Androgen-deprivation therapy for nonmetastatic prostate cancer is associated with an increased risk of peripheral arterial disease and venous thromboembolism

[Cardiovascular risk of androgen deprivation therapy for treatment of hormone-dependent prostate cancer : Differences between GnRH antagonists and GnRH agonists]

BACKGROUND

Several studies have indicated that reduction of testosterone levels in patients with prostate cancer undergoing androgen deprivation therapy (ADT) with gonadotropin-releasing hormone (GnRH) agonists can be associated with an increased risk of cardiovascular events. The GnRH antagonists have a different mode of action compared with GnRH agonists and may be preferred in ADT for patients with cardiovascular disease.

OBJECTIVE

This review article discusses potential mechanisms underlying the development of cardiovascular events associated with ADT when using GnRH agonists and explains the differences in mode of action between GnRH agonists and GnRH antagonists. Additionally, relevant studies are presented and practical recommendations for the clinical practice are provided.

MATERIAL AND METHODS

A literature search was performed. Full publications and abstracts published in the last 10 years up to September 2015 were considered to be eligible.

RESULTS

The GnRH antagonists were associated with a decreased risk of cardiovascular events compared with GnRH agonists in prostate cancer patients undergoing ADT and particularly in patients with cardiovascular risk factors or a history of cardiovascular disease. This decrease may be due to the different mode of action of GnRH antagonists compared with GnRH agonists.

CONCLUSION

Prostate cancer patients with either cardiovascular disease or an increased risk of experiencing a cardiovascular event undergoing ADT should be preferentially treated with GnRH antagonists.

Androgen receptor (AR) in cardiovascular diseases

Cardiovascular diseases (CVDs) are still the highest leading cause of death worldwide. Several risk factors have been linked to CVDs, including smoking, diabetes, hyperlipidemia, and gender among others. Sex hormones, especially the androgen and its receptor, androgen receptor (AR), have been linked to many diseases with a clear gender difference. Here, we summarize the effects of androgen/AR on CVDs, including hypertension, stroke, atherosclerosis, abdominal aortic aneurysm (AAA), myocardial hypertrophy, and heart failure, as well as the metabolic syndrome/diabetes and their impacts on CVDs. Androgen/AR signaling exacerbates hypertension, and anti-androgens may suppress hypertension. Androgen/AR signaling plays dual roles in strokes, depending on different kinds of factors; however, generally males have a higher incidence of strokes than females. Androgen and AR differentially modulate atherosclerosis. Androgen deficiency causes elevated lipid accumulation to enhance atherosclerosis; however, targeting AR in selective cells without altering serum androgen levels would suppress atherosclerosis progression. Androgen/AR signaling is crucial in AAA development and progression, and targeting androgen/AR profoundly restricts AAA progression. Men have increased cardiac hypertrophy compared with age-matched women that may be due to androgens. Finally, androgen/AR plays important roles in contributing to obesity and insulin/leptin resistance to increase the metabolic syndrome.

Relationship between androgen deprivation therapy and community-acquired respiratory infections in patients with prostate cancer

OBJECTIVES

To investigate the dose-dependent effect of androgen deprivation therapy on community-acquired respiratory infections in patients with localized prostate cancer.

METHODS

We identified 52 905 men diagnosed with localized prostate cancer within the Surveillance, Epidemiology and End Results-Medicare database between 1991 and 2006. We compared those who did not receive androgen deprivation therapy with those who received androgen deprivation therapy within 2 years of diagnosis, calculated as monthly equivalent doses (<7, 7-11, >11 doses), or orchiectomy. Adjusted Cox hazard models were fitted to predict the risk of community-acquired respiratory infections (acute sinusitis, acute bronchitis, [severe] pneumonia) in patients treated with medical androgen deprivation therapy versus orchiectomy versus none.

RESULTS

Overall, 43.4% received medical androgen deprivation therapy. These patients more likely experienced respiratory events compared with those who did not receive androgen deprivation therapy or who underwent orchiectomy (62.2% vs 54.5% vs 47.8%, P < 0.001). The risk of experiencing any respiratory event increased with the number of doses received. For example, men receiving >11 doses of androgen deprivation therapy were at greatest risk of acute sinusitis, acute bronchitis and pneumonia (HR 1.13, 1.26 and 1.15, respectively, all P < 0.001), except severe pneumonia. Furthermore, we did not detect any relationship between orchiectomy and respiratory events. Study limitations include the utilization of a retrospective population-based dataset.

