP, a detectable serum PSA has been considered suggestive of PCA recurrence. After RT, the ASTRO definition of BCR has been widely used to define BCR. Both of these definitions of BCR are subject to dispute. The kinetics of a rising PSA (PSA doubling time) appears to be the best surrogate marker for disease risk, clinical progression, and ultimately cancer-specific death. Therapeutic options include salvage RT after primary RP or systemic HT through surgical/chemical castration, antiandrogens, or nontraditional HT. Re-cent studies suggest that early HT can provide modest survival benefits, but at both an economic cost and decreased quality of life. The diminished side effects of an oral antiandrogen are appealing, and may be as efficacious as castration therapies in low-volume disease. More clinical trials are needed to determine the best treatments, alone and in combination. The potential opportunities for novel therapeutic agents with low associated morbidity are great.

Health-related quality of life measurement in randomized clinical trials in surgical oncology

PURPOSE

There is debate about the value of measuring health-related quality of life (HRQL) in clinical trials in oncology because of evidence suggesting that HRQL does not influence clinical decisions. Analysis of HRQL in surgical trials, however, may inform decision making because it provides detailed assessment of the immediate detrimental short-term impact of surgery on HRQL that needs to be considered against the long-term survival benefits and functional outcomes of surgery. This study evaluated whether HRQL in randomized trials in surgical oncology contributes to clinical decision making.

METHODS

A systematic review identified randomized trials in surgical oncology with HRQL. Trials were evaluated independently by two reviewers and the value of HRQL in clinical decision making was categorized in three ways: whether trial investigators reported that HRQL influenced final treatment recommendations, whether trial investigators reported that HRQL would be useful for informed consent, and whether HRQL was assessed robustly according to predefined criteria.

RESULTS

Thirty-three randomized trials with valid HRQL questionnaires were identified; 22 (67%) concluded that HRQL outcomes influenced treatment decisions or provided valuable data for informed consent, and seven of these trials had robust HRQL design. Another five trials had robust HRQL design but investigators reported that HRQL outcomes were not clinically important enough to influence treatment recommendations.

CONCLUSION

In surgical trials in oncology, HRQL informed clinical decision making. It is recommended that HRQL be included in relevant surgical trials, and that information be used to inform clinicians and patients about the impact of surgery on short- and long-term HRQL.

INCIDENCE AND MANAGEMENT OF GYNECOMASTIA IN MEN TREATED FOR PROSTATE CANCER

PURPOSE

Gynecomastia is a potentially treatment limiting adverse event in men receiving hormone therapy for prostate cancer.

MATERIALS AND METHODS

In large, randomized, placebo controlled studies approximately 50% or more of patients with prostate cancer experienced gynecomastia due to multiple mechanisms. Although its severity was mostly reported as mild to moderate, gynecomastia was cited as the reason for most premature withdrawals from therapy. In patients with advanced forms of prostate cancer bilateral orchiectomy was associated with the lowest incidence of gynecomastia, followed by nonsteroidal antiandrogen therapy, diethylstilbestrol and estrogen in rank order.

RESULTS

It is important that gynecomastia is well managed in patients with prostate cancer who want to proceed with hormone therapy. Patients should be assessed for the likely etiology of gynecomastia and preventive therapy or treatment for established gynecomastia should be instituted. Prophylactic radiotherapy has been shown to decrease the incidence of hormone induced gynecomastia by more than 50%. An alternative course of action, which may be more convenient for the patient, is the prophylactic use of tamoxifen. Tamoxifen may also mitigate or resolve gynecomastia during its early or proliferative phase. In severe long-standing gynecomastia surgery is warranted since medical therapies are less likely to succeed. Aromatase inhibitors and 4-hydroxytamoxifen are investigational.

CONCLUSIONS

Gynecomastia is a significant problem in men undergoing hormonal therapy for prostate cancer. It requires prompt recognition, evaluation and management.

