The time for serum testosterone to reach castrate level after bilateral orchiectomy or oral estrogen in the management of metastatic prostatic cancer

Bilateral orchiectomy deteriorates the structure and function of seminal vesicles in a rat model

The effects of hormone levels on ejaculation are known. In addition to thyroid hormone levels, testosterone levels are also associated with ejaculation, but no consensus has been reached on this issue. Thus, we investigated the effect of decreased testosterone levels due to bilateral orchiectomy on the chemical stimulation-induced ejaculation phases in rats. Twenty-one male Wistar rats were randomized into the orchiectomy, sham, and control groups, with seven rats in each group. Bilateral orchiectomy was performed. The ejaculation parameters were evaluated 5 days after the sham and bilateral orchiectomy operations and the waiting period in the control group. The seminal vesicle (SV) phasic contraction number and increase in basal pressure amplitude were significantly lower in the orchiectomy group (6.9 ± 3.3 and 0.6 ± 0.3 mmHg) than in the sham and control groups (11.2 ± 1.7 and 1.0 ± 0.4 mmHg, and 14.5 ± 6.6 and 1.1 ± 0.2 mmHg, respectively; p = 0.016 and p = 0.03, respectively). The interval between the SV contractions was significantly longer in the orchiectomy group (166.2 ± 104.3 s) than in the sham and control groups (76.0 ± 15.5 s and 63.1 ± 31.1 s, respectively; p = 0.014 (between groups), orchiectomy vs sham p = 0.040 and orchiectomy vs control p = 0.018). The SV weights of the rats were significantly lower in the orchiectomy group (0.14 ± 0.01 g) than in the sham and control groups (0.37 ± 0.05 g and 0.48 ± 0.03 g respectively; p < 0.0001 (between groups), orchiectomy vs sham p < 0.0001 and orchiectomy vs control p < 0.0001). The groups showed no significant differences in ejaculation time, SV basal pressure, SV maximum amplitude, and bulbospongiosus muscle contraction electromyographic activity. Our results partially clarified the relationship between decreased testosterone levels and ejaculation. Decreased testosterone levels caused statistically significant changes in SV functions and affected the ejaculation emission phase.

Perioperative growth hormone levels as an early predictor of new-onset secondary adrenal insufficiency following transsphenoidal pituitary tumor resection

OBJECTIVE

This study aims to predict new-onset secondary adrenal insufficiency (NOSAI) after transsphenoidal pituitary tumor resection surgery using perioperative growth hormone (GH) and prolactin (PRL) levels, among other factors.

METHODS

A cohort of 124 adult patients who underwent transsphenoidal resection for non-functioning pituitary adenoma, with routine perioperative glucocorticoid use, was used to develop the predictive regression model. An additional 46 patients served as the validation cohort. Generalized additive models were used to identify optimal cut-off points for the variables.

RESULTS

The GH level on postoperative day one (POD1) can be a simple predictor by implementing a cut-off point of 0.41 ng/ml. A value ≤ 0.41 ng/mL predicted NOSAI with 0.6316 sensitivity and 0.7810 specificity for the original cohort and 1.0000 sensitivity and 0.7143 specificity for the validation cohort. The multiple logistic regression model included perioperative PRL level difference, perioperative GH level difference, intraoperative cerebrospinal fluid (CSF) leakage, tumor size, and the combined effect of diabetes insipidus (DI) and relative perioperative GH level difference. The areas under the receiver operating characteristic curves were 0.9410 (original cohort) and 0.9494 (validation cohort) for the regression model.

CONCLUSION

Early morning GH level on POD1 can predict NOSAI with fair accuracy when perioperative stress dose glucocorticoid is administered. Prediction accuracy can be improved by considering CSF leakage, DI, and perioperative changes in GH and PRL in the final regression model.

