Obesity and sex steroids during gonadotropin-releasing hormone agonist treatment for prostate cancer

Correlation Between Serum Prostate-Specific Antigen and Testosterone Following Bilateral Total Orchidectomy for Patients with Advanced Prostate Cancer in Jos, Nigeria

Background

Prostate cancer is a common malignancy affecting men beyond the middle age. Monitoring of treatment of the disease using serum testosterone and prostate-specific antigen (PSA) offers an index of treatment efficacy and a reflection of disease progression, respectively. The objective of this study was to determine the relationship between changing values of serum PSA and serum testosterone in patients with advanced prostate cancer following bilateral total orchidectomy (BTO).

Materials and Methods

This was a prospective longitudinal study carried out over a 1-year period among patients who met the inclusion criteria. Each patient underwent detailed clinical evaluation including history, as well as physical examination with digital rectal examination of the prostate. Also, samples of serum PSA and testosterone were obtained and sent to the same chemical pathology laboratory before intervention with BTO, then at 2, 4, and 6 months. The values of serum PSA and testosterone were obtained and changes over this period were compared for both parameters. The analyses included independent inferential analysis of serum testosterone and serum PSA over a period of 6 months and a correlation of the two parameters over the same period. Results were analysed using SPSS version 23. P value of <0.05 was regarded significant. Charts and tables were used for data expression. Kruskal-Wallis and Wilcoxon tests were used for individual inferential analysis of serum testosterone and PSA. The Spearman ranked correlation coefficient test was used to determine the degree of correlation of serum testosterone and serum PSA levels while Pearson correlation coefficient test was used to determine the degree of correlation between the percentage changes in serum testosterone and PSA measured over the period of the study.

Results

A total of forty-two men with mean age of 68.49 ± 8.86 years who had advanced prostate cancer were recruited. The histologic type of prostate cancer diagnosed for all the patients was adenocarcinoma. The mean Gleason score was 7.98 ± 1.09, while the modal Gleason grade group represented was grade group 5. There were statistically significant changes in serum testosterone and PSA levels in response to bilateral total orchidectomy with P value of <0.001. However, there was no statistically significant correlation between serum testosterone and serum PSA levels following bilateral total orchidectomy with p values of 0.492, 0.358, 0.134, and 0.842 at baseline, 2, 4, and 6 months, respectively. There was a significant correlation between the percentage changes in serum testosterone and PSA measured between baseline and 2 months with P value of <0.001. However, there was no statistically significant correlation between the percentage changes in serum testosterone and PSA measured between baseline measured against 4 months and 6 months with P value of 0.998 and 0.638, respectively.

Conclusion

The study showed that reduction in serum levels of testosterone and PSA following BTO was significant. It also revealed no statistically significant correlation between serum testosterone and serum PSA measured over 6 months following bilateral total orchidectomy.

Absence of nuclear receptors LXRs impairs immune response to androgen deprivation and leads to prostate neoplasia

Chronic inflammation is now a well-known precursor for cancer development. Infectious prostatitis are the most common causes of prostate inflammation, but emerging evidence points the role of metabolic disorders as a potential source of cancer-related inflammation. Although the widely used treatment for prostate cancer based on androgen deprivation therapy (ADT) effectively decreases tumor size, it also causes profound alterations in immune tumor microenvironment within the prostate. Here, we demonstrate that prostates of a mouse model invalidated for nuclear receptors liver X receptors (LXRs), crucial lipid metabolism and inflammation integrators, respond in an unexpected way to androgen deprivation. Indeed, we observed profound alterations in immune cells composition, which was associated with chronic inflammation of the prostate. This was explained by the recruitment of phagocytosis-deficient macrophages leading to aberrant hyporesponse to castration. This phenotypic alteration was sufficient to allow prostatic neoplasia. Altogether, these data suggest that ADT and inflammation resulting from metabolic alterations interact to promote aberrant proliferation of epithelial prostate cells and development of neoplasia. This raises the question of the benefit of ADT for patients with metabolic disorders.

Mice lacking the liver X nuclear receptors (LXRs), crucial integrators of lipid metabolism, were used to study the response of the prostate to androgen deprivation. This reveals that lack of androgens leads to chronic inflammation due to impaired clearance of castration-induced apoptotic cells, allowing production of pro-inflammatory cytokines and promoting prostate neoplasia.

Obesity, race, and long-term prostate cancer outcomes

BACKGROUND

The authors previously found that obesity was linked with prostate cancer (PC)-specific mortality (PCSM) among men who underwent radical prostatectomy (RP). Herein, in a larger RP cohort, the authors investigated whether the association between obesity and long-term PC outcomes, including PCSM, differed by race.

METHODS

Data from 5929 patients who underwent RP and were in the Shared Equal Access Regional Cancer Hospital (SEARCH) database were analyzed. Prior to RP, body mass index (BMI) was measured and recorded in the medical records. BMI was categorized as normal weight (<25 kg/m² ), overweight (25-29.9 kg/m² ), and obese (≥30 kg/m² ). The authors assessed the association between BMI and biochemical disease recurrence (BCR), castration-resistant prostate cancer (CRPC), metastasis, and PCSM, accounting for confounders.

RESULTS

Of the 5929 patients, 1983 (33%) were black, 1321 (22%) were of normal weight, 2605 (44%) were overweight, and 2003 (34%) were obese. Compared with white men, black men were younger; had higher prostate-specific antigen levels; and were more likely to have a BMI ≥30 kg/m² , seminal vesicle invasion, and positive surgical margins (all P ≤ .032). During a median follow-up of 7.4 years, a total of 1891 patients (32%) developed BCR, 181 patients (3%) developed CRPC, 259 patients (4%) had metastasis, and 135 patients (2%) had died of PC. On multivariable analysis, obesity was found to be associated with an increased risk of PCSM (hazard ratio, 1.78; 95% confidence interval, 1.04-3.04 [P = .035]). No interaction was found between BMI and race in predicting PCSM (P ≥ .88), BCR (P ≥ .81), CRPC (P ≥ .88), or metastasis (P ≥ .60). Neither overweight nor obesity was associated with risk of BCR, CRPC, or metastasis (all P ≥ .18).

CONCLUSIONS

Obese men undergoing RP at several Veterans Affairs hospitals were found to be at an increased risk of PCSM, regardless of race.

Relationship between body composition and hormone sensitivity for androgen deprivation therapy in patients with metastatic prostate cancer

Background

To evaluate the relationship between body composition and the oncological outcome of androgen deprivation therapy (ADT), we investigated whether body composition features including the psoas muscle may be predictive factors of ADT.

Methods

This study enrolled patients with hormone-naïve metastatic prostate cancer who were treated with primary ADT from April 1996 to November 2013 at Kyushu University Hospital and who underwent a computed tomography scan before primary ADT for calculating body fat percentage, psoas muscle ratio (psoas muscle, cm³/height, cm), and body mass index.