CONCLUSIONS

Increased exposure to medical androgen deprivation therapy for men with localized prostate cancer is associated with a higher risk of community-acquired respiratory infections. Our results suggest that respiratory complications represent potentially underreported complications of medical androgen deprivation therapy.

Androgen Deprivation Therapy and Future Alzheimer's Disease Risk

PURPOSE

To test the association of androgen deprivation therapy (ADT) in the treatment of prostate cancer with subsequent Alzheimer's disease risk.

METHODS

We used a previously validated and implemented text-processing pipeline to analyze electronic medical record data in a retrospective cohort of patients at Stanford University and Mt. Sinai hospitals. Specifically, we extracted International Classification of Diseases-9th revision diagnosis and Current Procedural Terminology codes, medication lists, and positive-present mentions of drug and disease concepts from all clinical notes. We then tested the effect of ADT on risk of Alzheimer's disease using 1:5 propensity score-matched and traditional multivariable-adjusted Cox proportional hazards models. The duration of ADT use was also tested for association with Alzheimer's disease risk.

RESULTS

There were 16,888 individuals with prostate cancer meeting all inclusion and exclusion criteria, with 2,397 (14.2%) receiving ADT during a median follow-up period of 2.7 years (interquartile range, 1.0-5.4 years). Propensity score-matched analysis (hazard ratio, 1.88; 95% CI, 1.10 to 3.20; P = .021) and traditional multivariable-adjusted Cox regression analysis (hazard ratio, 1.66; 95% CI, 1.05 to 2.64; P = .031) both supported a statistically significant association between ADT use and Alzheimer's disease risk. We also observed a statistically significant increased risk of Alzheimer's disease with increasing duration of ADT (P = .016).

CONCLUSION

Our results support an association between the use of ADT in the treatment of prostate cancer and an increased risk of Alzheimer's disease in a general population cohort. This study demonstrates the utility of novel methods to analyze electronic medical record data to generate practice-based evidence.

Androgen deprivation therapy and cardiovascular disease: what is the linking mechanism?

The past decade has brought increased awareness of the potential adverse effects of androgen deprivation therapy (ADT) in men with prostate cancer. Arguably the most important and controversial of these is the increased risk of cardiovascular morbidity and mortality. Although multiple observational studies have shown that men treated with ADT are at increased risk of developing atherosclerotic cardiovascular disease, our understanding of the biological mechanisms that might underlie this phenomenon is still evolving. In this review, we discuss some of the mechanisms that have been proposed to date, including ADT-induced metabolic changes that promote the development and progression of atherosclerotic plaques as well as direct local effects of hormonal factors on plaque growth, rupture and thrombosis.

Risk of thromboembolic disease in men with prostate cancer undergoing androgen deprivation therapy

OBJECTIVES

To investigate the risk of thromboembolic disease (TED) in men with prostate cancer (PCa) on androgen deprivation therapy (ADT), while accounting for known TED risk factors.

MATERIALS AND METHODS

We assessed TED risk for 42 263 men with PCa who were receiving ADT compared with a matched cohort of 190 930 without PCa. The associations between ADT and deep vein thrombosis (DVT) or pulmonary embolism (PE) were analysed using multivariate Cox proportional hazard regression models, while accounting for previous PCa-related surgeries and the following proxies for disease progression: transurethral resection of the prostate, palliative radiotherapy and nephrostomy.

RESULTS

Between 1997 and 2013, 11 242 men with PCa received anti-androgen monotherapy, 26 959 men received gonadotropin-releasing hormone (GnRH) agonists, 1 091 men received combined androgen blockade and 3 789 men underwent orchiectomy. When accounting for previous surgeries and proxies of disease progression, GnRH agonist users and surgically castrated men had a higher risk of TED than the comparison cohort: hazard ratios (HRs) 1.67 (95% confidence interval [CI] 1.40-1.98) and 1.61 (95% CI 1.15-2.28), respectively. Men on anti-androgen monotherapy had a lower risk: HR for DVT 0.49 (95% CI 0.33-0.74). TED risk was highest among those who switched from anti-androgen to GnRH agonists: HR for PE 2.55 (95% CI 1.76-3.70). This increased from 2.52 (95% CI 1.54-4.12) in year 1, to 4.05 (95% CI 2.51-6.55) in year 2.