Population PK and Semimechanistic PK/PD Modeling and Simulation of Relugolix Effects on Testosterone Suppression in Men with Prostate Cancer

Relugolix, the first orally active, nonpeptide gonadotropin-releasing hormone receptor antagonist, is approved in the United States and the European Union for the treatment of adult patients with advanced prostate cancer. The recommended dosing regimen is a 360-mg loading dose followed by a 120-mg daily dose. Relugolix and testosterone concentration data and clinical information from two phase I studies, two phase II studies, and the phase III safety and efficacy study (HERO) were used to develop a population pharmacokinetic (PopPK) model and a semimechanistic population pharmacokinetic/pharmacodynamic (PopPK/PD) model that characterized relugolix exposure and its relationship to testosterone concentrations. Age, body weight, and Black/African American race had at most minimal effects on relugolix exposure or testosterone concentrations with no clinical relevance. Simulations using the PopPK/PD model confirmed the recommended dosing regimen of relugolix, with the median simulated testosterone concentrations predicted to achieve castration levels (< 50 ng/dL) and profound castration levels (< 20 ng/dL) by day 2 and day 9, respectively, and demonstrated that 97.3% and 85.5% of the patients remained at castration levels (< 50 ng/dL) upon temporary interruption of treatment for 7 days and 14 days, respectively. Collectively, simulations based on the PopPK and PopPK/PD models were consistent with actual data from clinical studies, reflecting the high predictiveness of the models and supporting the reliability of model-based simulations. These models can be used to provide guidance regarding dosing recommendations under various circumstances (e.g., temporary interruption of treatment, if needed) for relugolix.

Utilization and Outcomes of Surgical Castration in Comparison to Medical Castration in Metastatic Prostate Cancer

Androgen deprivation therapy is the gold standard for metastatic prostate cancer, which can be achieved either by surgical or medical castration. In this study of 33,585 patients in the National Cancer Database, there was significant decline in the trend of utilization of surgical castration from 8.6% in 2004 to 3.1% in 2014. However, there was no survival difference with surgical castration when compared with medical castration. Increasing the utilization of surgical castration could help reduce health care expenditures. Patients and physicians need to be aware of treatment options and their financial implications.

Effect of testosterone on the differentiation control of stromal vascular cells isolated from longissimus muscle of Hanwoo beef cattle

Testosterone, as an influential factor in marbling score, requires strict management for uniform development of adipocytes in-between muscle bundles. Present study investigated effect of castration timing and testosterone levels on adipocyte development using SVCs. Isolated SVCs exhibited classical MSC markers, CD31^-, CD34^-, CD45^-, CD90⁺, and CD105⁺. ELISA analysis indicated that serum testosterone concentration was highest in non-castrated calves while no significant difference was observed between female, early and late castrated calves. CCK-8 assay showed that concentration of testosterone had no effect on cell proliferation. However, the real-time PCR demonstrated that 20 ng/ml of testosterone suppressed expression of preadipocyte markers, pref-1 and zfp423, but encouraged expression of myoblast markers, myf5 and myoD, via the AR. Consequently, expression of adipogenic markers C/EBPα and PPARγ, as well as accumulation of triglyceride, were decreased in 20 ng/ml testosterone treatment under adipogenic conditions. These findings suggest that by castrating calves before level of testosterone increases, may improve marbling development in the Hanwoo beef industry.

TrkB is necessary for male copulatory behavior in the Syrian Hamster (Mesocricetus auratus)

The magnocellular medial preoptic nucleus (MPN mag), a subdivision of the medial preoptic area (MPOA), plays a critical role in the regulation of copulation in the male Syrian hamster; in part by mediating the effects of gonadal steroids. For example, ablation of the MPN mag eliminates mating and testosterone placed in the MPN mag restores mating in castrated males. Furthermore, testosterone treatment enhances synaptic density and dendritic spines in the MPN mag. Thus, copulatory behaviors are correlated with increases in synaptic morphology in the MPN mag. As brain derived neurotrophic factor (BDNF) and its receptor, tyrosine receptor kinase-B (TrkB), effect neuronal growth and synaptic plasticity, this study explored the role of TrkB and BDNF in mediating testosterone's effects on the MPN mag and behavior. Testosterone treatment increased BDNF expression and conversely lowered TrkB expression in the MPOA. siRNA-mediated TrkB knockdown in the MPN mag eliminated copulation two-days post injection and the behavior was restored one week later. These data indicate that testosterone influences the expression of BDNF and TrkB in the MPOA and that expression of copulation is dependent on the presence of TrkB. Taken together our findings support a role for TrkB and BDNF in mediating the effects of testosterone on copulatory behavior in the Syrian hamster.

