Longitudinal evaluation of serum androgen levels in men with and without prostate cancer

Prostate enlargement and altered urinary function are part of the aging process

Prostate disease incidence, both benign and malignant, directly correlates with age. Men under 40 years of age are rarely diagnosed with benign or malignant prostate disease, while 90% of men over the age of 80 have histological evidence of benign disease (benign prostatic hyperplasia; BPH). Although rodent models have been invaluable in the study of disease progression and treatment efficacy, the effect of age is often not considered. In examining aged (24-month-old) mice, we observed changes within the lower urinary tract that is typically associated with lower urinary tract dysfunction (LUTD) similar to models of BPH. In this study, we identify LUTD using functional testing as well as various imaging technologies. We also characterize the histological differences within the lower urinary tract between young (2-month-old) and aged mice including proliferation, stromal remodeling, and collagen deposition. Additionally, we examined serum steroid hormone levels, as steroid changes drive LUTD in mice and are known to change with age. We conclude that, with age, changes in prostate function, consistent with LUTD, are a consequence. Therapeutic targeting of endocrine and prostatic factors including smooth muscle function, prostate growth and fibrosis are likely to reestablish normal urinary function.

Parameter identification of a model for prostate cancer treated by intermittent therapy

Adenocarcinoma is the most frequent cancer affecting the prostate walnut-size gland in the male reproductive system. Such cancer may have a very slow progression or may be associated with a "dark prognosis" when tumor cells are spreading very quickly. Prostate cancers have the particular properties to be marked by the level of prostate specific antigen (PSA) in blood which allows to follow its evolution. At least in its first phase, prostate adenocarcinoma is most often hormone-dependent and, consequently, hormone therapy is a possible treatment. Since few years, hormone therapy started to be provided intermittently for improving patient's quality of life. Today, durations of on- and off-treatment periods are still chosen empirically, most likely explaining why there is no clear benefit from the survival point of view. We therefore developed a model for describing the interaction between the tumor environment, the PSA produced by hormone-dependent and hormone-independent tumor cells, respectively, and the level of androgens. Model parameters were identified using a genetic algorithm applied to the PSA time series measured in a few patients who initially received prostatectomy and were then treated by intermittent hormone therapy (LHRH analogs and anti-androgen). The measured PSA time series is quite correctly reproduced by free runs over the whole follow-up. Model parameter values allow for distinguishing different types of patient (age and Gleason score) meaning that the model can be individualized. We thus showed that the long-term evolution of the cancer can be affected by durations of on- and off-treatment periods.

Current opinion on the role of testosterone in the development of prostate cancer: a dynamic model

BACKGROUND

Since the landmark study conducted by Huggins and Hodges in 1941, a failure to distinguish between the role of testosterone in prostate cancer development and progression has led to the prevailing opinion that high levels of testosterone increase the risk of prostate cancer. To date, this claim remains unproven.

PRESENTATION OF THE HYPOTHESIS

We present a novel dynamic mode of the relationship between testosterone and prostate cancer by hypothesizing that the magnitude of age-related declines in testosterone, rather than a static level of testosterone measured at a single point, may trigger and promote the development of prostate cancer.

TESTING THE HYPOTHESIS

Although not easily testable currently, prospective cohort studies with population-representative samples and repeated measurements of testosterone or retrospective cohorts with stored blood samples from different ages are warranted in future to test the hypothesis.

IMPLICATIONS OF THE HYPOTHESIS

Our dynamic model can satisfactorily explain the observed age patterns of prostate cancer incidence, the apparent conflicts in epidemiological findings on testosterone and risk of prostate cancer, racial disparities in prostate cancer incidence, risk factors associated with prostate cancer, and the role of testosterone in prostate cancer progression. Our dynamic model may also have implications for testosterone replacement therapy.

Do evolutionary life-history trade-offs influence prostate cancer risk? a review of population variation in testosterone levels and prostate cancer disparities

An accumulation of evidence suggests that increased exposure to androgens is associated with prostate cancer risk. The unrestricted energy budget that is typical of Western diets represents a novel departure from the conditions in which men's steroid physiology evolved and is capable of supporting distinctly elevated testosterone levels. Although nutritional constraints likely underlie divergent patterns of testosterone secretion between Westernized and non-Western men, considerable variability exists in men's testosterone levels and prostate cancer rates within Westernized populations. Here, I use evolutionary life history theory as a framework to examine prostate cancer risk. Life history theory posits trade-offs between investment in early reproduction and long-term survival. One corollary of life history theory is the 'challenge hypothesis', which predicts that males augment testosterone levels in response to intrasexual competition occurring within reproductive contexts. Understanding men's evolved steroid physiology may contribute toward understanding susceptibility to prostate cancer. Among well-nourished populations of Westerners, men's testosterone levels already represent an outlier of cross-cultural variation. I hypothesize that Westernized men in aggressive social environments, characterized by intense male-male competition, will further augment testosterone production aggravating prostate cancer risk.

A safety study of administration of parenteral testosterone undecanoate to elderly men over minimally 24 months

This study investigated the safety of administration of long-acting parenteral testosterone undecanoate (TU) to 122 hypogonadal, mainly elderly men, aged 59.6 ± 8.0 years (range 18-83 years old), with baseline testosterone levels between 5.8 and 12.1 nmol l(-1) (mean ± SD = 9.3 ± 1.7). Patients were followed for 24 months. Plasma testosterone rose from 9.3 ± 1.7 to 14.9 ± 4.5 nmol l(-1) (P< 0.01) at 3 months, then stabilised at 19.2 ± 4.6 nmol l(-1) after 6 months. International Prostate Symptoms Scores and Residual Bladder Volumes decreased significantly (P <0.01) over the study period. Prostate volume and prostate-specific antigen levels fluctuated over the study period but had not increased significantly after 24 month. Haemoglobin concentrations increased significantly (P < 0.001) over the 24 months while the haematocrit increased significantly (P < 0.001) during the first 15 months and then levelled off. Statistical analysis with expressing values as means ± SD masks excesses above reference values of individual patients. These excesses were noted in low numbers, were permanently present in some but not in other individuals, and did not increase in number over the 24 month study period. Over 24 months treatment with TU appeared acceptably safe, but longer and larger scale studies are needed.

