Intermittent androgen deprivation in prostate cancer patients: factors predictive of prolonged time off therapy

A randomized phase II trial on the addition of dutasteride to combined androgen blockade therapy versus combined androgen blockade therapy alone in patients with advanced or metastatic salivary duct carcinoma - the DUCT study protocol

BACKGROUND

Salivary duct carcinoma (SDC) is a rare and aggressive subtype of salivary gland cancer, frequently associated with incurable recurrences and distant metastases (R/M). Proliferation of SDC relies on androgen receptor (AR) signalling, prompting the use of combined androgen blockade (CAB, i.e., luteinizing hormone-releasing hormone agonist and/or AR antagonists) to R/M SDC patients. However, only a subset of patients benefits from such treatments. We have shown that response to CAB is associated with steroid 5α-reductase 1 (SRD5A1) mRNA expression. SRD5A1 catalyses the intracellular conversion of testosterone into the more potent AR-agonist dihydrotestosterone. This conversion can be inhibited by dutasteride, a potent SRD5A1-inhibitor, which is currently prescribed for benign prostatic hyperplasia. We hypothesize that repurposing dutasteride to target AR signalling in SDC could enhance therapeutic response and clinical outcome in SDC patients.

METHODS

This prospective, open-label, randomized controlled phase II clinical trial, is designed to investigate whether dutasteride as an adjunct drug to CAB improves response rate and clinical outcome in patients with AR-positive R/M SDC. Patients are divided in two cohorts based on their prior systemic treatments. In cohort A, CAB-naïve patients (n = 74) will be randomly assigned to either a control arm (Arm 1) receiving CAB (goserelin 10.8 mg/3m and bicalutamide 50 mg/OD) or an experimental arm (Arm 2) where dutasteride (0.5 mg/OD) is added to the CAB regimen. In cohort B, patients with disease progression after adjuvant or first-line palliative CAB therapy (max. n = 24) will receive goserelin, bicalutamide, and dutasteride to assess whether the addition of dutasteride can overcome therapy resistance. The primary endpoints are the objective response rate and duration of response. Secondary endpoints are progression-free survival, overall survival, clinical benefit rate, quality of life, and safety. Translational research will be performed to explore molecular target expression differences and their correlation with clinical outcome.

DISCUSSION

The DUCT study addresses an unmet medical need by investigating the repurposing of dutasteride to enhance treatment response and improve clinical outcome for patients with R/M SDC, especially those with limited alternative treatment options, such as HER2-negative cases. By repurposing a registered low-cost drug, this trial's findings could be readily applied into clinical practice.

TRIAL REGISTRATION

Clinicaltrials.gov Identifier: NCT05513365. Date of registration: August 24, 2022.

PROTOCOL VERSION

Current protocol version 4.0, February 21, 2024.

Intermetastatic and Intrametastatic Heterogeneity Shapes Adaptive Therapy Cycling Dynamics

Adaptive therapies that alternate between drug applications and drug-free vacations can exploit competition between sensitive and resistant cells to maximize the time to progression. However, optimal dosing schedules depend on the properties of metastases, which are often not directly measurable in clinical practice. Here, we proposed a framework for estimating features of metastases through tumor response dynamics during the first adaptive therapy treatment cycle. Longitudinal prostate-specific antigen (PSA) levels in 16 patients with metastatic castration-resistant prostate cancer undergoing adaptive androgen deprivation treatment were analyzed to investigate relationships between cycle dynamics and clinical variables such as Gleason score, the change in the number of metastases over a cycle, and the total number of cycles over the course of treatment. The first cycle of adaptive therapy, which consists of a response period (applying therapy until 50% PSA reduction), and a regrowth period (removing treatment until reaching initial PSA levels), delineated several features of the computational metastatic system: larger metastases had longer cycles; a higher proportion of drug-resistant cells slowed the cycles; and a faster cell turnover rate sped up drug response time and slowed regrowth time. The number of metastases did not affect cycle times, as response dynamics were dominated by the largest tumors rather than the aggregate. In addition, systems with higher intermetastasis heterogeneity responded better to continuous therapy and correlated with dynamics from patients with high or low Gleason scores. Conversely, systems with higher intrametastasis heterogeneity responded better to adaptive therapy and correlated with dynamics from patients with intermediate Gleason scores.

SIGNIFICANCE

Multiscale mathematical modeling combined with biomarker dynamics during adaptive therapy helps identify underlying features of metastatic cancer to inform treatment decisions.

Population-based estimate of the use of intermittent androgen deprivation therapy in prostate cancer patients in Catalonia, Spain

PURPOSE

To estimate the use of intermittent androgen deprivation (IAD) therapy in patients with prostate cancer (PCa).

METHODS

Retrospective, non-interventional study based on electronic pharmacy dispensation data of luteinizing hormone-releasing hormone (LHRH) analogs and anti-androgens in Catalonia (Spain). Intermittency was defined as the percentage of time off treatment (%IAD), which was calculated for the whole sample by dividing the sum of all off-IAD periods by the total time on any LHRH analog regimen. The prevalence of patients on an IAD regimen (P_IAD ) was also estimated. A small validation study based on data from clinical records confirmed the excellent sensitivity and specificity of this approach.

RESULTS

A total of 515 803 prescriptions for LHRH analog were dispensed over a 5-year period (2008 to 2012) to 35 089 PCa patients. The mean age (±SD) was 77 years (±9). The %IAD in the cohort was 1.7% whereas the 5-year prevalence (P_IAD ) was 4.2%. Only 2.5% of patients on IAD were on IAD for >6 months. Of the physicians (n = 1638) who prescribed hormonal treatment, 24% used IAD at least once. Total expenditures for LHRH analogs were 1.2% of total drug expenditure in this population.

CONCLUSIONS

This study confirms the validity of the method developed to estimate IAD use based on electronic pharmacy dispensation data. Given the large potential clinical and economic benefits that greater use of IAD could provide, future studies are needed to confirm these findings and to identify new strategies to increase the use of IAD.

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.

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.