Testosterone monitoring for men with advanced prostate cancer: Review of current practices and a survey of Canadian physicians

Androgen-deprivation therapy (ADT) is a standard of care in the treatment of advanced prostate cancer; however, testosterone monitoring practices for men undergoing ADT vary across Canada. Although a testosterone level of 1.7 nmol/L or lower has historically been defined as the accepted castrate level, newer assays with improved sensitivity have shown that both medical and surgical castration can suppress testosterone levels to below 0.7 nmol/L. This review explores the evidence supporting a redefinition of the castrate testosterone level as 0.7 nmol/L or lower, and presents results of a survey of testosterone monitoring practices among 153 Canadian urologists, uro-oncologists, and radiation oncologists who manage the treatment of men with hormone-sensitive prostate cancer.

Degarelix versus luteinizing hormone-releasing hormone agonists for the treatment of prostate cancer

INTRODUCTION

Androgen deprivation therapy (ADT) is the mainstay for advanced, hormone-sensitive prostate cancer, and options include surgical castration, luteinizing hormone-releasing hormone (LHRH) agonist, and more recently, gonadotropin releasing hormone (GnRH) antagonist therapy. Our understanding of the mechanisms and adverse effects of ADT has increased substantially, including the class-specific adverse effects of ADT. Areas covered: This review will summarize the pharmacodynamic and pharmacokinetic properties of the GnRH antagonist degarelix and its role in the management of advanced prostate cancer, the clinical evidence supporting its regulatory approval, as well as potential benefits and disadvantages over traditional LHRH agonist therapy. Expert opinion: Degarelix represents a newer class of ADT that results in a rapid and reliable decline in serum testosterone, a quality that makes it particularly advantageous in men presenting with symptomatic, hormone-sensitive prostate cancer. Due to differences in mechanism of action, there is observational data suggesting a potential cardiovascular and even oncologic benefit over traditional LHRH agonist therapy. Further research is ongoing to more clearly define this potential benefit.

Efficacy of switching therapy of luteinizing hormone-releasing hormone analogue for advanced prostate cancer

This study was conducted to determine the efficacy of switching therapy with a second-line luteinizing hormone-releasing hormone (LHRH) analogue after prostate-specific antigen (PSA) progression for advanced prostate cancer. We enrolled 200 patients, from December 2005 to September 2013, with nodal positive, metastatic prostate cancer or disease progression after definite treatment receiving continuous LHRH analogue therapy with monthly depot leuprorelin(sc) acetate 3.75 mg/vial (LA) or goserelin acetate(sc) 3.6 mg/vial (GA). If the patients had castration-resistant prostate cancer, the treatment choice of switching therapy (from LA to GA or from GA to LA) prior to starting chemotherapy was given. The LH, testosterone level, and PSA change were recorded. The records showed that there were 127 patients receiving LA as initial ADT therapy, whereas the other 73 patients were in GA therapy. A total of 92 patients received LHRH analogue switching therapy (54 patients switched from LA to GA and 38 switched from GA to LA). The effect of LH and testosterone reduction prior to and after switching therapy was comparable between the two groups, and increased PSA level after 3 months of treatment was seen in both groups (median PSA: 15.7-67.7 ng/mL in the LA to GA group; 15.2-71.4 ng/mL in the GA to LA group). This study concluded that switching therapy for patients with PSA progression after ADT has no efficacy of further PSA response.