Role of the androgen receptor CAG repeat polymorphism in prostate cancer, and spinal and bulbar muscular atrophy

Androgens are involved in the development of several tissues, including prostate, skeletal muscle, bone marrow, hair follicles, and brain. Most of the biological effects of the androgens are mediated through an intracellular transcription factor, the androgen receptor (AR) at the level of gene regulation. Several types of mutations in the AR gene have been linked to endocrine dysfunctions. The expansion of CAG codon repeat, coding for a polyglutamine (PolyQ) tract in the N-terminal domain is one such mutation. The polyQ chain length impacts AR's ability to interact with critical coregulators, which in turn modulates its transcriptional efficacy. Pathologic manifestations of variations in polyQ chain length have been associated with prostate cancer susceptibility, and the Spinal and Bulbar Muscular Atrophy (SBMA), a neurodegenerative disease. In this review article, we discuss multiple aspects of the role of polyQ chain length in the actions of the AR, their importance in prostate cancer development and progression, and SBMA with an aim to understand the underlying mechanisms involved in these diseases, which can be targeted for future therapeutic approaches.

The role of testosterone in the etiology and treatment of obesity, the metabolic syndrome, and diabetes mellitus type 2

Obesity has become a major health problem. Testosterone plays a significant role in obesity, glucose homeostasis, and lipid metabolism. The metabolic syndrome is a clustering of risk factors predisposing to diabetes mellitus type 2, atherosclerosis, and cardiovascular morbidity and mortality. The main components of the syndrome are visceral obesity, insulin resistance, glucose intolerance, raised blood pressure and dyslipidemia (elevated triglycerides, low levels of high-density lipoprotein cholesterol), and a proinflammatory and thrombogenic state. Cross-sectional epidemiological studies have reported a direct correlation between plasma testosterone and insulin sensitivity, and low testosterone levels are associated with an increased risk of type 2 diabetes mellitus, dramatically illustrated by androgen deprivation in men with prostate carcinoma. Lower total testosterone and sex hormone-binding globulin (SHBG) predict a higher incidence of the metabolic syndrome. Administration of testosterone to hypogonadal men reverses part of the unfavorable risk profile for the development of diabetes and atherosclerosis.

Testosterone in older men after the Institute of Medicine Report: where do we go from here?

Despite nearly a half-century of research on aging and sex steroids in men, answers to key questions that would allow us to confidently assess risk:benefit ratios for androgen replacement in older men with the partial androgen deficiency of aging men (PADAM) syndrome remain uncertain. Although it is now reasonably clear that a significant percentage of otherwise healthy older men have decreases in testosterone and bioavailable testosterone to levels consistent with hypogonadism, the clinical implications of this change remain uncertain. Data suggest that low testosterone in older men is correlated to varying degrees with loss of lean body mass and muscle strength, and increased total and central body fat. Less certain, but suggestive, are data relating low testosterone levels to decreased bone density, loss of insulin sensitivity, and cognitive and affective deterioration, as well as reduced sexual function. Replacement of testosterone in older men has shown some positive effects on each of these variables, but findings have been inconsistent, perhaps because studies have employed different preparations and doses of androgens, treated for various durations, and defined their target populations in different ways. As important as beneficial effects is the potential for adverse effects, which may be greater in older men. Possible problems include sleep apnea, erythrocytosis, dyslipidemia with acceleration of atherosclerosis, and, of greatest concern, prostate cancer or hyperplasia. Studies to date have suggested that these outcomes are not major risks, but, in the absence of a large, randomized trial or trials, definitive information is not available. The US National Academies Institute of Medicine's recent report recommends that the National Institutes of Health support small efficacy trials aimed at treatment of androgen deficiency-related clinical conditions, but not a large, randomized trial to elucidate risk:benefit ratios. This recommendation, if adhered to, is likely to delay, rather than foster, progress in this important area.

Androgen-Deprivation Therapy in Prostate Cancer: Clinical Evidence and Future Perspectives

Androgens are involved in the development and progression of prostate cancer even if the mechanism is not well-recognized. For this reason androgen-deprivation therapy remains a milestone for the treatment of patients with advanced and metastatic disease and, in the last years, in conjunction with radiotherapy and surgery in locally advanced tumors. Alternative options, such as intermittent deprivation suppression, seem to be promising in terms of clinical benefits and toxicity profile. However, current therapies present side effects, such as testosterone surge with consequent clinical flare-up, metabolic syndrome and hormone-resistance, which develops after a variable number of years. Novel therapies such as LH-RH antagonists and prolonged depot LH-RH analogues have been developed in order to avoid clinical flare-up and testosterone microsurges. Novel androgen synthesis inhibitors, such as abiraterone acetate and MDV3100, have been recently discovered and tested as promising hormonal second-line agents in patients with castration-resistant prostate cancer. Finally, long-term side effects from androgen deprivation, such as osteoporosis, sarcopenic obesity and cardiovascular morbidity should be carefully monitored and properly treated.