Treating the Biochemical Recurrence of Prostate Cancer After Definitive Primary Therapy

As increasing numbers of men are living longer with prostate cancer, larger proportions will eventually present to our collective practices with increasing prostate-specific antigen (PSA) levels. Such PSA relapses, conservatively estimated to affect approximately 50,000 men each year, have become the most common form of advanced prostate cancer. Salvage radiation therapy and salvage prostatectomy have important roles in our therapeutic armamentarium and should be valid options for young, healthy men. Counseling patients regarding expectations for cancer control and treatment morbidity has become better because of reports from larger series of patients who have had salvage radiation therapy and surgery. Some patients may not be appropriate candidates for salvage local therapies. A growing body of evidence suggests early hormonal therapy improves progression-free survival (PFS) and could alter cancer-specific survival. This benefit seems to be greatest when hormonal therapy is initiated while PSA levels are low, before clinically measurable disease becomes apparent. However, there is a cost to be paid in side effects and health care dollars when androgen deprivation is administered over prolonged periods. The nonsteroidal antiandrogen agent bicalutamide could offer PFS equivalent to that seen with castration without the complications of androgen deprivation. Observational data seem to indicate that individuals at high risk could also receive benefit from therapy administered before PSA detection. The potential opportunities for novel therapeutic agents with low associated morbidity are great.

Rising prostate-specific antigen after primary prostate cancer therapy

An estimated 20-40% of men experience a biochemical recurrence within 10 years of definitive prostate cancer treatment. No single prostate-specific antigen (PSA) value is invariably associated with clinical metastasis or cancer-specific survival; PSA kinetics might prove to be a more important predictor of eventual progression-free survival and cancer-specific survival than absolute PSA level alone. With only one-third of patients progressing from biochemical recurrence to clinical disease, therapeutic morbidity should not outpace risk of disease progression. Salvage radiation therapy following radical prostatectomy has widely variable long-term biochemical control rates (from 18 to 64% depending on the follow-up period). Early hormonal therapy delivered as castration or complete androgen blockade might delay clinical metastasis in patients with high-risk pathologic disease; however, the adverse effects and morbidity of long-term therapy must not be underestimated. Non-steroidal antiandrogens as monotherapy for early biochemical recurrence, particularly for younger men who wish to preserve their libido and sexual potency, have received considerable attention, but there are conflicting data on long-term outcomes. Because of their favorable adverse-effect profiles, non-traditional therapies that exert localized hormonal or cellular effects are receiving considerable attention for treatment of early, PSA-only recurrence. Data from animal models provide a rationale for the use of these therapies, but there is a lack of evidence to support prolongation of progression-free survival or cancer-specific survival.

Androgen deprivation therapy for prostate cancer: current status and future prospects

Androgens play a major role in promoting the development and progression of prostate cancer. As a result, androgen ablation or blockade of androgen action through the androgen receptor (AR) has been the cornerstone of treatment of advanced prostate cancer. Different strategies involving this hormonal therapy produce a significant clinical response in most of the patients, but most responders eventually lose dependency, resulting in mortality. Thus, whether hormonal therapy contributes to the improvement of overall survival rates, especially in patients with advanced prostate cancer, remains controversial. However, patients with advanced disease clearly have a benefit from androgen deprivation-based treatment for palliating their symptoms and for improving the quality of their lives. In order to improve overall survival, novel treatment strategies that prolong the androgen-dependent state and that are useful for androgen-independent disease based on specific molecular mechanisms need to be identified.

Bicalutamide (Casodex) in the treatment of prostate cancer

Prostate cancer is an important healthcare issue in men worldwide. With the advent of prostate-specific antigen screening and improved diagnostic techniques, prostate cancer is now being diagnosed in younger men and at earlier disease stages. As a result, patients often live with their disease for many years after diagnosis. This shift in the patient profile has focused attention to the impact of treatment on quality of life. Medical/surgical castration has traditionally been the mainstay of hormonal therapy but is associated with side effects including loss of libido and impotence. Nonsteroidal antiandrogens such as bicalutamide (Casodex) offer an effective alternative to castration with potential quality-of-life benefits. This paper reviews the evidence concerning the use of bicalutamide at all stages of the disease.