Challenges of managing elderly men with prostate cancer

The incidence of prostate cancer increases with age. Current evidence suggests that prostate cancer is under treated in patients aged ≥70 years, despite evidence of efficacy and acceptable toxicity. Radical cystectomy and definitive radiotherapy are often denied owing to fears of post-operative complications and radiotherapy-associated gastrointestinal and genitourinary toxicity. However, modern radical prostatectomy techniques provide excellent clinical outcomes with low perioperative morbidity. Moreover, volume-restricted intensity-modulated radiation therapy is a significant improvement over previous 2D conformal radiotherapy with similar efficacy and lower toxicity. Androgen-deprivation therapy is also under-prescribed among the elderly, owing to concerns of increases in cardiac deaths and osteoporosis acceleration. However, prospective trials have not identified any increase in cardiovascular mortality among elderly men receiving androgen-deprivation therapy compared to age-matched controls. Most patients on androgen deprivation eventually progress to a castration-resistant state. At this stage, the disease still responds to newer agents that target the androgen pathway and to chemotherapy. Among the elderly, chemotherapy is under-prescribed even though it has been demonstrated to be palliative and improve survival. We describe the trends in prostate cancer management in the elderly and the importance of assessing comorbidity status, tumour characteristics, and health status, including a complete geriatric evaluation, before making treatment recommendations.

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

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

Surgical castration for androgen-deprivation therapy of prostate cancer – relevance in current practice

Objective:

Rapid control of the disease is essential in the management of patients with critical and symptomatic metastatic prostate cancer. Pharmacological castration has become the main form of androgen-deprivation therapy (ADT) for prostate cancer, with luteinising hormone-releasing hormone (LHRH) agonists being used in more than 90% of cases. Surgical castration has become the less preferred modality. This article aims to explore the clinical and economic advantages of bilateral sub-capsular orchidectomy (BSCO).

Method:

Pre- and post-operative serial testosterone levels were taken from patients who had BSCO for adenocarcinoma of the prostate. The half-life of testosterone was calculated. The cost of surgical castration on the National Health Service (NHS) was compared to the cost of LHRH agonists.

Results:

Ten patients with a median prostate-specific antigen (PSA) level of 93 ng/ml (range 26 to 4557 ng/ml) were included. Their mean random pre-operative testosterone level was 13.8 ng/ml (range 6.8 to 21.8 ng/ml). The mean half-life of testosterone was 61.7 minutes when calculated from the first two hours, and 67 minutes when calculated from the total drop with no significant variation ( p = 0.464). Four patients reached castrate levels of testosterone within four to six hours. The total cost of an inpatient BSCO in the NHS was £850 to £1154. This was more or less equivalent to one year’s worth of the commonly used LHRH agonists without including the cost of medical services.

Conclusions:

Testosterone has a short half-life and reaches castrate levels within hours of the BSCO procedure. Rapid castration by BSCO would benefit patients with critical metastatic disease. BSCO on the NHS in patients with more than one year of life expectancy is also economically beneficial.

[New perspectives in prostate cancer management]

The treatment of prostate cancer is experiencing important innovations. Hormone therapy includes a new class of drugs: LHRH antagonists, which induce a rapid, fast and sustained reduction of testosterone levels. Active surveillance enables to avoid an aggressive treatment without decreasing survival, provided that strict eligibility and follow-up criteria are applied. New imaging techniques and laboratory assays lead to early diagnosis of small size tumors. Lastly, focal therapy has the potential to target localized cancers without deterioration of surrounding structures. These concomitant improvements offer the clinician and the patient attractive options for prostate cancer management. However, they are not devoid of limitations and constraints. Thus, it is crucial to define the most appropriate patient's profile for each therapeutic option, taking into account the objective characteristics of the tumor and the psychological features of the patient.

