American Society of Clinical Oncology recommendations for the initial hormonal management of androgen-sensitive metastatic, recurrent, or progressive prostate cancer

Pharmacoeconomics of available treatment options for metastatic prostate cancer

The resources devoted to managing metastatic prostate cancer are enormous, yet little attention has been given to directly measuring the economic consequences of treatment alternatives. The purpose of this article was to evaluate the pharmacoeconomics of available treatments for metastatic prostate cancer, including hormone-sensitive disease, androgen-independent prostate cancer and locally advanced/progressive disease. We identified 58 articles addressing economic issues related to metastatic prostate cancer. Treatment alternatives with considerably different costs are available in many areas of disease management, most notably, medical androgen deprivation therapy (ADT) versus surgical castration; combined androgen blockage (CAB) versus monotherapy for initial treatment of hormone-sensitive disease; as well as bisphosphonates and bone-targeted radioisotopes for palliation. The few available pharmacoeconomic studies indicate that the additional costs are not supported by clear and compelling evidence of differences in survival or quality-of-life (QOL) outcomes. Our review revealed that authors often use considerably different assumptions about efficacy and survival outcomes in their analyses, which may be due to the inconsistency of available clinical evidence. Although there have been many clinical trials comparing various therapies, we identified only three trials that included economic assessments. Thus, few sources of economic data are available and most pharmacoeconomic studies rely on information mined from indirect sources. We note that, while there has been considerable enthusiasm about the role of docetaxel regimens in the past 2 years, no study has yet examined the costs of these therapies. Survival remains poor for metastatic disease, thus QOL is the primary consideration for many therapies. However, QOL for treatment of metastatic disease is poorly measured and, in most analyses, the impact of therapy on QOL was inferred based on speculation by the authors. Given the large cost burdens of these treatments, it is essential that we more fully understand the true QOL gains potentially offered by more expensive therapies. The economic studies of advanced prostate cancer highlight several aspects of clinical care that are filled with considerable uncertainty and remain guided by forces other than optimal resource allocation. It is essential that we address the weaknesses in our understanding of the economic consequences of therapies for prostate cancer, and find ways to include economic information into the process of determining optimal therapy.

Guidelines and counselling for treatment options in the management of prostate cancer

Prostate cancer is often a complex disease and one in which many aspects of the disease and the affected patient must be taken into consideration before decisions about diagnostic work-up, treatments, follow-up, etc. can be made. The current chapter reflects the current recommendations of the European Prostate Cancer Guideline Group made on the basis of criteria of evidence-based medicine after extensive review of the literature available up to December 2005.

The Case for Early Chemotherapy for the Treatment of Metastatic Disease

PURPOSE

Several important questions are raised by the data from Southwest Oncology Group 99-16 and TAX 327. What is the optimal timing of chemotherapy for metastatic hormone refractory prostate cancer? Should asymptomatic patients be treated? Is there a theoretical survival advantage for treatment for hormone sensitive prostate cancer? We reviewed arguments for the early use of docetaxel in the hormone sensitive and hormone naïve disease states.

MATERIALS AND METHODS

Androgen independent prostate cancer was traditionally viewed as a chemoresistant disease. At best palliation of bone pain but not improved survival could be achieved with the combination of mitoxantrone and prednisone. Median survival rates for chemotherapy in this disease state were reported to be between 10 and 12 months. Phase II studies administering docetaxel weekly or every 3 weeks as a single agent or in combination with estramustine demonstrated median survival rates of 14 to 23 months, which appeared to be an improvement over standard therapy. Consequently the 2 randomized trials, Southwest Oncology Group 99-16 and TAX 327, were designed to confirm the preliminary observations of improved survival with docetaxel based therapy.

RESULTS

TAX 327 and Southwest Oncology Group 99-16 treated asymptomatic as well as symptomatic patients. Thus, in contrast with mitoxantrone/prednisone, which was approved in symptomatic men with hormone refractory prostate cancer, the exact timing of the initiation of chemotherapy in docetaxel treated patients is still the subject of debate.

CONCLUSIONS

Studies should be performed to investigate the optimal timing of chemotherapy as well as sequencing with androgen ablation in patients at high risk for progression and death from metastatic prostate cancer. Prognostic factors for death that have been identified in patients with androgen independent prostate cancer are hemoglobin, alkaline phosphatase, visceral disease and performance status.