An evaluation of bicalutamide in the treatment of prostate cancer

Although prostate cancer is traditionally considered a disease of old age, improved diagnostic techniques have resulted in early diagnosis, and many men are now treated while still physically and sexually active. Current therapies for prostate cancer often include medical or surgical castration, which cause adverse effects on physical and sexual function; therefore, greater attention has been focused on quality of life. The nonsteroidal antiandrogen bicalutamide is an effective agent with a favorable tolerability profile and, in some settings, represents an alternative to castration. Mature survival data reveal that bicalutamide monotherapy provides survival benefits for untreated locally advanced disease that do not differ significantly from those of castration and maintains better physical capacity and sexual interest. Recent data from a prospective randomized trial demonstrate that bicalutamide given as immediate therapy, either alone or as adjuvant to therapy of curative intent, significantly reduces the risk of objective disease progression in patients with localized or locally advanced prostate cancer. Antiandrogens are also used in combination with castration, a treatment known as combined androgen blockade (CAB), for advanced disease. A randomized trial demonstrated that CAB with bicalutamide is associated with similar survival outcome to CAB with flutamide and is better tolerated. Current evidence demonstrates that bicalutamide currently has a favorable risk-benefit ratio in several stages of prostate cancer and that the role of bicalutamide will be further defined by ongoing studies.

Finasteride and flutamide therapy in patients with advanced prostate cancer: response to subsequent castration and long-term follow-up

OBJECTIVES

To report the efficacy of castration after progression on finasteride and flutamide. Standard androgen deprivation strategies for prostate cancer typically lead to castrate levels of testosterone. One alternative is the use of finasteride and flutamide.

METHODS

A Phase II trial evaluated the combination of finasteride (5 mg/day) and flutamide (250 mg three times daily) in patients with rising prostate-specific antigen levels after local treatment for prostate cancer or with newly discovered metastatic disease. Patients were followed up for subsequent events, including castration-free, androgen-independent prostate cancer (AIPC)-free, and overall survival.

RESULTS

With a median follow-up of 88 months, 5 patients (25%) continued on finasteride and flutamide, and 12 had stopped this combination and subsequently underwent medical or surgical castration. No patients experienced a flutamide withdrawal effect. All patients experienced more than a 50% decline in prostate-specific antigen after castration (mean 89%). The median protocol treatment failure-free survival was 29.9 months, the median castration-free survival was 37 months, and the median AIPC-free survival was 48.6 months. At 5 years, the overall survival rate was 65% (95% confidence interval 47% to 90%); 29% were alive and have not required castration, and 35% were alive and free of AIPC.

CONCLUSIONS

Finasteride and flutamide have a durable effect in suppressing prostate-specific antigen progression in some men with advanced prostate cancer. Furthermore, castration induces secondary responses that may be of shorter duration than if started initially, although the overall period of hormonally responsive prostate cancer is more than 4 years.

Variables in predicting survival based on treating "PSA-only" relapse

Prostate cancer recurrence (after prior local treatment) that is detectable only by a rise in serum prostate specific antigen (PSA) level is a very common problem facing clinicians. Given that the majority of contemporary era men with PSA-only or biochemical recurrence are relatively young and otherwise healthy, treatment requires approaches that both improve clinical outcomes and preserve quality of life. Treatment is in one of two broad categories, additional local therapies, termed "salvage" local therapy and systemic therapies. For radical prostatectomy patients, salvage external beam radiotherapy to the prostate bed is commonly employed, being reserved for early biochemical recurrence in men with low risk at distant metastases. For primary radiation patients, salvage radical prostatectomy or cryotherapy can similarly be used for those men felt not to harbor distant metastases. Systemic therapy generally involves hormonal therapy. Traditional hormonal therapy (orchiectomy, luteinizing hormone-releasing hormone agonists, or maximum androgen blockade) is the current mainstay of systemic treatment for biochemical recurrence, although nontraditional approaches, such as antiandrogen monotherapy, are increasingly being used. Variables in predicting survival based on treating PSA relapse is problematic. The condition of biochemical failure has only been recognized in the last decade and few "PSA-era" patients with biochemical recurrence have actually died of disease. Hence, the validation of prediction variables in this setting is just emerging. Early work would suggest that timing of recurrence, Gleason grade, and PSA velocity or doubling time during relapse are important prognostic factors. New data on PSA doubling time will be presented.