CONCLUSION

The incidence of TED among men on ADT increased with the duration of therapy and the risk was highest for those who switched regimen, suggesting that disease progression as well as ADT contribute to the propagation of TED risk. Nonetheless, these findings support the hypothesis that only men with a relevant indication should receive systemic ADT.

Cardiovascular mortality in patients with prostate cancer exposed to androgen deprivation therapy

INTRODUCTION

A relationship between the administration of GnRH agonists and the risk of acute myocardial infarction (AMC) in patients with prostate cancer has been showed in the third observational study published in April 2014. The association AMC-orchiectomy was not found in any of these studies.

OBJECTIVE

Define risk factors for cardiovascular disease in patients treated with GnRH agonist. Their probable underlying pathogenic mechanism in the myocardium and peripheral vascular tree was also analyzed.

EVIDENCE ACQUISITION

English articles cited in PubMed were reviewed. No time period is specified. The last search date was 11/30/14.

EVIDENCE SYNTHESIS

In patients with coronary history of AMC or congestive heart failure, hormonal neoadjuvant therapy increased cardiovascular mortality rates (HR: 1.96, IC 95%: 1.04-3.71; P=.04) as well as cardiovascular-specific mortality rates (AHR: 3.28; IC 95%: 1.01-10.64; P=.048). Two possible mechanisms can be involved: a) direct mechanism through myocardial receptor for GnRH/PKA along with atherogenic plaques; and b) indirect mechanism related with metabolic disturbances.

CONCLUSIONS

Patients with AMC or congestive heart failure history could present a higher risk of death related to the use of GnRH agonists. In these cases, should carefully consider appropriateness of such treatment. These effects can explained by a direct mechanism on myocardium and peripheral vascular tree and indirect ones related with modified metabolic syndrome.

The Prevalence of Cardiac Risk Factors in Men with Localized Prostate Cancer Undergoing Androgen Deprivation Therapy in British Columbia, Canada

Background. While androgen deprivation therapy (ADT) reduces the risk of prostate cancer-specific mortality in high-risk localized prostate cancer, it adversely affects cardiovascular (CV) risk factor profiles in treated men. Methods. We retrospectively reviewed the charts of 100 consecutive men with intermediate- or high-risk localized prostate cancer referred to the British Columbia Cancer Agency for ADT. Data on CV risk factors and disease were collected and Framingham risk scores were calculated. Results. The median age of the study cohort was 73 years. Established cardiovascular disease was present in 25% of patients. Among patients without established CV disease, calculated Framingham risk was high in 65%, intermediate in 33%, and low in 1%. Baseline hypertension was present in 58% of patients, dyslipidemia in 51%, and diabetes or impaired glucose tolerance in 24%. Hypertension was more prevalent in the study cohort than in an age- and sex-matched population sample (OR 1.74, P = 0.006); diabetes had a similar prevalence (OR 0.93, P = 0.8). Conclusions. Patients receiving ADT have a high prevalence of cardiovascular disease and risk factors and are more likely to be hypertensive than population controls. Low rates of CV risk screening suggest opportunities for improved primary and secondary prevention of CV disease in this population.

Cardiovascular effects of hormone therapy for prostate cancer

Androgen deprivation therapy (ADT) has been the mainstay of treatment for advanced prostate cancer for decades, and has been shown to control disease and improve symptoms. In addition, for men with high-risk localized or locally advanced prostate cancer, short-course ADT in combination with radiotherapy improves survival. There is evidence that ADT increases cardiovascular risk, particularly in men with preexisting cardiovascular disease. This increased risk may apply even with short-course ADT. In an individual patient, the benefits of ADT should be balanced against the risk, and patients who require ADT should have risk factors for cardiovascular disease optimized. There is some evidence to suggest that more contemporary methods of delivering ADT may reduce cardiovascular risk.

