Testosterone and Prostate Cancer: Revisiting Old Paradigms

Sex hormone-binding globulin and its critical role in prostate cancer: A comprehensive review

Prostate cancer (PC) is a common and widespread cancer that affects men globally. A complicated interaction of hormonal variables influences its development. Sex hormone-binding globulin (SHBG) is a crucial element in controlling the availability of sex hormones, especially androgens, which have a notable impact on the development and progression of PC. SHBG controls the levels of free, active androgens in the body, which helps regulate androgen-dependent processes associated with PC. The equilibrium between SHBG and androgens plays a critical role in maintaining the stability of the prostate. When this balance is disrupted, it is associated with the development and advancement of PC. The processes responsible for SHBG's role in PC are complex and have multiple aspects. SHBG primarily binds to androgens, preventing them from interacting with androgen receptors (ARs) in prostate cells. It reduces the activation of androgen signaling pathways essential for tumor development and survival. In addition, SHBG can directly affect prostate cells by interacting with specific receptors on the cell surface. This review thoroughly examines the role of SHBG in PC, including its physiological activities, methods of action, and clinical consequences.

Feasibility of robot-assisted radical prostatectomy in men at senior age ≥75 years: perioperative, functional, and oncological outcomes of a high-volume center

OBJECTIVES

The aim of this study was to assess whether age ≥75 years impairs surgical, functional, and oncological outcomes after robot-assisted radical prostatectomy (RARP).

MATERIALS AND METHODS

Patients with prostate cancer (PCa) were stratified in ≥75(n = 669) vs. <70 years(n = 8,268). Multivariable cox regression analyses (MVA) tested for effect of senior age on erectile function-, urinary continence-recovery, biochemical recurrence (BCR), and metastatic progression (MP).

RESULTS

RARP duration, blood loss, and 30d complication rates were similar between groups. For patients ≥75 vs. <70 years, rates of erectile function after 36 and urinary continence after 12 months were 27 vs. 56% (p < 0.001) and 85 vs. 86% (p = 0.99), respectively. Mean quality of life (QoL) score after 12 months improved in both groups (p = 0.9). At 48 months, BCR- and MP-free rates were 77 vs. 85% (p < 0.001) and 97 vs. 98% (p = 0.3), respectively. MVA confirmed the negative effect of senior age on erectile function but no significant effect on urinary continence, BCR or MP, before and after propensity score matching.

CONCLUSION

Apart from erectile function, senior age has no significant effect on urinary continence recovery, BCR- or MP-free rates after RARP. Post-RARP QoL improved even in senior patients. Modern therapy of senior PCa patients should be based on individual counseling than just age.

Prostate weight and prostate cancer outcomes after radical prostatectomy: Results from the SEARCH cohort study

BACKGROUND

Smaller prostates have been linked to unfavorable clinical characteristics and poor short-term outcomes following radical prostatectomy (RP). We examined the relation between prostate weight at RP and prostate cancer (PC) outcomes post-RP.

METHODS

Men in the SEARCH cohort undergoing RP between 1988 and 2017 (N = 6242) were studied for PC-specific mortality (PCSM) as the primary outcome, and for biochemical recurrence (BCR), castration-resistant PC (CRPC) and metastasis as secondary outcomes. Hazard ratios (HR) and 95% confidence intervals (CI) were determined for associations between prostate weight and outcomes using Fine-Gray competing risk regression multivariable analyses. Sensitivity analyses were also carried out following exclusion of: (i) men with extreme prostate weights (<20 g and ≥100 g); and (ii) men with elevated prostate specific antigen (PSA) levels.

RESULTS

Median values for age, pre-RP PSA and prostate weight were 63 years, 6.6 ng/ml, and 42.0 g, respectively. During a median follow-up of 7.9 years, 153 (3%) died from PC, 2103 (34%) had BCR, 203 (3%) developed CRPC, and 289 (5%) developed metastases. Prostate weight was not associated with PCSM in the main analyses (multivariable HR = 1.43; 95% CI: 0.87-2.34) or in sensitivity analyses. Prostate weight was inversely associated with BCR in the main analyses (multivariable HR = 0.70; 95%CI: 0.61-0.79) which was unchanged in sensitivity analyses. HRs for prostate weight and CRPC and metastasis were elevated but statistical significance was not attained. Similar results were observed in sensitivity analyses.

CONCLUSIONS

Inconsistent results for prostate weight and short-term vs longer-term outcomes highlight the need to better understand the complex biology leading to prostate size and the relevance of prostate size as a predictor of PC outcomes.

Testosterone Therapy After Prostate Cancer Treatment: A Review of Literature

INTRODUCTION

Although testosterone therapy (TTh) is the standard practice in otherwise healthy hypogonadal men, this therapy has historically been contraindicated in men with a history of prostate cancer. Recent evidence suggests that there is minimal or no prostate cancer growth in the setting of TTh administration in men definitively treated for non-metastatic prostate cancer.

OBJECTIVE

To review the evidence supporting the safety and efficacy of TTh in patients previously treated for localized prostate cancer.

METHODS

A literature review of the PubMed database was performed to identify studies evaluating the safety and efficacy of TTh in patients with a history of prostate cancer. Search terms included Testosterone Therapy, Testosterone Replacement Therapy and Radical Prostatectomy, Radiotherapy, External Beam Radiation Therapy, EBRT, Brachytherapy; Prostate Cancer and Hypogonadism, Low Testosterone; Bipolar Androgen Therapy.