Results

Of the 178 patients enrolled, 60 patients died during follow-up. Median follow-up was 32 months, and progression-free survival and overall survival (OS) were 28 and 80 months, respectively. Multivariate analysis revealed that the psoas muscle ratio was correlated with OS (hazard ratio: 0.448; 95% confidence interval = 0.206–0.922; p = 0.028).

Conclusions

This study demonstrated that higher psoas muscle ratio predicts longer OS among patients with nonlocalized prostate cancer treated with primary ADT.

The skeletal impact of cancer therapies

Both cancer and therapies used in the treatment of cancer can have significant deleterious effects on the skeleton, increasing the risks for both bone loss and fracture development. While advancements in cancer therapies have resulted in enhanced cancer survivorship for patients with many types of malignancies, it is increasingly recognized that efforts to reduce bone loss and limit fractures must be considered for nearly all patients undergoing cancer therapy in order to diminish the anticipated future skeletal consequences. To date, most studies examining the impact of cancer therapies on skeletal outcomes have focused on endocrine-associated cancers of the breast and prostate, with more recent advances in our understanding of bone loss and fracture risk in other malignancies. Pharmacologic efforts to limit the adverse effects of cancer therapies on bone have nearly universally employed anti-resorptive approaches, although studies have frequently relied on surrogate outcomes such as changes in bone mineral density or bone turnover markers, rather than on fractures or other skeletal-related events, as primary study endpoints. Compounding current deficiencies for the provision of optimal care is the recognition that despite clearly written and straightforward society-based guidelines, vulnerable eligible patients are very often neither identified nor provided with appropriate treatments to limit the skeletal impact of their cancer therapies.

Obesity, risk of biochemical recurrence, and prostate-specific antigen doubling time after radical prostatectomy: results from the SEARCH database

OBJECTIVES

To examine the association between body mass index (BMI) and aggressive biochemical recurrence (BCR) using the Shared Equal Access Regional Cancer Hospital (SEARCH) database.

MATERIAL AND METHODS

We identified 4123 men with complete data treated by radical prostatectomy between 1988 and 2015. We tested the association between BMI and BCR using Cox models, and among men with BCR, prostate-specific antigen doubling time (PSADT) was compared across BMI categories using linear regression. Models were adjusted for age, race, prostate-specific antigen, biopsy Gleason score, clinical stage, year and surgical centre.

RESULTS

Overall, 922 men (22%) were of normal weight (BMI <25 kg/m² ), 1863 (45%) were overweight (BMI 25-29.9 kg/m² ), 968 (24%) were obese (BMI 30-34.9 kg/m² ), and 370 (9%) were moderately or severely obese (BMI ≥35 kg/m² ). After adjustment for multiple clinical characteristics, higher BMI was significantly associated with higher risk of BCR (P = 0.008). Among men with BCR, men in the four BMI categories had similar multivariable-adjusted PSADT values (increasing BMI categories: 20.9 vs 21.3 vs 21.0 vs 14.9 months; P = 0.48).

CONCLUSION

While we confirmed that higher BMI was associated with BCR, we found no link between BMI and PSADT at the time of recurrence. Our data suggest obese men do not have more aggressive recurrences. Future studies are needed to test whether obesity predicts response to salvage therapies.

Obesity and prostate cancer

PURPOSE OF REVIEW

To investigate the association between obesity and prostate cancer (PCa).

RECENT FINDINGS

Obesity has been proposed to be involved in the pathogenesis of PCa through different biological mechanisms that include deregulation of the insulin axis, sex hormone secretion, adipokines signaling, and oxidative stress. Hypertrophic peritumoral adipocytes may also facilitate the local spread of PCa through the chemo-attraction of tumor cells. Clinical studies demonstrate that obesity might have clinical implications also in disease detection and management. Obese men have been shown to be less likely to be diagnosed with early-stage disease. Moreover, they are at increased risk of experiencing upgrading and upstaging when managed with active surveillance. However, the association between obesity and the risk of PCa recurrence and mortality after radical treatment is still debated.

SUMMARY

Obesity may facilitate the development and progression of PCa trough different biologic mechanisms that may pose obese men at higher risk of advanced and high-grade disease. However, the association between obesity and long-term oncologic outcome after radical treatments appears unclear.

Acute Testosterone Deficiency Alters Adipose Tissue Fatty Acid Storage

CONTEXT

Although the long-term effects of testosterone on adipose tissue lipid metabolism in men have been defined, the short-term regulation of these effects is not well understood.

OBJECTIVE

We examined the effects of acute testosterone withdrawal on subcutaneous abdominal and femoral adipose tissue fatty acid (FA) storage and cellular mechanisms.

DESIGN

This was a prospective, randomized trial.

SETTING

Mayo Clinic Clinical Research Unit.

PATIENTS OR PARTICIPANTS

Thirty-two male volunteers ages 18 to 50 participated in these studies.

INTERVENTIONS

Volunteers were randomized to receive (1) no treatment (control), (2) injections (7.5 mg) of Lupron®, or (3) Lupron and testosterone (L+T) replacement for 49 days, resulting in 4 weeks of sex steroid suppression in the Lupron group.

MAIN OUTCOME MEASURES

We measured body composition, fat cell size, adipose tissue meal FA and direct free FA storage, lipoprotein lipase (LPL), acyl coenzyme A synthetase (ACS), diacylglycerol acyltransferase activities, and CD36 content.

RESULTS

Compared with control and L+T groups, acute testosterone deficiency resulted in greater femoral adipose tissue meal FA storage rates, fasting and fed LPL activity, and ACS activity.

CONCLUSIONS

These results suggest that in men, testosterone plays a tonic role in restraining FA storage in femoral adipose tissue via suppression of LPL and ACS activities. FA storage mechanisms in men appear sensitive to short-term changes in testosterone concentrations.

Efficacy of Testosterone Suppression with Sustained-Release Triptorelin in Advanced Prostate Cancer

Introduction

Androgen deprivation therapy (ADT) is a mainstay of treatment against advanced prostate cancer (PC). As a treatment goal, suppression of plasma testosterone levels to <50 ng/dl has been established over decades. Evidence is growing though that suppression to even lower levels may add further clinical benefit. Therefore, we undertook a pooled retrospective analysis on the efficacy of 1-, 3-, and 6-month sustained-release (SR) formulations of the gonadotropin-releasing hormone (GnRH) agonist triptorelin to suppress serum testosterone concentrations beyond current standards.

Methods

Data of 920 male patients with PC enrolled in 9 prospective studies using testosterone serum concentrations as primary endpoint were pooled. Patients aged 42–96 years had to be eligible for ADT and to be either naïve to hormonal treatment or have undergone appropriate washout prior to enrolment. Patients were treated with triptorelin SR formulations for 2–12 months. Primary endpoints of this analysis were serum testosterone concentrations under treatment and success rates overall and per formulation, based on a testosterone target threshold of 20 ng/dl.