Long-term side effects of androgen deprivation therapy in men with non-metastatic prostate cancer: A systematic literature review

Increasing numbers of men with non-metastatic disease are receiving androgen deprivation therapy (ADT) for a variety of indications, some of which are supported by evidence from randomized trials. Balanced against possible survival benefits and better disease control are data that ADT adversely affects quality of life, particularly in the areas of sexual function, physical function, and energy. There is some evidence of worsening upper extremity physical strength but no clear evidence of decline in daily function with ADT. The impact of ADT on cognitive function is not clear at this time. ADT is associated with declines in bone mineral density within 6-12 months of commencing treatment, with increased fracture rates within 5 years of treatment. ADT use is also associated with a 10-15g/L decline in hemoglobin, although the clinical significance of this drop appears to be limited for most patients. It is reasonable for physicians who are about to start men on ADT to obtain a baseline bone mineral density, to counsel them about the impact on sexual function and possible treatments for sexual dysfunction, and to encourage regular exercise. Further insight into adverse effects of ADT and strategies to minimize these adverse effects await data from ongoing studies.

Clinical Trials in a Molecular World

New therapies aimed at molecular abnormalities are often more efficacious and less toxic than nontargeted therapies; however, with current technology, major treatment decisions are being made with inadequate data. This problem needs to be fixed by molecular imaging technology, enabling he noninvasive establishment of the presence of a molecular target, its spatial distribution and heterogeneity, and how this changes over time. This article discusses the status of molecular imaging in clinical trails today, and looks forward to what physicians would like it to become.

The natural history of noncastrate metastatic prostate cancer after radical prostatectomy

OBJECTIVES

To characterise the natural history of metastatic prostate cancer after radical prostatectomy (RP) in patients followed expectantly for rising prostate-specific antigen (PSA) (noncastrate metastases).

METHODS

Cox proportional hazards analyses were used to assess predictors of survival among 95 patients who developed clinically detectable noncastrate metastases after RP. The initial metastatic phenotype was characterised as minimal (nodal or axial skeletal involvement) or extensive (appendicular skeletal involvement or visceral metastases). Estimates of survival after diagnosis of metastases were generated with the Kaplan-Meier method.

RESULTS

Median disease-specific survival from diagnosis of noncastrate metastases was 6.6 yr (95% confidence interval [CI], 5.2, 7.9). The initial site of metastatic disease was bone, lymph node, and viscera in 63%, 36%, and 6% of patients, respectively. Thirteen patients (14%) had extensive disease at their first metastatic manifestation. Longer PSA doubling time in the rising PSA state (hazard ratio [HR] 0.8 for each month increase in doubling time; 95%CI, 0.67-0.94) and the initial metastatic phenotype (HR 0.3 for minimal vs. extensive disease; 95%CI, 0.1-0.6) were associated with improved survival. The prostatectomy Gleason score, lymph node status at RP, PSA level at diagnosis of metastases, and interval from surgery to diagnosis of metastases did not correlate with outcome.

CONCLUSION

Men who develop noncastrate metastases after RP may have a durable survival. Favourable prognostic indicators include longer PSA doubling time preceding diagnosis of metastases and initial involvement of axial skeleton or lymph nodes.

Luteinizing hormone-releasing hormone agonists in the treatment of prostate cancer: A review of their discovery, development, and place in therapy

BACKGROUND

Early identification of the biological activity of luteinizing hormone-releasing hormone (LHRH) paved the way for the synthesis of analogues with enhanced potency and biological properties. Early testing in animal models and humans provided insight into the potential clinical uses of these substances, and, within 10 years, LHRH-agonist therapy had become available for use in patients with advanced prostate cancer (PC). Over time, the role of LHRH-agonist therapy has expanded to include use as part of multimodal treatment regimens throughout the course of the disease.

OBJECTIVES

This article reviews the discovery and development of LHRH agonists and summarizes the clinical evidence for their efficacy in PC.

METHODS

Relevant clinical studies were identified through searches of the English-language literature indexed on MEDLINE through May 2006. The main search terms were prostate cancer and LHRH agonist.

