Intermittent versus continuous total androgen blockade in the treatment of patients with advanced hormone-naive prostate cancer: results of a prospective randomized multicenter trial

Selective treatment de-escalation in advanced prostate cancer: have we come full circle?

Compelling evidence has solidified the notion of early treatment intensification in managing patients with metastatic hormone-sensitive prostate cancer (mHSPC). Landmark trials have provided Level 1 evidence for the survival benefits achieved by combining multiple agents. The efficacy of combined therapy relies not only on how treatment is intensified but also on how it is de-escalated. This underscores the importance of tailored treatment approaches, potentially involving a reduction in therapy for specific patients, to strike a balance between the benefits of hormonal treatment and its associated adverse effects. While de-escalation of therapy in mHSPC remains challenging due to limited evidence, it is recommended for elderly or frail patients, those with poor performance status, or experiencing significant toxicity. However, for patients with excellent prostate-specific antigen responses or favourable biomarkers, decisions should be personalised, weighing the potential benefits of continued treatment against the risk of long-term side effects, using risk stratification tools where appropriate.

"Nanoparticle-based sensitizers in prostate cancer treatment: Enhancing radiotherapy efficacy through innovative nanotechnology: Narrative review"

For men with localized prostate cancer, radiotherapy (RT) remains a common therapeutic option. Although radiotherapy has had significant success, it remains an intractable issue in promoting radiation damage to tumor tissue while reducing adverse effects on healthy tissue. Chemicals or pharmacological substances known as radiosensitizers can increase the killing effect on tumor cells by accelerating DNA damage and indirectly producing free radicals. Of all the approaches to improving RT management outcomes, metal nanoparticle-enhanced radiation for prostate cancer patient therapy is a unique strategy that has sparked scientific attention in the past decade. Most current data is based on targeted RT with gold nanoparticles, among the most studied materials. Nevertheless, several novel materials have also been employed in preclinical settings. This study assesses existing dosimetric data on prostate cancer tissue as well as the likely future influence on treatment options and patient outcomes since further research in a clinical setting is necessary.

Advances with androgen deprivation therapy for prostate cancer

INTRODUCTION

Androgen deprivation therapy (ADT) has been a treatment of choice for prostate cancer in almost all phases, particularly in the locally advanced, metastatic setting in both hormone-sensitive and castration-resistant diseaseand in those who are unfit for any local therapy. Different ways of administering ADT comes in the form of surgical or chemical castration with the use of gonadotropin-releasing hormone (GnRH-agonists) being the foremost way of delivering ADT.

AREAS COVERED

This review encompasses ADT history, use of leuprolide, degarelix, and relugolix, with contextual use of ADT in combination with androgen-signaling inhibitors and potential mechanisms of resistance. Novel approaches with regard to hormone therapy are also discussed.

EXPERT OPINION

The use of GnRH-agonists and GnRH-antagonists yields efficacy that is likely equivalent in resulting in testosterone suppression. While the side-effect profile with ADT are generally equivalent, effects on cardiovascular morbidity may be improved with the use of oral relugolix though this is noted with caution since the cardiovascular side-effects were a result of secondary subgroup analyses. The choice of ADT hinges upon cost, availability, ease of administration, and preference amongst physicians and patients alike.

Initial Management of Noncastrate Advanced, Recurrent, or Metastatic Prostate Cancer: ASCO Guideline Update

PURPOSE

Update all preceding ASCO guidelines on initial hormonal management of noncastrate advanced, recurrent, or metastatic prostate cancer.

METHODS

The Expert Panel based recommendations on a systematic literature review. Recommendations were approved by the Expert Panel and the ASCO Clinical Practice Guidelines Committee.

RESULTS

Four clinical practice guidelines, one clinical practice guidelines endorsement, 19 systematic reviews with or without meta-analyses, 47 phase III randomized controlled trials, nine cohort studies, and two review papers informed the guideline update.

RECOMMENDATIONS

Docetaxel, abiraterone, enzalutamide, or apalutamide, each when administered with androgen deprivation therapy (ADT), represent four separate standards of care for noncastrate metastatic prostate cancer. Currently, the use of any of these agents in any particular combination or series cannot be recommended. ADT plus docetaxel, abiraterone, enzalutamide, or apalutamide should be offered to men with metastatic noncastrate prostate cancer, including those who received prior therapies, but have not yet progressed. The combination of ADT plus abiraterone and prednisolone should be considered for men with noncastrate locally advanced nonmetastatic prostate cancer who have undergone radiotherapy, rather than castration monotherapy. Immediate ADT may be offered to men who initially present with noncastrate locally advanced nonmetastatic disease who have not undergone previous local treatment and are unwilling or unable to undergo radiotherapy. Intermittent ADT may be offered to men with high-risk biochemically recurrent nonmetastatic prostate cancer. Active surveillance may be offered to men with low-risk biochemically recurrent nonmetastatic prostate cancer. The panel does not support use of either micronized abiraterone acetate or the 250 mg dose of abiraterone with a low-fat breakfast in the noncastrate setting at this time.Additional information is available at www.asco.org/genitourinary-cancer-guidelines.

Resistance to Antiandrogens in Prostate Cancer: Is It Inevitable, Intrinsic or Induced?

Increasingly sophisticated therapies for chemical castration dominate first-line treatments for locally advanced prostate cancer. However, androgen deprivation therapy (ADT) offers little prospect of a cure, as resistant tumors emerge rather rapidly, normally within 30 months. Cells have multiple mechanisms of resistance to even the most sophisticated drug regimes, and both tumor cell heterogeneity in prostate cancer and the multiple salvage pathways result in castration-resistant disease related genetically to the original hormone-naive cancer. The timing and mechanisms of cell death after ADT for prostate cancer are not well understood, and off-target effects after long-term ADT due to functional extra-prostatic expression of the androgen receptor protein are now increasingly being recorded. Our knowledge of how these widely used treatments fail at a biological level in patients is deficient. In this review, I will discuss whether there are pre-existing drug-resistant cells in a tumor mass, or whether resistance is induced/selected by the ADT. Equally, what is the cell of origin of this resistance, and does it differ from the treatment-naïve tumor cells by differentiation or dedifferentiation? Conflicting evidence also emerges from studies in the range of biological systems and species employed to answer this key question. It is only by improving our understanding of this aspect of treatment and not simply devising another new means of androgen inhibition that we can improve patient outcomes.