RESULTS

Available literature provides evidence for the safe application of TTh in patients previously treated for prostate cancer with either radical prostatectomy or radiotherapy. Furthermore, there exists evidence that severely hypogonadal levels of testosterone may lead to worse oncological outcomes. More recent research has begun to elucidate the effectiveness of bipolar androgen deprivation therapy in the treatment of prostate cancer. This mechanism of action increases the level of evidence indicating that the traditional management of maintaining testosterone levels at low levels may no longer be standard of care. TTh likely has a role in improved erectile function and other quality-of-life concerns in patients developing testosterone deficiency after being treated for prostate cancer.

CONCLUSIONS

TTh should be offered to select hypogonadal patients who have a history of definitively treated prostate cancer. Adequately designed randomized controlled trials are necessary to confirm the safety and efficacy of TTh in this population. Natale C, Carlos C, Hong J, et al. Testosterone Replacement Therapy After Prostate Cancer Treatment: A Review of Literature. Sex Med Rev 2021;9:393-405.

Testosterone Therapy in Relation to Prostate Cancer in a U.S. Commercial Insurance Claims Database

BACKGROUND

We conducted a study to assess whether testosterone therapy (TT) alters prostate cancer risk using a large U.S. commercial insurance research database.

METHODS

From the HealthCore Integrated Research Database (HIRD), we selected men ages 30 years or greater who were new users of TT during 2007 to 2015. We selected two comparison groups: (i) unexposed (matched 10:1) and (ii) new users of phosphodiesterase type 5 inhibitor (PDE5i). Incident prostate cancer was defined as diagnosis of prostate cancer within 4 weeks following prostate biopsy. Propensity scores and inverse probability of treatment weights were used in Poisson regression models to estimate adjusted incidence rates, incidence rate ratios (IRR), and 95% confidence intervals (CI). Subgroup analyses included stratification by prostate cancer screening, hypogonadism, and follow-up time.

RESULTS

The adjusted prostate cancer IRR was 0.77 (95% CI, 0.68-0.86) when comparing TT with the unexposed group and 0.85 (95% CI, 0.79-0.91) in comparison with the PDE5i group. Inverse associations between TT and prostate cancer were observed in a majority of subgroup analyses, although in both comparisons estimates generally attenuated with increasing time following initial exposure. Among TT users, duration of exposure was not associated with prostate cancer.

CONCLUSIONS

Men who received TT did not have a higher rate of prostate cancer compared with the unexposed or PDE5i comparison groups. The inverse association between TT and prostate cancer could be the result of residual confounding, contraindication bias, or undefined biological effect.

IMPACT

This study suggests that limited TT exposure does not increase risk of prostate cancer in the short term.

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.

GONADOPENIA AND AGING IN MEN

OBJECTIVE

The decrease in testosterone levels that occurs with aging has become an important clinical issue both due to the growth of the geriatric population and patient interest in testosterone therapy. The decision to assess for testosterone deficiency and the ability to determine whether the benefits exceed the risks require a comprehensive evaluation of the aging patient. This article is part of a series of papers focused on the endocrinology of aging. This review addresses common issues needed for clinical decision making, including how to interpret test results, differential diagnosis, potential impact of testosterone treatment on insulin resistance and cardiovascular disease, and options for therapy.

METHODS

Papers reviewed were identified through literature searches conducted on PubMed.

RESULTS

Assessment of testosterone levels in the geriatric male requires an understanding of the limitations of the assay that is used, the symptoms associated with low testosterone, the impact of comorbid conditions on levels, and risks of therapy. Successful treatment requires setting realistic expectations of the benefits of replacement therapy.

CONCLUSION

While the prevalence of low testosterone concentrations is increased with aging, the common comorbidities such as obesity and diabetes may contribute to changes in testosterone levels. Clinical trial evidence shows modest benefit for treatment of low testosterone in the presence of symptoms. Assessment of the geriatric male should include evaluation of their testosterone level in the context of their functional status and comorbidities.

ABBREVIATIONS

CDC = Centers for Disease Control and Prevention; CI = confidence interval; CVD = cardiovascular disease; DXA = dual-energy X-ray absorptiometry; EMAS = European Male Aging Study; FDA = U.S. Food and Drug Administration; FHS = Framingham Heart Study; HDL = high-density lipoprotein; HOMA-IR = homeostasis model assessment of insulin resistance; LH = luteinizing hormone; OR = odds ratio; PSA = prostate-specific antigen; SHBG = sex hormone-binding globulin; T2DM = type 2 diabetes mellitus; vBMD = volumetric bone mineral density.

Low serum testosterone is a predictor of high-grade disease in patients with prostate cancer

OBJECTIVE

To evaluate the relation between serum total testosterone (TT) and prostate cancer (PCa) grade and the effect of race and demographic characteristics on such association.

METHOD

We analyzed 695 patients undergoing radical prostatectomy (RP), of whom 423 had serum TT collected. Patients were classified as having hypogonadism or eugonadism based on two thresholds of testosterone: threshold 1 (300 ng/dL) and threshold 2 (250 ng/dL). We evaluated the relation between TT levels and a Gleason score (GS) ≥ 7 in RP specimens. Outcomes were evaluated using univariate and multivariate analyses, accounting for race and other demographic predictors.