Results

After 1, 3, 6, 9, and 12 months of treatment, 79%, 92%, 93%, 90%, and 91% of patients reached testosterone levels <20 ng/dl, respectively. For the 1-, 3-, and 6-month formulations success rates ranged from 80–92%, from 83–93%, and from 65–97% with median (interquartile range) serum testosterone values of 2.9 (2.9–6.5), 5.0 (2.9–8.7), and 8.7 (5.8–14.1) ng/dl at study end, respectively.

Conclusion

In the large majority of patients, triptorelin SR formulations suppressed serum testosterone concentrations to even <20 ng/dl. Testosterone should be routinely monitored in PC patients on ADT although further studies on the clinical benefit of very low testosterone levels and the target concentrations are still warranted.

Electronic supplementary material

The online version of this article (doi:10.1007/s12325-016-0466-7) contains supplementary material, which is available to authorized users.

Peculiarities of the obese patient with cancer: a national consensus statement by the Spanish Society for the Study of Obesity and the Spanish Society of Medical Oncology

The relationship between obesity and cancer is clear and is present at all times during course of the disease. The importance of obesity in increasing the risk of developing cancer is well known, and some of the most prevalent tumours (breast, colorectal, and prostate) are directly related to this risk increase. However, there is less information available on the role that obesity plays when the patient has already been diagnosed with cancer. Certain data demonstrate that in some types of cancer, obese patients tolerate the treatments more poorly. Obesity is also known to have an impact on the prognosis, favouring lower survival rates or the appearance of secondary tumours. In this consensus statement, we will analyse the scientific evidence on the role that obesity plays in patients already diagnosed with cancer, and the available data on how obesity control can improve the quality of daily life for the cancer patient.

Association between Body Mass Index and Cancer Survival in a Pooled Analysis of 22 Clinical Trials

BACKGROUND

Data are inconsistent on the association between body mass index (BMI) at time of cancer diagnosis and prognosis. We used data from 22 clinical treatment trials to examine the association between BMI and survival across multiple cancer types and stages.

METHODS

Trials with ≥5 years of follow-up were selected. Patients with BMI < 18.5 kg/m2 were excluded. Within a disease, analyses were limited to patients on similar treatment regimens. Variable cutpoint analysis identified a BMI cutpoint that maximized differences in survival. Multivariable Cox regression analyses compared survival between patients with BMI above versus below the cutpoint, adjusting for age, race, sex, and important disease-specific clinical prognostic factors.

RESULTS

A total of 11,724 patients from 22 trials were identified. Fourteen analyses were performed by disease site and treatment regimen. A cutpoint of BMI = 25 kg/m2 maximized survival differences. No statistically significant trend across all 14 analyses was observed (mean HR = 0.96; P = 0.06). In no cancer/treatment combination was elevated BMI associated with an increased risk of death; for some cancers there was a survival advantage for higher BMI. In sex-stratified analyses, BMI ≥ 25 kg/m2 was associated with better overall survival among men (HR = 0.82; P = 0.003), but not women (HR = 1.04; P = 0.86). The association persisted when sex-specific cancers were excluded, when treatment regimens were restricted to dose based on body surface area, and when early-stage cancers were excluded.

CONCLUSION

The association between BMI and survival is not consistent across cancer types and stages.

IMPACT

Our findings suggest that disease, stage, and gender-specific body size recommendations for cancer survivors may be warranted. Cancer Epidemiol Biomarkers Prev; 26(1); 21-29. ©2016 AACR SEE ALL THE ARTICLES IN THIS CEBP FOCUS SECTION, "THE OBESITY PARADOX IN CANCER EVIDENCE AND NEW DIRECTIONS".

Role of free testosterone levels in patients with metastatic castration-resistant prostate cancer receiving second-line therapy

A range of new treatment options has recently become available for patients with advanced metastatic castration-resistant prostate cancer (mCRPC). Androgen deprivation therapy (ADT) with luteinizing hormone-releasing hormone is continued when performing chemotherapy or androgen deprivation with new second-generation therapeutic agents such as enzalutamide or abiraterone acetate. Despite the fact that free testosterone (FT) is the biologically active form, it is common practice that androgen suppression is monitored via total testosterone levels only. The aim of the present study was to evaluate the role of FT as a prognostic biomarker for cancer-specific survival (CSS) and its feasibility as an ADT monitoring biomarker in patients with mCRPC for the first time. The requirement for continued ADT in mCRPC patients is discussed within the basis of the current literature. A total of 34 patients with continuous measurements of FT levels and mCRPC status underwent therapy with docetaxel, abiraterone acetate, enzalutamide, cabozantinib, carboplatin or cabazitaxel. Data were obtained from the Departments of Urology and Urological Oncology, Hannover Medical School (Hannover, Germany) between March 2009 and April 2014. A cutoff point of 0.5 pg/ml was used to discriminate between patients according to FT levels. Statistical evaluation of CSS was performed by applying Kaplan Meier survival estimates, multivariate Cox regression analyses and log-rank tests. The median age of all 34 patients was 72 years (range, 51–86 years). The mean follow-up interval was 16.1 months (range, 0.7–55.6 months). Despite the fact that all patients were undergoing androgen deprivation, the mean serum FT levels for each patient varied; the mean FT concentration in the cohort was 0.328 pg/ml, ranging from 0.01–9.1 pg/ml. A notable difference with regard to CSS was observed for patients with regard to serum FT concentration; CSS was significantly longer for patients with a serum FT level below the cutoff level (43.6 vs. 17.3 months, respectively, P=0.0063). Upon multivariate Cox regression analysis, the mean FT concentration during treatment remained a significant prognostic factor for CSS (hazard ratio, 1.22; 95% confidence interval, 1.03–1.43; P=0.0182). In conclusion, in patients with mCRPC, the serum FT level is a strong predictor of CSS in patients under therapy with second-line anti-hormonal therapeutic medication and chemotherapy. It may be concluded that FT levels should be included into the routine control of androgen suppression while under treatment with ADT and second-generation hormonal therapy.

Obesity and prostate cancer-specific mortality after radical prostatectomy: results from the Shared Equal Access Regional Cancer Hospital (SEARCH) database

Background:

At the population level, obesity is associated with prostate cancer (PC) mortality. However, few studies analyzed the associations between obesity and long-term PC-specific outcomes after initial treatment.

Methods:

We conducted a retrospective analysis of 4268 radical prostatectomy patients within the Shared Equal Access Regional Cancer Hospital (SEARCH) database. Cox models accounting for known risk factors were used to examine the associations between body mass index (BMI) and PC-specific mortality (PCSM; primary outcome). Secondary outcomes included biochemical recurrence (BCR) and castration-resistant PC (CRPC). BMI was used as a continuous and categorical variable (normal <25 kg/m², overweight 25–29.9 kg/m² and obese ⩾30 kg/m²). Median follow-up among all men who were alive at last follow-up was 6.8 years (interquartile range=3.5–11.0). During this time, 1384 men developed BCR, 117 developed CRPC and 84 died from PC. Hazard ratios were analyzed using competing-risks regression analysis accounting for non-PC death as a competing risk.