Health related quality of life in prostate carcinoma patients: a systematic review of randomized controlled trials

BACKGROUND

Health related quality of life (HRQOL) is increasingly reported as an important endpoint in cancer clinical trials. However, evidence suggests that HRQOL reporting is often inadequate. Given this, the authors undertook a systematic review to evaluate HRQOL assessment methodology and reported outcomes of randomized controlled clinical trials (RCTs) with prostate carcinoma patients.

METHODS

A comprehensive search of the literature from 1980 to 2001, mainly on the following databases, was undertaken: MedLine, Cancerlit, and the Cochrane Controlled Trials Register. Studies were identified according to a predefined coding scheme, including HRQOL measure, cultural validity, compliance data reported and the clinical significance of the results.

RESULTS

Twenty-five RCTs were identified, involving 8015 patients primarily with metastatic cancer. Bicalutamide was the medical treatment against which most treatment comparisons were made. Limitations identified included the fact that only 44% of the studies gave a rationale for selecting a specific HRQOL measure, 64% of the studies failed to report information about the administration of the HRQOL measure, and 56% failed to report compliance at baseline. The measure most often used was the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-Care 30 (EORTC QLQ-C30), although some studies used non-validated HRQOL tools.

CONCLUSIONS

The current study revealed a lack of a uniform approach to HRQOL assessment and several methodologic limitations. It is possible that such methodologic limitations have influenced trial findings for HRQOL outcomes.

Will the experience with tamoxifen in breast cancer help define the role of antiandrogens in prostate cancer?

Breast and prostate cancers are the two predominant hormone-responsive tumours. The use of the antioestrogen tamoxifen in the treatment of breast cancer has evolved over the past 30 y from treatment for advanced breast cancer to prevention. Tamoxifen is currently the endocrine treatment of choice for advanced breast cancer and for adjuvant therapy in a broad spectrum of women whose primary tumours have functional oestrogen receptors. It has also been shown to reduce the incidence of breast cancer in high-risk women. Non-steroidal antiandrogen therapy is used in the treatment of prostate cancer, but its role is still being defined. The clinical development of tamoxifen and that of the antiandrogens are reviewed and parallels are uncovered which provide insight into contemporary and future management of hormone-responsive prostate cancer.Prostate Cancer and Prostatic Diseases (2001) 4, 72-80

An evaluation of bicalutamide in the treatment of prostate cancer

Prostate cancer is a major health problem in men, causing significant morbidity and mortality. Although traditionally considered a disease of old age, improved diagnostic techniques have resulted in earlier diagnosis and many men are now treated while still physically and sexually active. Current therapies for prostate cancer, which include medical or surgical castration, have a significant impact on many aspects of quality of life. The non-steroidal antiandrogen bicalutamide (Casodex, AstraZeneca) has a favourable tolerability profile with demonstrated efficacy in several stages of prostate cancer and represents an alternative therapeutic strategy to castration. Mature survival data from men with previously untreated, locally-advanced disease reveal that bicalutamide monotherapy provides survival benefits that do not differ significantly from castration, while offering important advantages with respect to the maintenance of physical capacity and sexual interest. Recent data from a prospective randomised trial, the largest prostate cancer treatment study ever conducted, demonstrate that immediate therapy with bicalutamide (alone or as an adjuvant to therapy of curative intent) significantly reduces the risk of objective disease progression in patients with localised or locally-advanced prostate cancer. Antiandrogens are also used in combination with castration (combined androgen blockade) for advanced disease. Another large, randomised trial demonstrated that combined androgen blockade with bicalutamide is associated with a similar survival outcome to combined androgen blockade with flutamide and is better tolerated. The evidence reviewed demonstrates that bicalutamide currently has a favourable risk:benefit ratio in several stages of prostate cancer. The role of bicalutamide will be further defined by ongoing studies.