Medical androgen deprivation therapy and increased non-cancer mortality in non-metastatic prostate cancer patients aged ≥66 years

PURPOSE

To examine the potential relationship between androgen deprivation therapy and other-cause mortality (OCM) in patients with prostate cancer treated with medical primary-androgen deprivation therapy, prostatectomy, or radiation.

METHODS

A total of 137,524 patients with non-metastatic PCa treated between 1995 and 2009 within the Surveillance Epidemiology and End Results Medicare-linked database were included. Cox-regression analysis tested the association of ADT with OCM. A 40-item comorbidity score was used for adjustment.

RESULTS

Overall, 9.3% of patients harbored stage III-IV disease, and 57.7% of patients received ADT. The mean duration of ADT exposure was 22.9 months (median: 9.1; IQR: 2.8-31.5). Mean and median follow-up were 66.9, and 60.4 months, respectively. At 10 years, overall-OCM rate was 36.5%; it was 30.6% in patients treated without ADT vs. 40.1% in patients treated with ADT (p < 0.001). In multivariable-analysis, ADT was associated with an increased risk of OCM (Hazard-ratio [HR]: 1.11, 95% Confidence-interval [95% CI]: 1.08-1.13). Patients with no comorbidity (10-year OCM excess risk: 9%) were more subject to harm from ADT than patients with high comorbidity (10-year OCM excess risk: 4.7%).

CONCLUSIONS

In patients with PCa, treatment with medical ADT may increase the risk of mortality due to causes other than PCa. Whether this is a simple association or a cause-effect relationship is unknown and warrants further study in prospective studies.

Overdetection of recurrence after radical prostatectomy: estimates based on patient and tumor characteristics

PURPOSE

Prostate-specific antigen recurrence (PSA-R) after radical prostatectomy (RP) can occur years before metastasis. This study estimates the chance that an untreated PSA-R would not progress to clinical metastasis within the patient's lifetime, that is, that recurrence is overdetected.

EXPERIMENTAL DESIGN

Times from PSA-R to metastasis were estimated from patients with RP treated at Johns Hopkins University (Baltimore, MD) who did not receive salvage treatment (n = 441) at PSA-R. Times to other-cause death were based on U.S. life tables adjusted to reflect other-cause survival among RP cases in the Surveillance, Epidemiology, and End Results (SEER) registry. We used competing risks simulation to estimate lower bounds on the chance that other-cause death would precede clinical metastasis for patients with disease characteristics at diagnosis based on the Cancer of the Prostate Strategic Urologic Research Endeavor (CaPSURE) database (n = 4,455).

RESULTS

Cumulative incidence of PSA-R in CaPSURE was 13.6% at 5 years and 19.9% at 10 years. The risk of other-cause death among patients with RP in SEER was 60% lower than the age-matched U.S. population. At least 9.1% of patients with PSA-R <5 years after RP and at least 15.6% of patients with PSA-R 5 to 10 years after RP were overdetected. At least 31.4% of patients over the age of 70 years at diagnosis, who recurred <10 years of diagnosis, were overdetected.

CONCLUSIONS

This analysis indicates that PSA-R after RP may be overdetected, with risk depending on patient age and tumor characteristics. The potential for overdetection of recurrence confirms the need for approaches to determine whether and when to initiate salvage therapies.

Prostate cancer, comorbidity, and the risk of venous thromboembolism: A cohort study of 44,035 Danish prostate cancer patients, 1995-2011

BACKGROUND

Venous thromboembolism (VTE) is a serious complication of cancer. It is unknown whether comorbidity interacts clinically with prostate cancer (PC) to increase the VTE rate beyond that explained by PC and comorbidity alone, for example, by delaying diagnosis or precluding treatment.

METHODS

A nationwide, registry-based cohort study of all 44,035 Danish patients diagnosed with PC from 1995 to 2011 and 213,810 men from the general population matched 5:1 on age, calendar time, and comorbidities. The authors calculated VTE rate ratios and the interaction contrast as a measure on the additive scale of the excess VTE rate explained by synergy between PC and comorbidity.