Androgens and male aging: Current evidence of safety and efficacy

Many signs of aging, such as sexual dysfunction, visceral obesity, impaired bone and muscle strength, bear a close resemblance to features of hypogonadism in younger men. The statistical decline of serum testosterone in aging men is solidly documented. It has been presumed that the above features of aging are related to the concurrent decline of androgens, and that correction of the lower-than-normal circulating levels of testosterone will lead to improvement of symptoms of aging. But in essence, the pivotal question whether the age-related decline of testosterone must be viewed as hypogonadism, in the best case reversed by testosterone treatment, has not been definitively resolved. Studies in elderly men with lower-than-normal testosterone report improvement of features of the metabolic syndrome, bone mineral density, of mood and of sexual functioning. But as yet there is no definitive proof of the beneficial effects of restoring testosterone levels to normal in elderly men on clinical parameters. Few of these studies meet as yet rigorous standards of scientific enquiry: double-blind, placebo-controlled design of the study. The above applies also to the assessment of safety of testosterone administration to elderly men. There is so far no convincing evidence that testosterone is a main factor in the development of prostate cancer in elderly men and guidelines for monitoring the development of prostate disease have been developed. It is of note that there are presently no long-term safety data with regard to the prostate. Polycythemia is another potential complication of testosterone treatment. It is dose dependent and can be managed with dose adjustment.

Serum testosterone is associated with aggressive prostate cancer in older men: results from the Baltimore Longitudinal Study of Aging

STUDY TYPE

Prognosis (inception cohort).

LEVEL OF EVIDENCE

1b.

OBJECTIVE

To evaluate the relationship between testosterone levels and the development of high-risk prostate cancer, by prospectively examining serum androgen concentrations in a well-studied cohort, as the role of testosterone in prostate cancer progression is debated.

PATIENTS AND METHODS

The study comprised 781 men in the Baltimore Longitudinal Study of Aging who had sex steroid measurements before a diagnosis of prostate cancer, or at their last visit for those without cancer (no cancer, 636; cancer, not high risk, 109; cancer, high risk, 36). High-risk cancer was defined as death from prostate cancer, a prostate specific antigen (PSA) level of > or =20 ng/mL at diagnosis, or a Gleason score of > or =8. The hazard ratio (HR) of high-risk disease was determined using a Cox proportional hazards regression model with simple updating, and risk rates were stratified by age and tercile for androgens of interest based on the proportional hazards analyses.

RESULTS

The likelihood of high-risk prostate cancer doubled per unit (0.1) increase in the free testosterone index (FTI) for patients aged >65 years (HR 2.07, 95% confidence interval, CI, 1.01-4.23; P = 0.047); the likelihood for men aged < or =65 years was inversely related to the FTI (HR 0.96, 95% CI 0.35-2.6; P = 0.9). The risk rate per person-years increased from lowest to highest tercile of FTI for the oldest men (age >70 years) but this trend was not apparent among younger men.

CONCLUSION

Higher levels of serum free testosterone are associated with an increased risk of aggressive prostate cancer among older men. These data highlight the importance of prospective trials to insure the safety of testosterone-replacement therapy.

The benefits and risks of testosterone replacement therapy: a review

Increased longevity and population aging will increase the number of men with late onset hypogonadism. It is a common condition, but often underdiagnosed and undertreated. The indication of testosterone-replacement therapy (TRT) treatment requires the presence of low testosterone level, and symptoms and signs of hypogonadism. Although controversy remains regarding indications for testosterone supplementation in aging men due to lack of large-scale, long-term studies assessing the benefits and risks of testosterone-replacement therapy in men, reports indicate that TRT may produce a wide range of benefits for men with hypogonadism that include improvement in libido and sexual function, bone density, muscle mass, body composition, mood, erythropoiesis, cognition, quality of life and cardiovascular disease. Perhaps the most controversial area is the issue of risk, especially possible stimulation of prostate cancer by testosterone, even though no evidence to support this risk exists. Other possible risks include worsening symptoms of benign prostatic hypertrophy, liver toxicity, hyperviscosity, erythrocytosis, worsening untreated sleep apnea or severe heart failure. Despite this controversy, testosterone supplementation in the United States has increased substantially over the past several years. The physician should discuss with the patient the potential benefits and risks of TRT. The purpose of this review is to discuss what is known and not known regarding the benefits and risks of TRT.

Novel biomarkers for risk of prostate cancer: results from a case-control study

BACKGROUND

Although the estrogens estrone and estradiol are recognized to play very important roles in the risk of developing prostate cancer (Pca), the molecular mechanism by which estrogens initiate and/or promote Pca is still unknown. Substantial evidence supports that specific metabolites of estrogens, catechol estrogen quinones, can react with DNA to form depurinating estrogen-DNA adducts. Apurinic sites derived from depurination of these adducts can induce mutations leading to cancer. Once released from DNA, depurinating estrogen-DNA adducts are shed from cells into the bloodstream and excreted in urine. By analyzing profiles of estrogen metabolites, conjugates, and depurinating DNA adducts in urine from men with and without prostate cancer, potential biomarkers of Pca can be detected. The goal of this case-control study was to detect and identify potential biomarkers of Pca.

METHODS

Urine samples from fourteen cases, men diagnosed with Pca, and 125 controls, men who had not been diagnosed with Pca, were partially purified by solid phase extraction and analyzed by ultraperformance liquid chromatography/tandem mass spectrometry. The urinary levels of androgens, estrogens, estrogen metabolites, conjugates and depurinating DNA adducts were measured.

RESULTS

The ratio of depurinating estrogen-DNA adducts to the sum of the corresponding estrogen metabolites and conjugates was significantly higher in cases (median: 57.34) compared to controls (median: 23.39) (P < 0.001).

CONCLUSIONS

This study suggests that depurinating estrogen-DNA adducts could serve as potential biomarkers to predict risk of Pca. They also could be useful tools for early clinical diagnosis and development of suitable strategies to prevent Pca.