Concept and viability of androgen annihilation for advanced prostate cancer

There remains no standard of care for patients with a rising prostate-specific antigen level after radical prostatectomy or radiotherapy but who have no radiographic metastases, even though this is the second largest group of patients with prostate cancer (CaP) in the United States. Androgen deprivation therapy (ADT) may cure some men with advanced CaP based on single-institution series and a randomized clinical trial of immediate versus delayed ADT for men found to have pelvic lymph node metastasis at the time of radical prostatectomy. ADT may be more effective when initiated for minimal disease burden, which can be detected using PSA after radical prostatectomy or radiotherapy, and if more complete disruption of the androgen axis using newer agents decreases the chance that androgen-sensitive cells survive to adapt to a low-androgen environment. Androgens may be "annihilated" simultaneously using a luteinizing hormone-releasing hormone antagonist or agonist to inhibit testicular production of testosterone, a P45017A1 (CYP17A1) inhibitor to diminish metabolism of testosterone via the adrenal pathway and dihydrotestosterone (DHT) via the backdoor pathway, a 5α-reductase (SRD5A) inhibitor to diminish testosterone reduction to DHT and backdoor metabolism of progesterone substrates to DHT, and a newer antiandrogen to compete better with DHT for the androgen receptor ligand-binding domain. Early initiation of androgen annihilation for induction as part of planned intermittent ADT should be safe, may reduce tumor burden below a threshold that allows eradication by the immune system, and may cure many men who have failed definitive local therapy.

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.

Androgen deprivation therapy for prostate cancer: implications for cardiometabolic clinical care

Prostate cancer (PCa) is the most common malignancy in men. Androgen deprivation therapy (ADT) plays an important role in the management of locally advanced and metastatic PCa. Its use in combination with external beam radiation and as an adjuvant therapy has resulted in improved survival in a subset of patients with locally advanced disease. In men with metastatic disease, ADT results in improvement in pain and overall quality of life. In addition to these two clinical settings where ADT has proven benefits, it is also being increasingly used in patients experiencing biochemical recurrence and those with early stage localized disease, even though no survival advantage has been demonstrated. ADT has significant adverse effects such as sexual dysfunction, decreased lean mass, increased fat mass, decreased quality of life, anemia, and osteoporosis. Recently, insulin resistance, diabetes, and metabolic syndrome have emerged as complications of ADT. Some data also suggests that ADT might be responsible for incident cardiovascular disease. Since the majority of men with PCa die of conditions other than their malignancy, recognition and management of these adverse effects is important. This paper serves as a focused review of recent studies examining the metabolic abnormalities and cardiovascular disease related to ADT.

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.

The change of PSA doubling time and its association with disease progression in patients with biochemically relapsed prostate cancer treated with intermittent androgen deprivation

BACKGROUND

We sought to determine the change of PSA doubling time (PSADT) and its association with disease progression during intermittent androgen deprivation (IAD) therapy for prostate cancer.

METHODS

Data were retrospectively analyzed in 96 patients with biochemically relapsed prostate cancer (BRPC) treated with IAD since 1995. IAD consisted of LHRH-agonists ± antiandrogen given usually at PSA threshold (ng/ml) of 10-20, for 6-9 months. Cycles were repeated until the development of castration resistance. Mixed effects model was used to study PSADT change over cycles. Multivariate cox regression model was used to identify outcome-associated variables.

RESULTS

Patients received a mean of 2.8 treatment cycles over a mean follow-up time of 71 months. Fifty-seven (59%) remain on treatment and 39 (41%) developed PSA refractoriness (n = 8) or positive scans (n = 31). First off treatment interval PSADT (median 2.3 months) was significantly shorter than the baseline (median 7.34) but remained stable in subsequent cycles. Off treatment interval PSADT adjusted for testosterone recovery (median 3.7) was significantly longer than that based on all PSA determinations (median 2). Factors associated with disease progression were pre-treatment PSADT (≥6 vs. <6), first off treatment interval PSADT (≥3 vs. <3), and PSA nadir during the first treatment interval (<0.1 vs. ≥0.1).

CONCLUSIONS

During IAD for BRPC, PSADT becomes shorter, and is associated with testosterone recovery. PSADT before treatment and during the first off treatment interval is associated with disease progression. If prospectively validated these data may guide treatment with IAD and clinical trial design.

Intermittent androgen suppression for prostate cancer

Although androgen deprivation therapy (ADT) has been a cornerstone of the management of prostate cancer for more than 50 years, controversy remains regarding its optimum application. Intermittent androgen suppression (IAS) has been researched since the mid-1980s as a way of reducing the adverse effects and cost of continuous androgen suppression. With preclinical evidence suggesting a potential benefit in terms of time to androgen independence, IAS has been the focus of a number of clinical phase II and III trials. Overall, these trials suggest that IAS is neither inferior nor superior to continuous androgen suppression, with respect to time to castration resistance and cancer-specific survival, but has significant advantages in terms of adverse effects, quality of life and cost. A number of unresolved questions remain, however, including how to select patients for therapy, the optimum duration of therapy, when to restart therapy after the off cycle, and how to define progression to castration-resistant disease. Landmark randomized clinical trials comparing IAS to continuous androgen suppression are in progress and will hopefully answer many of these questions. In future, the use of second-line drugs in the off-treatment phase holds potential for delaying disease progression in men on IAS. At present, men with advanced disease who are deemed candidates for ADT should be informed of IAS as a treatment option, considered experimental from an informed consent point of view, but promising based on current evidence.

Intermittent versus continuous androgen suppression therapy: do we have consensus yet?

Androgen deprivation therapy (ADT) has been a cornerstone in the management of advanced prostate cancer for more than 50 years, but several aspects of the therapy remain controversial. Research since the mid-1980s has looked at the use of intermittent androgen suppression (IAS) as a way to reduce the side effects and costs of continuous androgen suppression. During that same time, testing for prostate-specific antigen resulted in forward stage migration both at diagnosis and at the time of treatment initiation. Earlier treatment has led to prolonged periods of ADT and increasing recognition of the resultant metabolic complications. With preclinical evidence suggesting a potential benefit for ias in terms of time to androgen independence, with phase II and III studies producing optimistic results, and with the potential for reductions in cost and complications, ias has become a popular modality of therapy around the globe. Large prospective randomized studies, currently ongoing, will ultimately determine the legitimate place of IAS in the treatment of prostate cancer.