RESULTS

In total, 849 patients in the PC cohort and 2360 men from the general population had VTE during 5 years of follow-up, and their risk of VTE was 2.2% and 1.3%, respectively. The 1-year VTE standardized rate among PC patients who had high comorbidity levels was 15 per 1000 person-years (PYs) (95% confidence interval, 6.8-24 per 1000 PYs), and 29% of that rate was explained by an interaction between PC and comorbidity. The VTE risk was increased among older patients, those with metastases, those with high Gleason scores, those in the D'Amico high-risk group, and those who underwent surgery.

CONCLUSIONS

PC interacted clinically with high comorbidity levels and increased the VTE rate. Because of the large PC burden, reducing VTEs associated with comorbidities may have an impact on VTE risk and the potential to improve prognosis. Clinical interactions between high levels of comorbidity and PC on the risk of VTE were observed. Almost 30% of all episodes of VTE occurred among patients who had high levels of comorbidity.

Cardiovascular risk with androgen deprivation therapy for prostate cancer: potential mechanisms

Androgen deprivation therapy (ADT) is frequently used for the treatment of advanced prostate cancer. ADT is associated with numerous side effects related to its mode of action, namely the suppression of testosterone to castrate levels. Recently, several large retrospective studies have also reported an increased risk of diabetes and cardiovascular disease in men receiving ADT, although these risks have not been confirmed by prospective randomized trials. We review the literature to consider the risk of cardiovascular disease with different forms of ADT and examine in detail potential mechanisms by which any such risk could be mediated. Mechanisms discussed include the metabolic syndrome resulting from low testosterone level and the potential roles of testosterone flare, gonadotropin-releasing hormone receptors outside the pituitary gland, and altered levels of follicle-stimulating hormone. Finally, the clinical implications for men prescribed ADT for the treatment of advanced prostate cancer are considered.

Quantifying observational evidence for risk of fatal and nonfatal cardiovascular disease following androgen deprivation therapy for prostate cancer: a meta-analysis

CONTEXT

Whether androgen deprivation therapy (ADT) for men with prostate cancer (PCa) increases the risk of cardiovascular disease (CVD) remains controversial. Pooled analyses using data from randomised controlled trials suggest no increased risk of fatal CVD following ADT, but no pooled analyses exist for observational studies.

OBJECTIVE

To perform a meta-analysis using observational data on ADT and risk of CVD events in men with PCa.

EVIDENCE ACQUISITION

PubMed and Embase were searched using predefined inclusion criteria to perform meta-analyses on associations between types of ADT and nonfatal and fatal CVD outcomes using information from observational studies. Random effects meta-analyses were conducted to estimate relative risks (RRs) and 95% confidence intervals (CIs).

EVIDENCE SYNTHESIS

A total of eight observational studies were identified studying at least one type of ADT and a nonfatal or fatal CVD outcome. The RR for risk of any type of nonfatal CVD was 1.38 (95% CI, 1.29-1.48) for men with PCa on gonadotropin-releasing hormone (GnRH) agonists, compared with men not treated with ADT. When analysing nonfatal ischemic heart disease only, the RR was 1.39 (95% CI, 1.26-1.54). The associations between GnRH agonists and nonfatal or fatal myocardial infarction or stroke were even stronger: RR: 1.57 (95% CI, 1.26-1.94) and RR: 1.51 (95% CI, 1.24-1.84), respectively. The results for other types of ADT in relation to the risk of any nonfatal CVD were RR: 1.44 (95% CI, 1.28-1.62) for orchiectomy and RR: 1.21 (95% CI, 1.07-1.367) for antiandrogens.

CONCLUSIONS

Observational data show a consistent positive association between ADT and the risk of CVD. This finding supports the need for future randomised trials of PCa patients that include older patients and men with multiple comorbidities to better reflect the general population.

PATIENT SUMMARY

We investigated all the available data from observational studies on hormonal treatment for prostate cancer and its possible cardiovascular adverse effects. We found consistent evidence that this treatment may increase the risk of cardiovascular disease.