Serum steroid and sex hormone-binding globulin concentrations and the risk of incident benign prostatic hyperplasia: results from the prostate cancer prevention trial

The authors conducted a nested case-control study of serum steroid concentrations and risk of benign prostatic hyperplasia (BPH), using data from the placebo arm of the Prostate Cancer Prevention Trial (1993-2003). Incident BPH over 7 years (n = 708) was defined as receipt of treatment, a report of 2 International Prostate Symptom Score (IPSS) values greater than 14, or 2 increases of 5 or more from baseline IPSS values with at least 1 value greater than or equal to 12. Controls (n = 709) were selected from men who reported no BPH treatment or any IPSS greater than 7. Baseline serum was analyzed for testosterone, estradiol, estrone, 5alpha-androstane-3alpha, 17beta-diol-glucuronide, and sex hormone-binding globulin. Covariate-adjusted odds ratios contrasting the highest quartiles with the lowest quartiles of testosterone, estradiol, and testosterone:17beta-diol-glucuronide ratio were 0.64 (95% confidence interval (CI): 0.43, 0.95; P(trend) = 0.04), 0.72 (95% CI: 0.53, 0.98; P(trend) = 0.09), and 0.64 (95% CI: 0.46, 0.89; P(trend) = 0.004), respectively. Findings did not differ by age, body mass index, time to BPH endpoint, or type of BPH endpoint. High testosterone levels, estradiol levels, and testosterone:17beta-diol-glucuronide ratio are associated with reduced BPH risk, which may reflect decreased activity of 5-alpha-reductase. Genetic or environmental factors that affect the activity of 5-alpha-reductase may be important in the development of symptomatic BPH.

Androgens and prostate cancer risk

Androgens have been implicated in prostate tumourigenesis. However, no association between circulating levels of androgens and prostate cancer risk was found in a recent large pooled analysis of prospective studies. A decreased risk of prostate cancer among men treated with finasteride, a 5 alpha-reductase inhibitor which reduces levels of dihydrotestosterone, was observed in the Prostate Cancer Prevention Trial (PCPT), a large clinical trial. In the PCPT, a higher number of high-grade tumours was found in the finasteride group than in the control group; the reason for this finding is still unclear. Treatment of symptoms of late-onset hypogonadism - such as decreased muscle and bone mass and decreased cognition and libido - has become more prevalent with the advent of new forms of administration of testosterone replacement therapy. One small placebo-controlled study showed no increase in incidence of prostate cancer after 6 months of testosterone therapy, but data on the safety of testosterone replacement therapy remain limited.

Testosterone for the aging male; current evidence and recommended practice

An international consensus document was recently published and provides guidance on the diagnosis, treatment and monitoring of late-onset hypogonadism (LOH) in men. The diagnosis of LOH requires biochemical and clinical components. Controversy in defining the clinical syndrome continues due to the high prevalence of hypogonadal symptoms in the aging male population and the non-specific nature of these symptoms. Further controversy surrounds setting a lower limit of normal testosterone, the limitations of the commonly available total testosterone result in assessing some patients and the unavailability of reliable measures of bioavailable or free testosterone for general clinical use. As with any clinical intervention testosterone treatment should be judged on a balance of risk versus benefit. The traditional benefits of testosterone on sexual function, mood, strength and quality of life remain the primary goals of treatment but possible beneficial effects on other parameters such as bone density, obesity, insulin resistance and angina are emerging and will be reviewed. Potential concerns regarding the effects of testosterone on prostate disease, aggression and polycythaemia will also be addressed. The options available for treatment have increased in recent years with the availability of a number of testosterone preparations which can reliably produce physiological serum concentrations.

The role of testosterone in the pathogenesis of prostate cancer

Relationships between androgenic hormones and prostatic tissue growth are complex. It is certainly true that the prostate will not develop without androgens and the gland will atrophy if androgen support is withdrawn. The hormonal hypothesis remains one of the most important hypotheses in the etiology of prostate cancer (PCa), and efforts are continuing to improve the understanding of androgen actions in PCa. Although evidence from epidemiological studies of associations between circulating levels of androgens and PCa risk has been inconsistent, the traditional view that higher testosterone (T) levels represent a risk factor for PCa appears to have little evidentiary support. Reinvestigation of the relationship between T and PCa seems important and necessary if a new, clinically and scientifically rewarding concept is to be constructed. The present review considers the metabolism and intraprostatic action of T, epidemiological evidence, and the association between T and PCa risk.

Estrone sulfate (E1S), a prognosis marker for tumor aggressiveness in prostate cancer (PCa)

Seeking insight into the possible role of estrogens in prostate cancer (PCa) evolution, we assayed serum E2, estrone (E1), and estrone sulfate (E1S) in 349 PCa and 100 benign prostatic hyperplasia (BPH) patients, and in 208 control subjects in the same age range (50-74 years). E1 (pmol/L+/-S.D.) and E1S (nmol/L+/-S.D.) in the PCa and BPH patients (respectively 126.1+/-66.1 and 2.82+/-1.78, and 127.8+/-56.4 and 2.78+/-2.12) were significantly higher than in the controls (113.8+/-47.6 and 2.11+/-0.96). E2 was not significantly different among the PCa, BPH, and control groups. These assays were also carried out in PCa patients after partition by prognosis (PSA, Gleason score (GS), histological stage, and surgical margins (SM)). Significantly higher E1S levels were found in PCa with: PSA>10 ng/L (3.05+/-1.92) versus PSA<or=10 ng/mL (2.60+/-1.55), stage pT3-T4 (2.99+/-1.80) versus pT2 (2.58+/-1.58), and positive (3.26+/-1.95) versus negative margins (2.52+/-1.48). E1 was higher in poor- than in better-prognosis PCa. E2 was significantly higher in PCa with GS>or=4+3 (109.5+/-43.8) versus GS<or=3+4 (100.6+/-36.5) and increased significantly when GS increased from 3+3 to 4+4. Estrogens, especially E1S appeared to be possible markers of PCa progression. Attempting to identify potential sources of E2 in PCa according to prognosis, as well as in BPH, we found a significant correlation coefficient between E1S and E2 (0.266-0.347) in poor-prognosis PCa and no correlation in BPH (0.026) and better-prognosis PCa (0.013-0.104). It is as though during progression of PCa from good to poor prognosis there were a shift in the E1 to E2 metabolic pathway from predominantly oxidative to predominantly reductive.