Normalization of serum testosterone levels in patients treated with neoadjuvant hormonal therapy and three-dimensional conformal radiotherapy for prostate cancer

PURPOSE

To determine the expected time to serum testosterone normalization after short-course neoadjuvant androgen deprivation therapy (NAAD) and three-dimensional conformal radiotherapy for patients with localized prostate cancer and to identify pretreatment predictors that correlated with the time to testosterone normalization.

METHODS

Between 1993 and 1999, 88 patients with localized prostate cancer, treated with NAAD and external beam radiotherapy, were prospectively monitored after treatment with sequential testosterone levels. NAAD was administered before and during the entire course of radiotherapy and discontinued at the end of treatment. The median duration of NAAD was 6 months. The actuarial rate of serum testosterone normalization from the end of treatment was evaluated, and the presence or absence of androgen deprivation-related symptoms was correlated with serum testosterone levels. Symptoms assessed included weight gain, loss of libido, breast tenderness, breast enlargement, hot flashes, and fatigue.

RESULTS

Serum testosterone levels returned to the normal range in 57 (65%) of the 88 patients and failed to normalize in 31 patients (35%). The median time to normalization was 18.3 months. The actuarial rate of normalization at 3, 6, 12, and 24 months was 10%, 26%, 38%, and 59%, respectively. In a multivariate analysis, a pretreatment testosterone level in the lower range of normal was the only variable that predicted for delayed testosterone normalization after NAAD (p = 0.00047). Among 45 patients with information concerning androgen deprivation-related symptoms recorded 1 year after cessation of NAAD, 24 (53%) had normalized testosterone levels, but in 21 patients (47%), the levels had not yet returned to normal. At 1 year, only 1 (4%) of 24 patients whose testosterone level had returned to normal experienced NAAD-related symptoms compared with 14 (67%) of 21 patients who did not have normal testosterone levels (p <0.001).

CONCLUSION

Testosterone levels often remain depressed for extended periods after cessation of short-course NAAD. Lower baseline testosterone levels predict for a delay in testosterone normalization, and the persistence of symptoms related to androgen deprivation correlates with low testosterone levels.

Androgen deprivation therapy for patients with clinically localized (stages T1 to T3) prostate cancer and for patients with biochemical recurrence after radical prostatectomy

Recently published studies suggest a benefit for androgen deprivation therapy (ADT) delivered early in the course of prostate cancer. However, the use of ADT specifically in patients with clinically localized disease or biochemical-disease recurrence after local therapy is not well defined. Potential candidates for primary ADT include patients who are poor candidates for definitive local therapy because of advanced age or comorbid conditions, as well as patients with significant local disease who refuse standard therapy. Treatment strategies designed to minimize the side effects of prolonged therapy, such as intermittent ADT or antiandrogen monotherapy, show promise as alternatives to continuous ADT in some patients. The role of ADT in patients with clinically localized and recurrent prostate cancer, whether it is delivered in a continuous or intermittent fashion, must be determined in randomized, prospective trials.

Quality of life in patients with prostate cancer

OBJECTIVES

Quality of life (QOL) issues are important for patients with prostate cancer because side effects from treatment are substantial, while the disease itself may be indolent. This article reviews prostate cancer QOL studies.

DATA SOURCES

Selected studies published on QOL in prostate cancer using validated patient-assessed tools from the last 5 years.

CONCLUSIONS

Prostate cancer treatments are associated with side effects: prostatectomy has more urinary and sexual side effects, while external radiation therapy has more bowel symptoms. Side effects are not highly correlated with overall QOL.

IMPLICATIONS FOR NURSING PRACTICE

Patients must be made aware of potential gains in life expectancy as well as side effects of treatments to make informed decisions about treatment.