RESULTS

Results of the initial therapeutic trials of sustained-release depot formulations of LHRH agonists in patients with PC were reported in the mid-1980s, indicating that these agents were effective and well tolerated in improving clinical symptoms and producing medical castration. Longer-term studies and subsequent meta-analyses of randomized controlled trials in patients with advanced PC found no significant differences in overall survival when single-therapy androgen suppression was achieved through the use of LHRH-agonist therapy or orchiectomy. Randomized trials have reported significant improvements in disease-free and overall survival in patients with locally advanced or high-grade PC treated with LHRH agonists in addition to radiotherapy. Several prospective randomized trials have reported decreases in rates of positive surgical margins with short-term (6 weeks to 4 months) neoadjuvant LHRH-agonist therapy in patients with stage T1 to T3a PC undergoing prostatectomy. Definitive comparisons of immediate and delayed treatment in patients with biochemical relapse have not been reported. However, the results of several studies suggest that immediate LHRH-agonist therapy (or orchiectomy) may improve the course of disease progression and survival. The risks of long-term treatment (eg, osteoporosis; fracture; anabolic loss of muscle mass, with a tendency toward weight gain) must be considered carefully in patients who are likely to receive chronic LHRH-agonist therapy. Intermittent schedules have been developed to reduce the adverse effects associated with LHRH-agonist therapy; some reports support sparing effects on bone and muscle mass and relative improvements in toxicities during off-therapy periods, whereas others have documented continuing decreases in bone mineral density (BMD), with the rate of bone loss highest during the early cycles of therapy. Bisphosphonate therapy has been shown to increase BMD in patients with PC and may therefore be beneficial when overt symptoms of osteopenia or osteoporosis are present.

CONCLUSIONS

LHRH-agonist therapy has been the mainstay of treatment for advanced PC for >20 years. Clinical evidence supports expanding use of these agents at an earlier stage of disease and as part of multimodal regimens that include radiotherapy. There is a need for further study of the efficacy of adjuvant LHRH-agonist therapy along with prostatectomy, in patients with biochemical failure, in intermittent regimens, and in conjunction with cytotoxic therapies in late-stage disease.

Use of hormonal therapy in men with metastatic prostate cancer

PURPOSE

Bilateral orchiectomy or luteinizing hormone releasing hormone agonists represent the standard of care for metastatic prostate cancer. In this population based study we assessed the use rates of these therapies in men who died of prostate cancer.

MATERIAL AND METHODS

A total of 9,110 men 65 years or older who died of prostate cancer in 1991 to 2000 were identified through the population based Surveillance, Epidemiology and End Results, and Medicare linked database to determine hormonal therapy use rates. A modified Poisson regression model was used to estimate the adjusted effects of various factors associated with hormone use.

RESULTS

Approximately 38% of black and 25% of white men did not receive hormonal therapy before dying of prostate cancer. After adjusting for cancer status at diagnosis and other potential confounding factors black race and residence in low income areas were associated with lower hormonal therapy use (relative risk 0.73, 95% CI 0.67 to 0.80 and 0.91, 95% CI 0.85 to 0.98, respectively). Hormonal therapy use was most comprehensive in the Northeast.

CONCLUSIONS

A substantial number of men who die as a consequence of prostate cancer never receive hormonal therapy. The use of hormonal therapy varies significantly. Further studies are warranted to determine factors that may be associated with the incomplete use of hormonal therapy for metastatic prostate cancer.

[18F]fluorocholine PET/CT imaging for the detection of recurrent prostate cancer at PSA relapse: experience in 100 consecutive patients

PURPOSE

We evaluated the potential of PET/CT and [(18)F]fluoromethylcholine (FCH) in the assessment of suspected recurrence of prostate cancer after treatment.

METHODS

One hundred consecutive prostate cancer patients with a persistent increase in serum PSA (>0.1 ng/ml) after radical prostatectomy (58 cases), radiotherapy (21 cases) or hormonal therapy alone (21 cases) were investigated. After injection of 3.7-4.07 MBq/kg of FCH, both early (at <15 min) and delayed (at >60 min) PET/CT scans were performed in 43 patients, delayed PET/CT scans in 53 patients and early PET/CT scans in four patients.

RESULTS

Of the 100 patients, 54 (PSA 0.22-511.79 ng/ml) showed positive FCH PET/CT scans. Thirty-seven patients had bone and/or abdominal lymph node uptake, while 17 showed pelvic activity. Malignant disease was confirmed in all but one. Delayed SUV(max) of bone metastases was significantly higher (p<0.0001 by paired t test) than that measured at <15 min, whereas no differences were observed between early and delayed SUVs of malignant lymph nodes or pelvic disease. Forty-six patients (PSA 0.12-14.3 ng/ml) showed negative FCH PET/CT scans. Of the negative PET/CT scans, 89% were obtained in patients with serum PSA <4 ng/ml and 87% in patients with a Gleason score <8. In none of these cases could recurrent tumour be proven clinically during a follow-up of 6 months.