Intermittent versus continuous androgen deprivation therapy for advanced prostate cancer

Androgen deprivation therapy (ADT) is still a mainstay of treatment for advanced prostate cancer. Continuous ADT causes considerable patient morbidity including sexual dysfunction, poor mood and physical capacity, changes in body composition and health-care-related costs. Intermittent ADT has been used as an approach to ADT monotherapy to limit morbidity by enabling cyclical recovery of serum testosterone levels. To date, a number of well-performed randomized controlled trials and meta-analyses have demonstrated statistically insignificant differences in oncological outcomes between intermittent and continuous ADT monotherapy. Sexual outcomes, morbidity profiles and cost-savings favour intermittent therapy in most randomized trials, but the benefit for clinical practice is unclear. Despite the growing body of evidence, the optimal administration regime for ADT has not been clearly established and incorporation of adjunctive upfront treatments such as chemotherapy and novel anti-androgen agents has further hampered progress. Recommendations by authoritative urological and oncological societies regarding the use of intermittent ADT are limited. The potential benefits of reduced morbidity for a particular patient must be considered in light of the possible oncological outcomes. Although the oncological changes associated with intermittent ADT are controversial, intermittent ADT does seem to provide symptomatic benefit in patients compared with continuous ADT. However, careful selection of suitable patients is crucial.

Parameter identification of a model for prostate cancer treated by intermittent therapy

Adenocarcinoma is the most frequent cancer affecting the prostate walnut-size gland in the male reproductive system. Such cancer may have a very slow progression or may be associated with a "dark prognosis" when tumor cells are spreading very quickly. Prostate cancers have the particular properties to be marked by the level of prostate specific antigen (PSA) in blood which allows to follow its evolution. At least in its first phase, prostate adenocarcinoma is most often hormone-dependent and, consequently, hormone therapy is a possible treatment. Since few years, hormone therapy started to be provided intermittently for improving patient's quality of life. Today, durations of on- and off-treatment periods are still chosen empirically, most likely explaining why there is no clear benefit from the survival point of view. We therefore developed a model for describing the interaction between the tumor environment, the PSA produced by hormone-dependent and hormone-independent tumor cells, respectively, and the level of androgens. Model parameters were identified using a genetic algorithm applied to the PSA time series measured in a few patients who initially received prostatectomy and were then treated by intermittent hormone therapy (LHRH analogs and anti-androgen). The measured PSA time series is quite correctly reproduced by free runs over the whole follow-up. Model parameter values allow for distinguishing different types of patient (age and Gleason score) meaning that the model can be individualized. We thus showed that the long-term evolution of the cancer can be affected by durations of on- and off-treatment periods.

Long-term treatment outcomes of intermittent androgen deprivation therapy for relapsed prostate cancer after radical prostatectomy

PURPOSE

Intermittent androgen deprivation therapy is an effective treatment for metastatic prostate cancer. However, no study to date has evaluated the long-term outcomes of this treatment among patients with prostate cancer after radical prostatectomy. We retrospectively examined the treatment outcomes of patients with prostate-specific antigen recurrence who underwent radical prostatectomy at our department.

MATERIALS AND METHODS

Of the 690 patients who underwent radical prostatectomy for local prostate cancer between 1988 and 2011, 129 patients who received androgen deprivation therapy for prostate-specific antigen recurrence were included in this study. Patient characteristics, luteinizing hormone-releasing hormone agonist administration, and outcomes were compared between the intermittent androgen deprivation group (n = 66) and the continuous androgen deprivation therapy group (n = 63). The non-recurrence and overall survival rates were compared between groups.

RESULTS

Thirty-six patients (27.9%) experienced recurrence after luteinizing hormone-releasing hormone agonist administration. The 5-year non-recurrence rate and 10-year overall survival rate were higher in the intermittent group (92.9%) than in the continuous group (92.9 vs 57.9%, P < 0.001; and 95.9% vs 84.3%, P = 0.047, respectively). Furthermore, 63 patients (48.8%) showed a PSA nadir of less than 0.01 ng/mL after initiation of luteinizing hormone-releasing hormone agonist; among these patients, the non-recurrence rate was significantly higher in the intermittent androgen deprivation group (P = 0.003).

CONCLUSIONS

Intermittent androgen deprivation therapy for prostate specific antigen recurrence after radical prostatectomy contributed to improvement of the non-recurrence rate and overall survival, and can be considered an effective therapy for better prognosis.

Intermittent, low-dose, antiandrogen monotherapy as an alternative therapeutic option for patients with positive surgical margins after radical prostatectomy

The aim of the present study was to determine whether oncologic outcomes and adverse events associated with active on/off intermittent antiandrogen monotherapy (daily bicalutamide, 50 mg per day) are comparable with those of standard external beam radiation therapy (EBRT) or combined androgen blockade (CAB) therapy in prostate cancers with positive surgical margins after radical prostatectomy. Two hundred twenty-three patients with positive surgical margins post-radical prostatectomy who underwent active surveillance (AS, n = 32), EBRT without hormone therapy (n = 55), intermittent antiandrogen monotherapy without EBRT (IAAM, n = 50), or CAB without EBRT (n = 86), between 2007 and 2014, were reviewed retrospectively. Pathologic outcomes, biochemical recurrence rates, radiological disease progression, and adverse events were collected from medical records. Biochemical recurrence rates, biochemical recurrence-free survival rates, and radiological recurrence were not different between the groups (P = 0.225, 0.896, and 0.284, respectively). Adverse event rates and severities were lower for IAAM compared with EBRT or CAB (both P < 0.05), but were comparable to those for AS (P = 0.591 and 0.990, respectively). Grade ≥3 adverse events were not reported in the IAAM or AS groups. Erectile dysfunction and loss of libido rates were lower in the IAAM group compared with the EBRT and CAB groups (P = 0.032). Gastrointestinal complications were more frequently reported in the EBRT group (P = 0.008). Active on/off IAAM treatment might be an appropriate treatment option for patients with positive surgical margins after radical prostatectomy. Furthermore, regarding oncologic outcomes, IAAM was comparable to standard EBRT but had a milder adverse event profile.

Older cancer patients in cancer clinical trials are underrepresented. Systematic literature review of almost 5000 meta- and pooled analyses of phase III randomized trials of survival from breast, prostate and lung cancer

BACKGROUND

Older people represent increasing proportions of the population with cancer. To understand the representivity of cancer treatments in older people, we performed a systematic literature review using PRISMA guidelines of the age distribution of clinical trial participants for three leading cancer types, namely breast, prostate, and lung.

METHODS

We used PubMed to identify articles detailing meta or pooled-analyses of phase III, randomised controlled trials (RCTs) of survival for breast, prostate and lung cancer, published ≤5 years from 2016. We compared the age distribution of participants to that of these cancers for "More developed regions".

RESULTS

4993 potential papers were identified, but only three papers on breast cancer, three on lung cancer, and none on prostate cancer presented the age distribution of their participants. Except for one paper of breast cancer, participants ≥70 years in all other papers were underrepresented.