Survival of patients who had salvage castration after failure on bicalutamide monotherapy for stage (D2) prostate cancer

Patients with hormone-naive stage D2 prostate cancer often benefit from castration. This treatment, however, frequently produces many unacceptable physical and psychological side effects, especially in younger and sexually active patients. Bicalutamide is an oral antiandrogen with excellent tolerance and preservation of sexual function. Three institutions participated in phase II and III trials of bicalutamide monotherapy (50 mg daily) as primary therapy in hormone-naive patients with stage D2 prostate cancer. Upon bicalutamide failure, all patients underwent castration and were followed until death. Fifty-four patients received bicalutamide 50 mg orally once a day. One patient (2%) had complete response, 9 patients (17%) had partial response, and 27 patients (50%) had stable disease. Seventeen patients (31%) had progressive disease. The median time to bicalutamide failure was 47.4 weeks, 70.5 weeks for the responders vs. 25.4 weeks for the nonresponders (p < 0.001). The median survival time after the sequential use of bicalutamide and castration was 119.2 weeks for all 54 patients, 162.0 weeks for the responders, and 73.5 weeks for nonresponders (p < 0.0001). The median survival time after initiation of castration was 71.1 weeks for all 54 patients, 91.4 weeks for bicalutamide responders, and 42.1 weeks for nonresponders (p < 0.01). In hormone-naive patients with stage D2 prostate cancer, sequential treatment with bicalutamide monotherapy followed by castration upon failure may produce survival time within the range reported for initial treatment with castration. Thus, considering the favorable quality of life profile of bicalutamide, further studies are needed to define the role of sequential hormonal therapy in younger sexually active patients.

Hormone therapy of prostate cancer: is there a role for antiandrogen monotherapy?

Androgen suppressive maneuvers still represent the gold standard for prostate cancer patients. However, they are associated with side effects (fatigue, sexual impotence, hot flushes, anemia, anxiety, depression and osteoporosis) all of which have a negative impact on quality of life. Nonsteroidal antiandrogens compete with dihydrotestosterone for the linkage of its own receptors. These compounds are commonly used in combination with suppressive maneuvers. However, there is a growing experience with them as monotherapy, based on the possibility to spare gonadal function and therefore prevent the effects related to its suppression. Many studies have demonstrated the feasibility and safety of this approach, which can represent a valuable alternative to suppressive maneuvers for patients wishing to retain sexual function, especially for those without distant metastases. Unfortunately, none of the comparative studies performed so far had the power to detect the equivalence between monotherapy and castration.

Single-therapy androgen suppression in men with advanced prostate cancer: a systematic review and meta-analysis

PURPOSE

To compare luteinizing hormone-releasing hormone (LHRH) agonists with orchiectomy or diethylstilbestrol, and to compare antiandrogens with any of these three alternatives.

DATA SOURCES

A search of the MEDLINE, Cancerlit, EMBASE, and Cochrane Library databases from 1966 to March 1998 and Current Contents to 24 August 1998 for articles comparing the outcomes of the specified treatments. The search was limited to studies on prostatic neoplasms in humans. Total yield was 1477 studies.

STUDY SELECTION

Reports of efficacy outcomes were limited to randomized, controlled trials. Twenty-four trials involving more than 6600 patients, phase II studies that reported on withdrawals from therapy (the most reliable indicator of adverse effects), and all studies reporting on quality of life were abstracted.

DATA EXTRACTION

Two independent reviewers abstracted each article by following a prospectively designed protocol. The meta-analysis combined data on 2-year overall survival by using a random-effects model and; reported results as a hazard ratio relative to orchiectomy.