CONCLUSION

FCH PET/CT is not likely to have a significant impact on the care of prostate cancer patients with biochemical recurrence until PSA increases to above 4 ng/ml. However, in selected patients, FCH PET/CT helps to exclude distant metastases when salvage local treatment is intended.

Using prostate-specific antigen screening and nomograms to assess risk and predict outcomes in the management of prostate cancer

We review the role of prostate-specific antigen (PSA) and the importance of patient education in the management of prostate cancer, based on discussions held at a European symposium on managing prostate cancer. Although PSA is the most widely used serum marker for detecting prostate cancer and for monitoring treatment responses, its use as a diagnostic marker is controversial due to concerns of over-diagnosis and low specificity. PSA isoforms, as well as PSA doubling time, might improve the specificity for earlier prostate cancer detection and can be used as surrogate markers for treatment efficacy. Patients can differ considerably in the importance they place on health-related quality of life aspects and fear of cancer progression. Consequently, there needs to be active, educated discussion of risk and outcomes between physicians and patients. Risk assessment tools, e.g. validated nomograms, enable clinicians to improve their decision analysis and form the basis for subsequent discussion of treatment options between the physician and patient, thereby enabling informed consent and appropriate decision-making.

Deferred combined androgen blockade therapy using bicalutamide in patients with hormone-refractory prostate cancer during androgen deprivation monotherapy

OBJECTIVE

To assess the effect of adding bicalutamide on serum prostate-specific antigen (PSA) levels in patients with hormone-refractory prostate cancer (HRPC) during androgen deprivation monotherapy (ADMT).

PATIENTS AND METHODS

Forty-four patients with HRPC were treated with deferred combined androgen blockade (CAB) therapy, administering bicalutamide 80 mg once daily. HRPC was defined biochemically as three consecutive rises in PSA level during ADMT. The treatment response was defined as a > or = 50% decline in PSA levels. Prognostic values of various pretreatment variables for responsiveness to deferred CAB were determined statistically. When the disease relapsed during deferred CAB, bicalutamide was discontinued and the patients were evaluated for the antiandrogen withdrawal syndrome (AWS).

RESULTS

Of the 44 patients, 29 (66%) had a PSA response; the median PSA failure-free survival was 9.2+ months. Biopsy Gleason score was the only pretreatment variable predictive of a PSA response (mean Gleason score 7.9 in responders and 8.7 in nonresponders). The PSA doubling time (PSA-DT) was the only statistically significant variable of PSA failure-free survival in a multivariate analysis. The 1- and 2-year PSA failure-free survival rates were 43% and 31% in patients with a PSA-DT of >4 months, while it was 21% and none, respectively, in those with a PSA-DT of <4 months. Responders to deferred CAB had a statistically longer cancer-specific survival than nonresponders. None of 20 patients who were evaluated for AWS had the condition.

CONCLUSIONS

Deferred CAB therapy using bicalutamide is effective in patients with progression during ADMT, particularly in those with lower Gleason score tumours or a longer PSA-DT. AWS after deferred CAB is uncommon.

Androgen-deprivation therapy as primary treatment for localized prostate cancer: data from Cancer of the Prostate Strategic Urologic Research Endeavor (CaPSURE)

BACKGROUND

Prostate cancer is largely an androgen-sensitive disease. Androgen-deprivation therapy (ADT) generally has been used for patients with advanced disease. However, ADT is used increasingly as monotherapy for patients with clinically localized disease. The objective of the current report was to describe the characteristics of patients who underwent ADT for the management of localized disease.

METHODS

Cancer of the Prostate Strategic Urologic Endeavor (CaPSURE), which is a national disease registry of men with prostate cancer, was screened to identify patients who received treatment with primary ADT (PADT) between 1989 and 2002 for clinically localized disease (T1-T3,Nx/N0,Mx/M0). Clinical data (including Gleason score, prostate-specific antigen [PSA] level, and T classification) and sociodemographic data (including age, race, education, income, and insurance coverage) were analyzed with chi-square statistical tests. Time to failure data were analyzed using log-rank tests, the Kaplan-Meier method, and Cox proportional hazards regression analyses.