Endogenous sex hormones and prostate cancer: a collaborative analysis of 18 prospective studies

BACKGROUND

Sex hormones in serum have been hypothesized to influence the risk of prostate cancer. We performed a collaborative analysis of the existing worldwide epidemiologic data to examine these associations in a uniform manner and to provide more precise estimates of risks.

METHODS

Data on serum concentrations of sex hormones from 18 prospective studies that included 3886 men with incident prostate cancer and 6438 control subjects were pooled by the Endogenous Hormones and Prostate Cancer Collaborative Group. Relative risks (RRs) of prostate cancer by fifths of serum hormone concentration were estimated by use of conditional logistic regression with stratification by study, age at recruitment, and year of recruitment. All statistical tests were two-sided.

RESULTS

No associations were found between the risk of prostate cancer and serum concentrations of testosterone, calculated free testosterone, dihydrotestosterone, dehydroepiandrosterone sulfate, androstenedione, androstanediol glucuronide, estradiol, or calculated free estradiol. The serum concentration of sex hormone-binding globulin was modestly inversely associated with prostate cancer risk (RR in the highest vs lowest fifth = 0.86, 95% confidence interval = 0.75 to 0.98; P(trend) = .01). There was no statistical evidence of heterogeneity among studies, and adjustment for potential confounders made little difference to the risk estimates.

CONCLUSIONS

In this collaborative analysis of the worldwide data on endogenous hormones and prostate cancer risk, serum concentrations of sex hormones were not associated with the risk of prostate cancer.

State of the Art Reviews: Male Menopause: Fact or Fiction?

The possible existence of a menopause-like process in aging men has been speculated, given certain age-related hormonal and other biological changes noted to occur. Specifically, a slow decline in serum testosterone levels has been reported to occur with normal male aging. Androgen deficiency, which may result from this process, could have an effect on various systems and physiologic parameters, including bone density, body composition, sexual function, and the cardiovascular system, thus significantly affecting health and quality-of-life issues in older men. There has been an increasing interest in evaluating the possible use of testosterone replacement in preventing some detrimental aspects of aging and age-related hypogonadism, as well as in the investigation of the potential adverse effects of this therapy on different target organs. It is the purpose of this review to summarize currently available information with regard to the changes in testosterone and other hormones in older men, discuss their possible clinical manifestations and relationship with other age-related changes, and provide an updated description of testosterone replacement therapy for older men, including its indications, formulations, and safety considerations.

Serum androgens and prostate cancer among 643 cases and 643 controls in the European Prospective Investigation into Cancer and Nutrition

We examined the hypothesis that serum concentrations of circulating androgens and sex hormone binding globulin (SHBG) are associated with risk for prostate cancer in a case-control study nested in the European Prospective Investigation into Cancer and Nutrition (EPIC). Concentrations of androstenedione, testosterone, androstanediol glucuronide and SHBG were measured in serum samples for 643 prostate cancer cases and 643 matched control participants, and concentrations of free testosterone were calculated. Conditional logistic regression models were used to calculate odds ratios for risk of prostate cancer in relation to the serum concentration of each hormone. After adjustment for potential confounders, there was no significant association with overall risk for prostate cancer for serum total or free testosterone concentrations (highest versus the lowest thirds: OR, 1.02; 95% CI, 0.73-1.41 and OR, 1.07, 95% CI, 0.74-1.55, respectively) or for other androgens or SHBG. Subgroup analyses showed significant heterogeneity for androstenedione by cancer stage, with a significant inverse association of androstenedione concentration and risk for advanced prostate cancer. There were also weak positive associations between free testosterone concentration and risk for total prostate cancer among younger men and risk for high-grade disease. In summary, in this large nested case-control study, concentrations of circulating androgens or SHBG were not strongly associated with risk for total prostate cancer. However, our findings are compatible with a positive association of free testosterone with risk in younger men and possible heterogeneity in the association with androstenedione concentration by stage of disease; these findings warrant further investigation.

Hypogonadism in the man with erectile dysfunction: what to look for and when to treat

Hypogonadism (low serum testosterone) is commonly associated with erectile dysfunction (ED). However, many urologists may lack appreciation of the relative merits of treating hypogonadism compared with oral phosphodiesterase inhibitors for sexual dysfunction. Testosterone-replacement therapy (TRT) may be the best treatment for men with ED when the presentation includes diminished libido or other sexual symptoms or when non-sexual symptoms such as depressed mood, decreased sense of vitality, and increased fatigue also exist. The health benefits of TRT also include improvements in body composition, bone density, cognition, and sense of well-being. Thus, there may be good reasons to use TRT as first-line therapy for the man with ED. Concerns regarding prostatic and cardiovascular risks of TRT have not been supported by the literature. Nevertheless, men receiving TRT must be monitored at regular intervals with digital rectal examination and blood testing for prostate-specific antigen. Hematocrit or hemoglobin also should be obtained regularly due to the risk of erythrocytosis. Awareness of the benefits of TRT in the man with ED may improve clinical outcomes.

Serum testosterone and the risk of prostate cancer: potential implications for testosterone therapy

OBJECTIVE

A potential risk of testosterone replacement therapy is an increase in the incidence of prostate cancer, but it is unclear whether higher levels of serum testosterone are associated with a higher risk of prostate cancer. We prospectively evaluated serum androgen concentrations and prostate cancer risk.

METHOD

Included were 794 members of the Baltimore Longitudinal Study of Aging. We estimated the rate ratio (RR) of prostate cancer by entering serial measures of serum total testosterone, dehydroepiandrosterone sulfate, sex hormone binding globulin, calculated free testosterone, and free testosterone index (FTI) into a Cox proportional hazards regression model with simple updating.