CONCLUSIONS

We recommend the age distribution of patients be clearly reported in all clinical trials, as per guidelines. Clinical trials ought to be more representative of the populations most affected by the disease for which treatments are being tested. This should lead to better knowledge of effectiveness of treatments and better translation of trial results to optimal care of older cancer patients.

Intermittent androgen deprivation therapy in patients with prostate cancer: Connecting the dots

Intermittent androgen deprivation therapy (IADT) is now being increasingly opted by the treating physicians and patients with prostate cancer. The most common reason driving this is the availability of an off-treatment period to the patients that provides some relief from treatment-related side-effects, and reduced treatment costs. IADT may also delay the progression to castration-resistant prostate cancer. However, the use of IADT in the setting of prostate cancer has not been strongly substantiated by data from clinical trials. Multiple factors seem to contribute towards this inadequacy of supportive data for the use of IADT in patients with prostate cancer, e.g., population characteristics (both demographic and clinical), study design, treatment regimen, on- and off-treatment criteria, duration of active treatment, endpoints, and analysis. The present review article focuses on seven clinical trials that evaluated the efficacy of IADT vs. continuous androgen deprivation therapy for the treatment of prostate cancer. The results from these clinical trials have been discussed in light of the factors that may impact the treatment outcomes, especially the disease (tumor) burden. Based on evidence, potential candidate population for IADT has been suggested along with recommendations for the use of IADT in patients with prostate cancer.

Three cases of nonmetastatic prostate cancer treated successfully with primary intermittent androgen deprivation therapy over 10 years

We report three cases of nonmetastatic prostate cancer treated effectively with long-term primary intermittent androgen deprivation (IAD). IAD is not a standard therapy for patients with nonmetastatic prostate cancer. However, based on our experience, we suggest that IAD is one of useful therapeutic tools under certain patients' condition.

International survey of androgen deprivation therapy (ADT) for non-metastatic prostate cancer in 19 countries

Background

Continuous androgen deprivation therapy (CADT) is commonly used for patients with non-metastatic prostate cancer as primary therapy for high-risk disease, adjuvant therapy together with radiation or for recurrence after initial local therapy. Intermittent ADT (IADT), a recently developed alternative strategy for providing ADT, is thought to potentially reduce adverse effects, but little is known about practice patterns relating to it. We aimed to describe factors related to physicians’ ADT use and modality for patients with non-metastatic prostate cancer.

Methods

A 45 min online survey was completed by urologists and oncologists responsible for treatment decisions for non-metastatic prostate cancer from 19 countries with high or increasing prevalence of non-metastatic prostate cancer.

Results

There were 441 treating physicians who completed the survey which represented 99 177 patients with prostate cancer under their care, of which 76 386 (77%) had non-metastatic prostate cancer. Of patients with non-metastatic prostate cancer, 38% received ADT (37% gonadotropin-releasing hormone (GnRH), 2% orchiectomy); among patients on GnRH, 54% received CADT (≥6 without >3 months interruption), 23% IADT and 23% <6 months. Highest rates of ADT were reported among oncologists (62%) and in Eastern Europe (Czech Republic, Hungary and Poland). Prostate-specific antigen (PSA) levels (65%), Gleason score (52%) and treatment guidelines (48%) were the most common reasons for CADT whereas PSA levels (54%), patient request (48%), desire to maintain sexual function (40%), patient age and comorbidities (38%) were cited most frequently as reasons for IADT.

Conclusions

This international survey with 441 treating physicians from 19 countries showed that ADT is commonly used in treating patients with non-metastatic prostate cancer, and type of ADT is influenced by high-risk criteria (PSA and Gleason), treatment guidelines and patient preferences. IADT use was primarily driven by PSA levels, patient request and patient age/comorbidities, likely reflecting an attempt to minimise adverse effects of ADT in patients with lower risk tumours.

Androgen Deprivation Therapy in Prostate Cancer - Current Status in M1 Patients

Androgen deprivation therapy is the cornerstone treatment for metastatic prostate cancer. It can be done either surgically or medically. Luteinizing hormone-releasing hormone agonists and antagonist are the most effective drugs, with different side effects and modes of action, but no clear efficacy differences. Adding a non-steroidal antiandrogen adds a marginal benefit but also significant side effects and costs. Non-steroidal antiandrogens should not be used as monotherapy. In most patients with metastases, immediate castration is the standard of care. The intermittent modality is apparently non-inferior to the continuous one, with some other benefits. Upfront chemotherapy added to castration should be considered as the new standard of care in many metastatic patients. Castration leads to many adverse effects, some potentially life-threatening such as cardiovascular side effects.

The role of intermittent androgen deprivation therapy in the management of biochemically recurrent or metastatic prostate cancer

Androgen deprivation therapy (ADT) is a well-established treatment for locally advanced, biochemically recurrent and metastatic prostate cancer. However, it is associated with significant side effects including hot flashes, loss of libido and erectile function, muscular atrophy, metabolic abnormalities, and osteoporosis. In attempt to mitigate the side effects of ADT while retaining the oncological benefits, an approach of intermittent ADT (IAD) has been investigated. IAD involves alternating periods of treatment with intervals off treatment to allow hormone recovery. PSA thresholds are triggers for withdrawing and reinitiating therapy. Potential advantages of IAD include improved quality of life with fewer side effects and reduced cost. Delays in the development of hormone resistance have not been demonstrated clinically. The appropriate use of IAD requires patient selection and close monitoring of quality of life and disease status. This review presents the most recent evidence on the role of IAD in the management of prostate cancer.

Systemic therapy for the treatment of hormone-sensitive metastatic prostate cancer: from intermittent androgen deprivation therapy to chemotherapy

Treatment of advanced prostate cancer has changed considerably in recent years, but the vast majority of advances have been made in patients with metastatic castration-resistant disease. There have been relatively fewer advances in the earlier, hormonally responsive stage of metastatic disease. Since the empiric establishment of androgen deprivation therapy as first-line therapy for metastatic prostate cancer decades ago, there have been multiple studies looking at variations of suppressing testosterone, but the overall paradigm has not been strongly challenged until more recently. In particular, the dramatic results reported by the CHAARTED trial not only bring chemotherapy to an arena historically dominated solely by hormonal therapy but also stimulate renewed efforts into improving upon our management of metastatic hormone-sensitive prostate cancer.