Results:

On crude analysis, higher BMI was not associated with risk of PCSM (P=0.112), BCR (0.259) and CRPC (P=0.277). However, when BMI was categorized, overweight (hazard ratio (HR) 1.99, P=0.034) and obesity (HR 1.97, P=0.048) were significantly associated with PCSM. Obesity and overweight were not associated with BCR or CRPC (all P⩾0.189). On multivariable analysis adjusting for both clinical and pathological features, results were little changed in that obesity (HR=2.05, P=0.039) and overweight (HR=1.88, P=0.061) were associated with higher risk of PCSM, but not with BCR or CRPC (all P⩾0.114) with the exception that the association for overweight was no longer statistical significant.

Conclusions:

Overweight and obesity were associated with increased risk of PCSM after radical prostatectomy. If validated in larger studies with longer follow-up, obesity may be established as a potentially modifiable risk factor for PCSM.

Cardiovascular Disease Risk Factors: How Relevant in African Men With Prostate Cancer Receiving Androgen-Deprivation Therapy?

Purpose

Cardiovascular disease risk factors have been associated with androgen-deprivation therapy (ADT) in white and Hispanic populations. It is therefore relevant to determine if there exists a relationship between these parameters in the African population.

Patients and Methods

The design of the study was cross sectional. Prostate-specific antigen concentration, waist circumference, body mass index (BMI), lipid profile, glucose level, and insulin level were determined in 153 patients with prostate cancer and 80 controls. The patients with prostate cancer were divided into subgroups of treatment-naïve patients and those receiving ADT.

Results

Mean total cholesterol (P = .010), LDL cholesterol (P = .021), BMI (P = .001), and waist circumference (P = .029) values were significantly higher in patients treated with ADT when compared with treatment-naïve patients. In patients treated with ADT for up to 1 year, only mean BMI was significantly higher than in treatment-naïve patients, whereas those treated with ADT for more than 1 year had significantly higher mean BMI, waist circumference, total cholesterol, and LDL cholesterol values when compared with treatment-naïve patients. There were no significant differences in insulin or glucose levels. Those undergoing hormone manipulation after orchiectomy had fewer cardiovascular risk factors compared with those undergoing hormone manipulation alone.

Conclusion

This study shows that ADT results in elevated total cholesterol, LDL cholesterol, BMI, and waist circumference values, all of which are risk factors of cardiovascular disease. Screening for cardiovascular risk factors should be included in treatment plans for patients with prostate cancer.

Obesity and cancer: mechanistic insights from transdisciplinary studies

Obesity is associated with a range of health outcomes that are of clinical and public health significance, including cancer. Herein, we summarize epidemiologic and preclinical evidence for an association between obesity and increased risk of breast and prostate cancer incidence and mortality. Moreover, we describe data from observational studies of weight change in humans and from calorie-restriction studies in mouse models that support a potential role for weight loss in counteracting tumor-promoting properties of obesity in breast and prostate cancers. Given that weight loss is challenging to achieve and maintain, we also consider evidence linking treatments for obesity-associated co-morbidities, including metformin, statins and non-steroidal anti-inflammatory drugs, with reduced breast and prostate cancer incidence and mortality. Finally, we highlight several challenges that should be considered when conducting epidemiologic and preclinical research in the area of obesity and cancer, including the measurement of obesity in population-based studies, the timing of obesity and weight change in relation to tumor latency and cancer diagnosis, and the heterogeneous nature of obesity and its associated co-morbidities. Given that obesity is a complex trait, comprised of behavioral, epidemiologic and molecular/metabolic factors, we argue that a transdisciplinary approach is the key to understanding the mechanisms linking obesity and cancer. As such, this review highlights the critical need to integrate evidence from both epidemiologic and preclinical studies to gain insight into both biologic and non-biologic mechanisms contributing to the obesity-cancer link.

Foreign Body Granulomas Induced by Intramuscular Leuprorelin Acetate Injection for Prostate Cancer: Clinical Mimics of Soft Tissue Sarcoma

We describe two cases of florid, foreign body granulomatous reaction occurring in the upper arms of males in their eighth decade, who were undergoing treatment with depot injection of leuprorelin acetate for prostatic carcinoma. These patients presented with rapidly enlarging extremity soft tissue masses and were referred to a tertiary sarcoma center with clinical suspicion of a primary soft tissue neoplasm. The occurrence of injection site granulomas secondary to leuprorelin acetate administration is rarely known outside the urological and dermatological communities, and their recognition is important due to the spectrum of clinical differential diagnoses and potential for diagnostic confusion with metastatic prostatic cancer and primary sarcoma and in order to avoid unnecessary stress and clinical intervention for patients.

Correlation Between Testosterone and PSA Kinetics in Metastatic Prostate Cancer Patients Treated With Diverse Chemical Castrations

To assess total testosterone and prostatic-specific antigen (PSA) kinetics among diverse chemical castrations, advanced-stage prostate cancer patients were randomized into three groups of 20: Group 1, Leuprolide 3.75 mg; Group 2, Leuprolide 7.5 mg; and Group 3, Goserelin 3.6 mg. All groups were treated with monthly application of the respective drugs. The patients' levels of serum total testosterone and PSA were evaluated at two time periods: before the treatment and 3 months after the treatment. Spearman's rank correlation coefficient was utilized to verify the hypothesis of linear correlation between total testosterone and PSA levels. At the beginning the patients' age, stage, grade, PSA, and total testosterone were similar within the three groups, with median age 72, 70, and 70 years in Groups 1, 2, and 3, respectively. Three months after the treatment, patients who received Leuprolide 7.5 mg presented significantly lower median total testosterone levels compared with Goserelin 3.6 mg and Leuprolide 3.75 mg (9.5 ng/dL vs. 20.0 ng/dL vs. 30.0 ng/dL, respectively; p = .0072), while those who received Goserelin 3.6 mg presented significantly lower PSA levels compared with Leuprolide 7.5 mg and Leuprolide 3.75 mg (0.67 vs. 1.86 vs. 2.57, respectively; p = .0067). There was no linear correlation between total testosterone and PSA levels. Overall, regarding castration levels of total testosterone, 28.77% of patients did not obtain levels ≤50 ng/dL and 47.80% did not obtain levels ≤20 ng/dL. There was no correlation between total testosterone and PSA kinetics and no equivalence among different pharmacological castrations.