RESULTS

Higher calculated free testosterone was associated with an increased age-adjusted risk of prostate cancer {RRs by quartile: 1.00, 1.52 [95% confidence interval (95% CI), 0.93-2.50], 1.16 (95% CI, 0.61-2.20), 2.59 (95% CI, 1.28-5.25); P(trend) = 0.03}, which persisted after excluding measures in men <45 years of age [RRs by quartile: 1.00, 1.33 (95% CI, 0.78-2.25), 1.26 (95% CI, 0.68-2.33), 1.89 (95% CI, 0.99-3.61); P(trend) = 0.03]. Compared to men with eugonadal FTI (> or = 0.153), men with hypogonadal FTI had a decreased risk of prostate cancer (RR, 0.51; 95% CI, 0.31-0.82).

CONCLUSION

Higher levels of calculated serum free testosterone are associated with an increased risk of prostate cancer. These findings suggest that men receiving testosterone therapy should be regularly monitored for prostate cancer and underscore the need for prospective trials of testosterone therapy incorporating incidence of prostate cancer as a primary safety end point.

Testosterone replacement therapy for late onset hypogonadism: what is the risk of inducing prostate cancer?

Prescription sales of testosterone have risen considerably over the last decade and are likely to continue to grow as further preparations become available. Testosterone promotes existing prostate cancer; however, concern does exist as to whether or not testosterone therapy induces prostate cancer. The aim of this article is to review the evidence for such a link.

Influence of demographic factors and biochemical characteristics on the prostate-specific antigen (PSA) response to testosterone replacement therapy

A retrospective study was performed to evaluate how the prostate-specific antigen (PSA) response to testosterone replacement therapy (TRT) varies with age, mode of testosterone treatment, and baseline levels of PSA and testosterone. In total, 48 consecutive hypogonadal men who completed 1 year of TRT were evaluated. All men had a negative prostate biopsy obtained prior to initiating TRT. Men received TRT in the form of intramuscular injections (n = 33) or topical gel (n = 25) based on clinical response. Comparisons in the change in PSA after 1 year of TRT were made based on various thresholds for age and baseline values of PSA, total testosterone (TT), and free testosterone (FT). Baseline levels of TT (297.7+/-156.6 vs 292.7+/-89.7 ng/dl; P = 0.88) and FT (0.95+/-0.3 vs 1.1+/-0.3 ng/dl; P = 0.08) were similar for the injection and transdermal groups, and both groups also had similar baseline PSA values (1.92+/-1.9 vs 1.71+/-1.9 ng/ml, respectively; P = 0.67). After 1 year of TRT, mean PSA values did not differ significantly between groups, nor did the mean increase in PSA (P > 0.05). The overall mean increase in PSA was 0.31+/-0.76 ng/ml. After one year of TRT, PSA was decreased in 21%, unchanged in 22%, and increased in 57%. Only 24% of the entire group demonstrated a PSA increase of 0.5 ng/ml or greater. No statistical difference was found in the change in PSA based on patient age, baseline PSA levels, or baseline levels of TT or FT. TRT causes only a mild increase in PSA in most hypogonadal men, and does not appear to be influenced by the mode of TRT, age, or baseline levels of PSA or testosterone.

Use of combined intracorporal injection and a phosphodiesterase-5 inhibitor therapy for men with a suboptimal response to sildenafil and/or vardenafil monotherapy after radical retropubic prostatectomy

OBJECTIVE

To report experience with combined therapy using intracorporal injection (ICI) of alprostadil and oral phosphodiesterase 5 (PDE-5) inhibitors for the minimally invasive treatment of erectile dysfunction (ED) after radical prostatectomy (RP), as PDE-5 inhibitors are effective but a few patients may have a suboptimal response.

PATIENTS AND METHODS

In a retrospective study, 34 men (aged 46-66 years) had a nerve-sparing retropubic RP and subsequent ED. Patients were titrated on sildenafil citrate or vardenafil to maximum doses. All had a suboptimal response after a maximum of eight doses of oral therapy and were then treated with ICI therapy using 15 or 20 microg alprostadil. Erectile function was assessed with the Sexual Health Inventory for Men (SHIM).

RESULTS

Of the 32 patients who continued combined therapy, 22 (68%) had an improvement in erectile function after ICI therapy, as assessed by the SHIM score. On follow-up, 36% of these patients used ICI therapy only intermittently, instead of regularly, as they felt that this was adequate enough for good results.

CONCLUSIONS

PDE-5 oral pharmacotherapy is the most commonly used effective therapy for ED but may not be as effective in patients who have radical surgery; the addition of testosterone patches may have side-effects or be considered a risk in patients with a history of prostate cancer. The use of ICI therapy as an adjunct or maintenance therapy to their oral medication may be another alternative in these patients.

The epidemiology of sex steroid hormones and their signaling and metabolic pathways in the etiology of prostate cancer

The purpose of this review is to discuss the epidemiologic literature on the association of sex steroid hormones and components of their signaling and metabolic pathways with prostate cancer and to describe data evaluating racial variation in sex steroid hormone pathways as a possible explanation for the notably higher risk of prostate cancer in African-American men compared to white or Asian men. Although sex steroid hormones likely contribute to the growth and progression of prostate cancer, associations between hormones and prostate cancer risk across the range of normal levels have been difficult to reliably demonstrate epidemiologically. Methodologic issues no doubt have made the detection of these associations difficult. Of particular importance are (1) the inadequacy of measuring circulating hormones in middle age as a surrogate for the exposure in the target cells in the prostate at the relevant time in life and (2) the current inability to integrate across components of the sex steroid hormone signaling pathway to fully capture target cell androgenic and estrogenic stimulation. Although the approach of evaluating polymorphisms in genes involved in sex steroid hormone signaling or metabolism as a way to minimize some of the issues in the direct measurement of hormones is logical, the findings among these studies are somewhat difficult to reconcile as well. The problems of the changing case mix due to screening for elevated PSA, small sample sizes increasing the likelihood of false negative and false positive results, the controls and their allele frequencies not being representative of the population at risk, and lack of knowledge of the functional consequence of a polymorphism in relation to other polymorphisms in that gene or without consideration of other genes involved in the same pathway may be contributory. The primary result of the Prostate Cancer Prevention Trial confirms that intraprostatic dihydrotestosterone levels in the normal range indeed do contribute to the growth of prostate adenocarcinoma. However, the secondary result of higher-grade disease in cases in the finasteride arm coupled with clinical studies showing higher grade disease in non-metastatic cases with lower serum androgens, if not a pathological artifact or detection bias in the finasteride arm, possibly suggests a complex relationship between androgens and the growth versus differentiation of a prostate tumor. Finally, racial variation in components of the sex steroid hormone pathway do appear to exist, but whether the extent of the variation is adequately great such that it accounts for some of the substantial differences in prostate cancer incidence among blacks, whites, and Asians is unclear.