The multi-disciplinary management of high-risk prostate cancer

Prostate cancer is the most frequently diagnosed cancer and the second most common cause of cancer death in men in the United States. Such men can experience a continuum of disease presentations from indolent to highly aggressive. For physicians who care for these men, a significant challenge has been and continues to be identifying and treating those men with localized cancer who are at a higher risk of dying from their disease. We discuss the risk stratification of patients in order to better identify those patients at higher risk of progression. A comprehensive review of the literature was then performed reviewing the roles of surgery, radiotherapy, hormone therapy, and chemotherapy, as well as combinations of these modalities, in treating these challenging patients. An integrated approach combining local and systemic therapies can be beneficial in the management of high-risk localized prostate cancer. The choice of therapy or combination of therapies is dependant upon many considerations, including patient preference and quality of life aspects. It is becoming clearer that the addition of hormonal therapies or chemotherapies to established therapies, such as radiotherapy or surgery, will have significant benefits. As evidence accumulates regarding the efficacy of these new regimens, our hope is that the challenge of optimizing the management of high-risk prostate cancer will be delivered. However, many important questions remain unresolved regarding the optimal type, combination, timing of therapy, and duration of therapy. Such questions will only be answered with large, well-designed prospective clinical trials.

Correlation between pretreatment serum biochemical markers and treatment outcome for prostatic cancer with bony metastasis

BACKGROUND

This study was undertaken to evaluate whether or not pretreatment serum biochemical markers are prognostic factors for prostatic cancer with bony metastasis in patients on hormonal treatment.

METHODS

Between 1983 and 1998, 127 patients with prostatic cancer and bony metastasis were included for evaluation. Serum prostate-specific antigen, alkaline phosphatase, calcium (Ca), lactic dehydrogenase, inorganic phosphate, gamma-glutamine transpeptidase, uric acid, albumin (Alb), iron, cholesterol (Cho), triglyceride, alanine aminotransferase, aspartate aminotransferase, and hemoglobin (Hb) were checked before treatment. The patients were divided into 2 groups according to their response (group 1, good response; group 2, poor response).

RESULTS

There were 54 patients in group 1 and 73 patients in group 2. Pretreatment levels of serum Ca, Alb, Cho and Hb were higher in group 1 than in group 2, while the other parameters were lower in group 1 than in group 2; only pretreatment levels of serum Ca, Alb and Hb were significantly different between groups (p < 0.05). When stratified by tumor grading, patients in group 1 still had significantly higher pretreatment levels of Ca, Alb and Hb than those in group 2.

CONCLUSION

Higher pretreatment serum levels of Ca, Alb and Hb are good prognostic factors for patients with metastatic prostatic cancer on hormonal treatment, irrespective of tumor grading.

[Androgen deprivation for advanced prostate cancer]

Androgen deprivation (ADT) by medical or surgical castration represents the standard therapeutic approach for managing prostate cancer (PCA) with systemic or locoregional metastases. Although ADT has been successfully used for more than 60 years, there are still major controversies with regard to the initiation (early versus delayed), type (complete versus monotherapy), and duration (continuous versus intermittent) of treatment. It is the purpose of this review to critically present the results of the various ADT options. Bilateral orchiectomy and subcutaneous application of luteinising hormone-releasing hormone (LHRH) analogues represent the guideline-recommended standard treatment for metastatic PCA, whereas estrogens are no longer recommended because of significant cardiovascular side effects despite comparable therapeutic efficacy. Antiandrogen monotherapy with bicalutamide is comparable to LHRH analogues in men with minimal tumour burden. However, survival rates are inferior in patients with extensive metastatic disease, in whom medical or surgical castration should be favoured. Complete ADT results in a median survival benefit of about 5% in men with low metastatic tumour burden, and it cannot be recommended for routine use. Early ADT is associated with a significant advantage in terms of symptom-free survival and prevention of metastasis-associated complications, but it does not result in a prolonged progression-free and overall survival when compared with delayed ADT. Despite encouraging results, intermittent ADT remains an experimental therapeutic approach that should be considered on an individual basis in carefully selected patients. Adjuvant ADT is still discussed controversially for men after radical prostatectomy, whereas it has become the standard approach in patients who undergo external beam radiation for locally advanced PCA.

Management of advanced prostate cancer: can we improve on androgen deprivation therapy?