Intermittent hormone therapy versus continuous hormone therapy for locally advanced prostate cancer: a meta-analysis

Few randomized studies have compared intermittent hormone therapy (IHT) with continuous hormone therapy (CHT) for the treatment of locally advanced prostate cancer (PCa). Here, we report the results of a meta-analysis of a randomized controlled trial, evaluating the effectiveness of IHT versus CHT for patients with locally advanced PCa. Types of intervention were IHT versus CHT. The primary endpoint of this study is overall mortality and the secondary endpoints are any progression of disease, quality of life (QOL) and adverse effects between two groups. Six randomized controlled trials totaling 2996 patients were included. Results are as follows: after hormone therapy, patients undergoing IHT demonstrated no significant difference from those undergoing CHT in terms of the overall mortality (OR = 1.0, 95% CI [0.86, 1.17]) and disease progression (OR = 1.16, 95% CI [0.86, 1.57]). Men treated with IHT also reported better QOL, fewer adverse effects and considerable economic benefit for the individual and the community. With no difference in overall mortality and incidence of progression, current clinical studies confirm that both therapeutic methods were safe and effective. However, our study also takes into account QOL. When these secondary measures are considered, IHT may be a better option over CHT as patients report a more affordable treatment with improved QOL and fewer adverse effects.

Saudi oncology society and Saudi urology association combined clinical management guidelines for prostate cancer

In this report, updated guidelines for the evaluation, medical, and surgical management of prostate cancer are presented. They are categorized according the stage of the disease using the tumor node metastasis staging system 7(th) edition. The recommendations are presented with supporting evidence level.

A review of continuous vs intermittent androgen deprivation therapy: redefining the gold standard in the treatment of advanced prostate cancer. Myths, facts and new data on a ″perpetual dispute″

OBJECTIVES

To review the literature and present new data of continuous androgen deprivation therapy (ADT) vs intermittent androgen deprivation (IAD) as therapies for prostate cancer in terms of survival and quality of life and clarify practical issues in the use of IAD.

MATERIALS AND METHODS

We conducted a systematic search on Medline and Embase databases using ″prostatic neoplasm″ and ″intermittent androgen deprivation″ as search terms. We reviewed meta-analyses, randomised controlled trials, reviews, clinical trials and practise guidelines written in English from 2000 and onwards until 01/04/2013. Ten randomized controlled trials were identified. Seven of them published extensive data and results randomizing 4675 patients to IAD versus CAD. Data from the other three randomized trials were limited.

RESULTS

Over the last years studies confirmed that IAD is an effective alternative approach to hormonal deprivation providing simultaneously several potential benefits in terms of quality of life and cost effectiveness. Thus, in patients with non metastatic, advanced prostate cancer IAD could be used as standard treatment, while in metastatic prostate cancer IAD role still remains ambiguous.

CONCLUSIONS

Nowadays, revaluation of the gold standard of ADT in advanced prostate cancer appears essential. Recent data established that IAD should no longer be consi¬dered as investigational, since its effectiveness has been proven, especially in patients suffering from non-metastatic advanced prostate cancer.

Relationships between times to testosterone and prostate-specific antigen rises during the first off-treatment interval of intermittent androgen deprivation are prognostic for castration resistance in men with nonmetastatic prostate cancer

BACKGROUND

Intermittent androgen deprivation (IAD) represents an alternative to continuous AD with quality-of-life benefit and no evidence of inferior overall survival for nonmetastatic prostate cancer. Early markers of prognosis for men treated with IAD have not been described.

PATIENTS AND METHODS

Men with nonmetastatic prostate cancer were treated with 9 months of leuprolide and flutamide followed by a variable off-treatment interval; AD was resumed when prostate specific antigen (PSA) reached a prespecified value (1 ng/mL, radical prostatectomy; 4 ng/mL, intact prostate). Cycles were repeated until castration resistance (marking the advent of castration-resistant prostate cancer [CRPC]), defined as 2 PSA rises with testosterone (T) ≤ 50 ng/dL. Kinetics and relationships of PSA and T levels were evaluated, with a focus on times to rise in each level, during the first off-treatment interval. Associations with CRPC and prostate cancer mortality were estimated using Cox proportional hazards models controlling for age and Gleason score.

RESULTS

Each 30-day increase in time to PSA rise was associated with a 21% reduction in the risk of developing CRPC (95% CI, 3%-36%; P = .02). Longer time (≥ 60 days) to PSA rise after rise to T > 50 ng/dL was associated with a 71% reduction in the risk of developing CRPC (95% CI, 92% reduction to 2% inflation; P = .05). Time to first T > 50 ng/dL and PSA doubling time were not prognostic for progression to CRPC. No time interval was prognostic for prostate cancer mortality.

CONCLUSION

During the first off-treatment interval of IAD, longer times to PSA rise overall and after T > 50 ng/dL were associated with reduced risk of developing CRPC.

Is intermittent androgen-deprivation therapy beneficial for patients with advanced prostate cancer?

Use of intermittent androgen-deprivation therapy (IADT) in patients with prostate cancer has been evaluated in several studies, in an attempt to delay the development of castration resistance and reduce side-effects associated with ADT. However it is still not clear whether survival is adversely affected in patients treated with IADT. In this review, we explore the available data in an attempt to identify the most suitable candidate patients for IADT, and discuss factors that may inform appropriate patient stratification. ADT is first-line treatment for advanced/metastatic prostate cancer and is also recommended for use with definitive radiotherapy for high-risk localised prostate cancer. The changes in hormone levels induced by ADT can lead to short- and long-term side-effects which, although treatable in most cases, can significantly reduce the tolerability of ADT treatment. IADT has been investigated in several phase II and phase III studies in patients with locally advanced or metastatic prostate cancer, in an attempt to delay time to tumour progression and reduce the side-effect burden of ADT. In selected patient groups IADT is no less effective than continuous ADT, ameliorating the impact of ADT-related side-effects, and, to a degree, their impact on patient health-related quality of life (HRQL). Further comparative study is required, particularly in relation to HRQL and long-term complications associated with ADT.

The role of intermittent androgen suppression in biochemically recurrent or newly diagnosed metastatic prostate cancer

PURPOSE OF REVIEW

To review the current status of intermittent androgen suppression in the management of biochemically recurrent or newly diagnosed metastatic prostate cancer with respect to two recently reported multicenter phase III randomized trials.

RECENT FINDINGS

The Canadian lead trial for men with biochemically recurrent prostate cancer after definitive radiotherapy (National Cancer Institute of Canada Clinical Trials Group PR7) randomized 1386 men and found a hazard ratio for death of 1.03 at a median follow-up of 6.9 years, declaring intermittent therapy noninferior to continuous for the trial algorithm. Over the same time frame, the South West Oncology Group (SWOG) compared continuous to intermittent therapy in metastatic prostate cancer. Although results were very similar in absolute terms, at 9.8 years follow-up, the hazard ratio for death was 1.1 in favor of the continuous approach. Intermittent therapy could not be declared noninferior. Both trials reported improved quality of life in the intermittent arms.