RESULTS

Out of 423 patients, 37.8% had hypogonadism based on the threshold 1 and 23.9% based on the threshold 2. Patients with hypogonadism, in both thresholds, had a higher chance of GS ≥ 7 (OR 1.79, p=0.02 and OR 2.08, p=0.012, respectively). In the multivariate analysis, adjusted for age, TT, body mass index (BMI) and race, low TT (p=0.023) and age (p=0.002) were found to be independent risk factors for GS ≥ 7. Among Black individuals, low serum TT was a stronger predictor of high-grade disease compared to White men (p=0.02).

CONCLUSION

Hypogonadism is independently associated to higher GS in localized PCa. The effect of this association is significantly more pronounced among Black men and could partly explain aggressive characteristics of PCa found in this race.

Low free and bioavailable testosterone levels may predict pathologically-proven high-risk prostate cancer: a prospective, clinical trial

OBJECTIVE

To determine the predictive value of free and bioavailable testosterone levels on the detection of high-grade prostate cancer proven by histopathological examination of transrectal prostate biopsy specimens.

MATERIAL AND METHODS

A total of 405 patients who underwent transrectal prostate biopsy due to high prostatic specific antigen (PSA) (>2.5 ng/mL) and/or abnormal findings at digital rectal examination were included in this study. Blood free and bioavailable testosterone levels were calculated by the formula recommended by International Society for the Study of the Aging Male (ISSAM). The patients were stratified according to the D'Amico classification based on PSA levels and histological outcomes of prostate biopsies as benign, low, intermediate and high-risk prostate cancer. Patients were also divided into five groups according to the percentage of cancerous cores.

RESULTS

Prostate cancer was detected in 160 of 405 (39.5%) patients. Total, free and bioavailable testosterone levels did not differ significantly between the patients with benign or malign histology. However, mean free (6.2 vs. 5.2 ng/dL, p=0.02) and bioavailable (151 vs. 125 ng/dL, p=0.001) testosterone levels were found to be significantly different in men with low-intermediate and high-risk prostate cancer. Moreover, a significant correlation was found between free, and bioavailable testosterone levels and percentage of cores with cancer (p=0.002 for free and p=0.016 for bioavailable testosterone, respectively).

CONCLUSION

This prospective clinical study demonstrates that reduced levels of calculated blood free and bioavailable testosterone levels are associated with an increased risk of high-grade prostate cancer. Based on these findings blood free and bioavailable testosterone levels may be be thought to be an adjunctive factor in the prediction of high-risk prostate cancer.

Additional value of the ratio of serum total testosterone to total prostate-specific antigen in the diagnosis of prostate cancer in a Chinese population

We investigated whether serum testosterone and testosterone/prostate-specific antigen ratio (T/PSA) might be prostate cancer (PCa) biomarkers. We retrospectively reviewed 92 patients with benign prostatic hyperplasia (BPH) and 164 patients with PCa treated at Zhongshan Hospital, China (April 2012 to November 2013). The BPH and PCa groups had similar serum total testosterone (median, 15.8 versus 16.3 nmol/L).Compared with the BPH group, the PCa group had higher PSA (16.8 versus 5.1 ng/ml) and lower free/total PSA (9.5% versus 19.3%) and T/PSA (1.37 versus 4.69) (all p < .001).Patients with PCa and PSA ≤20 ng/ml had higher testosterone (17.5 versus 12.9 ng/ml; p = .002) and T/PSA (2.24 versus 0.29; p < .001) than those with PSA >20 ng/ml. Patients with PCa and Gleason score ≤7 had higher testosterone (18.3 versus 14.1 ng/ml; p = .023) and T/PSA (1.93 versus 0.72; p < .001) than those with Gleason score >7. In patients with PSA ≤20 ng/ml, T/PSA was higher in those with BPH than in those with PCa (4.69 versus 2.24; p < .001). ROC curve analysis yielded an AUC of 0.712; for the optimal cut-off of 4.43, specificity and sensitivity were 52% and 97% respectively. T/PSA may improve the accuracy of PCa diagnosis in patients with a PSA level ≤20 ng/ml.

Testosterone Levels Correlate With Grade Group 5 Prostate Cancer: Another Step Toward Personalized Medicine

BACKGROUND

Controversial results have shown a significant association with either low or high total testosterone (tT) levels and high risk prostate cancer (PCa). We tested the relationship between circulating tT and grade group 5 (G5) PCa at radical prostatectomy (RP) in patients with preoperative low- to intermediate-risk disease.

METHODS

Serum sex hormones were assessed the day before RP in a cohort of 846 patients with low- to intermediate-risk PCa. Patients were segregated using the new 5-tiered Gleason grade groups. Restricted cubic spline functions and logistic regression analyses tested the association between sex hormones and G5 PCa. Differences in potential predictive accuracy (PA) were assessed for tT and prostate-specific antigen (PSA) levels.

RESULTS

Overall, 27 men (3.2%) had G5 PCa at RP, and this group had higher PSA values than patients with G1-G4 PCa (P = 0.02). The groups did not differ in terms of preoperative mean hormonal values. Both low and high circulating tT values depicted a nonlinear U-shaped correlation with G5 PCa at RP. The lowest and highest (10th and 90th percentiles) tT values and biopsy PCa grade emerged as multivariable independent predictors of G5 PCa at RP (all P < 0.05). PA for G5 PCa did not differ between tT (area under the curve [AUC] 0.631) and PSA (AUC 0.636).

CONCLUSIONS

Circulating tT was a significant predictor of G5 PCa at RP in patients with preoperative low- to intermediate-risk disease. Preoperative tT and PSA values showed similar PA for the most aggressive disease, confirming a potential role for circulating androgens in preoperative risk assessment of PCa patients. Prostate 77:234-241, 2017. © 2016 Wiley Periodicals, Inc.