Potential benefits of intermittent androgen suppression therapy in the treatment of prostate cancer: a systematic review of the literature

CONTEXT

The well-known side-effect profile of androgen-deprivation therapy (ADT) has significant quality-of-life (QoL) implications. Intermittent androgen deprivation (IAD) alternates androgen blockade with treatment cessation to allow hormonal recovery between treatment cycles, thus potentially improving tolerability and QoL.

OBJECTIVE

To evaluate available evidence regarding the efficacy and tolerability of IAD and assess its value in the treatment of prostate cancer (PCa).

EVIDENCE ACQUISITION

Key phase 2/3 clinical trials of IAD in PCa published within the last 10 yr were identified on Medline using the terms prostatic neoplasms [MeSH], intermittent androgen suppression, intermittent hormonal deprivation, intermittent androgen deprivation, and intermittent hormonal therapy. Abstracts from trials reported at 2008-2009 conferences were also included.

EVIDENCE SYNTHESIS

Data from 19 phase 2 studies are discussed with respect to prostate-specific antigen values for treatment suspension/reinitiation, treatment regimens, cycle lengths, testosterone normalisation, and tolerability. Outcome data were promising: Most trials reported an improvement in QoL during the off-therapy periods. Interim data from eight phase 3 trials comparing IAD and continuous androgen deprivation (CAD) support the phase 2 results. IAD generally showed comparable efficacy to CAD with respect to various outcomes, including biochemical progression, progression-free survival, and overall survival. However, IAD was significantly better than CAD with respect to 3-yr risk of progression in one study, and it demonstrated tolerability benefits, particularly with respect to sexual function. Patients most likely to benefit from IAD and factors predictive of poor response are also discussed.

CONCLUSIONS

IAD seems to be as effective as CAD while showing tolerability and QoL advantages, especially recovery of sexual potency; however, there are as yet insufficient data to determine whether IAD has the potential to prevent or reverse the long-term complications associated with ADT.

Conventional treatments of localized prostate cancer

Established therapeutic approaches for clinically localized prostate cancer include watchful waiting (active surveillance), radical prostatectomy, and radiotherapy. The risk of progression during surveillance is related to the initial cancer stage and grade; reasonable evidence has supported the safety and feasibility, during a period of 5-10 years, of an active surveillance regimen for men with low-risk prostate cancer. The progression rates at >10 years have not yet been studied in modern trials. Patients with low-risk tumor characteristics can be actively monitored without sacrificing the possibility of cure and without being exposed to an undue risk of disease progression, although some patients will not accept the emotional burden of living with an untreated cancer. Focal ablation might be an attractive alternative to active surveillance for some patients with low-risk cancer, if it proves to have minimal adverse effects on their quality of life. Radical prostatectomy is an effective form of therapy for patients with clinically significant prostate cancer; however, outcomes are highly sensitive to variations in surgical technique. Because of the risks of perioperative complications and urinary and sexual dysfunction, which appear to be as great with robotic-assisted prostatectomy as with any other technique, patients with low-risk cancer, especially those >60 years, might be attracted to more conservative alternatives, including active surveillance, radiotherapy, and focal ablation. External beam radiotherapy is an effective, noninvasive form of therapy, but it carries the long-term risks of troublesome bowel and sexual and urinary dysfunction. It might be too aggressive for many low-risk cancers detected in screened populations. For more aggressive cancers, local recurrence after radiotherapy carries substantial morbidity and low rates of long-term cancer control. Brachytherapy, a convenient, effective form of radiotherapy, is targeted at selected patients with clinically confined cancer and a prostate size of <60 g without evidence of extraprostatic extension on imaging. However, excellent outcomes require meticulous technique; acute urinary symptoms are frequent; and the long-term risks of proctitis and erectile dysfunction are comparable to the risks associated with external beam radiotherapy. Androgen-deprivation therapy is not recommended for men with localized prostate cancer who would otherwise be candidates for surgery or radiotherapy, because, even with short-term use, the risk of side effects, including osteopenic fracture and major cardiovascular events, serious. For locally extensive cancer, androgen-deprivation therapy should be used alone only for the relief of local symptoms in men with a life expectancy of <5 years who are not eligible for more aggressive treatment.

Intermittent versus continuous androgen suppression for prostatic cancer

BACKGROUND

After lung cancer, prostate cancer is the most common cause of death among males. The aim of treatment is to prevent disease-related morbidity and mortality while minimizing intervention-related adverse events. Androgen suppression therapy (AST) to reduce circulating serum testosterone and disease progression is considered a mainstay of treatment for men with advanced prostate cancer. It has been increasingly utilized for early stage disease despite a lack of evidence of effectiveness.

OBJECTIVES

Evaluate the effectiveness and safety of intermittent androgen suppression (IAS) compared to continuous androgen suppression for treating prostatic cancer.

SEARCH STRATEGY

The following databases were searched to identify randomised or quasi-randomised, controlled trials comparing intermittent and continuous androgen suppression in the treatment of any stage of prostate cancer: the Cochrane Central Register of Controlled Trials; EMBASE and LILACS.

SELECTION CRITERIA

Studies were included if they were randomised or quasi-randomized, and compare the effects of IAS versus CAS.

DATA COLLECTION AND ANALYSIS

Two reviewers selected relevant trials, assessed methodological quality and extracted data.

MAIN RESULTS

Five randomized studies involving 1382 patients were included in this review. All the included studies involved advanced (T3 or T4) prostate cancer, had relatively small populations, and were of short duration. Few events were reported and did not assess disease-specific survival or metastatic disease. Only one study (N = 77) evaluated biochemical outcomes. A subgroup analysis found no significant differences in biochemical progression (defined by the authors as PSA >/= 10 ng/mL) between IAS and CAS for Gleason scores 4 - 6, 7, and 8 - 10. For patients with a Gleason score > 6, reduction in biochemical progression favoured the IAS group (RR 0.10, 95% CI 0.01 to 0.67, P = 0.02). Studies primarily reported on adverse events. One trial (N = 43) found no difference in adverse effects (gastrointestinal, gynecomastia and asthenia) between IAS ( two events) and CAS (five events), with the exception of impotence, which was significantly lower in the IAS group (RR 0.72, 95% CI 0.56 to 0.92, P = 0.008).