SUMMARY

There is a small increased risk for death from prostate cancer with the use of intermittent androgen suppression in both these patient populations. This situation may be especially true for higher Gleason score tumors (8-10) and in men with symptomatic bone metastases. Quality-of-life benefits may make this approach worthwhile for some individuals.

Comparison of intermittent and continuous androgen deprivation and quality of life between patients with locally advanced and patients with metastatic prostate cancer: a post hoc analysis of the randomized FinnProstate Study VII

OBJECTIVE

The aim of the study was to compare intermittent (IAD) and continuous (CAD) androgen deprivation therapy (ADT) between locally advanced (M0) and metastatic (M1) prostate cancer, and the effect of ADT on the quality of life.

MATERIAL AND METHODS

In total, 852 men with advanced prostate cancer were enrolled to receive goserelin acetate for 24 weeks. Of these, 554 patients whose prostate-specific antigen (PSA) decreased to less than 10 ng/ml or by at least 50% (<20 ng/ml at baseline) were randomized to IAD or CAD. In the IAD arm, ADT was resumed for at least 24 weeks whenever PSA increased to greater than 20 ng/ml or above baseline.

RESULTS

Median follow-up time was 65 months. Median times from randomization to progression, death, prostate cancer death and treatment failure in M0 and M1 patients were 46.8 and 21.4, 57.6 and 40.3, 59.5 and 40.7, and 41.9 and 20.0 months, respectively (p < 0.001). No significant differences emerged between IAD and CAD. ADT showed a beneficial effect on pain, activity limitation and social functioning in M1 patients, and a deleterious effect on physical capacity in M0 patients and on sexual functioning in both groups. IAD offered extra benefit for activity limitation, social functioning and recovery of sexual functioning.

CONCLUSIONS

IAD is as efficient as CAD in treatment of locally advanced and metastatic prostate cancer. ADT improves quality of life in M1 patients, with IAD offering extra benefit.

Intermittent versus continuous androgen deprivation therapy in advanced prostate cancer

Intermittent androgen deprivation is increasingly employed as an alternative to continuous life long androgen deprivation therapy for men with advanced or recurrent prostate cancer. Two recent phase III trials have clarified the benefits of intermittent therapy. In men with non-metastatic disease with PSA recurrence after definitive local therapy, intermittent therapy showed equivalent survival to continuous therapy, with significant improvements in quality of life. Patients on intermittent therapy experience improved bone health, less metabolic and hematologic disturbances, fewer hot flashes, as well as improved sexual function. In men with metastatic disease, the data is less clear. The long-awaited results of SWOG 9324 comparing intermittent to continuous therapy in metastatic disease showed a trend to worse outcome in the patients with 'minimal' metastatic disease, and no difference in those with widespread bone mets. The significance of this observation is in dispute. This review also addresses practical issues in the use intermittent therapy, including patient selection, follow-up and cycling of therapy. The recent results of randomized clinical trials now establish that intermittent androgen deprivation therapy is an approach that should be considered the standard of care for most patients with non-metastatic prostate cancer requiring hormonal therapy.

Intermittent versus continuous androgen deprivation for locally advanced, recurrent or metastatic prostate cancer: a systematic review and meta-analysis

BACKGROUND

Prostate cancer is the most common cancer in older men in the United States (USA) and Western Europe. Androgen deprivation (AD) constitutes, in most cases, the first-line of treatment for these cases. The negative impact of CAD in quality of life, secondary to the adverse events of sustained hormone deprivation, plus the costs of this therapy, motivated the intermittent treatment approach. The objective of this study is to to perform a systematic review and meta-analysis of all randomized controlled trials that compared the efficacy and adverse events profile of intermittent versus continuous androgen deprivation for locally advanced, recurrent or metastatic hormone-sensitive prostate cancer.

METHODS

Several databases were searched, including MEDLINE, EMBASE, LILACS, and CENTRAL. The endpoints were overall survival (OS), cancer-specific survival (CSS), time to progression (TTP) and adverse events. We performed a meta-analysis (MA) of the published data. The results were expressed as Hazard Ratio (HR) or Risk Ratio (RR), with their corresponding 95% Confidence Intervals (CI 95%).

RESULTS

The final analysis included 13 trials comprising 6,419 patients with hormone-sensitive prostate cancer. TTP was similar in patients who received intermittent androgen deprivation (IAD) or continuous androgen deprivation (CAD) (fixed effect: HR = 1.04; CI 95% = 0.96 to 1.14; p = 0.3). OS and CSS were also similar in patients treated with IAD or CAD (OS: fixed effect: HR = 1.02; CI 95% = 0.95 to 1.09; p = 0.56 and CSS: fixed effect: HR = 1.06; CI 95% = 0.96 to 1.18; p = 0.26).

CONCLUSION

Overall survival was similar between IAD and CAD in patients with locally advanced, recurrent or metastatic hormone-sensitive prostate cancer. Data on CSS are weak and the benefits of IAD on this outcome remain uncertain. Impact in QoL was similar for both groups, however, sexual activity scores were higher and the incidence of hot flushes was lower in patients treated with IAD.

EAU guidelines on prostate cancer. Part II: Treatment of advanced, relapsing, and castration-resistant prostate cancer

OBJECTIVE

To present a summary of the 2013 version of the European Association of Urology (EAU) guidelines on the treatment of advanced, relapsing, and castration-resistant prostate cancer (CRPC).

EVIDENCE ACQUISITION

The working panel performed a literature review of the new data (2011-2013). The guidelines were updated, and levels of evidence and/or grades of recommendation were added to the text based on a systematic review of the literature that included a search of online databases and bibliographic reviews.

EVIDENCE SYNTHESIS

Luteinising hormone-releasing hormone (LHRH) agonists are the standard of care in metastatic prostate cancer (PCa). LHRH antagonists decrease testosterone without any testosterone surge, and they may be associated with an oncologic benefit compared with LHRH analogues. Complete androgen blockade has a small survival benefit of about 5%. Intermittent androgen deprivation results in noninferior oncologic efficacy when compared with continuous androgen-deprivation therapy (ADT) in well-selected populations. In locally advanced and metastatic PCa, early ADT does not result in a significant survival advantage when compared with delayed ADT. Relapse after local therapy is defined by prostate-specific antigen (PSA) values >0.2 ng/ml following radical prostatectomy (RP) and >2 ng/ml above the nadir and after radiation therapy (RT). Therapy for PSA relapse after RP includes salvage RT (SRT) at PSA levels <0.5 ng/ml and SRP or cryosurgical ablation of the prostate in radiation failures. Endorectal magnetic resonance imaging and 11C-choline positron emission tomography/computed tomography (PET/CT) are of limited importance if the PSA is <1.0 ng/ml; bone scans and CT can be omitted unless PSA is >20 ng/ml. Follow-up after ADT should include analysis of PSA and testosterone levels, and screening for cardiovascular disease and metabolic syndrome. Treatment of CRPC includes sipuleucel-T, abiraterone acetate plus prednisone (AA/P), or chemotherapy with docetaxel at 75mg/m(2) every 3 wk. Cabazitaxel, AA/P, enzalutamide, and radium-223 are available for second-line treatment of CRPC following docetaxel. Zoledronic acid and denosumab can be used in men with CRPC and osseous metastases to prevent skeletal-related complications.