Low serum testosterone is associated with tumor aggressiveness and poor prognosis in prostate cancer

Serum testosterone is a potential marker to distinguish between indolent and aggressive prostate cancer (PCa). The present study aimed to investigate whether low levels of total serum testosterone at diagnosis were associated with aggressive PCa and poor clinical outcomes. In total, 762 non-Hispanic Caucasian men with previously untreated PCa were recruited from The University of Texas MD Anderson Cancer Center (Houston, TX, USA). Patients were categorized into three groups based on their total serum testosterone levels according to clinical guidelines [low (<230 ng/dl), intermediate (230-350 ng/dl) and normal (>350 ng/dl)]. PCa aggressiveness (low-, intermediate- or high-risk, or metastatic) was compared using multinomial logistic regression. Rates of disease progression, mortality from any cause and PCa-specific mortality were compared using the multivariate Cox proportional hazards model. Testosterone levels significantly decreased as PCa aggressiveness increased (P<0.001). Compared with the normal testosterone group, the low testosterone group had 2.9-fold (OR, 2.92; 95% CI, 1.74-4.90; P<0.001), 5.6-fold (OR, 5.63; 95% CI, 3.14-10.12; P<0.001) and 72.4-fold (OR, 72.40; 95% CI, 20.89-250.89; P<0.001) increased risks of having intermediate-risk, high-risk and metastatic PCa, respectively. Furthermore, low levels of testosterone were significantly associated with a 10.7-fold (HR, 10.68; 95% CI, 1.35-84.44; P=0.03) increased risk of PCa-specific mortality. The results of the present study indicate that low levels of total serum testosterone at diagnosis are associated with aggressive PCa and predict poor PCa-specific survival.

Effect of serum testosterone and percent tumor volume on extra-prostatic extension and biochemical recurrence after laparoscopic radical prostatectomy

Several studies have revealed that the preoperative serum testosterone and percent tumor volume (PTV) predict extra-prostatic extension (EPE) and biochemical recurrence (BCR) after radical prostatectomy. This study investigated the prognostic significance of serum testosterone and PTV in relation to EPE and BCR after laparoscopic radical prostatectomy (LRP). We reviewed 520 patients who underwent LRP between 2004 and 2012. PTV was determined as the sum of all visually estimated tumor foci in every section. BCR was defined as two consecutive increases in the postoperative prostate-specific antigen (PSA) >0.2 ng ml-1 . The threshold for serum total testosterone was 3.0 ng ml-1 . Multivariate logistic regression was used to define the effect of variables on the risk of EPE and BCR. A low serum testosterone (<3.0 ng ml-1 ) was associated with a high serum PSA, Gleason score, positive core percentage of the prostate biopsy, PTV, and all pathological variables. On multivariate analysis, similar to previous studies, the serum PSA, biopsy positive core percentage, Gleason score, and pathological variables predicted EPE and BCR. In addition, low serum testosterone (<3.0 ng ml-1 , adjusted OR, 8.52; 95% CI, 5.04-14.4, P= 0.001) predicted EPE and PTV (adjusted OR, 1.02; 95% CI, 1.01-1.05, P= 0.046) predicted BCR. In addition to previous predictors of EPE and BCR, low serum testosterone and PTV are valuable predictors of EPE and BCR after LRP.

Stable Intraprostatic Dihydrotestosterone in Healthy Medically Castrate Men Treated With Exogenous Testosterone

CONTEXT

Concern exists that T replacement therapy (TRT) might increase the risk of prostate disease. There are limited data regarding the impact of TRT on prostate androgen concentrations.

OBJECTIVE

Determine the dose-dependent effects of exogenous T administration on intraprostatic androgen concentrations.

DESIGN

Twelve-week, double-blinded, randomized, placebo-controlled trial.

SETTING

Academic medical center.

PARTICIPANTS

Sixty-two healthy eugonadal men, aged 25-55 years.

INTERVENTIONS

Subjects were randomly assigned to receive injections of acyline, a GnRH antagonist (used to achieve medical castration), every 2 weeks plus transdermal T gel (1.25 g, 2.5 g, 5.0 g, 10 g, or 15 g daily), or placebo injections and transdermal gel for 12 weeks.

MAIN OUTCOMES

Serum T and dihydrotestosterone (DHT) were measured at baseline and every 2 weeks during treatment. Intraprostatic T and DHT concentrations were assessed from tissue obtained through ultrasound-guided prostate needle biopsies at week 12. Androgens were quantified by liquid chromatography-tandem mass spectrometry.

RESULTS

51 men completed the study and were included in the analysis. There were no significant adverse events. Exogenous T resulted in a dose-dependent increase in serum T and DHT concentrations (190-770 and 60-180 ng/dL, respectively). Although intraprostatic T differed among dose groups (P = .01), intraprostatic DHT was comparable regardless of T dose (P = .11) and was 10- to 20-fold greater than intraprostatic T.

CONCLUSIONS

In healthy, medically castrate men receiving exogenous T, the total intraprostatic androgen concentration (predominantly DHT) remained stable across serum T concentrations within the physiological range. These findings further our knowledge of the relationship between serum and intraprostatic androgens and suggest that physiological serum T achieved by TRT is unlikely to alter the prostate hormonal milieu.

The effect of testosterone treatment on prostate histology and apoptosis in men with late-onset hypogonadism

OBJECTIVES

To investigate the effect of testosterone replacement therapy (TRT) on prostate histology and apoptosis in men with late-onset hypogonadism (LOH).