Nonparametric Bounds and Sensitivity Analysis of Treatment Effects

This paper considers conducting inference about the effect of a treatment (or exposure) on an outcome of interest. In the ideal setting where treatment is assigned randomly, under certain assumptions the treatment effect is identifiable from the observable data and inference is straightforward. However, in other settings such as observational studies or randomized trials with noncompliance, the treatment effect is no longer identifiable without relying on untestable assumptions. Nonetheless, the observable data often do provide some information about the effect of treatment, that is, the parameter of interest is partially identifiable. Two approaches are often employed in this setting: (i) bounds are derived for the treatment effect under minimal assumptions, or (ii) additional untestable assumptions are invoked that render the treatment effect identifiable and then sensitivity analysis is conducted to assess how inference about the treatment effect changes as the untestable assumptions are varied. Approaches (i) and (ii) are considered in various settings, including assessing principal strata effects, direct and indirect effects and effects of time-varying exposures. Methods for drawing formal inference about partially identified parameters are also discussed.

Cardiovascular risk profile of veteran men beginning androgen deprivation therapy

We sought to describe the cardiovascular profile of veteran men before beginning androgen deprivation therapy (ADT), with the eventual benefit of targeting treatments to manage harmful cardiovascular side effects. We performed a secondary analysis with chi-square and Fisher's exact tests for associations between demographics and cardiovascular comorbidities on 375 veteran men diagnosed with prostate cancer. Those who were overweight and current smokers were more likely to be younger, whereas men with a systolic blood pressure >120 mmHg were more likely to be older (all P < 0.05). Men with total cholesterol 180 mg/dL were more likely to be identified in the Hispanic/other/unknown ethnicity category. Interventions to manage cardiovascular risk should focus on preventive lifestyle changes for younger men, and chronic disease management for older men. Men in the smaller Hispanic/other/unknown category are at risk for marginalization within the Veteran Administration system owing to their low numbers and should be closely monitored for cholesterol levels when receiving ADT.

Adverse effects of androgen deprivation therapy and strategies to mitigate them

CONTEXT

Androgen-deprivation therapy (ADT) is a key component of treatment for aggressive and advanced prostate cancer, but it has also been associated with adverse effects on bone, metabolic, cardiovascular, sexual, and cognitive health as well as body composition.

OBJECTIVE

To review the current literature on the adverse effects of ADT and strategies for ameliorating harm from ADT.

EVIDENCE ACQUISITION

The Medline database (through PubMed) was searched from inception to August 1, 2013, for studies documenting the side effects of ADT and for randomized and prospective trials of interventions to mitigate those side effects.

EVIDENCE SYNTHESIS

Adverse effects of ADT include decreases in bone mineral density; metabolic changes such as weight gain, decreased muscle mass, and increased insulin resistance; decreased libido and sexual dysfunction; hot flashes; gynecomastia; reduced testicle size; anemia; and fatigue. Several observational studies suggest an increased risk of diabetes and cardiovascular events, although most published studies report that ADT is not linked to greater cardiovascular mortality. Randomized trials have found value in treatments for some adverse effects including bone loss (bisphosphonates, denosumab, selective estrogen receptor modulators), markers of metabolic syndrome (exercise, diet, metformin), gynecomastia (tamoxifen, prophylactic radiation), muscle loss (resistance and aerobic exercise), and hot flashes (venlafaxine, medroxyprogesterone, cyproterone acetate, gabapentin).

CONCLUSIONS

ADT is often a necessary component of the treatment of aggressive prostate cancer, yet it has known harms that can impair health and quality of life. Clinicians should be aware of interventions that can help mitigate these adverse effects.

PATIENT SUMMARY

Androgen deprivation therapy is a critical component of the management of aggressive and advanced prostate cancer, but it causes adverse effects including bone loss, metabolic changes, gynecomastia, muscle loss, hot flashes, and possibly increased cardiovascular events. Clinicians should be aware of interventions that can help mitigate these adverse effects.

Crucial role of androgen receptor in vascular H2S biosynthesis induced by testosterone

BACKGROUND AND PURPOSE

Hydrogen sulphide (H2S) is a gaseous mediator strongly involved in cardiovascular homeostasis, where it provokes vasodilatation. Having previously shown that H2 S contributes to testosterone-induced vasorelaxation, here we aim to uncover the mechanisms underlying this effect.

EXPERIMENTAL APPROACH

H2 S biosynthesis was evaluated in rat isolated aortic rings following androgen receptor (NR3C4) stimulation. Co-immunoprecipitation and surface plasmon resonance analysis were performed to investigate mechanisms involved in NR3C4 activation.