CONCLUSIONS

The knowledge in the field of advanced, metastatic, and castration-resistant PCa is rapidly changing. These EAU guidelines on PCa summarise the most recent findings and put them into clinical practice. A full version is available at the EAU office or at www.uroweb.org.

PATIENT SUMMARY

We present a summary of the 2013 version of the European Association of Urology guidelines on treatment of advanced, relapsing, and castration-resistant prostate cancer (CRPC). Luteinising hormone-releasing hormone (LHRH) agonists are the standard of care in metastatic prostate cancer (PCa). LHRH antagonists decrease testosterone without any testosterone surge, and they might be associated with an oncologic benefit compared with LHRH analogues. Complete androgen blockade has a small survival benefit of about 5%. Intermittent androgen deprivation results in noninferior oncologic efficacy when compared with continuous androgen-deprivation therapy (ADT) in well-selected populations. In locally advanced and metastatic PCa, early ADT does not result in a significant survival advantage when compared with delayed ADT. Relapse after local therapy is defined by prostate-specific antigen (PSA) values >0.2 ng/ml following radical prostatectomy (RP) and >2 ng/ml above the nadir and after radiation therapy. Therapy for PSA relapse after RP includes salvage radiation therapy at PSA levels <0.5 ng/ml and salvage RP or cryosurgical ablation of the prostate in radiation failures. Multiparametric magnetic resonance imaging and 11C-choline positron emission tomography/computed tomography (PET/CT) are of limited importance if the PSA is <1.0 ng/ml; bone scans, and CT can be omitted unless PSA is >20 ng/ml. Follow-up after ADT should include analysis of PSA and testosterone levels, and screening for cardiovascular disease and metabolic syndrome. Treatment of castration-resistant CRPC includes sipuleucel-T, abiraterone acetate plus prednisone (AA/P), or chemotherapy with docetaxel 75 mg/m(2) every 3 wk. Cabazitaxel, AA/P, enzalutamide, and radium-223 are available for second-line treatment of CRPC following docetaxel. Zoledronic acid and denosumab can be used in men with CRPC and osseous metastases to prevent skeletal-related complications. The guidelines reported should be adhered to in daily routine to improve the quality of care in PCa patients. As we have shown recently, guideline compliance is only in the area of 30-40%.

Efficacy of intermittent androgen deprivation therapy vs conventional continuous androgen deprivation therapy for advanced prostate cancer: a meta-analysis

OBJECTIVE

To compare the efficacy of intermittent androgen deprivation therapy (IADT) vs continuous androgen deprivation therapy (CADT) for the treatment of advanced prostate cancer; we performed a meta-analysis of randomized controlled trials (RCTs), assessing the risks of disease progression, all-cause, and disease-specific mortality.

MATERIALS AND METHODS

We conducted a systematic search of several bibliographic systems to identify all RCTs of IADT in men with newly diagnosed metastatic or biochemical only prostate cancer. We abstracted outcome data, study characteristics, and participant demographics. We performed heterogeneity tests and calculated the summarized risk differences (RD) and risk ratios at 95% confidence intervals (CI), using inverse variance methods in random-effects approaches.

RESULTS

We identified 8 RCTs (N = 4664) comparing mortality between IADT and CADT. For all men combined, we observed small but nonsignificant differences in all-cause mortality (RD = 0.02, 95% CI = -0.02, 0.06), disease-specific mortality (RD = 0.04, 95% CI = -0.01, 0.08), and disease progression (RD = -0.03, 95% CI = -0.09, 0.04). Among the prespecified subgroup with histologically confirmed, newly diagnosed metastatic disease, we found no difference in overall survival (RD = 0.00, 95% CI = -0.09, 0.09).

CONCLUSION

We found no difference in overall survival, but a small increased risk in disease-specific survival for men treated with IADT relative to CADT was observed. IADT could be considered as an alternative to CADT because of better quality of life outcome. Patients should be informed of the possible risks and benefits of both therapies. More research confirming the benefits of IADT vs CADT is needed to inform treatment decisions.

Treatment of prostate cancer with intermittent versus continuous androgen deprivation: a systematic review of randomized trials

PURPOSE

Uncertainty exists regarding benefits of intermittent androgen deprivation (IAD) compared with continuous androgen deprivation (CAD) for treatment of prostate cancer. On the basis of a systematic review of evidence, our aim was to formulate a recommendation for either IAD or CAD to treat relapsing, locally advanced, or metastatic prostate cancer.

METHODS

We searched literature published up to September 2012 from MEDLINE, EMBASE, the Cochrane Library, and major conference proceedings. We included randomized controlled trials comparing IAD and CAD if they reported overall survival (OS) or biochemical/radiologic time to disease progression.

RESULTS

Nine studies with 5,508 patients met our criteria. There were no significant differences in time-to-event outcomes between the groups in any studies. The pooled hazard ratio (HR) for OS was 1.02 (95% CI, 0.94 to 1.11) for IAD compared with CAD, and the HR for progression-free survival was 0.96 (95% CI, 0.76 to 1.20). More prostate cancer-related deaths with IAD tended to be balanced by more deaths not related to prostate cancer with CAD. Superiority of IAD for sexual function, physical activity, and general well-being was observed in some trials. Median cost savings with IAD was estimated to be 48%.

CONCLUSION

There is fair evidence to recommend use of IAD instead of CAD for the treatment of men with relapsing, locally advanced, or metastatic prostate cancer who achieve a good initial response to androgen deprivation. This recommendation is based on evidence against superiority of either strategy for time-to-event outcomes and substantial decrease with IAD in exposure to androgen deprivation, resulting in less cost, inconvenience, and potential toxicity.

Intermittent androgen-deprivation therapy in prostate cancer: a critical review focused on phase 3 trials

CONTEXT

Intermittent androgen deprivation (IAD) in prostate cancer (PCa) patients has been proposed to delay development of castration resistance and to reduce the side effects and costs of androgen deprivation therapy (ADT).