AUTHORS' CONCLUSIONS

Data from RCTs comparing IAS to CAS are limited by small sample size and short duration. There are no data for the relative effectiveness of IAS versus CAS for overall survival, prostate cancer-specific survival, or disease progression. Limited information suggests IAS may have slightly reduced adverse events. Overall, IAS was also as effective as CAS for potency, but was superior during the interval of cycles (96%).

Mature Results of the Ottawa Phase II Study of Intermittent Androgen-Suppression Therapy in Prostate Cancer: Clinical Predictors of Outcome

PURPOSE

To present the mature experience of a phase II trial of intermittent androgen suppression (IAS).

METHODS AND MATERIALS

Intermittent androgen-suppression therapy was initiated in prostate-cancer patients to delay hormone resistance and minimize potential side effects of androgen-deprivation therapy (ADT). Patients received cyclical periods of ADT and observation (off-treatment interval [OTI]). Androgen-deprivation therapy was reinitiated when the level of prostate-specific antigen (PSA) rose above 10 ng/ml, or for disease progression. Associations between clinical factors and eligibility for OTI were measured. Kaplan-Meier and Cox regression analyses were used to determine factors predicting the duration of OTIs.

RESULTS

Ninety-five patients completed 187 cycles of treatment. The median duration of OTIs was 8.5 months. Patients with higher PSA and metastatic disease were less likely to be eligible for the first OTI (p < 0.01). In multivariate analysis, patients with higher PSA and local relapse had significantly longer OTIs (p < 0.01) compared with metastatic patients. The median time to withdrawal from the study was 37 months.

CONCLUSIONS

Intermittent androgen suppression appears to be a favorable treatment option for patients with biochemically (according to level of PSA) or locally recurrent prostate cancer with favorable long-term survival, a high probability of eligibility for OTIs, and durable OTIs.

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.

International study into the use of intermittent hormone therapy in the treatment of carcinoma of the prostate: a meta-analysis of 1446 patients

OBJECTIVE

To review pooled phase II data to identify features of different regimens of intermittent hormone therapy (IHT), developed to reduce the morbidity of treating metastatic prostate cancer, and which carries a theoretical advantage of delaying the onset of androgen-independent prostate cancer, (AIPC) that are associated with success, highlighting features which require exploration with prospective trials to establish the best strategies for using this treatment.

METHODS

Individual data were collated on 1446 patients with adequate information, from 10 phase II studies with >50 cases, identified through Pubmed.

RESULTS

Univariate and multivariate Cox proportional hazard models were developed to predict treatment success with a high degree of statistical success. The prostate-specific antigen (PSA) nadir, the PSA threshold to restart treatment, and medication type and duration, were important predictors of outcome.

CONCLUSIONS

The duration of biochemical remission after a period of HT is a durable early indicator of how rapidly AIPC and death will occur, and will make a useful endpoint in future trials to investigate the best ways to use IHT based on the important treatment cycling variables described above. Patients spent a mean of 39% of the time off treatment. The initial PSA level and PSA nadir allow the identification of patients with prostate cancer in whom it might be possible to avoid radical therapy.

Intermittent hormone therapy in nonmetastatic prostate cancer

PURPOSE

The object of this study was to evaluate the duration of response to intermittent androgen deprivation (IAD) in patients with nonmetastatic recurrent or localized prostate cancer.

PATIENTS AND METHODS

One hundred ten patients received IAD from February 1992 to February 2005. One hundred three patients were treated after failure of primary radiation therapy and/or prostatectomy, with the remaining 7 patients treated primarily with IAD. The median duration of treatment cycle was 6 months. Patients were considered resistant to hormone therapy if the prostate-specific antigen (PSA) level increased, with castrate levels of testosterone. At the time of initial diagnosis, the median Gleason score was 7 (range, 4-9), and tumor stages were as follows: T1/T2 (n = 73), T3 and T4 N1 (n = 34), and other (n = 3). The median PSA at the initiation of IAD was 8.25 ng/mL.

RESULTS

The median follow-up after beginning IAD was 45.5 months. Patients received a median of 2 cycles (range, 1-9 cycles). Ninety-four of 110 patients (85.5%) remained responsive to IAD. Sixteen patients (14.5%) progressed to become refractory to primary hormone treatment. Patients with a higher tumor stage (T3 and T4) were significantly more likely to develop resistance. The median time to become refractory to hormone therapy was 47.9 months (range, 9.4-93.4 months). Five patients were put on secondary continuous hormone treatment, and 3 of them developed resistance at a median of 9 months. One patient was put on a secondary IAD and was still responding at the last follow-up.

CONCLUSION

With 85.5% of the original patient population still responding to the primary hormone therapy at 45.5 months of follow-up, IAD appears to be a viable option for patients with biochemical failure after local radiation therapy. A pattern of shortening time between cycles and an increasing nadir PSA level with each successive cycle is consistent with the gradual development of hormone resistance.

Intermittent androgen deprivation: clinical experience and practical applications

Prostate cancer is more frequently being diagnosed at an earlier age, men are dying of prostate cancer at an older age, and men are now treated with androgen deprivation for biochemical relapse. As a result, the amount of time that patients are potentially subjected to androgen deprivation is increasing. Intermittent androgen deprivation (IAD) has been investigated as a potential alternative to continuous androgen deprivation (CAD) in order to improve quality of life and potentially delay the progression to androgen independence. Along with the increased use of primary hormonal therapy in clinically localized prostate cancer, IAD may supplant the traditional surgical or radiotherapy options, specifically in men who have underlying co-morbidities and decreased life expectancy. There are ongoing multi-institutional, randomized trials that will lend insight into the utility, efficacy, and feasibility of IAD versus CAD. This article discusses the theoretical benefits and rationale of IAD and reviews the completed and on-going IAD trials. Finally, the controversies, practical applications, and future directions of IAD are addressed.

Final results of the Canadian prospective phase II trial of intermittent androgen suppression for men in biochemical recurrence after radiotherapy for locally advanced prostate cancer

BACKGROUND

This prospective Phase II study was undertaken to evaluate intermittent androgen suppression as a form of therapy in men with localized prostate cancer who failed after they received external beam irradiation.