KEY RESULTS

Pretreatment with NR3C4 antagonist nilutamide prevented testosterone-induced increase in H2S and reduced its vasodilator effect. Androgen agonist mesterolone also increased H2S and induced vasodilatation; effects attenuated by the selective cystathionine-γ lyase (CSE) inhibitor propargylglycine. The NR3C4-multicomplex-derived heat shock protein 90 (hsp90) was also involved in this effect; its specific inhibitor geldanamycin strongly reduced testosterone-induced H2S production. Neither progesterone nor 17-β-oestradiol induced H2S release. Furthermore, we demonstrated that CSE, the main vascular H2S-synthesizing enzyme, is physically associated with the NR3C4/hsp90 complex and the generation of such a ternary system represents a key event leading to CSE activation. Finally, H2S levels in human blood collected from male healthy volunteers were higher than those in female samples.

CONCLUSIONS AND IMPLICATIONS

We demonstrated that selective activation of the NR3C4 is essential for H2S biosynthesis within vascular tissue, and this event is based on the formation of a ternary complex between cystathionine-γ lyase, NR3C4and hsp90. This novel molecular mechanism operating in the vasculature, corroborated by higher H2S levels in males, suggests that the L-cysteine/CSE/H2S pathway may be preferentially activated in males leading to gender-specific H2S biosynthesis.

Testosterone replacement therapy following the diagnosis of prostate cancer: outcomes and utilization trends

INTRODUCTION

Late-onset hypogonadism may impair quality of life and contribute to metabolic and cardiovascular comorbidity in aging men. Testosterone replacement therapy is effective in treating hypogonadism. However, for the millions of men with a history of prostate cancer, exogenous testosterone has long been considered contraindicated, even though little data in such men are available. Clarification of this safety issue could allow treatment to be considered for a sizeable segment of the aging male population.

AIM

The aim of this study is to examine population-based utilization and impact of testosterone replacement therapy in men with prostate cancer.

METHODS

Using linked Surveillance, Epidemiology, and End Results-Medicare data, we identified 149,354 men diagnosed with prostate cancer from 1992 to 2007. Of those, 1181 (0.79%) men received exogenous testosterone following their cancer diagnosis. We used propensity scoring analysis to examine the effect of testosterone replacement on the use of salvage hormone therapy and overall and prostate cancer-specific mortality.

MAIN OUTCOME MEASURES

We assessed overall mortality, cancer-specific mortality, and the use of salvage hormone therapy.

RESULTS

Following prostate cancer diagnosis, testosterone replacement was directly related to income and educational status and inversely related to age (all P < 0.001). Men undergoing radical prostatectomy and men with well-differentiated tumors were more likely to receive testosterone (all P < 0.001). On adjusted analysis, testosterone replacement therapy was not associated with overall or cancer-specific mortality or with the use of salvage hormone therapy.

CONCLUSIONS

In this population-based observational study of testosterone replacement therapy in men with a history of prostate cancer, treatment was not associated with increased overall or cancer-specific mortality. These findings suggest testosterone replacement therapy may be considered in men with a history of prostate cancer, but confirmatory prospective studies are needed.

Understanding cardiovascular injury after treatment for cancer: an overview of current uses and future directions of cardiovascular magnetic resonance

While cancer-free survival has improved over the past 20 years for many individuals with prostate, renal, breast, and hematologic malignancies, the increasingly recognized prevalence of cardiovascular (CV) events in cancer survivors has been an unintended consequence of many of the therapies that have improved these survival rates. The increase in CV events threatens to offset the improvement in cancer related survival. As a result, there is an emerging need to develop methods to identify those individuals treated for cancer at increased risk of cardiovascular events. With its inherent ability to characterize myocardial tissue and identify both cardiac and vascular dysfunction, cardiovascular magnetic resonance (CMR) has the potential to identify both subclinical and early clinical CV injury before the development of an overt catastrophic event such as a myocardial infarction, stroke, or premature cardiac death. Early identification provides an opportunity for the implementation of primary prevention strategies to prevent such events, thereby improving overall cancer survivorship and quality of life. This article reviews the etiology of CV events associated with cancer therapy and the unique potential of CMR to provide early diagnosis of subclinical CV injury related to the administration of these therapies.