OBJECTIVE

This review analyzes (1) the oncologic and quality of life (QoL) results from randomized phase 3 trials comparing IAD and continuous ADT and (2) the prognostic parameters for IAD.

EVIDENCE ACQUISITION

We searched the Medline and Cochrane Library databases (primary fields: prostate neoplasm and intermittent androgen deprivation; secondary fields: randomized trials, survival, quality of life, predictors) without language restriction.

EVIDENCE SYNTHESIS

We found seven extensively described phase 3 trials randomizing 4675 patients to IAD versus continuous ADT. Other randomized trials investigating IAD have been performed, but available data are limited and have been published only in preliminary fashion. In all seven trials, patients spent most of their time on, rather than off, ADT. The induction periods ranged from 3 mo to 8 mo; in all but one trial, the PSA level designated for ADT discontinuation was <4 ng/ml. Mean follow-up ranged from 40-108 mo. Collectively, these trials support the concept that, mainly in metastatic cases, IAD can produce oncologic results similar to continuous ADT. In terms of overall survival, the hazard ratios for IAD and continuous ADT were very similar (range: 0.98-1.08). The QoL benefit of IAD appears to be modest at best. With IAD, QoL is likely influenced by the duration of the off-treatment periods and by the rate of testosterone recovery.

CONCLUSIONS

The evidence indicates that IAD is not inferior to continuous ADT. Data are insufficient to determine whether IAD is able to prevent the long-term complications of ADT. More comparative analysis focused on QoL is warranted.

Intermittent versus continuous androgen deprivation in prostate cancer

BACKGROUND

Castration resistance occurs in most patients with metastatic hormone-sensitive prostate cancer who are receiving androgen-deprivation therapy. Replacing androgens before progression of the disease is hypothesized to prolong androgen dependence.

METHODS

Men with newly diagnosed, metastatic, hormone-sensitive prostate cancer, a performance status of 0 to 2, and a prostate-specific antigen (PSA) level of 5 ng per milliliter or higher received a luteinizing hormone-releasing hormone analogue and an antiandrogen agent for 7 months. We then randomly assigned patients in whom the PSA level fell to 4 ng per milliliter or lower to continuous or intermittent androgen deprivation, with patients stratified according to prior or no prior hormonal therapy, performance status, and extent of disease (minimal or extensive). The coprimary objectives were to assess whether intermittent therapy was noninferior to continuous therapy with respect to survival, with a one-sided test with an upper boundary of the hazard ratio of 1.20, and whether quality of life differed between the groups 3 months after randomization.

RESULTS

A total of 3040 patients were enrolled, of whom 1535 were included in the analysis: 765 randomly assigned to continuous androgen deprivation and 770 assigned to intermittent androgen deprivation. The median follow-up period was 9.8 years. Median survival was 5.8 years in the continuous-therapy group and 5.1 years in the intermittent-therapy group (hazard ratio for death with intermittent therapy, 1.10; 90% confidence interval, 0.99 to 1.23). Intermittent therapy was associated with better erectile function and mental health (P<0.001 and P=0.003, respectively) at month 3 but not thereafter. There were no significant differences between the groups in the number of treatment-related high-grade adverse events.

CONCLUSIONS

Our findings were statistically inconclusive. In patients with metastatic hormone-sensitive prostate cancer, the confidence interval for survival exceeded the upper boundary for noninferiority, suggesting that we cannot rule out a 20% greater risk of death with intermittent therapy than with continuous therapy, but too few events occurred to rule out significant inferiority of intermittent therapy. Intermittent therapy resulted in small improvements in quality of life. (Funded by the National Cancer Institute and others; ClinicalTrials.gov number, NCT00002651.).

Androgen deprivation therapy in advanced prostate cancer: is intermittent therapy the new standard of care?

PURPOSE

Intermittent androgen deprivation is increasingly used as an alternative to continuous life-long androgen deprivation therapy for men with advanced or recurrent prostate cancer.

RECENT FINDINGS

Two recent phase iii trials have clarified the benefits of intermittent therapy. The Canadian-led pr.7 trial in men with nonmetastatic disease and prostate-specific antigen recurrence after definitive local therapy showed that intermittent therapy resulted in survival equivalent to that with continuous therapy, with significant improvements in quality of life. Patients on intermittent therapy experienced improved bone health, fewer metabolic and hematologic disturbances, fewer hot flashes, and improved sexual function. In men with metastatic disease, the data are less clear. The long-awaited results of the Southwest Oncology Group 9346 trial, comparing intermittent with continuous therapy in metastatic disease, showed no difference in overall survival. Post hoc stratification analysis showed a worse outcome in patients with "minimal" metastatic disease, and no difference in those with widespread bone metastases. The significance of that observation is in dispute. The present review also addresses practical issues in the use of intermittent therapy, including patient selection, follow-up, and therapy cycling.

SUMMARY

The recent results of randomized clinical trials now establish that intermittent androgen deprivation therapy is an approach that should be considered the standard of care in most patients with nonmetastatic prostate cancer requiring hormonal therapy and in selected patients with metastatic disease.

KEY POINTS

Level i evidence supports the oncologic equivalence of intermittent compared with continuous androgen blockade in men with biochemical failure.Compared with continuous androgen deprivation, intermittent therapy demonstrates improved quality of life and fewer side effects.Patient selection for intermittent therapy is important to maintain good oncologic results.Monitoring of prostate-specific androgen response and duration of off-treatment intervals allow for stratification of patients by risk of progression.

[Current evidence about intermittent androgenic deprivation in prostate cancer]

OBJECTIVES

To identify clinical application of intermittent hormonotherapy in prostatic carcinoma.

MATERIAL AND METHODS

We conducted a systematic review in MEDLINE database and COCHRANE Library using the words MeSH "prostate cancer, androgenic deprivation and intermittent". There were included those with the best level of evidence and published in the last 10 years.

RESULTS

Intermittent hormone therapy is one of the tools we use in urological armamentarium for special circumstances. This analysis highlights: possibility to regain sexual function during the period of suspension of treatment (time off) due to the recovery of testosterone levels also demonstrating an improvement in symptoms, decreased costs preserving the same oncological control compared to complete androgenic deprivation.

CONCLUSIONS

There is still controversy about the benefits in quality of life and the emergence of long-term side effects typical of continuous hormonal therapy. Therefore and until now, we should only propose intermittent therapy in selected patients.

The FinnProstate Study VII: intermittent versus continuous androgen deprivation in patients with advanced prostate cancer

PURPOSE

We conducted a randomized trial to compare intermittent and continuous androgen deprivation in patients with advanced prostate cancer. We studied time to progression, overall and prostate cancer specific survival, and time to treatment failure.