Osteoporosis in men: a review

Osteoporosis and consequent fracture are not limited to postmenopausal women. There is increasing attention being paid to osteoporosis in older men. Men suffer osteoporotic fractures about 10 years later in life than women, but life expectancy is increasing faster in men than women. Thus, men are living long enough to fracture, and when they do the consequences are greater than in women, with men having about twice the 1-year fatality rate after hip fracture, compared to women. Men at high risk for fracture include those men who have already had a fragility fracture, men on oral glucocorticoids or those men being treated for prostate cancer with androgen deprivation therapy. Beyond these high risk men, there are many other risk factors and secondary causes of osteoporosis in men. Evaluation includes careful history and physical examination to reveal potential secondary causes, including many medications, a short list of laboratory tests, and bone mineral density testing by dual energy X-ray absorptiometry (DXA) of spine and hip. Recently, international organizations have advocated a single normative database for interpreting DXA testing in men and women. The consequences of this change need to be determined. There are several choices of therapy for osteoporosis in men, with most fracture reduction estimation based on studies in women.

Is high-dose leuprorelin acetate effective and safe in asian men with prostate cancer? An open-label, non-comparative, multi-center clinical trial

PURPOSE

Leuprorelin is a well known luteinizing hormone releasing hormone agonist. However, there are insufficient data on the efficacy and safety of high dose leuprorelin acetate, especially in Asian patients with prostate cancer. We aimed to investigate the safety and efficacy of leuprorelin acetate 22.5 mg administered at three-month intervals in patients with prostate cancer.

MATERIALS AND METHODS

In an open, prospective clinical trial enrolling 47 patients, we aimed to assess the efficacy and safety of leuprorelin acetate 22.5 mg in treating patients with histologically confirmed prostate cancer. The primary objective of this study was to evaluate the efficacy of the leuprorelin acetate 22.5 mg in producing and maintaining castration levels of testosterone over a 6-month follow-up period and to determine its safety profile.

RESULTS

All 42 patients achieved serum testosterone levels within the castration range by 4 weeks. A breakthrough response was observed in one of 36 patients by 8 weeks. However, this patient was medically castrated by 12 weeks. There were no significant prostate-specific antigen (PSA) or testosterone changes according to clinical stage or body mass index. Twenty adverse events (AEs) in 15 of 42 patients (35.7%) were observed during this study. The most common AEs were hot flushes (n=4, 20.0%) with mild intensity, pain (n=2, 10.0%), and infection (n=2, 10.0%). No patient withdrew from the study due to AEs.

CONCLUSION

Leuprorelin acetate 22.5 mg was shown to be effective and safe in Asian patients with prostate cancer, even though sexual function decreased.

Osteoporosis and cancer

Cancer is a major risk factor for bone loss and fractures. This is due both to direct effects of cancer cells on the skeleton and to deleterious effects of cancer-specific therapies on bone cells. Marked improvements in survival for many cancers mean that strategies to limit bone loss and reduce fracture risk must be incorporated into the care plans for nearly all patients with cancer. The vast majority of effort thus far has focused on bone loss in patients with breast and prostate cancers, with comparatively few studies in other malignancies. Antiresorptive therapies have proven nearly universally effective for limiting bone loss in cancer patients, although few studies have been powered sufficiently to include fractures as primary endpoints, and patients are frequently neither identified nor treated according to published guidelines. Nonpharmacologic approaches to limit falls, particularly in elderly patients, are also likely important adjunctive measures for most cancer patients.

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.

Relationship between body mass index and serum testosterone concentration in patients receiving luteinizing hormone-releasing hormone agonist therapy for prostate cancer

OBJECTIVE

To evaluate the relationship between the body mass index (BMI) and serum testosterone concentrations in men receiving luteinizing hormone-releasing hormone (LHRH) agonist therapy for prostate cancer.

MATERIALS AND METHODS

A total of 66 white men were included in the present study. All subjects had received LHRH agonist therapy for ≥ 3 months. The BMI was calculated, and the subjects were classified as normal weight (i.e. BMI <25 kg/m(2)), overweight (BMI 25-30 kg/m(2)), or obese (BMI >30 kg/m(2)). The serum testosterone concentration was determined using the highly sensitive isotope dilution-liquid chromatography-tandem mass spectrometry technique. The sex hormone-binding globulin level was determined using an immunometric assay, and the free serum testosterone concentration was calculated.

RESULTS

The median serum testosterone concentration of the patients with a BMI <25 kg/m(2) was 5.5 ng/dL. The patients with a BMI of 25-30 kg/m(2) had a median serum testosterone concentration of 3.8 ng/dL. Those patients with a BMI >30 kg/m(2) had a median concentration of 5.7 ng/dL. No significant difference in the serum testosterone concentrations among the 3 groups was found. The sex hormone-binding globulin levels declined with an increasing BMI. The concentration of free testosterone was significantly greater in the obese men.

CONCLUSION

Using an ultrasensitive technique of serum testosterone measurement, the present data have shown that no difference exists in the serum testosterone concentration in the castrate range among normal weight, overweight, and obese patients receiving LHRH agonist therapy for prostate cancer. From our findings and current knowledge, more stringent follow-up or changes in dosage or dosage intervals of LHRH agonist therapy in those with a greater or high BMI is not warranted.

Detectable prostate-specific antigen Nadir during androgen-deprivation therapy predicts adverse prostate cancer-specific outcomes: results from the SEARCH database

BACKGROUND

A prostate-specific antigen (PSA) level <0.2 ng/ml 8 mo after starting on androgen-deprivation therapy (ADT) is correlated with better outcomes. However, not all men reach a nadir PSA level within 8 mo. Whether the lowest PSA on ADT-specifically, <0.2 ng/ml-can be used for risk stratification is untested.

OBJECTIVE

We examined the predictive value of small but detectable PSA nadir values on prostate cancer (PCa)-specific outcomes in men treated with early ADT after radical prostatectomy (RP).

DESIGN, SETTING, AND PARTICIPANTS

We performed a retrospective review of men treated with ADT after RP before metastases from the SEARCH database. We identified 402 men treated with ADT for elevated PSA following RP, of whom 294 men had complete data. Median follow-up after PSA nadir was 49 mo. All men had a PSA nadir <4 ng/ml; 223 men (76%) had an undetectable nadir.

INTERVENTION

ADT for an elevated PSA following RP with no radiographic evidence of metastatic disease.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

PSA nadir on ADT was defined as the lowest PSA value during ADT. Proportional hazards models and the C index were used to test the association and predictive accuracy, respectively, between PSA nadir and PCa-specific outcomes.

RESULTS AND LIMITATIONS

Men with a PSA nadir between 0.01 and 0.2 ng/ml had a greater risk of progression to castration-resistant PCa (CRPC) (hazard ratio [HR]: 5.14; p<0.001), metastases (HR: 3.98; p=0.006), and PCa-specific mortality (PCSM) (HR: 5.33; p=0.003) than men with an undetectable nadir. When data were restricted to men followed with ultrasensitive PSA values (sensitivity of 0.01 ng/ml), the C index of PSA nadir alone for predicting CRPC, metastases, and PCSM was 0.88, 0.91, and 0.96, respectively.