METHODS

Patients who demonstrated a rising serum prostate-specific antigen (PSA) level after they received radiotherapy and who were without evidence of distant metastasis were accepted into the study. Treatment in each cycle consisted of cyproterone acetate given as lead-in therapy for 4 weeks, followed by a combination of leuprolide acetate and cyproterone acetate, which ended after a total of 36 weeks.

RESULTS

Of 109 patients registered, 103 patients were eligible for interruption of treatment, yielding a PSA response rate of 95%. The study continued for 6 years with a mean follow-up of 3.7 years (median follow-up, 4.2 years). The time off treatment averaged 53% of the total cycle time but, in absolute terms, decreased with each succeeding cycle, ranging from 63.7 weeks in Cycle 1 to 25.6 weeks in Cycle 5. Prostate volume was reduced by 40% in Cycle 1 and by 34% in Cycle 2, and there were no decreases in Cycle 3 or Cycle 4. At the end of the trial, 38.5% of patients still were receiving treatment, 23.9% of patients had failed, and 15.6% of patients had died. Only 2% of deaths were cancer-specific.

CONCLUSIONS

Biochemical recurrence after irradiation for localized prostate cancer was amenable to cyclic androgen withdrawal therapy and showed a high response rate. Despite progressively shorter treatment cycles, the off-treatment interval remained appreciable, ranging from 65% in Cycle 1 to 46% in Cycle 5.

Should intermittent androgen deprivation be used in routine clinical practice?

For several decades, androgen deprivation (AD) has been the mainstay for treating metastatic prostate cancer. AD can be attained by a variety of means; however, irrespective of modality and a gratifying initial high response rate, almost all patients advance to a state of androgen independence and ultimately a hormone-refractory state. Improved understanding of the biology and mechanisms of progression to androgen independence coupled with promising preclinical data have led to investigating intermittent AD (IAD) as a way of improving disease control while maintaining quality of life. Preliminary published clinical experience, mostly from uncontrolled trials, suggests the feasibility of this approach. Two ongoing cooperative-group phase III trials are evaluating the survival impact of IAD both in patients with metastatic disease and in those with prostate-specific antigen failure post-radiation therapy. There are several unanswered questions regarding this approach, and until more definitive data regarding its safety and impact on survival are available, IAD should be considered experimental. In this review, we detail the background and preclinical scientific rational for investigating IAD, and we review published clinical experience and describe the ongoing phase III clinical trials. We also discuss special considerations for using IAD outside the context of a clinical trial.

Actualización del tratamiento del cáncer de próstata avanzado y de sus complicaciones

Prostate adenocarcinoma is the leading cause of cancer in Spain, among men older than 65. 1,200 new cases out of every 100,000 males are diagnosed with prostate cancer on an annual basis. In the United States, this illness represents the second leading cause of death due to cancer in males. In those patients whose prostate tumors progress after surgery or radiotherapy, or have metastatic disease when diagnosed, a systemic approach in order to improve their quality of life and overall survival is mandatory. First line hormone therapies usually reach a proper control of the tumor maintaining an acceptable quality of life. However, most of these tumors becomes androgen-independent over time and behave as a more aggressive cancer type. In these patients, combination therapy protocols have recently demonstrated a benefit not only in terms of symptoms control and response rates but also in improving survival. In addition, several new molecules are currently under study. The accurate knowledge of the symptoms due to disease spreading as well as treatment's side effects is necessary to provide an appropriate palliative management that contributes to an improvement of the quality of life in advanced prostate cancer patients.

Long-term side-effects of intermittent androgen suppression therapy in prostate cancer: results of a phase II study

OBJECTIVE

To assess the feasibility and tolerability of intermittent androgen suppression therapy (IAS) in prostate cancer.

PATIENTS AND METHODS

Patients with recurrent or metastic prostate cancer received cyclical periods of treatment with leuprolide acetate and nilutamide for 8 months, and rest periods. Cycles were repeated at progression until the treatment failed to achieve normal prostate-specific antigen (PSA) levels. Patients were followed with PSA level, testosterone level, haemoglobin level, weight and bone mineral density evaluations. The median time to treatment failure, recovery from anaemia, or normalization of testosterone level was estimated by the Kaplan-Meier method.

RESULTS

In all, 95 patients received 245 cycles; the median duration of rest periods was 8 months and median time to treatment failure 47 months. Testosterone recovery during rest periods was documented in 117 (61%) of cycles. Anaemia was mild and reported in 33%, 44% and 67% of cycles 1, 2 and 3, respectively. Sexual function recovered during the rest periods in 47% of cycles. There was no significant overall change in body mass index at the end of the treatment period. Osteoporosis was documented in at least one site evaluated in 41 patients (37%).

CONCLUSIONS

IAS has the potential to reduce side-effects, including recovery of haemoglobin level, return of sexual function and absence of weight gain at the end of the study period.

Clinical correlation, ecographic and levels of prostate specific antigen in patients with prostate cancer

PURPOSE

This report provides information about clinical correlation, ecographic and levels of prostate specific antigen in patients with prostate cancer in the Regional Hospital from Trujillo, Peru.

MATERIALS AND METHODS

Retrospective, descriptive observation study of all the clinical histories from patients with histopathology diagnosis of prostate cancer during the period of January 2000 - December 2004. The sample was constituted by 60 patients with clinics histories, study by image based on the prostate ecography and the prostate specific antigen results. The average of age found was of 75.4 years old; the most frequent clinical case reported a 91.6% of patients with obstructive and irritative symptoms. In the levels of prostate antigen the PSA found values between 10-50 ng/ml, in 48.78% of the patients. In the ecography prostate study there where evidence of hypoecogenic images in 56%, hyperecogenics images 12%, heterogenics images 20% and 12% homogenics images. In the TNM classification the higher percentage is located in T stage with an 81.67%, and in smaller proportions in the N1 and M1 stages with 8.33% and 10.0% respectively. According to Gleason it was found levels from 2-4 with 36.67%, in the level 5-7 with 23.33% and in the level 8-10 with 40.0%.

CONCLUSIONS

All the patients with prostate cancer showed a clinical symptoms about, obstructive and irritative and in other organs a less percentage of symptoms that shows metastases; in more than a half of the patients, the digital rectal examination showed nodules and irregularities in its surface; in the prostate ecography it is report a higher percentage of hypoecogenics images suggestive of neoplasia. The levels of specific prostate antigen in more than 70% of the patients where over of 10 ng/ml; in the totally of the patients the histological type most frequent is the Adenocarcinoma, with a high grade of percentage of patients who had been bad prognosticated according to the Gleason score. According the NTM, more of the two thirds parts of patients with prostate cancer are in T stage, with a high percentage extending on the prostatic capsule.