Dietary manipulation, ethnicity, and serum PSA levels

OBJECTIVES

To examine whether a diet low in fat and high in fiber, fruits, and vegetables and ethnicity had any influence on serum prostate-specific antigen (PSA) levels, because serum PSA is a marker for the presence of prostate cancer. The incidence of prostate cancer increases with age, varies by ethnicity, and is greater among men with a first-degree relative who has had the disease. Large international variations in the rates of prostate cancer incidence and mortality, as well as the incidence changes in migrants and their offspring, also suggest that exogenous factors, including diet, have a strong influence on the development of this disease.

METHODS

We used data and blood samples from the Polyp Prevention Trial, a multicenter randomized trial designed to evaluate the impact of a diet low in fat and high in fiber, fruits, and vegetables on the recurrence of colorectal adenomas. Recruitment was from 1991 through 1994. Participants were followed up from their baseline recruitment date for 4 years. From this group, we identified 1100 white men and 97 black men who were 35 years of age or older, did not have prostate cancer, and had serum samples available for study.

RESULTS

At baseline, no difference was present in the fat intake for the black and white men (mean +/- SE, 90 +/- 3.6 g/day and 84 +/- 1.0 g/day, respectively; P = 0.15). The baseline serum PSA levels did not vary by ethnicity. For black men, the mean serum PSA level was 2.2 +/- 0.36 ng/mL compared with 2.0 +/- 0.07 ng/mL for white men (P = 0.64). Although all men assigned to the intervention group markedly reduced their fat intake by approximately 15% and increased their fruit and vegetable intake by approximately 2.25 servings per day, no difference was noted in the kinetics of the serum PSA levels by dietary intervention or race.

CONCLUSIONS

Although ethnic differences in the incidence of prostate cancer are well defined, we found no difference in the baseline fat intake among black and white men that might have contributed to this difference. Serum PSA, a marker often used in early detection programs for prostate cancer, was not associated with manipulation of the amount of fat in the diet, regardless of ethnicity.

Androgen deficiency in the aging male: benefits and risks of androgen supplementation

There is now convincing evidence that in a subset of aging men, increasing with age, plasma testosterone levels fall below a critical level resulting in hypogonadism. This state of testosterone deficiency has an impact on bone, muscle and brain function and is maybe a factor in the accumulation of visceral fat which again has a significant impact on the cardiovascular risk profile. From the above it follows that androgen replacement to selected men with proven androgen deficiency will have beneficial effects. There is, however a concern that androgen administration to aging men may be harmful in view of effects on prostate disease. Benign prostate hyperplasia (BPH) and prostate cancer are typically diseases of the aging male, steeply increasing with age. But epidemiological studies provide no clues that the levels of circulating androgen are correlated with or predict prostate disease. Similarly, androgen replacement studies in men do not suggest that these men suffer in a higher degree from prostate disease than control subjects. It seems a defensible practice to treat aging men with androgens if and when they are testosterone-deficient, but long-term studies including sufficient numbers of men are needed.

High levels of circulating testosterone are not associated with increased prostate cancer risk: A pooled prospective study

Androgens stimulate prostate cancer in vitro and in vivo. However, evidence from epidemiologic studies of an association between circulating levels of androgens and prostate cancer risk has been inconsistent. We investigated the association of serum levels of testosterone, the principal androgen in circulation, and sex hormone-binding globulin (SHBG) with risk in a case-control study nested in cohorts in Finland, Norway and Sweden of 708 men who were diagnosed with prostate cancer after blood collection and among 2,242 men who were not. In conditional logistic regression analyses, modest but significant decreases in risk were seen for increasing levels of total testosterone down to odds ratio for top vs. bottom quintile of 0.80 (95% CI = 0.59-1.06; p(trend) = 0.05); for SHBG, the corresponding odds ratio was 0.76 (95% CI = 0.57-1.01; p(trend) = 0.07). For free testosterone, calculated from total testosterone and SHBG, a bell-shaped risk pattern was seen with a decrease in odds ratio for top vs. bottom quintile of 0.82 (95% CI = 0.60-1.14; p(trend) = 0.44). No support was found for the hypothesis that high levels of circulating androgens within a physiologic range stimulate development and growth of prostate cancer.

A pilot study analyzing PSA, serum testosterone, lipid profile, body mass index and race in a small sample of patients with and without carcinoma of the prostate

Androgens, diet, race and obesity are thought to play some roles in the pathogenesis of prostate cancer. We wanted to evaluate if there were any inter-relationships between prostate specific antigen (PSA), serum testosterone, serum cholesterol, HDL, triglycerides, body mass index (BMI) and race, in older patients with and without prostate cancer (CaP). We evaluated 308 patients referred to urologists in private practice offices and clinics with and without prostate cancer with regard to race, serum PSA, age, serum testosterone, full lipid profile, height and weight, and stage of cancer. We used multivariate analysis, Fisher's exact test and t-tests as well as logistic regression analysis. Data was analyzed using SPSS computer software, and P-values<0.05 were considered statistically significant. Significantly higher levels of serum testosterone were found in black men with CaP than black men without CaP (526+/-28 vs 404+/-19, respectively.) We also found significantly higher levels of serum testosterone in white men with CaP than white men without CaP (409+/-20 vs 302+/-14, respectively, P<0.05). HDL was higher in black men than white men, and triglycerides were higher in white men than black men. Cholesterol was similar across all groups, but BMI was highest in white men with CaP. We also found a significant association between BMI and pathological stage of prostate cancer patients among both black and white men (P<0.05). Our study demonstrated that black men who developed CaP had higher serum testosterone levels, on average, than white men who developed CaP. Furthermore, BMI was highest in white men developing CaP compared to black men, but we found a significant association between pathological stage and BMI in both black and white patients. Although it is controversial whether obesity is considered to be a risk factor for prostate cancer, this small pilot study suggests that BMI may play a role in the progression of the disease once it is established.Prostate Cancer and Prostatic Diseases (2001) 4, 101-105