RESULTS

Of 7045 men, 993 patients (14.1%) with clinically localized disease received primary ADT. Compared with patients who underwent standard treatment, patients who received PADT had higher risk disease (as defined by PSA level, T classification, and Gleason score) and had more comorbidities. Patients who underwent PADT were older, less educated, had lower income, and were more likely to have Medicare than private insurance. The dominant forms of hormone therapy were luteinizing hormone-releasing hormone (LHRH) monotherapy (48.6%) and combined androgen blockade (LHRH agonist and antiandrogens; 38.8%). At 5 years after the initiation of PADT, 67.3% of patients still were receiving treatment with only androgen deprivation, 103 patients (13.8%) had gone on to receive definitive second treatment (radical prostatectomy, external beam radiotherapy, brachytherapy, or cryotherapy), 27 patients (3.9%) underwent second-line therapy (chemotherapy or alternative hormone-deprivation therapy), 22 patients (4.1%) died of prostate cancer, and 146 patients (19%) died of all causes.

CONCLUSIONS

The use of PADT therapy appeared to control disease in the majority of patients who received it, at least for an intermediate period. However, such patients appeared to be unique based on sociodemographic characteristics, comorbidity status, and risk factors compared with patients who received other forms of therapy. The impact of PADT on quality of life needs to be compared with standard therapy, and its long-term durability should be assessed better in patients with prostate cancer.

Toremifene--a promising therapy for the prevention of prostate cancer and complications of androgen deprivation therapy

Deregulation of the estrogen axis in humans prompts a series of tissue-specific events. In the breast and prostate, alterations in estrogen signalling lead to genotypic and phenotypic molecular alterations that result in dysplastic cellular appearance, deregulated cell growth and carcinoma. In bone, decreased estrogen leads to increased osteoclastogenesis and bone resorption, decreased bone mineral density and a significant fracture risk. Toremifene is a selective estrogen receptor modulator that exerts pharmacological activity in the breast, bone and prostate. An intense interest in developing this agent for prostate cancer chemoprevention is based on the reduction of premalignant and malignant prostate lesions in a transgenic model of prostate cancer. Biological and clinical activity was demonstrated in Phase II trials by the prevention of progression to prostate cancer in men with high-grade prostate intraepithelial neoplasia and through suppression of bone turnover biomarkers and increased bone mineral density in men on androgen deprivation therapy for prostate cancer.

XAGE-1 mRNA expression in prostate cancer and antibody response in patients

To evaluate the feasibility of cancer vaccine targeting XAGE-1, we investigated the expression of 4 XAGE-1 transcript variants and the humoral immune response to XAGE-1 in prostate cancer patients. XAGE-1a, b, c, d mRNA expression was analyzed in 54 prostate cancer specimens and 8 specimens of benign prostate hypertrophy (BPH) by reverse transcription-polymerase chain reaction (RT-PCR). The humoral response to XAGE-1 was investigated in sera obtained from 278 patients with prostate cancer and 40 healthy volunteers by enzyme-linked immunosorbent assay (ELISA) using recombinant protein. XAGE-1b mRNA expression was observed in 14 of 54 (26%) prostate cancer specimens, while XAGE-1a, c, and d mRNA expressions were observed in 1, 1, and 3, respectively. None of the 4 XAGE-1 transcript variants was observed in the 8 BPH specimens. Antibody against XAGE-1 was detected in sera from 2 of 129 stage D2 patients, whereas none of sera from 149 patients with localized prostate cancer or lymph node metastasis had detectable XAGE-1 antibody. No reactivity to XAGE-1 was found in sera from the 40 healthy individuals.

A phase II study of nilutamide in men with prostate cancer after the failure of flutamide or bicalutamide therapy

OBJECTIVE

To determine the prostate-specific antigen (PSA) response and time to PSA or radiographic progression in men with prostate cancer refractory to bicalutamide and/or flutamide therapy.