CONCLUSIONS

A PSA nadir on ADT, even at a very low level, strongly predicts progression to CRPC, metastases, and PCSM. Men with a detectable PSA nadir during ADT should be considered for clinical trials.

Obesity and prostate cancer: weighing the evidence

CONTEXT

Obesity and prostate cancer (PCa) affect substantial proportions of Western society. Mounting evidence, both epidemiologic and mechanistic, for an association between the two is of public health interest. An improved understanding of the role of this modifiable risk factor in PCa etiology is imperative to optimize screening, treatment, and prevention.

OBJECTIVE

To consolidate and evaluate the evidence for an epidemiologic link between obesity and PCa, in addition to examining the proposed underlying molecular mechanisms.

EVIDENCE ACQUISITION

A PubMed search for relevant articles published between 1991 and July 2012 was performed by combining the following terms: obesity, BMI, body mass index and prostate cancer risk, prostate cancer incidence, prostate cancer mortality, radical prostatectomy, androgen-deprivation therapy, external-beam radiation, brachytherapy, prostate cancer and quality of life, prostate cancer and active surveillance, in addition to obesity, BMI, body mass index and prostate cancer and insulin, insulin-like growth factor, androgen, estradiol, leptin, adiponectin, and IL-6. Articles were selected based on content, date of publication, and relevancy, and their references were also searched for relevant articles.

EVIDENCE SYNTHESIS

Increasing evidence suggests obesity is associated with elevated incidence of aggressive PCa, increased risk of biochemical failure following radical prostatectomy and external-beam radiotherapy, higher frequency of complications following androgen-deprivation therapy, and increased PCa-specific mortality, although perhaps a lower overall PCa incidence. These results may in part relate to difficulties in detecting and treating obese men. However, multiple molecular mechanisms could explain these associations as well. Weight loss slows PCa in animal models but has yet to be fully tested in human trials.

CONCLUSIONS

Obesity appears to be linked with aggressive PCa. We suggest clinical tips to better diagnose and treat obese men with PCa. Whether reversing obesity slows PCa growth is currently unknown, although it is an active area of research.

Variations of serum testosterone levels in prostate cancer patients under LH-releasing hormone therapy: an open question

The hypothesis 'the lower the better when achieving castration levels of testosterone' is based on the data from second-line hormonal manipulation and its molecular basis, and on better oncological results reported for lower castration levels in prostate cancer (PCa) patients, including those achieved with maximal androgen blockade. In this regard, the equivalence of surgical and different pharmacological castrations has been controversial. The modified amino acid structure that makes LH-releasing hormone (LHRH) analogs more potent than LHRH, and the method of delivering the analogs impacts on bioavailibility and potentially causes differences in androgen levels and in its final oncological efficacy. In addition to this, there is a myriad of circumstances, such as those related to ethnic variations and co-morbidities, which uniquely impact on the pharmacological approach in a highly heterogeneous population of castration-resistant prostate cancer (CRPC) patients. Ineffective testosterone suppression through hormonal escape is currently poorly recognized and may result in increased PCa mortality. Until now, the optimal serum testosterone level in patients under castration, and the impact of its variations in patients under LHRH therapy, remain open questions and have been merged to a broad spectra of patients who are highly heterogeneous. This heterogeneity relates to a number of mechanisms regarding response to treatment, which influences the biology of the relapsing tumor and the sensitivity to subsequent therapies in the individual patient. The rationale to achieve testosterone levels below 20-50 ng/dl warrant further investigation as these levels have recently rescued CRPC patients. In the last few years and months, important advancements in prostate cancer treatment have been achieved. Nevertheless, these advances are measured in a few months of additional survival and under high costs, not available to most of the world population, compared with the benefits of hormonal manipulation that are measured in years, there is a huge potential for accessible and durable effect expansion and optimization of treatment, particularly with the current tendency of a more individual approach.

Obesity is associated with castration-resistant disease and metastasis in men treated with androgen deprivation therapy after radical prostatectomy: results from the SEARCH database

Study Type - Prognosis (cohort series). Level of Evidence 2a. What's known on the subject? and What does the study add? The incidence and prevalence of obesity in the USA and Europe is increasing. Higher body mass index is associated with a lower risk of overall prostate cancer diagnosis but also with an increased risk of high grade prostate cancer. Obese men undergoing primary therapy with radical prostatectomy or external beam radiation are more likely to experience a biochemical recurrence after treatment compared with normal weight men. Finally, obesity is associated with increased prostate-cancer-specific mortality. We hypothesized that obese men on androgen deprivation therapy may be at increased risk for prostate cancer progression. Previous studies have shown that obese men have lower levels of testosterone compared with normal weight men. Additionally, one previous study found that obese men have higher levels of testosterone on androgen deprivation therapy. Men with higher levels of testosterone on androgen deprivation therapy are at increased risk of prostate cancer progression. We found that men with higher body mass index were at increased risk of progression to castration-resistant prostate cancer, development of metastases and prostate-cancer-specific mortality. When we adjusted for various clinicopathological characteristics, obese men were at increased risk of progression to castration-resistant prostate cancer and development of metastases. The results of our study help generate hypotheses for further study regarding the mechanisms between obesity and aggressive prostate cancer.

OBJECTIVE

• To investigate whether obesity predicts poor outcomes in men starting androgen deprivation therapy (ADT) before metastasis, since previous studies found worse outcomes after surgery and radiation for obese men.

METHODS

• A retrospective review was carried out of 287 men in the SEARCH database treated with radical prostatectomy between 1988 and 2009. • Body mass index (BMI) was categorized to <25, 25-29.9 and ≥ 30 kg/m2. • Proportional hazards models were used to test the association between BMI and time to castration-resistant prostate cancer (PC), metastases and PC-specific mortality adjusting for demographic and clinicopathological data.

RESULTS

• During a median 73-month follow-up after radical prostatectomy, 403 men (14%) received early ADT. • Among 287 men with complete data, median BMI was 28.3 kg/m2. • Median follow-up from the start of ADT was 52 months during which 44 men developed castration-resistant PC, 34 developed metastases and 24 died from PC. • In multivariate analysis, higher BMI was associated with a trend for greater risk of progression to castration-resistant PC (P= 0.063), a more than threefold increased risk of developing metastases (P= 0.027) and a trend toward worse PC-specific mortality (P= 0.119). • Prognostic biomarkers did not differ between BMI groups.

CONCLUSIONS

• Among men treated with early ADT, our results suggest that obese men may have increased risk of PC progression. • These data support the general hypothesis that obesity is associated with aggressive PC, although validation of these findings and further study of the mechanisms linking obesity and poor PC outcomes are required.