METHODS

The study included 25 men, having LOH with prostate-specific antigen (PSA) level of 4 ng/ml or less. All patients underwent transrectal ultrasound guided prostate biopsy at baseline, and received testosterone undecanoate treatment for 1 year. Prostate biopsy was repeated at the end of 1 year of testosterone therapy. In addition to clinical and biochemical parameters, prostate histology and apoptotic index (AI) were compared before and after the TRT.

RESULTS

The mean serum total testosterone significantly increased from 178.04 ± 51.92 to 496.28 ± 103.73 ng/dl (p = 0.001). No significant differences were observed in serum total and free PSA level, prostate volume and maximal urinary flow rate. There were also no significant differences in AI, stroma/epithelial cells ratio, Ki-67 positive cells and atrophy score of prostate tissue before and after the TRT.

CONCLUSIONS

This study demonstrated that TRT did not affect serum PSA level, prostate volume and maximal urinary flow rate. This study also suggests that TRT does not cause the risk for prostate cancer development, because of no significant differences in prostate histology after TRT.

Pubertal development and prostate cancer risk: Mendelian randomization study in a population-based cohort

BACKGROUND

Epidemiological studies have observed a positive association between an earlier age at sexual development and prostate cancer, but markers of sexual maturation in boys are imprecise and observational estimates are likely to suffer from a degree of uncontrolled confounding. To obtain causal estimates, we examined the role of pubertal development in prostate cancer using genetic polymorphisms associated with Tanner stage in adolescent boys in a Mendelian randomization (MR) approach.

METHODS

We derived a weighted genetic risk score for pubertal development, combining 13 SNPs associated with male Tanner stage. A higher score indicated a later puberty onset. We examined the association of this score with prostate cancer risk, stage and grade in the UK-based ProtecT case-control study (n = 2,927), and used the PRACTICAL consortium (n = 43,737) as a replication sample.

RESULTS

In ProtecT, the puberty genetic score was inversely associated with prostate cancer grade (odds ratio (OR) of high- vs. low-grade cancer, per tertile of the score: 0.76; 95 % CI, 0.64-0.89). In an instrumental variable estimation of the causal OR, later physical development in adolescence (equivalent to a difference of one Tanner stage between pubertal boys of the same age) was associated with a 77 % (95 % CI, 43-91 %) reduced odds of high Gleason prostate cancer. In PRACTICAL, the puberty genetic score was associated with prostate cancer stage (OR of advanced vs. localized cancer, per tertile: 0.95; 95 % CI, 0.91-1.00) and prostate cancer-specific mortality (hazard ratio amongst cases, per tertile: 0.94; 95 % CI, 0.90-0.98), but not with disease grade.

CONCLUSIONS

Older age at sexual maturation is causally linked to a reduced risk of later prostate cancer, especially aggressive disease.

Effect of extracellular calcium on regucalcin expression and cell viability in neoplastic and non-neoplastic human prostate cells

Extracellular calcium (Ca2+o) and its receptor, the Ca2+-sensing receptor (CaSR), play an important role in prostate physiology, and it has been shown that the deregulation of Ca2+ homeostasis and the overexpression of CaSR are involved in prostate cancer (PCa). Regucalcin (RGN), a Ca2+-binding protein that plays a relevant role in intracellular Ca2+ homeostasis, was identified as an under-expressed protein in human PCa. Moreover, RGN was associated with suppression of cell proliferation, suggesting that the loss of RGN may favor development and progression of PCa. This work aims to unveil the role of Ca2+o on RGN expression and viability of non-neoplastic (PNT1A) and neoplastic (LNCaP) prostate cell lines. It was demonstrated that Ca2+o up-regulates RGN expression in both cell lines, but important differences were found between cells for dose- and time-responses to Ca2+o treatment. It was also shown that high [Ca2+]o triggers different effects on cell proliferation of neoplastic and non-neoplastic PCa cells, which seems to be related with RGN expression levels. This suggests the involvement of RGN in the regulation of cell proliferation in response to Ca2+o treatment. Also, the effect of Ca2+o on CaSR expression seems to be dependent of RGN expression, which is strengthened by the fact that RGN-knockdown in PNT1A cells increases the CaSR expression, whereas transgenic rats overexpressing RGN exhibit low levels of CaSR. Overall, our results highlighted the importance of RGN as a regulatory protein in Ca2+-dependent signaling pathways and its deregulation of RGN expression by Ca2+o may contribute for onset and progression of PCa.

Preoperative Serum Sex Hormone-Binding Globulin Level Is an Independent Predictor of Biochemical Outcome After Radical Prostatectomy

To investigate the significance of preoperative serum sex hormone-binding globulin (SHBG) level regarding the postoperative biochemical outcome in patients who were followed up for relative longer periods after undergoing radical prostatectomy (RP). Preoperative serum levels of testosterone (T), free T, and SHBG level were prospectively analyzed in 307 consecutive patients who underwent RP at our institution between January 2006 and July 2007. We analyzed potential associations of sex hormones with postoperative biochemical recurrence (BCR)-free survival via multivariate Cox proportional regression analysis. Mean postoperative follow-up duration for 307 total patients was 72.1 ± 19.6 months. Kaplan-Meier curve demonstrated that BCR-free survival was significantly worse in patients with higher (≥ 40  ng/mL) SHBG level than others (P < 0.001). Serum T (P = 0.280) and free T (P = 0.606) levels showed no significant association with biochemical outcome. In multivariate analysis encompassing postoperative variables along with PSA, T, and free T, SHBG level (HR 1.825, 1.061-3.138; P = 0.030) was observed to be independently associated with BCR-free survival. Addition of SHBG level to the multivariate model for prediction of BCR-free survival resulted in increased accuracy (83.5% vs. 82.2%; P = 0.164). Our study of patients who were followed up for relative longer periods after RP shows that preoperative serum SHBG level, but not T, is an independent predictor of postoperative BCR-free survival. According to our findings, SHBG measurement may be useful in the selection of candidates for adjuvant treatment following RP.