PATIENTS AND METHODS

Men with histologically confirmed prostate cancer not amenable to curative surgery or radiation therapy were eligible for the study if they had radiographic or PSA progression on at least one antiandrogen (not nilutamide) despite continued androgen suppression and standard antiandrogen withdrawal periods. All men received nilutamide 150 mg/day orally for > or = 8 weeks unless there was unacceptable toxicity or disease progression. All men were evaluated for response, safety and toxicity. Baseline PSA levels, chest X-ray, bone scan and abdominopelvic computed tomography studies were obtained; the re-evaluation included PSA levels every 4 weeks and repeated imaging every 8 weeks in those with baseline abnormalities. The chest X-ray was repeated if there were pulmonary symptoms. Nineteen men were consented and 16 were evaluable for response.

RESULTS

The median (range) Gleason score was 7 (6-9) and the median number of previous second-line therapies was 2 (1-4). Bicalutamide therapy had failed in all patients. At baseline, 13 (of 16 men) had radiographically evident disease, nine with diffuse osseous and four with radiographically measurable metastases. There was no grade 3/4 toxicity; the commonest grade 1/2 toxicities were constipation (three), sensory neuropathy (four), fatigue (six), and visual changes (two) involving transiently altered colour vision and sensitivity to light, respectively. Responses included three partial and 13 with progressive disease.

CONCLUSIONS

The study was discontinued after a planned interim analysis because nilutamide had no apparent activity. Although well tolerated, nilutamide offers benefit to few men with prostate cancer in whom bicalutamide has failed.

Androgen deprivation for minimal metastatic disease: Threshold for achieving undetectable prostate-specific antigen

OBJECTIVES

To develop objective measures to select systemic therapies for study in large-scale trials for patients with lesser tumor burdens, we explored prostate-specific antigen (PSA) changes after androgen ablation in patients with disease progression after treatment of localized disease. Long-term follow-up of trials incorporating androgen-deprivation with local therapy have shown improved survival relative to local therapy alone. This suggests that the benchmark for treatment of minimal metastatic disease can be cure.

METHODS

Patients with a rising PSA level with or without clinical metastases after local therapy who received androgen deprivation at Memorial Sloan-Kettering Cancer were identified from two institutional databases. The primary outcome was the proportion achieving an undetectable PSA level, and the pretreatment parameters associated with this endpoint were evaluated.

RESULTS

A total of 130 patients who received androgen ablation and were followed up at Memorial Sloan-Kettering Cancer Center were identified. Overall, 31 (57%) of 54 (95% confidence interval 44% to 71%) patients with a rising PSA level alone and 28 (37%) of 76 (95% confidence interval 26% to 47%) patients with a rising PSA level and clinical metastases achieved an undetectable PSA level after androgen ablation (P = 0.02). The PSA level at the start of androgen ablation and the presence of metastases were the most significant predictive factors.

CONCLUSIONS

The probability of achieving an undetectable PSA level varied inversely with the disease extent. Although achieving an undetectable PSA level does not mean that a patient has been cured, it does establish an endpoint that can be used to identify approaches worthy of study in the Phase III setting.

Quality of life in prostate cancer

Little more than a decade ago, measurements of health-related quality of life (HRQOL) of prostate cancer patients began to enter the medical literature. Initially controversial and of little apparent relevance to clinical care, HRQOL has grown in importance in prostate cancer to the point that providing it in treatment discussions is now considered a core element of clinical care. The United States (US) Food and Drug Administration has used it to make approval decisions for prostate cancer drugs, and Europeans have endorsed its central role in prostate cancer as well [Altwein J, Ekman P, Barry M, et al. How is quality of life in prostate cancer patients influenced by modern treatment? The Wallenberg symposium. Urology 1997, 49(Suppl 4A), 66-76.]. We propose to characterise the treatment dilemmas facing patients with prostate cancer, the clinical relevance of HRQOL research, its central conceptual elements, the characteristics of some available instruments to measure it, the use of HRQOL in clinical studies, and some of the remaining challenges we have identified during our 13 years in the field.

The role of luteinizing hormone-releasing hormone therapy in locally advanced prostate cancer and biochemical failure: considerations for optimal use

BACKGROUND

More patients are being diagnosed with prostate cancer at an earlier age with earlier stage disease because of advances in screening and detection. Investigators continue to explore the use of hormone therapy, particularly luteinizing hormone-releasing hormone (LHRH) analogues, earlier in the course of disease.

OBJECTIVE

This review summarizes clinical evidence regarding the safety and efficacy of LHRH analogues in the treatment of locoregional disease or following biochemical failure.