Gonadotrophin-releasing hormone (GnRH) agonists are currently the mainstay in the management of advanced prostate cancer. Used either as monotherapy or combined with antiandrogens, GnRH agonists suppress serum testosterone levels and thus slow the growth of the tumour cells that depend on testosterone for growth. GnRH agonists have largely replaced orchidectomy in the management of advanced prostate cancer, because patients are reluctant to undergo surgical castration. However, can we do better in androgen-deprivation therapy? There is some evidence to suggest that GnRH agonists do not achieve the level of testosterone suppression attained with orchidectomy, or as rapidly, factors which could be expected to affect overall survival. Together, these observations highlight the need to develop newer agents that can achieve rapid, profound and sustained testosterone suppression, equivalent to that with orchidectomy. Preliminary data for the GnRH blocker, degarelix, suggest that this new agent might overcome the shortcomings associated with GnRH agonists. Further clinical data are therefore awaited with much interest.

[Time-course of plasma testosterone in patients with prostate cancer treated by endocrine therapy]

OBJECTIVE

To assess the time-course of plasma testosterone in patients with prostate cancer treated by endocrine therapy.

METHODS

A PubMed review of the literature on plasma testosterone and the various endocrine therapies for prostate cancer was performed.

RESULTS

The time-course of plasma testosterone varies according to the type of endocrine therapy. The effective castration level, classically considered to be 50 ng/dl, is currently tending to be replaced by 20 ng/dl. Following surgical castration, plasma testosterone reaches effective castration levels within several hours, while with LH-RH agonist therapy, plasma testosterone reaches its trough value after three to four weeks, and remains low for six months after stopping treatment. However, about 15% of patients treated with LH-RH agonists do not achieve effective castration levels. Plasma testosterone remains unchanged or even increases in response to anti-androgens. Plasma testosterone assay is of limited value in routine clinical practice in patients receiving endocrine therapy for prostate cancer, but should be performed in the case of elevation of PSA to ensure that the patient has achieved effective castration levels.

CONCLUSION

The correlation between plasma testosterone and progression of prostate cancer is unclear. Other studies are therefore necessary to define the value of plasma testosterone assay in patients treated for prostate cancer.

Pharmacotherapy for prostate cancer, with emphasis on hormonal treatments

For more than half a century, hormonal therapy has been one of the cornerstones of prostate cancer therapy. However, the position and timing of androgen deprivation therapy is continuously challenged. Nowadays, it is often combined with other types of treatment in a multi-modal approach, especially with radiation therapy. Besides the well-known luteinising hormone-releasing hormone agonists, several developments have been introduced (e.g., luteinising hormone-releasing hormone antagonists or improved depot formulations achieving a better pharmacokinetic slope and lower testosterone levels). Research developments include a better understanding of the different gonadotropin-releasing hormone isoforms, the ligand-independent transformation of the androgen receptor and androgen receptor overexpression in hormone-insensitive disease. Prostate cancer, previously thought to be chemotherapy insensitive, is now treated at the metastatic stage by taxane-based chemotherapies. The combination of hormonal therapy and chemotherapy is currently studied at various stages of the disease, as early as localised or locally advanced prostate cancer. It is very likely that, in the future, pharmacological treatment for prostate cancer will include combination therapies rather than monotherapies. The authors suggest an in-depth re-evaluation of the place of androgen deprivation therapy in prostate cancer.

Effect of a new leuprorelin formulation on testosterone levels in patients with advanced prostate cancer

BACKGROUND AND SCOPE

Leuprorelin is a well known luteinising hormone releasing hormone (LHRH) agonist. The drug is effective in the treatment of advanced prostate cancer and is well tolerated. This article reviews published literature (based on a search of PubMed, EMBASE and Biosis databases to the end of 2005) and other sources of data on a new formulation of leuprorelin acetate (Eligard) for use in the treatment of hormone-dependent advanced prostate cancer. This product takes advantage of a novel delivery system (Atrigel) which forms an implant in situ that is capable of delivering double doses of leuprorelin consistently to provide better, more sustained testosterone suppression compared with a microsphere leuprolide acetate formulation. Two formulations, 7.5 mg and 22.5 mg, are currently available with duration of action of 1 and 3 months, respectively. The 2-week stability at room temperature prior to mixing facilitates its use and reduces the potential for waste.