[Testosterone in the management of metastatic prostate cancer]

Background Among all cancer types, prostate cancer (PCa) is the most prevalent cancer and is the third-leading cause of cancer-related death in men. The biologic function of the prostate is decisively influenced by testosterone and its metabolic product dihydrotestosterone. However, there is general uncertainty about the role of testosterone in metastatic castration-resistant prostate cancer (mCRPC). For many years, the androgen hypothesis had been accepted to explain the correlation between testosterone levels and the development or progression of PCa. However, extensive study analyses revealed contradictory results, leading to a reconsideration of the androgen hypothesis. High serum testosterone levels do not predispose to PCa development and low serum testosterone levels are not protective. The importance of testosterone levels in patients with mCRPC has been shown in several registration studies with new drugs, such as abiraterone acetate and enzalutamide. There is growing evidence suggesting a prognostic role of testosterone levels in mCRPC.

[Testosterone replacement therapy and prostate cancer: the downfall of a paradigm?]

For six decades, it has been a part of the conventional medical wisdom that higher levels of testosterone increase the risk of prostate cancer. This belief is mostly derived from the well-documented regression of prostate cancer after surgical or pharmacological castration. However, there is an absence of scientific data supporting the concept that higher testosterone levels are associated with an increased risk of prostate cancer. Moreover, men with hypogonadism have substantial rates of prostate cancer in prostatic biopsies, suggesting that low testosterone has no protective effect against the development of prostate cancer. Moreover, prostate cancer rate is higher in elderly patients when hormonal levels are low. These results argue against an increased risk of prostate cancer with testosterone replacement therapy.

Current state of practice regarding testosterone supplementation therapy in men with prostate cancer

Hypogonadal men are characterized by low serum testosterone and symptoms of low energy, decreased libido, and muscle mass as well as impaired concentration and sexual functioning. Men with prostate cancer (PCa) currently on active surveillance or post-therapy, have traditionally been excluded from management paradigms given the decade-old concern that testosterone caused PCa growth. However, there appears to be little or no relationship between serum testosterone concentration and PCa. Androgen action in the prostate has long been known to be affected by the kinetics of receptor saturation and, as such, testosterone beyond a certain baseline is unable to stimulate prostatic growth due to complete intra-prostatic androgen receptor binding. Given this physiologic concept, many clinical investigators have begun to promote testosterone supplementation therapy (TST) as safe in men with PCa. This review examines the basics of testosterone physiology and summarizes the most recent findings on the use of TST in men with PCa on active surveillance and following treatment with external beam radiotherapy, brachytherapy and radical prostatectomy.

Racial Differences in Age-Related Variations of Testosterone Levels Among US Males: Potential Implications for Prostate Cancer and Personalized Medication

AIM

The magnitude of the age-related declines in testosterone rather than levels measured at single point in time may be related to the genesis of prostate cancer (PCa). We examined age-related variations of testosterone levels among black and white males, which may provide important insights into racial disparities in PCa incidence and mortality.

METHOD

We analyzed data from the 1999-2004 National Health and Nutritional Examination Survey to compare age-related variations in the testosterone levels of 355 black and 631 white males.

RESULT

Overall, between the ages of 12 and 15, black males had lower testosterone levels than white males. Testosterone levels increased rapidly with age and reached higher and earlier peak levels in black males compared to white males at 20-30 years of age. After reaching a peak level, testosterone levels declined earlier in blacks than in whites. Further analyses showed that black males had considerably higher levels of testosterone compared to white males aged 20-39 years after adjusting for covariates, including age, body mass index, cigarette smoking, physical activity, and waist circumference; however, no statistically significant differences were observed between the groups at any other age.

CONCLUSION

Our study revealed that testosterone levels in black males decrease substantially with increasing age compared to those in white males. This rapid drop in testosterone levels may contribute to racial disparities in PCa. Our findings also suggest that personalized medication for hormone replacement therapy may be necessary to avoid sudden drops in testosterone levels, particularly for black males.

Regucalcin is an androgen-target gene in the rat prostate modulating cell-cycle and apoptotic pathways

BACKGROUND

Regucalcin (RGN) is a calcium (Ca(2+) )-binding protein underexpressed in prostate adenocarcinoma comparatively to non-neoplastic prostate or benign prostate hyperplasia cases. Moreover, RGN expression is negatively associated with the cellular differentiation of prostate adenocarcinoma, suggesting that loss of RGN may be associated with tumor onset and progression. However, the RGN actions over the control of prostate cell growth have not been investigated.

METHODS

Androgens are implicated in the promotion of prostate cell proliferation, thus we studied the in vivo effect of androgens on RGN expression in rat prostate. The role of RGN modulating cell proliferation and apoptotic pathways in rat prostate was investigated using transgenic animals (Tg-RGN) overexpressing the protein.