Emerging therapies to prevent skeletal morbidity in men with prostate cancer

Skeletal morbidity is a prominent burden to men with advanced prostate cancer throughout the natural history of the disease. Bone metastases can cause pain and greatly elevate the risk for fractures and other structural complications. Distinct from the problem of metastases, treatment-related osteoporosis and associated fragility fractures are potential complications of androgen-deprivation therapy. Bone-targeted therapies for prostate cancer have therefore been the focus of considerable research and drug development efforts. The osteoclast is a validated therapeutic target in the management of prostate cancer. Osteoclast inhibition with zoledronic acid (a bisphosphonate) or with denosumab (a monoclonal antibody to RANK ligand) reduces risk for skeletal events in men with castration-resistant prostate cancer metastatic to bone. Osteoclast inhibition with any of several bisphosphonates improves bone mineral density, a surrogate for osteoporotic fracture risk. Denosumab and toremifene (a selective estrogen receptor modulator) have each been shown to reduce osteoporotic fracture risk among men receiving androgen-deprivation therapy. Beta-emitting radiopharmaceuticals reduce pain due to metastatic disease. Investigations involving alpha-emitting radium-223, endothelin-A receptor antagonists atrasentan and zibotentan, proto-oncogene tyrosine-protein kinase (SRC) inhibitor dasatinib, and tyrosine kinase inhibitor cabozantinib (XL184) are ongoing in clinical trials and are also discussed.

Contemporary therapeutic approaches targeting bone complications in prostate cancer

Skeletal complications are major causes of morbidity in patients with prostate cancer. Despite the osteoblastic appearance of prostate cancer bone metastases, elevated serum and urinary markers of bone resorption are indicative of high osteoclast activity. Increased osteoclast activity is independently associated with subsequent skeletal complications, disease progression, and death. Osteoclast-targeted therapies aim to reduce the risk for disease-related skeletal complications, bone metastases, and treatment-related fractures. This review focuses on recent advances in osteoclast-targeted therapies in the treatment and prevention of bone complications in prostate cancer. Osteoclast-targeted therapies have been extensively studied in men with prostate cancer. The potent bisphosphonate zoledronic acid significantly decreased the risk of skeletal complications in men with castration-resistant prostate cancer and bone metastases, and is Federal Drug Administration approved for this indication. Denosumab is a human monoclonal antibody that inhibits receptor activator of nuclear factor-κB (RANK) ligand, a critical mediator of osteoclast differentiation, activation, and survival. Data from recent phase III clinic trials demonstrate the emerging role for denosumab in the treatment of prostate cancer bone metastases and prevention of fractures associated with androgen deprivation therapy.

Treatment and prevention of bone complications from prostate cancer

Bone metastases and skeletal complications are major causes of morbidity in prostate cancer patients. Despite the osteoblastic appearance of bone metastases on imaging studies, patients have elevated serum and urinary markers of bone resorption, indicative of high osteoclast activity. Increased osteoclast activity is independently associated with higher risk of subsequent skeletal complications, disease progression, and death. Osteoclast-targeted therapies are therefore a rational approach to reduction of risk for disease-related skeletal complications, bone metastases, and treatment-related fractures. This review focuses on recent advances in osteoclast-targeted therapy in prostate cancer. Bisphosphonates have been extensively studied in men with prostate cancer. Zoledronic acid significantly decreased the risk of skeletal complications in men with castration-resistant prostate cancer and bone metastases, and it is FDA-approved for this indication. Denosumab is a human monoclonal antibody that binds and inactivates RANKL, a critical mediator of osteoclast differentiation, activation, and survival. Recent global phase 3 clinic trials demonstrated an emerging role for denosumab in the treatment of prostate cancer bone metastases and prevention of fractures associated with androgen deprivation therapy.

Evidence-based medicine: comparative analysis of luteinizing hormone-releasing hormone analogues in combination with external beam radiation and surgery in the treatment of carcinoma of the prostate

What's known on the subject? and What does the study add? Luteinizing hormone-releasing hormone analogues are a cornerstone in the management of many clinical situations in prostate cancer patients. The multiplicity of drugs make it difficult to decide which is the best drug to prescribe to each patient. Whether or not the different luteinizing hormone-releasing hormone analogues belong to the same drug class is only merely supposed. This study adds a systematic review of the literature in order to determine whether or not the luteinizing hormone-releasing hormone analogues available for prescription belong to the same drug class (same family, similar chemical structure, mechanism of action, and efficacy). The current evidence available is not enough to support a presumed drug class effect of the various analogues in the treatment of prostate carcinoma.

OBJECTIVE

• To study whether luteinizing hormone-releasing hormone (LHRH) analogues are agents of the same pharmacological class, i.e. whether they have the same clinical effect, using an evidence-based medicine approach.

MATERIAL AND METHODS

• We reviewed the evidence on the alleged 'drug class effect' among analogues and the existing bibliographic support for their use in various medical indications. We used PubMed as the main search source. Evidence level and degree of recommendation were assigned to each conclusion based on the 'Scottish Intercollegiate Guidelines Network'.

RESULTS

• There are no studies designed to answer the question of class effect between LHRH analogues or agonists. Reviews and meta-analyses have been performed on many other issues related to therapeutic management either with analogues alone, or in combination with radiation therapy and surgery. • Direct comparisons do not allow definitive conclusions to be reached. Indirect evidence is obtained from randomized studies comparing the different LHRH analogues with other treatments used to obtain androgen deprivation. Other issues related to pharmacokinetics and pharmacodynamics that can support either the existence or non-existence of class effect were evaluated.

CONCLUSION

• The current available evidence is not enough to support a presumed class effect of the drug among the different analogues in the treatment of prostate carcinoma in its various clinical situations.

Impact of body mass index on outcomes after conformal radiotherapy in patients with prostate cancer

PURPOSE

Several retrospective analyses have suggested that obese men with prostate cancer treated with external beam radiotherapy (EBRT) have outcomes inferior to those of normal-weight men. However, a recently presented analysis for the first time challenged this association between body mass index (BMI) and treatment failure. It is therefore important to provide further data on this issue.

METHODS AND MATERIALS

This was a retrospective analysis of 564 men treated with risk-adapted conformal EBRT at a single institution. Low-risk patients received EBRT alone, and the other patients received EBRT plus endocrine treatment. In addition, high-risk patients were treated to higher EBRT doses (74 Gy). A rectal balloon catheter for internal immobilization, which can be identified on portal images, was used in 261 patients (46%). Thus, localization did not rely on bony landmarks alone in these cases.

RESULTS

The median BMI was 26, and 15% of patients had BMI≥30. Neither univariate nor multivariate analyses detected any significant impact of BMI on biochemical relapse, prostate cancer-specific survival, or overall survival. The 5-year biochemical relapse rate was 21% and prostate cancer-specific survival 96%.

CONCLUSIONS

The present analysis of a large cohort of consecutively treated patients suggests that efforts to reduce prostate movement and geographic miss might result in comparable outcomes in obese and normal-weight patients.