FINDINGS

In clinical studies of the new leuprorelin acetate formulation reviewed here, all patients achieved testosterone levels < or = 50 ng/dL and up to 98% of patients showed levels comparable to those resulting from surgical bilateral orchidectomy (< or = 20 ng/dL). Both formulations showed minimal breakthroughs, defined as a rise in testosterone levels after reaching levels of 50 ng/dL. The safety profile is typical of LHRH agonists, with mild to moderately severe 'hot flushes' being the most common adverse event. The higher dose of 22.5 mg, with a volume of 0.375 mL is administered subcutaneously via a small 20G needle, causing little local discomfort.

CONCLUSION

Prostate cancer remains a major cause of morbidity and mortality in older men. In the majority of cases, suppression of serum testosterone levels is very effective. The level of testosterone suppression is currently under debate, with ideal suppression levels ranging from 20 to 50 ng/dL. Not all LHRH agonist therapy achieves the same degree of testosterone suppression as bilateral orchidectomy. The new leuprorelin acetate (Eligard) appears to achieve a testosterone suppression of 20 ng/dL in 98% of patients, while maintaining a side effect profile comparable to other products in its class.

EFFECTIVENESS OF CYPROTERONE ACETATE IN ACHIEVING CASTRATION AND PREVENTING LUTEINIZING HORMONE RELEASING HORMONE ANALOGUE INDUCED TESTOSTERONE SURGE IN PATIENTS WITH PROSTATE CANCER

PURPOSE

To our knowledge this study represents the first analysis monitoring the efficacy of cyproterone acetate (CPA) monotherapy for achieving castrate testosterone levels prior to administering a luteinizing hormone-releasing analogue (LHRHA) for treating prostate cancer in the prostate specific antigen (PSA) era.

MATERIALS AND METHODS

Patients with untreated locally advanced or metastatic prostate cancer were recruited prospectively. Treatment involved a 28-day course of oral cyproterone acetate and LHRHA depot injection on day 14. Patients had serum PSA, luteinizing hormone and testosterone monitored at intervals during a 56-day period.

RESULTS

A total of 15 patients with a mean age of 74 years completed the study. Near castrate serum testosterone was achieved on day 7 (mean +/- 95% CI 83.38 +/- 17.87 ng/dl). There was a significant testosterone increase after LHRHA administration on day 14 compared with the level of 160.23 +/- 36.60 ng/dl on day 16 (p <0.01). Serum luteinizing hormone mirrored testosterone, increasing from a mean of 4.93 +/- 0.61 to 15.4 +/- 6.12 nmol/l after LHRHA administration (p <0.01). Mean serum PSA demonstrated a decrease from 199.25 +/- 6.12 microg/l at day 0 to 43.77 +/- 33.08 microg/l by day 56. There was no increase in serum PSA after LHRHA administration.

CONCLUSIONS

Two weeks of priming with CPA does not eliminate the surge in serum testosterone (testosterone flare) upon LHRHA administration but the testosterone increase does not exceed pretreatment levels. Furthermore, 2 weeks of CPA may not offer a benefit over 1 week in lowering serum testosterone. Finally, there is no increase in serum PSA when LHRHA is administered after priming with CPA.

Pharmacotherapy for biochemical recurrences after therapy for localised prostate cancer

Prostate-specific antigen (PSA) has revolutionised screening for and monitoring of prostate cancer (CaP). Currently, most men failing potentially curative CaP therapies develop biochemical evidence of recurrent disease (defined by detectable PSA levels) long before the onset of clinical symptoms. Androgen deprivation therapy (ADT) remains the gold standard for the treatment of metastatic CaP. Conventional ADT is orchiectomy or luteinising hormone-releasing hormone agonists. ADT is most commonly associated with side effects such as erectile dysfunction, decreased libido, gynecomastia and osteoporosis. Intermittent ADT or oral anti-androgens may limit the side effects associated with ADT while retaining efficacy. Although widely studied, the optimal timing to begin ADT remains an important and unanswered question. Future advances in gene therapy and immunotherapy hold the greatest promise to provide effective treatments against recurrent CaP while minimising morbidity.