RESULTS

In vivo stimulation with 5α-dihydrotestosterone (DHT) down-regulated RGN expression in rat prostate. Cell proliferation index and prostate weight were reduced in Tg-RGN, which was concomitant with altered expression of cell-cycle regulators. Tg-RGN presented diminished expression of the oncogene H-ras and increased expression of cell-cycle inhibitor p21. Levels of anti-apoptotic Bcl-2, as well as the Bcl-2/Bax protein ratio were increased in prostates overexpressing RGN. Both caspase-3 expression and enzyme activity were decreased in the prostates of Tg-RGN.

CONCLUSIONS

Overexpression of RGN resulted in inhibition of cell proliferation and apoptotic pathways, which demonstrated its role maintaining prostate growth balance. Thus, deregulation of RGN expression may be an important event favoring the development of prostate cancer. Moreover, the DHT effect down-regulating RGN expression in rat prostate highlighted for the importance of this protein in prostatic physiology.

Prostate size and adverse pathologic features in men undergoing radical prostatectomy

OBJECTIVE

To investigate the relationship between prostate volume measured from preoperative imaging and adverse pathologic features at the time of radical prostatectomy and evaluate the potential effect of clinical stage on such relationship.

METHODS

In 1756 men who underwent preoperative magnetic resonance imaging and radical prostatectomy from 2000 to 2010, we examined associations of magnetic resonance imaging-measured prostate volume with pathologic outcomes using univariate logistic regression and with postoperative biochemical recurrence using Cox proportional hazards models. We also analyzed the effects of clinical stage on the relationship between prostate volume and adverse pathologic features via interaction analyses.

RESULTS

In univariate analyses, smaller prostate volume was significantly associated with high pathologic Gleason score (P<.0001), extracapsular extension (P<.0001), and positive surgical margins (P=.032). No significant interaction between clinical stage and prostate volume was observed in predicting adverse pathologic features (all P>.05). The association between prostate volume and recurrence was significant in a multivariable analysis adjusting for postoperative variables (P=.031) but missed statistical significance in the preoperative model (P=.053). Addition of prostate volume did not change C-Indices (0.78 and 0.83) of either model.

CONCLUSION

Although prostate size did not enhance the prediction of recurrence, it is associated with aggressiveness of prostate cancer. There is no evidence that this association differs depending on clinical stage. Prospective studies are warranted assessing the effect of initial method of detection on the relationship between volume and outcome.

Low free testosterone levels predict disease reclassification in men with prostate cancer undergoing active surveillance

OBJECTIVE

To determine whether total testosterone and free testosterone levels predict disease reclassification in a cohort of men with prostate cancer (PCa) on active surveillance (AS).

PATIENTS AND METHODS

Total testosterone and free testosterone concentrations were determined at the time the men began the AS protocol. Statistical analysis was performed using Student's t-test and a chi-squared test to compare groups. Odds ratios (ORs) with 95% confidence intervals (CIs) were obtained using univariate logistic regression. Receiver-operator characteristic curves were generated to determine the investigated testosterone thresholds. Kaplan-Meier curves were used to estimate time to disease reclassification. A Cox proportional hazard regression model was used for multivariate analysis.

RESULTS

A total of 154 men were included in the AS cohort, of whom 54 (35%) progressed to active treatment. Men who had disease reclassification had significantly lower free testosterone levels than those who were not reclassified (0.75 vs 1.02 ng/dL, P = 0.03). Men with free testosterone levels <0.45 ng/dL had a higher rate of disease reclassification than patients with free testosterone levels ≥0.45 (P = 0.032). Free testosterone levels <0.45 ng/dL were associated with a several-fold increase in the risk of disease reclassification (OR 4.3, 95% CI 1.25-14.73). Multivariate analysis showed that free testosterone and family history of PCa were independent predictors of disease reclassification.

CONCLUSIONS

Free testosterone levels were lower in men with PCa who had reclassification during AS. Men with moderately severe reductions in free testosterone level are at increased risk of disease reclassification.

Androgens and prostate disease

A growing body of literature has established the anabolic benefi ts of testosterone (T) therapy in hypogonadal men. However, there remains a paucity of data regarding the risks of exogenous androgen use in older men and the potential for adverse effects on the prostate gland. Whether T therapy in older, hypogonadal men might worsen lower urinary tract symptoms or exacerbate, unmask, or even incite prostate cancer development has tempered enthusiasm for T therapy, while known prostatic disease has served as a relative contraindication to T therapy. Androgens are necessary for the development and maintenance of the prostate gland. However, epidemiologic studies do not consistently fi nd a positive relationship between endogenous serum androgen concentrations and the risk of prostate disease. Recent data demonstrate that 5α-reductase inhibitors decrease the risk of low-grade prostate cancer, suggesting that modifying androgen metabolism may have beneficial effects on prostate health, yet similar reductions in high-grade disease have not been observed, thereby questioning the true clinical benefits of these agents for chemoprevention. Knowing how to best investigate the relationship between androgens and the development of prostate disease given the lack of large, randomized trials is difficult. Accumulating data challenges the assumption that alterations in serum androgens have parallel effects within the prostate hormonal environment or change androgen-regulated processes within the gland. Long-term intervention studies are needed to truly ascertain the effects of androgen manipulation on prostate tissue and disease risk. However, available data do not support the notion that restoring serum androgens to normal physiologic ranges drives prostate disease.