DATA SYNTHESIS

Ten trials of LHRH agonists involving 1908 patients reported no significant difference in overall survival. The hazard ratio showed LHRH agonists to be essentially equivalent to orchiectomy (hazard ratio, 1.1262 [corrected] [95% CI, 0.915 to 1.386]). There was no evidence of difference in overall survival among the LHRH agonists, although CIs were wider for leuprolide (hazard ratio, 1.0994 [CI, 0.207 to 5.835]) and buserelin (hazard ratio, 1.1315 [CI, 0.533 to 2.404]) than for goserelin (hazard ratio, 1.1172 [CI, 0.898 to 1.390]). Evidence from 8 trials involving 2717 patients suggests that nonsteroidal antiandrogens were associated with lower overall survival. The CI for the hazard ratio approached statistical significance (hazard ratio, 1.2158 [CI, 0.988 to 1.496]). Treatment withdrawals were less frequent with LHRH agonists (0% to 4%) than with nonsteroidal antiandrogens (4% to 10%).

CONCLUSIONS

Survival after therapy with an LHRH agonist was equivalent to that after orchiectomy. No evidence shows a difference in effectiveness among the LHRH agonists. Survival rates may be somewhat lower if a nonsteroidal antiandrogen is used as monotherapy.

Antiandrogens in prostate cancer

Antiandrogens competitively inhibit ligand binding to the androgen receptor (AR), and are used therapeutically in prostate cancer patients. The AR functions as a ligand dependent transcription factor that transduces androgen binding into increased transcription of androgen dependent genes. AR blockade induces programmed cell death in the vast majority of malignant and benign prostate cancer cells that have not previously been exposed to androgen ablation. The antiandrogens are divided structurally into the steroidal and non steroidal agents. The biological effects of the steroidal versus nonsteroidal agents are distinguished by differences in their effects on serum testosterone levels, and by their activity at receptors other than the androgen receptor. There is extensive clinical experience in the palliative and curative therapy of prostate cancer using antiandrogens as monotherapy or antiandrogens in combination with luteinizing hormone agonists or surgical castration. Prolonged therapy with antiandrogens selects for mutations in the AR that change the AR ligand specificity and permits stimulation by ligands that are usually inhibitory. These mutations give insight into one of the means by which prostate cancer progresses despite antiandrogen therapy, and also helps to explain the antiandrogen withdrawal syndrome. Areas of active research that may affect the future use of antiandrogens include the ongoing evaluation of antiandrogens in combination with 5 alpha reductase inhibitors to achieve AR blockade without inducing castrate testosterone levels. There is also interest in developing selective androgen receptor modulators (SARM) that can achieve AR blockade without causing the increased testosterone levels produced by the nonsteroidal antiandrogens currently in use.

Bicalutamide monotherapy versus flutamide plus goserelin in prostate cancer patients: results of an Italian Prostate Cancer Project study

PURPOSE

To compare the efficacy of bicalutamide monotherapy to maximal androgen blockade (MAB) in the treatment of advanced prostatic cancer.

PATIENTS AND METHODS

Previously untreated patients with histologically proven stage C or D disease (American Urological Association Staging System) were randomly allocated to receive either bicalutamide or MAB. After disease progression, patients treated with bicalutamide were assigned to castration. The primary end point for this trial was overall survival. Secondary end points included response to treatment, disease progression, treatment safety, quality-of-life (QOL), and sexual function.

RESULTS

A total of 108 patients received bicalutamide and 112 received MAB. There was no difference in the percentage of patients whose prostate-specific antigen returned to normal levels. At the time of the present analysis (median follow-up time, 38 months; range, 1 to 60 months), 129 patients progressed and 89 died. There was no difference in the duration of either progression-free survival or overall survival. However, a survival trend favored bicalutamide in stage C disease but MAB in stage D disease. Overall and subgroup trends were confirmed by multivariate analysis. Serious adverse events and treatment discontinuations were more common in patients receiving MAB (P =.08 and P =.04, respectively). Fewer patients in the bicalutamide group complained of loss of libido (P =. 01) and of erectile dysfunction (P =.002). Significant trends favored bicalutamide-treated patients also with respect to their QOL, namely relative to social functioning, vitality, emotional well-being, and physical capacity.

CONCLUSION

Bicalutamide monotherapy yielded comparable results relative to standard treatment with MAB, induced fewer side effects, and produced a better QOL.