Neoadjuvant hormonal therapy use and the risk of death in men with prostate cancer treated with brachytherapy who have no or at least a single risk factor for coronary artery disease

BACKGROUND

Neoadjuvant hormone therapy (NHT) use is associated with an increased risk of all-cause mortality (ACM) in men with a history of coronary artery disease (CAD)-induced congestive heart failure (CHF) or myocardial infarction (MI). However, its effect in men with no or at least a single risk factor for CAD stratified by prostate cancer (PCa) aggressiveness is unknown.

OBJECTIVE

To assess whether NHT use affects the risk of ACM in men with low-, intermediate-, and high-risk PCa treated with brachytherapy who have no or at least a single risk factor for CAD.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective study cohort consisted of 5411 men with low-risk PCa (prostate-specific antigen [PSA] <10 ng/ml, Gleason score 6, and clinical stage T1-T2a); 4365 men with intermediate-risk PCa (PSA 10-20 ng/ml or Gleason score <8 or clinical stage <T3); and 1360 men with localized or locally advanced, high-risk PCa consecutively treated in a community-based, multi-institutional setting between 1991 and 2006. CAD risk factors included at least a history of diabetes mellitus, hypercholesterolemia, or hypertension. The median follow-up for men with low-, intermediate-, and high-risk PCa were 4.1, 4.4, and 4.6 yr, respectively.

INTERVENTIONS

Men were treated with or without a median duration of 4 mo of NHT followed by brachytherapy with or without supplemental external-beam radiation therapy (EBRT).

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Cox regression multivariable analyses were performed to assess whether NHT use affected the risk of ACM in men with low-, intermediate-, and high-risk PCa, adjusting for age; year of brachytherapy; supplemental EBRT use; the presence of CAD risk factors; treatment propensity score; and known PCa prognostic factors, including pretreatment PSA level, biopsy Gleason score, and clinical stage.

RESULTS AND LIMITATIONS

NHT use was associated with a significantly increased risk of ACM in men with low-risk PCa (adjusted hazard ratio [HR]: 1.27; 95% confidence interval [CI], 1.07-1.51; p<0.01) but not in men with intermediate-risk (adjusted HR: 1.13; 95% CI, 0.96-1.35; p=0.15) or high-risk PCa (adjusted HR: 0.86; 95% CI, 0.66-1.13; p=0.28). Using an interaction model for the low-risk group, NHT use was associated with a significantly increased risk of ACM in the subgroup of men with at least a single CAD risk factor (adjusted HR: 1.36; 95% CI, 1.07-1.74; p=0.01) but not for men with no CAD risk factors (adjusted HR: 1.19; 95% CI, 0.95-1.51; p=0.13).

CONCLUSIONS

For men with no or at least a single risk factor for CAD, NHT use is associated with an increased risk of ACM in the setting of low-risk but not intermediate- or high-risk PCa. This effect is driven by the subgroup of men with at least a single risk factor for CAD. These results warrant prospective validation given the widespread use of NHT for prostate downsizing prior to brachytherapy.

Binding site of activators of the cystic fibrosis transmembrane conductance regulator in the nucleotide binding domains

The use of substances that could activate the defective chloride channels of the mutant cystic fibrosis transmembrane conductance regulator (CFTR) has been suggested as possible therapy for cystic fibrosis. Using epithelia formed by cells stably transfected with wildtype or mutant (G551D, G1349D) CFTR, we estimated the apparent dissociation constant, K(D), of a series of CFTR activators by measuring the increase in the apical membrane current. Modification of apparent K(D) of CFTR activators by mutations of the nucleotide-binding domains (NBDs) suggests that the binding site might be in these regions. The human NBD structure was predicted by homology with murine NBD1. An NBD1-NBD2 complex was constructed by overlying monomers to a bacterial ABC transporter NBD dimer in the "head-to-tail" conformation. Binding sites for CFTR activators were predicted by molecular docking. Comparison of theoretical binding free energy estimated in the model to free energy estimated from the apparent dissociation constants, K(D), resulted in a remarkably good correlation coefficient for one of the putative binding sites, located in the interface between NBD1 and NBD2.