Intermittent androgen deprivation therapy for prostate cancer

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

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

The aim of this study was to compare the efficacy of total intermittent androgen deprivation (IAD) versus total continuous androgen deprivation (CAD) for treating patients with advanced prostate cancer in a phase III randomized trial. A total of 68 evaluable patients with hormone-naive advanced or relapsing prostate cancer were randomized to receive combined androgen blockade according to a continuous (n = 33) or intermittent (n = 35) regimen. Therapeutic monitoring was assessed by use of serum prostate-specific antigen (PSA) measurements. Patients in the CAD and IAD groups were equally stratified for age, biopsy Gleason score, and baseline serum PSA levels. The outcome variable was time to androgen-independence of the tumor, which was defined as increasing serum PSA levels despite androgen blockade. Mean follow-up was 30.8 months. The 35 IAD-treated patients completed 91 cycles, and 19 of them (54.3%) completed > or = 3 cycles. Median cycle length and percentage of time off therapy were 9.0 months and 59.5, respectively. The estimated 3-year progression rate was significantly lower in the IAD group (7.0% +/- 4.8%) than in the CAD group (38.9% +/- 11.2%, P = 0.0052). Our data suggest that IAD treatment may maintain the androgen-dependent state of advanced human prostate cancer, as assessed by PSA measurements, at least as long as CAD treatment. Further studies with longer follow-up times and larger patient cohorts are needed to determine the comparative impacts of CAD and IAD on survival.

Intermittent Androgen Deprivation for Patients With Recurrent/Metastatic Prostate Cancer

This study was designed to assess the duration of response to intermittent androgen deprivation therapy (IAD) in patients with recurrent and/or metastatic prostate cancer. Between January 1993 and March 2000, 74 patients with recurrent and/or metastatic prostate cancer had IAD with either luteinizing hormone-releasing hormone agonist (LHRH) or an LHRH with an oral antiandrogen. Forty-one patients were treated for an increasing prostate-specific antigen (PSA) level after primary local treatment. Of the remaining 33 patients, 17 patients were treated for metastases (9 for bone metastases, 8 for lymph nodes metastases, and 16 for local recurrence). Patients who had undergone IAD completed between 1 and 6 cycles. A cycle was defined as the period during which the patient was actively taking the hormone medication. Seventy-four patients completed the first cycle, 49 completed the second cycle, and 23 completed the third cycle. The pattern of PSA changes with each cycle, the length of each cycle, and the time interval between successive cycles were studied. The time to progression (defined as an increasing PSA level on two consecutive measurements or radiologic evidence of progression of disease while the patient was on androgen deprivation) was also studied. The median PSA before the IAD was 11.4 ng/mL (range 0.12-378). The median PSA nadir at the end of each cycle increased progressively (0.1 ng/mL after the first cycle to 3.3 ng/mL after the fifth cycle). The time interval between the cycles progressively decreased from 9.5 months between the first and second cycles to 6 months between the third and fourth cycles. The 4-year actuarial androgen-independent free survival was 71%. For the subgroups of patients treated for biochemical failure, locoregional recurrence, and bone metastases, the 4-year actuarial progression-free survival rates were 80%, 67%, and 45% respectively (P = 0.018). The median time of 18 months to progression in patients with bone metastases is similar to that reported with continuous hormonal therapy. In patients with biochemical failure, the median time to progression (more than 5 years) suggests that the IAD approach may be a viable option for this group of patients.

Killing tumours by ceramide-induced apoptosis: a critique of available drugs

Over 1000 research papers have described the production of programmed cell death (apoptosis) by interventions that elevate the cell content of ceramide (Cer). Other interventions, which lower cellular Cer, have been found to interfere with apoptosis induced by other agents. Some studies have shown that slowing the formation of proliferation-stimulating sphingolipids also induces apoptosis. These relationships are due to the two different aspects of Cer: Cer itself produces apoptosis, but metabolic conversion of Cer into either sphingosine 1-phosphate or glucosphingolipids leads to cell proliferation. The balance between these two aspects is missing in cancer cells, and yet intervention by stimulating or blocking only one or two of the pathways in Cer metabolism is very likely to fail. This results from two properties of cancer cells: their high mutation rate and the preferential survival of the most malignant cells. Tumours treated with only one or two drugs that elevate Cer can adjust the uncontrolled processes to either maintain or to 'aggravate' the excessive growth, angiogenesis and metastasis characteristics of tumours. These treatments might simply elevate the production of growth factors, receptors and other substances that reduce the effectiveness of Cer. Tumour cells that do not adapt in this way undergo apoptosis, leaving the adapted cells free to grow and, ultimately, to 'subdue' their host. Thus it is important to kill every type of cancer cell present in the tumour rapidly and simultaneously, using as many different agents to control as many pathways as possible. To aid this approach, this article catalogues many of the drugs that act on different aspects of Cer metabolism. The techniques described here may lead to the development of practical chemotherapy for cancer and other diseases of excess proliferation.

Using splines to detect changes in PSA doubling times

BACKGROUND

PSA doubling time (PSADT) can predict the likelihood of clinical progression in patients with biochemical relapse after surgery or radiation for prostate cancer. Changes in PSA doubling time in response to therapy may be of clinical or investigational significance. How does one estimate PSADT before and after the initiation of therapy and determine if any change is statistically significant or simply the result of random variation? These are the type of questions addressed.

METHODS

Our technique uses a best-fitting spline (i.e., a broken-line approximation) to a graph of log PSA on time to estimate PSADTs before and after treatment initiation. A linear regression program is used to produce the fit and to evaluate the statistical significance of any change in PSADT. This method differs from previous methods in that it uses all the data, exploits the continuity of PSA at the time of treatment initiation, and allows one to make statistical significance statements about specific individuals.