Triptorelin 6-month formulation in the management of patients with locally advanced and metastatic prostate cancer: an open-label, non-comparative, multicentre, phase III study

BACKGROUND AND OBJECTIVES

Triptorelin 6-month formulation was developed to offer greater convenience to both patients and physicians by reducing the injection frequency. The efficacy, pharmacokinetics and safety of a new 6-month formulation of triptorelin were investigated over 12 months (48 weeks). The primary objective was to evaluate the formulation in achieving castrate serum testosterone levels (< or = 1.735 nmol/L or < or = 50 ng/dL) on day 29 and in maintaining castration at months 2-12. Absence of luteinizing hormone (LH) stimulation and change in prostate-specific antigen (PSA) level were also assessed.

METHODS

An open-label, non-comparative, phase III study in 120 patients with advanced prostate cancer was conducted from July 2006 to August 2007 in private and public institutions in South Africa. Each patient received two consecutive intramuscular injections of triptorelin embonate (pamoate) 22.5 mg at an interval of 24 weeks. In all patients, testosterone (primary outcome measurement) was measured at baseline and then every 4 weeks; LH was measured before and 2 hours after the two injections. PSA was measured on day 1 and at weeks 12, 24, 36 and 48. Adverse events were recorded at each visit.

RESULTS

In the intent-to-treat population, 97.5% (95% CI 92.9, 99.5) of patients achieved castrate serum testosterone levels by day 29, and 93.0% (95% CI 86.8, 97.0) maintained castration at months 2-12. After the second injection, 98.3% of patients showed absence of LH stimulation. The most frequent drug-related adverse events were hot flushes (71.7% of patients). No patient withdrew from the study as a result of an adverse event.

CONCLUSIONS

The triptorelin 6-month formulation was well tolerated and was able to achieve and maintain castration for the treatment of locally advanced and metastatic prostate cancer. By reducing the frequency of required injections, this new formulation offers a more convenient treatment regimen. (Clinical Trial Registration,NCT00751790 at www.clinicaltrials.gov).

Intermittent androgen deprivation therapy: redefining the standard of care?

As a clinical strategy, intermittent androgen deprivation therapy (IADT) has the potential to minimize adverse events associated with continuous androgen deprivation therapy while providing comparable efficacy for patients with advanced prostate cancer. Because most studies supporting IADT to date have been somewhat small and underpowered, additional large, randomized, controlled trials are needed before this strategy becomes the standard of care. However, the potential advantages of IADT, which include improved quality of life, the theoretical possibility of delaying hormone resistance, and possible reduction in expenses to the patient and health care payers, suggest it is a strategy worth further exploration.

Will GnRH antagonists improve prostate cancer treatment?

Androgen ablation forms a basis for treating prostate cancer and is achieved either by surgical castration, or pharmacologically using oestrogens, anti-androgens and/or gonadotropin-releasing hormone (GnRH) analogues. GnRH antagonists (or blockers) offer a new means of treatment by directly blocking GnRH receptors. Advantages of GnRH antagonists include lack of the initial stimulation of gonadotropin and testosterone production, lack of gonadotropin microsurges and sustained follicle-stimulating hormone suppression; disadvantages include increased histamine release. This review discusses advantages and disadvantages of the GnRH antagonists currently in development, in light of receptor physiology and pre-clinical and clinical data. Comparative clinical trials will ultimately establish their efficacy in comparison to other pharmacotherapies. Therefore, continuing development and refinement is needed to improve prostate cancer treatment.

Effective testosterone suppression for prostate cancer: is there a best castration therapy?

Achieving and maintaining effective suppression of serum testosterone levels in men treated with androgen ablation is one of the essential strategies in the management of prostate cancer. Historically, a serum testosterone below 50 ng/dL was considered to be the castrate level. Current data suggest that the new target for either surgical or chemical castration is a serum testosterone level of lower than 20 ng/dL in an attempt to maximize therapeutic outcomes. Testosterone breakthrough and the acute-on-chronic effects of administration of a luteinizing hormone-releasing hormone analogue may cause testosterone levels to periodically rise, sometimes to noncastrate levels. The goal of androgen ablation is to identify those agents that will most consistently achieve and maintain the lowest testosterone levels possible.

Kinetics of serum androgen normalization and factors associated with testosterone reserve after limited androgen deprivation therapy for nonmetastatic prostate cancer

PURPOSE

Groups have investigated time to testosterone recovery in patients who have undergone androgen deprivation therapy, usually by measuring androgen every 3 months, with varying results. To our knowledge this represents the largest study using monthly testosterone and dihydroxytestosterone measurement to evaluate the kinetics of androgen recovery following limited androgen deprivation therapy.

MATERIALS AND METHODS

Monthly serum androgen levels were analyzed following 2, 6-month cycles of gonadotropin-releasing hormone agonist therapy as part of a randomized, placebo controlled study of the role of thalidomide in delaying time to prostate specific androgen progression.

RESULTS

By the Kaplan-Meier method the median time to testosterone normalization in cycles 1 vs 2 was 15.4 vs 18.3 weeks with similar dihydroxytestosterone recovery times. Neither on-study prostate specific antigen, Gleason score nor thalidomide treatment had a significant impact on time to testosterone normalization. However, in cycle 1 men with low baseline dihydroxytestosterone and those who were more than 67 years old had significantly longer time to T normalization on Cox model analysis. Additionally, in cycle 2 patients with prior local radiation therapy had longer time to testosterone normalization, although this was no longer significant on Cox model analysis. Cox model analysis in cycle 2 showed that low baseline dihydroxytestosterone and testosterone, low testosterone nadir and white race were associated with longer time to testosterone normalization.

CONCLUSIONS

Findings of delayed testosterone recovery may be useful for designing and analyzing clinical trials of limited androgen deprivation therapy and for estimating the duration of treatment associated side effects in patients undergoing limited androgen deprivation therapy.

The relationship of body mass index and serum testosterone with disease outcomes in men with castration-resistant metastatic prostate cancer

The purpose of this study was to evaluate the relationship of baseline body mass index (BMI) and serum testosterone level with prostate cancer outcomes in men with castration-resistant metastatic prostate cancer (CRPC). BMI and testosterone levels were evaluated for their ability to predict overall survival (OS) and prostate-specific antigen (PSA) declines in the TAX327 clinical trial, an international phase III randomized trial of one of the two schedules of docetaxel and prednisone compared with mitoxantrone and prednisone. In this study of 1006 men with CRPC, the median serum testosterone level was 14.5 ng per 100 ml (range 0-270), the median BMI was 27 kg m(-2) (range 15.7-46.5), and 26% of men were obese or morbidly obese (BMI>or=30). Obesity was associated with younger age, lower PSA and alkaline phosphatase levels, and higher performance status, primary Gleason sum, testosterone and hemoglobin compared to absence of obesity. In multivariate analysis, neither BMI, presence of obesity, nor baseline testosterone was significantly associated with OS or PSA declines. Higher testosterone levels among obese men suggest incomplete gonadal suppression with current therapies, but these differences may not be clinically relevant in men with CRPC. There was evidence of potential hemodilution of PSA and alkaline phosphatase levels in obese men.