MATERIALS AND METHODS

Between May 1997 and February 2003, 852 men with locally advanced or metastatic prostate cancer were enrolled to receive androgen deprivation therapy for 24 weeks. Patients in whom prostate specific antigen decreased to less than 10 ng/ml, or by 50% or more if less than 20 ng/ml at baseline, were randomized to intermittent or continuous androgen deprivation. In the intermittent therapy arm androgen deprivation therapy was withdrawn and resumed again for at least 24 weeks based mainly on prostate specific antigen decrease and increase.

RESULTS

There were 298 patients who did not meet the randomization criteria. The remaining 554 patients were randomized, with 274 (49.5%) to intermittent androgen deprivation and 280 (50.5%) to the continuous androgen deprivation arm. Median followup was 65.0 months. Of these patients 392 (71%) died, including 186 (68%) in the intermittent androgen deprivation arm and 206 (74%) in the continuous androgen deprivation arm (p=0.12). There were 248 prostate cancer deaths, comprised of 117 (43%) in the intermittent androgen deprivation and 131 (47%) in the continuous androgen deprivation arm (p=0.29). Median times from randomization to progression were 34.5 and 30.2 months in the intermittent androgen deprivation and continuous androgen deprivation arms, respectively. Median times to death (all cause) were 45.2 and 45.7 months, to prostate cancer death 45.2 and 44.3 months, and to treatment failure 29.9 and 30.5 months, respectively.

CONCLUSIONS

Intermittent androgen deprivation is a feasible, efficient and safe method to treat advanced prostate cancer compared with continuous androgen deprivation.

Long-term dynamics of bone mineral density during intermittent androgen deprivation for men with nonmetastatic, hormone-sensitive prostate cancer

PURPOSE

To investigate changes in bone mineral density (BMD) and fracture risk in men who received intermittent androgen deprivation (IAD) for nonmetastatic, hormone-sensitive prostate cancer.

PATIENTS AND METHODS

Men with prostate cancer who lacked radiographically detectable metastases were treated in a prospective trial of IAD. After 9 months of treatment with leuprolide and flutamide, androgen deprivation therapy (ADT) was stopped until prostate-specific antigen reached a threshold (1 ng/mL for radical prostatectomy; 4 ng/mL for radiation or primary ADT) for a new cycle. Dual-energy x-ray absorptiometry (DXA) scans were performed before starting ADT and subsequently with each change in therapy. At least two consecutive DXA scans were required for this analysis. Computed tomography, bone scintigraphy, and lumbar spine x-rays were performed at the beginning and end of each treatment period.

RESULTS

Fifty-six of 100 patients met criteria for this analysis. The median age at study entry was 64.5 years (range, 49.8 to 80.9 years). The average percentage change in BMD during the first on-treatment period was -3.4% (P < .001) for the spine and -1.2% (P = .001) for the left hip. During the first off-treatment period (median, 37.4 weeks; range, 13.4 weeks to 8.7+ years), BMD recovery at the spine was significant, with an average percentage change of +1.4% (P = .002). Subsequent periods had heterogeneous changes of BMD without significant average changes. After a median of 5.5 years (range, 1.1 to 13.8+) years on trial, one patient (1.8%) had a compression fracture associated with trauma.

CONCLUSION

Patients experienced the greatest average change in BMD during early treatment periods of IAD with a smaller average change thereafter. Fractures were rare.

Safety and tolerability of intermittent androgen deprivation therapy: a literature review

Androgen deprivation therapy is commonly used in men with advanced prostate cancer; however, it is associated with many short- and long-term side-effects. Intermittent androgen deprivation therapy was first suggested as an alternative regimen in the early 1990s and is now part of treatment guidelines as a result of its ability to reduce adverse events associated with continuous androgen deprivation therapy without decreasing its efficacy. Although many publications evaluated intermittent androgen deprivation therapy's efficacy, the safety and tolerability information of this regimen is relatively limited. The goal of this literature review was to analyze clinical trials that have reported safety and tolerability data in prostate cancer patients treated with intermittent androgen deprivation therapy, as well as assessing quality of life outcomes. A literature search was carried out using biomedical and pharmaceutical databases for published information comparing intermittent androgen deprivation therapy with continuous androgen deprivation therapy. A total of 13 randomized and non-randomized studies were selected and reviewed based on their relevance to the safety, tolerability and quality of life of intermittent androgen deprivation therapy. Benefits for intermittent androgen deprivation therapy were observed for the short-term side-effects (hot flushes and sexual functions) mainly during the off-treatment phase, whereas the data for the long-term side-effects were not as conclusive. Quality of life evaluations are more in support of intermittent androgen deprivation therapy. Although there are some safety, tolerability and quality of life benefits associated with intermittent androgen deprivation therapy, the overall evidence is still limited.

A randomized, phase II study of pazopanib in castrate-sensitive prostate cancer: a University of Chicago Phase II Consortium/Department of Defense Prostate Cancer Clinical Trials Consortium study

BACKGROUND

Intermittent androgen suppression (IAS) is an increasingly popular treatment option for castrate-sensitive prostate cancer. On the basis of previous data with anti-angiogenic strategies, we hypothesized that pan-inhibition of the vascular endothelial growth factor receptor using pazopanib during the IAS off period would result in prolonged time to PSA failure.

METHODS

Men with biochemically recurrent prostate cancer, whose PSA was <0.5 ng ml(-1) after 6 months of androgen deprivation therapy were randomized to pazopanib 800 mg daily or observation. The planned primary outcome was time to PSA progression >4.0 ng ml(-1).

RESULTS

Thirty-seven patients were randomized. Of 18 patients randomized to pazopanib, at the time of study closure, 4 had progressive disease, 1 remained on treatment and 13 (72%) electively disenrolled, the most common reason being patient request due to grade 1/2 toxicity (8 patients). Two additional patients were removed from treatment due to adverse events. Of 19 patients randomized to observation, at the time of study closure, 4 had progressive disease, 7 remained under protocol-defined observation and 8 (42%) had disenrolled, most commonly due to non-compliance with protocol visits (3 patients). Because of high dropout rates in both arms, the study was halted.

CONCLUSIONS

IAS is a treatment approach that may facilitate investigation of novel agents in the hormone-sensitive state. This trial attempted to investigate the role of antiangiogenic therapy in this setting, but encountered several barriers, including toxicities and patient non-compliance, which can make implementation of such a study difficult. Future investigative efforts in this arena should carefully consider drug toxicity and employ a design that maximizes patient convenience to reduce the dropout rate.