RESULTS

Our technique is illustrated with data from a pilot clinical trial using a nutritional supplement in 12 men with prostate cancer. A detailed analysis of the first patient shows how the data are handled, how two lines of computer code are sufficient to fit the spline model, and how the doubling times and statistical significance of a change are read from the computer output. In the study, 9 of 12 patients had a statistically significant increase in doubling time. Because the study is preliminary and used only to illustrate our method, no medical discussion of the study is included. The last section of the study, in part expository, is devoted to explaining the underlying principles for those who may want to know not only what to do, but why it works.

CONCLUSIONS

The method presented here for determining changes in PSADT is both simple and broadly applicable. It allows the evaluation of the size and statistical significance of an observed change or increase in PSADT in response to therapy for prostate cancer. It can be done using essentially any statistical software and widely accepted statistical methods.

Intermittent androgen suppression in patients with prostate cancer

OBJECTIVES

To evaluate intermittent androgen suppression (IAS) in patients with prostate cancer and to try to define predictive factors for biochemical progression.

PATIENTS AND METHODS

From 1989 to 2001, 146 patients received IAS as a primary treatment for localized, advanced or metastatic prostate cancer (72 men) or as a treatment for prostate-specific antigen (PSA) recurrence after radical prostatectomy (RP) and/or radiation therapy (74 men). Androgen-deprivation treatment (ADT) was continued up to 6 months after PSA became undetectable or a nadir PSA level was reached. ADT was then re-instituted when the PSA level was> 4 ng/mL for patients who had RP or> 10 ng/mL for the others.

RESULTS

After a mean (range) follow-up of 45.6 (12-196.9) months, 24 patients had biochemical progression. These patients were younger than those with no biochemical progression (67 vs 72 years, P = 0.004) and had a statistically higher Gleason score (7.21 vs 6.52, P = 0.01) and PSA level (111.1 vs 32.1 ng/mL, P = 0.05), and a shorter first phase without treatment (7.6 vs 11.2 months, P = 0.05). Overall 5-year metastatic disease free survival of 91.3%. The overall 5-year biochemical recurrence-free survival was 68%. Using multivariate analysis, a Gleason score of >or= 8 (P = 0.021), first-phase duration with no treatment of < 1 year (P = 0.044), positive lymph nodes or metastatic disease at the time of starting IAS (P = 0.023) and age < 70 years (P = 0.037) were the strongest predictors of biochemical progression.

CONCLUSION

IAS appeared to be a feasible treatment; the best candidates being those aged> 70 years with localized prostate cancer and a Gleason score of <or= 7.

Highlights of contemporary issues in the medical management of prostate cancer

This paper highlights contemporary issues in the medical management of prostate cancer. Controversies surrounding adjuvant and neo-adjuvant hormonal therapy in localized prostate cancer are reviewed, as well as the use of chemohormonal therapy in high risk localized disease. The latent period of asymptomatic biochemical progression prior to clinical progression is an opportunity to evaluate new non-toxic therapies. In patients with advanced metastatic disease hormonal therapy and new alternatives are discussed. Chemotherapy in hormone refractory prostate cancer (HRPC) is extensively covered as well as the emerging role of molecular-targeted therapies.

Controversies in the systemic management of patients with evidence of biochemical failure following radical prostatectomy

The management of patients with evidence of a detectable prostate-specific antigen (PSA) following prostatectomy is an increasingly common and difficult issue for patients and clinicians alike. In the setting in which biochemical failure is believed representative of early systemic failure, therapeutic options primarily involve the use of hormonal therapy. Extrapolating results of early vs. delayed hormonal therapy from studies of patients with more advanced prostate cancer is problematic. Antiandrogen monotherapy and intermittent androgen deprivation are increasingly popular approaches, although their ultimate utility remains unproven. This patient subset is an optimal one in which to conduct clinical trials to both define the role of hormonal therapy and to investigate novel, non-hormonal approaches. The most appropriate therapeutic intervention for patients with evidence of biochemical failure following radical prostatectomy remains undefined.

Localized prostate cancer: effect of hormone deprivation therapy measured by using combined three-dimensional 1H MR spectroscopy and MR imaging: clinicopathologic case-controlled study

PURPOSE

To determine the accuracy of combined magnetic resonance (MR) imaging and three-dimensional (3D) proton MR spectroscopic imaging in localizing prostate cancer to a sextant of the gland in patients receiving hormone deprivation therapy.

MATERIALS AND METHODS

Combined MR imaging/3D MR spectroscopic imaging examinations were performed in 16 hormone-treated patients and 48 nontreated matched control patients before radical prostatectomy and step-section histopathologic analysis. At MR imaging, cancer presence within the peripheral zone was assessed on a per sextant basis by two readers. At 3D MR spectroscopic imaging, cancer was identified by using (choline plus creatine)-to-citrate ratios at cutoff values of 2 and 3 SDs above mean normal peripheral zone values. Data were compared by using receiver operating characteristic analysis.

RESULTS

There was no significant difference in the ability of combined MR imaging/3D MR spectroscopic imaging to localize prostate cancer in treated versus control patients. For MR imaging alone, the sensitivity and specificity were 91% and 48% (reader 1) and 75% and 60% (reader 2) in treated patients versus 79% and 60% (reader 1) and 84% and 43% (reader 2) in control patients. For 3D MR spectroscopic imaging alone (>3 SDs cutoff), higher specificity (treated, 80%; controls, 73%) but lower sensitivity (treated, 56%; controls, 53%) was attained. In treated patients, high sensitivity or specificity (up to 92%) was achieved when either or both modalities indicated cancer.

CONCLUSION

When performed within 4 months after initiating hormone deprivation therapy, combined MR imaging/3D MR spectroscopic imaging had the same accuracy in localizing prostate cancer as in nontreated patients.

Intermittent androgen deprivation: update of cycling characteristics in patients without clinically apparent metastatic prostate cancer

OBJECTIVES

To update the cycling characteristics and patterns of treatment in patients receiving intermittent androgen deprivation (IAD) for clinically localized and recurrent prostate cancer.