METHODS

Relevant information from clinical studies was identified through a MEDLINE search of the medical literature published in English in the last 5 years (search terms: LHRH and prostate cancer). The search included prospective and retrospective clinical studies on LHRH therapy in locally advanced prostate cancer. Additional relevant publications published before 1999 were identified from citations in the resulting articles.

RESULTS

The available clinical evidence suggests that the use of LHRH analogues as adjuvant or neoadjuvant therapy in conjunction with radiation therapy may improve survival outcomes. Few studies have evaluated the use of LHRH analogues after biochemical failure. However, several related studies indicate that initiating hormone therapy earlier rather than later may provide some clinical benefit. When considering early initiation of LHRH therapy, the potential risks of long-term treatment must be considered. Physiologic changes, such as deterioration of body composition and bone quality, may have important effects on the risk of developing cardiovascular disease and osteoporosis.

CONCLUSIONS

Although some clinical evidence supports the use of LHRH analogues as adjuvant or neoadjuvant therapy or following biochemical failure, further study is needed. In the meantime, clinicians should carefully weigh the potential benefits and risks of early hormone therapy when making treatment decisions.

Angiogenesis-targeted therapies in prostate cancer

Most patients with metastatic prostate cancer will respond initially to ablation of gonadal androgen production. Eventually, all patients will develop progressive disease despite continued androgen suppression, a condition called androgen-independent or hormone-refractory prostate cancer. Hormone-refractory prostate cancer is characterized by virulent biologic and clinical behavior. Recently, docetaxel-based chemotherapy has been shown to improve survival and quality of life in this disease when compared with mitoxantrone-based therapy. However, results remain suboptimal. Recently, there have been remarkable advances in the delineation of the mechanisms of cancer growth, metastasis, and the intricate interactions between tumor cells and the surrounding normal tissues. The accumulated evidence has confirmed the importance of angiogenesis in these processes and validated the theory that inhibition of neovascularization is a promising therapeutic anticancer strategy. Currently, dozens of compounds that interfere with different steps of the angiogenic cascade are in preclinical and clinical development. Some of these agents have exhibited promising antitumor activity in hormone-refractory prostate cancer. This review summarizes the molecular mechanisms implicating angiogenesis in the development and progression of advanced-stage prostate cancer, as well as the drug development efforts that are targeting this process.

Positron tomographic assessment of androgen receptors in prostatic carcinoma

PURPOSE

The purpose of this study was to evaluate the feasibility of androgen receptor (AR) imaging with 16beta-[18F]fluoro-5alpha-dihydrotestosterone (FDHT) by positron emission tomography (PET) and to assess the binding selectivity of FDHT to AR in patients with prostate cancer.

METHODS

Twenty men (age range 56-87 years) with advanced prostate cancer were studied. All except one had metastatic disease confirmed by biopsy and/or radiological studies. One patient who had radiological findings suggesting a single hepatic metastasis was found to have focal fatty infiltration on biopsy obtained after FDHT-PET and was excluded from further data analysis. FDHT uptake was assessed semiquantitatively by determination of the standardized uptake value (SUV) and tumor-to-muscle ratio (T/M). Additionally, to assess the AR binding selectivity of FDHT, patients with one or more foci of abnormally increased FDHT accumulation were studied after administration of an AR antagonist (flutamide).

RESULTS

Conventional imaging demonstrated innumerable lesions in two patients and 43 lesions in the remaining 17 patients with advanced prostate cancer. FDHT-PET was positive in 12 of 19 patients (sensitivity of 63%), including the two patients with innumerable lesions. FDHT-PET detected 24 of 28 known lesions (86%) in the remaining ten patients. In addition, FDHT-PET detected 17 unsuspected lesions in five of these ten patients. All 12 patients with positive FDHT-PET underwent a repeat PET study after receiving flutamide for 1 day (250 mg t.i.d.). In all of these patients, there was a decrease in tumor FDHT uptake after flutamide; the mean (+/- standard deviation) SUV and T/M decreased from 7.0+/-4.7 and 6.9+/-3.9, respectively, to 3.0+/-1.5 and 3.0+/-1.6, respectively (p=0.002). The mean PSA in patients with positive FDHT-PET was significantly higher than that in patients with negative FDHT-PET (p=0.006).

CONCLUSION

Our results document the feasibility of PET imaging of prostate cancer with FDHT and suggest that tumor uptake of FDHT is a receptor-mediated process. Positive PET studies were associated with higher PSA levels and thus, presumably, with greater tumor burden.