Hormones and prostate cancer: current perspectives and future directions

Prostate cancer is the most commonly diagnosed non-skin cancer in men in most western countries. Despite the high morbidity and mortality from prostate cancer, its etiology remains obscure. Although compelling laboratory data suggest a role for androgens in prostate carcinogenesis, most epidemiologic data on humans are inconclusive. To provide insights and directions for future epidemiologic research on hormones and prostate cancer, this review focuses on current perspectives of serum-based studies and polymorphisms in relevant hormone-related genes. We highlight the importance of methodologic studies and investigations of hormone levels in the prostatic tissue to help clarify the often-contradictory data on serologic studies. We recommend careful analysis and cautious interpretation of studies of genetic markers, including repeats and single nucleotide polymorphisms (SNPs), as false positive and negative results may arise in many current and future studies with limited statistical power and non-representative samples from the population. The review also highlights the reasons to perform functional analyses of SNPs, a critical and often under-appreciated component of molecular epidemiologic investigations. The time is ripe for large-scale multidisciplinary investigations that incorporate molecular genetics, biochemistry, histopathology, and endocrinology into traditional epidemiologic studies. Such collaboration will lead to a deeper understanding of the etiologic pathways of prostate cancer, ultimately yielding better preventive, diagnostic, and therapeutic strategies.

Clinical stage T1c prostate cancer: pathologic outcomes following radical prostatectomy in black and white men

BACKGROUND

The incidence of prostate cancer in black men is 50% to 70% higher than among age-matched white men. Black men have a twofold higher mortality rate and overall tend to have higher serum prostate-specific antigen (PSA) levels than white men. To determine whether racial differences exist in men whose prostate cancer was diagnosed based solely on an elevated serum PSA level, we compared clinical and pathologic features in black and white men undergoing radical prostatectomy (RP) for clinical stage T1c prostate cancer.

METHODS

We used a prospectively collected database to identify all men undergoing RP for clinical T1c prostate cancer between July 1995 and October 2000. A total of 129 consecutive men (56 black men and 73 white men) were compared for age at diagnosis, serum PSA level, biopsy Gleason score, pathologic stage, RP specimen Gleason score, incidence of lymph node metastasis, and incidence of positive surgical margins.

RESULTS

Statistically significant differences were not found by race in patients' ages, serum PSA levels, biopsy Gleason score, pathologic stage, incidence of lymph node metastases, or incidence of positive surgical margins. The RP specimen Gleason score was more heterogeneous in black men than white men (P=0.02).

CONCLUSIONS

Racial differences in the incidence and mortality rate of prostate cancer are well known, but differences in the clinical and pathologic features between black and white men with prostate cancer identified solely based on an elevated serum PSA level with negative results on digital rectal examination (clinical stage T1c ) have been poorly studied. Our results suggest that men with clinical stage T1c prostate cancer have similar clinical and pathologic findings regardless of race. These results suggest that early-detection programs using serum PSA testing for prostate cancer in black men potentially can result in improvements in prostate cancer outcomes in this high-risk group.

Low serum testosterone level predicts worse response to endocrine therapy in Japanese patients with metastatic prostate cancer

Patients with prostate cancer generally respond to androgen withdrawal therapy, but progression to androgen-independence is frequently observed later. To examine whether pretreatment serum androgen status could predict disease progression in metastatic prostate cancer, pretreatment serum testosterone, histological grade, extent of bony metastasis, serum prostate-specific antigen (PSA) response to hormone therapy, and prognosis of the 40 patients with untreated metastatic prostate cancer who received endocrine therapy were evaluated. Although there were no differences in age, pretreatment PSA level, extent of bony disease and histological grade between patients with normal testosterone and those with low testosterone, PSA response after endocrine therapy was better in normal testosterone group. There was a significantly longer interval to disease progression in patients with normal testosterone than in those with low testosterone. The patients with metastatic prostate cancer with low serum testosterone were in the high risk group of worse response to endocrine therapy. Additional therapy might be considered in those patients.

Androgen replacement therapy and prostate safety

Progress in the understanding of the action of exogenous testosterone has diminished many of the concerns that existed regarding its safety. The major interest is now focused on the effects of androgen supplementation on the prostate gland. Many such concerns have been addressed but others remain to be fully elucidated. It is well established that hypogonadal men receiving adequate androgen therapy develop a prostate with a volume similar to what would be expected from their eugonadal counterparts. Androgen therapy results in modest elevations in the PSA and minor changes in flow parameters. Prostate cancer, on the other hand, remains the most prominent of the safety concerns. Although there is no evidence that normal levels of testosterone promote the development of cancer of the prostate, it is clear that the administration of testosterone enhances a pre-existing prostatic malignancy. Androgen supplementation studies have been, in most cases, of short duration and lacked a control cohort. The current evidence does not support the view that appropriate treatment of hypogonadal elderly men with androgens has a causal relationship with prostate cancer. Larger experience, however, is needed. The same criteria applies to the use of other hormones such as dehydrotestosterone, dehydroepiandrosterone follicle stimulating and growth hormone. A set of recommendations regarding androgen replacement therapy and prostate safety is proposed.