METHODS

We report our experience with 61 patients treated with IAD. Thirty-four patients had received no prior treatment, and 27 had developed recurrent disease after previous local therapy. No patient had clinically apparent metastatic disease before the initiation of therapy. The mean and median serum prostate-specific antigen (PSA) level before treatment was 25.3 ng/mL and 16.0 ng/mL, respectively (range 0.5 to 190 ng/mL). For each cycle, androgen deprivation was continued until PSA became undetectable or a nadir level was reached. Patients were then observed without treatment, and therapy was reinstituted after the serum PSA value reached a predetermined level. Patients were no longer eligible to cycle off treatment when their serum PSA increased despite ongoing androgen deprivation or if any objective evidence of disease progression was present on imaging studies.

RESULTS

Follow-up ranged from 7 to 60 months (mean 30) from the start of treatment. Patients received from one to five treatment cycles (median two), with a median cycle length of 14 months. The median nadir serum PSA level during androgen deprivation was 0.01 ng/mL and was reached within an average of 6 months (range 4 to 9) after beginning treatment. Patients spent an average of 45% of the time not receiving therapy, but the time off therapy decreased as the number of treatment cycles increased. Five patients (8.1%) demonstrated progressive disease, with a median time to progression of 48 months. When examining the cycling characteristics of these patients, no consistent pattern of failure emerged.

CONCLUSIONS

IAD appears to be a viable treatment option in select patients with localized prostate cancer. With each consecutive cycle, the amount of time the patient was not receiving therapy decreased, despite achieving a low nadir PSA. Longer follow-up with more patients failing IAD will be required before clear patterns of failure emerge in these patients.

Treatment of localized prostate cancer with intermittent triple androgen blockade: preliminary results in 110 consecutive patients

OBJECTIVES

To determine the effectiveness of triple androgen blockade as an alternative to watchful waiting, radical prostatectomy or radiation therapy in the management of patients with clinical stage T1 to T3 prostate cancer.

METHODS

The records of 110 consecutive patients were retrospectively evaluated. Patients were treated with a three-drug androgen blockade regimen, consisting of a luteinizing hormone-releasing hormone agonist (leuprolide or goserelin) plus an antiandrogen (flutamide or bicalutamide) plus finasteride (a 5-alpha-reductase inhibitor), followed by finasteride maintenance therapy, as the sole intervention. All patients refused local therapy and had their prostates intact. Determinants of efficacy included serum prostate-specific antigen (PSA) levels and disease-specific survival.

RESULTS

Patients were treated for a median of 13 months with triple androgen blockade. At baseline, mean PSA level was 13.2 +/- 1.2 ng/ml (range, 0.39-100 ng/ml), and mean Gleason score was 6.6 +/- 0.1 (range, 4-10). During treatment, PSA levels declined to < or =0.1 ng/ml in all patients, with a median time of 3 months. After a median follow-up of 36 months since initiation of treatment, PSA levels have remained stable in 105 of 110 patients (95.5%). At a median follow-up of 55 months (range, 38-125 months), the mean PSA level for the first 57 patients treated in this series is 1.88 +/- 0.1 (range, 0-11.0 ng/ml). Only 9 of 110 (8.1%) patients have a PSA level > or =4.0 ng/ml. To date, no patient has received a second cycle of hormone blockade.

CONCLUSIONS

Although median follow-up is short, triple androgen blockade therapy followed by finasteride maintenance appears to be a promising alternative for the management of patients with clinically localized or locally advanced prostate cancer. Further study of this approach is warranted.

Time-dependent effects of hormone-deprivation therapy on prostate metabolism as detected by combined magnetic resonance imaging and 3D magnetic resonance spectroscopic imaging

Combined MRI and 3D spectroscopic imaging (MRI/3D-MRSI) was used to study the metabolic effects of hormone-deprivation therapy in 65 prostate cancer patients, who underwent either short, intermediate, or long-term therapy, compared to 30 untreated control patients. There was a significant time-dependent loss of the prostatic metabolites choline, creatine, citrate, and polyamines during hormone-deprivation therapy, resulting in the complete loss of all observable metabolites (total metabolic atrophy) in 25% of patients on long-term therapy. The amount and time-course of metabolite loss during therapy significantly differed for healthy and malignant tissues. Citrate levels decreased faster than choline and creatine levels during therapy, resulting in an increase in the mean (choline + creatine)/citrate ratio with duration of therapy. Due to a loss of all MRSI detectable citrate, this ratio could not be used to identify cancer in 69% of patients on long-term therapy. In the absence of citrate, however, residual prostate cancer could still be detected by elevated choline levels (choline/creatine ratio > or =1.5), or the presence of only choline in the proton spectrum. The loss of citrate and the presence of total metabolic atrophy correlated roughly with decreasing serum prostatic specific antigen levels with increasing therapy. In summary, MRI/3D-MRSI provided both a measure of residual cancer and a time-course of metabolic response following hormone-deprivation therapy. Magn Reson Med 46:49-57, 2001.

Hormonal treatment for prostate cancer

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

Prolonged response to a single androgen suppression phase in a subpopulation of prostate cancer patients

BACKGROUND

In an intermittent androgen suppression therapy (IAS) trial we observed regular cycles of tumor suppression and regrowth in the majority of patients (17 +/- 2.6 month), with a subpopulation of patients (14 of 72) exhibiting a prolonged response of 28 +/- 7 month (range 18-64+ month) to the first eight-month androgen suppression cycle.

PURPOSE

To compare clinical data and laboratory tests (testosterone, prostate-specific antigen, and tissue polypeptide-specific antigen) of matched IAS patients showing either regular treatment cycles (n = 16) or prolonged response (n = 14).

RESULTS

Periods of androgen suppression resulted in reversible reduction of serum testosterone (< 1 nmol/l), PSA (< 1 ng/ml) indicating partial growth arrest and apoptotic regression of the tumors. The long-term response subgroup showed significantly lower mean values of tumor gradings, of pretreatment PSA values (11.36 +/- 4.54 vs. 47.5 +/- 12.4 ng/ml PSA), of PSA nadirs during androgen suppression (0.5 vs. 1 ng/ml PSA), and of overall testosterone values (3.9 +/- 1.14 vs. 6.6 +/- 1.18 mmol/l pretreatment) associated with low TPS values.

CONCLUSIONS

Patients exhibiting prolonged response to a single cycle of androgen suppression during IAS are characterized by a lower tumor burden, slow growing and less aggressive tumors, lower testosterone serum concentrations and lower absolute PSA nadirs during androgen suppression compared to a matched control group of short-term responders.