The correlation between pretreatment serum hormone levels and treatment outcome for patients with prostatic cancer and bony metastasis

OBJECTIVE

To evaluate whether pretreatment serum hormone levels are a prognostic factor for prostatic cancer with bony metastasis under hormonal treatment.

PATIENTS AND METHODS

Between 1980 and 1994, 96 patients with prostate cancer and bony metastasis were included for an evaluation by a retrospective review of their charts. All 96 had received hormonal treatment after a diagnosis of metastatic prostatic carcinoma. Serum testosterone, luteinizing hormone (LH), follicle-stimulating hormone (FSH) and prolactin were assessed before treatment. The patients were divided into two groups according to their response during the follow-up. Group 1 (good response) had no change or resolution of metastatic lesion(s) on the bone scan and a declining prostate-specific antigen (PSA) level. Group 2 had increased PSA or progression of metastatic lesion(s) on the bone scan. Tumours were graded as low (2-4), intermediate (5-7) and high (8-10) using the Gleason score.

RESULTS

There were 43 patients in group 1 and 53 in group 2; the overall mean (sd) age was 72.5 (6.8) years and the follow-up 29.5 (0.5) months. The respective mean (sd) levels of testosterone, LH, FSH and prolactin before treatment were 4.6 (1.6) ng/mL, 20.2 (13.3) mIU/mL, 19.6 (18.6) mIU/mL and 20.7 (12.1) ng/mL in group 1, and 2.6 (1.0) ng/mL, 27.3 (11.0) mIU/mL, 27.1 (9.8) mIU/mL and 41.3 (28.4) ng/mL in group 2. The level of testosterone was significantly higher in group 1 than in group 2, while LH, FSH and prolactin were significantly lower in group 1 than in group 2. When stratified by tumour grade, patients in group 1 still had significantly higher pretreatment testosterone and lower LH, FSH and prolactin than those in group 2.

CONCLUSION

Higher testosterone and lower LH, FSH and prolactin levels were good prognostic factors for patients with metastatic prostatic cancer under hormonal treatment, irrespective of tumour grading.

Serum testosterone-based luteinizing hormone-releasing hormone agonist redosing schedule for chronic androgen ablation: a phase I assessment

OBJECTIVES

To assess the potential for using the serum testosterone level as the guide for redosing depot luteinizing hormone-releasing hormone (LHRH) agonist and to characterize the duration of castrate level testosterone after the last 22.5-mg leuprolide injection repeatedly administered for the control of prostate cancer.

METHODS

Informed consent was obtained from 32 men with prostate cancer (Stage T3N+/- M+/- or greater) treated with 3-month (22.5-mg) leuprolide acetate injection. Serum testosterone and prostate-specific antigen levels were obtained every 28 days beginning on the 90th day after the last 22.5-mg leuprolide injection. The duration of action was the calculated interval, in months, between the last injection and the first noncastrate serum testosterone (greater than 0.2 ng/mL) value.

RESULTS

The median duration of castrate level testosterone was 6.0 months (SE +/- 0.15; upper and lower quartile 5.3 and 7.0, respectively). Prostate cancer biochemical (prostate-specific antigen) activity at enrollment and when the castrate testosterone threshold of 0.2 ng/mL was exceeded remained stable, with no significant change observed during this interval (P = 0.52). A significant association was observed between an increasing duration of castration after LHRH agonist injection and advancing patient age (P = 0.03) and increasing duration of hormonal therapy (P = 0.05).

CONCLUSIONS

These results suggest that using the serum testosterone level to guide in redosing of long-acting LHRH agonist may provide a novel, effective, and economical method to administer hormonal ablative therapy in patients with prostate cancer. These observations have important implications for product dosing and the design and interpretation of neoadjuvant and intermittent androgen ablative trials.