Serum testosterone level, testosterone replacement treatment, and prostate cancer

There has been an increase in the number of individuals seeking testosterone (T) replacement treatment (TRT) due to a decrease in their blood T levels. Prostate cancer (PCa) is also an important issue in the same age group. However, we, urologists, are anxious about PCa development after T treatment. This is because it has been assumed that T may cause PCa or exacerbate insidious PCa which is already present. In this paper, recent developments regarding the relationship between serum levels of sex hormone and prostate tissue, the causal relationship between T and development of PCa, the effect of TRT on the group of patients who are at high risk of developing PCa, the suitability of TRT for patients who have already been diagnosed with PCa, and the effect of TRT on serum prostate-specific antigen level are analyzed.

Molecular pathogenesis and progression of prostate cancer

Prostate cancer (PCa) is the most commonly diagnosed noncutaneous malignancy and second leading cause of cancer-related deaths in US males. Clinically, locally confined disease is treated surgically and/or with radiation therapy. Invasive disease, however, must be treated with pharmacological inhibitors of androgen receptor (AR) activity, since disease progression is fundamentally reliant on AR activation. However, despite initially effective treatment options, recurrent castration-resistant PCa (CRPC) often occurs due to aberrant reactivation of AR. Additionally, it is appreciated that many other signaling molecules, such as transcription factors, oncogenes, and tumor suppressors, are often perturbed and significantly contribute to PCa initiation and progression to incurable disease. Understanding the interplay between AR signaling and other signaling networks altered in PCa will advance therapeutic approaches. Overall, comprehension of the molecular composition promoting neoplastic growth and formation of CRPC is paramount for developing durable treatment options.

A new era of testosterone and prostate cancer: from physiology to clinical implications

CONTEXT

Decades-old beliefs regarding androgens and prostate cancer (PCa) have undergone dramatic shifts in light of modern evidence and new theoretical constructs, but considerable confusion remains on this topic, particularly with regard to the use of testosterone therapy in men with any history of PCa.

OBJECTIVE

To review current literature regarding the relationship of serum testosterone on PCa and in particular the effect of testosterone therapy on PCa progression and recurrence.

EVIDENCE ACQUISITION

A Medline search was conducted to identify all original and review articles assessing the effect of androgens on the prostate and the use of testosterone in men with a history of treated and untreated PCa.

EVIDENCE SYNTHESIS

Contrary to traditional teaching, high endogenous serum testosterone does not increase the risk of developing PCa, and low serum testosterone does not protect against PCa. Although limited in size and duration, current studies similarly fail to indicate any increased risk of PCa in men receiving testosterone therapy. These results indicate a finite ability of androgens to stimulate PCa growth (the saturation model). A majority of studies demonstrate an association between low serum testosterone and poor prognostic features of PCa, including high-grade disease, advanced pathologic stage, and increased risk of biochemical recurrence following radical prostatectomy. The prostate-specific antigen-to-testosterone ratio predicted PCa risk in several biopsy studies. Multiple reports of testosterone therapy in men after treatment for localized PCa have shown low or absent recurrence rates. Some men with untreated PCa have received testosterone therapy without evidence for PCa progression.

CONCLUSIONS

The long-held belief that PCa risk is related to high serum androgen concentrations can no longer be supported. Current evidence indicates that maximal androgen-stimulated PCa growth is achieved at relatively low serum testosterone concentrations. It may therefore be reasonable to consider testosterone therapy in selected men with PCa and symptomatic hypogonadism.

Preoperative hormonal pattern in patients undergoing radical prostatectomy due to prostate cancer

OBJECTIVE

There is controversial evidence regarding preoperative testosterone (T) levels related to poor prognosis factors after radical prostatectomy (RP). The aim of this manuscript is to determine the relationship between preoperative T levels and final pathologic report together to biochemical recurrence after RP.

MATERIALS AND METHODS

We prospectively analysed 143 patients submitted to RP from February 2008 to June 2010 in our centre. Pretreatment T and sex hormone-binding globulin levels were determined as part of our clinical protocol. Free calculated (fT) and bioavailable (bioT) T were calculated using Vermeulen's formula. Low T levels were defined as 346 ng/dL or less. A comparative analysis with variables pTNM, positive margins, tumour burden, Gleason score, multifocality and biochemical recurrence (using both PSA>0.4 ng/dL and PSA>0.2 ng/dL as cut-off values) was performed, according to preoperative levels of T.

RESULTS

Variables Gleason score, rate and number of positive margins, tumour burden, tumour multifocality, time to biochemical recurrence and pathological stage were not related to preoperative hormonal levels. Preoperative T<346 ng/dL was not found to be related to PSA recurrence (PSA>0,4 ng/dL log-rank, P=.512), although a trend was observed when PSA>0,2 ng/dL (log-rank, P=.097).

CONCLUSION

Preoperative T levels were not related to final pathological report or to biochemical recurrence.

Serum testosterone levels, testis volume, and the risk of prostate cancer: are these factors related?

OBJECTIVE

Inconclusive results have been published in the literature regarding the relationship between free and total serum testosterone levels and prostate cancer. We investigated the relationship between total and free serum testosterone levels, testes volume, and prostate cancer in our patient population.

MATERIAL AND METHODS

Total and free serum testosterone levels and serum PSA levels were recorded for 102 consecutive patients. All of the patients underwent transrectal ultrasonography-guided prostate biopsy due to an abnormal digital rectal examination finding and/or a serum PSA level of >4.0 ng/mL. All of the transrectal and testis US examinations and prostate biopsies were performed by the same radiologist. The testis length, width, and height were measured from transverse and longitudinal gray scale images, and the testis volume was calculated.

RESULTS

Prostate cancer was detected in 32 of 102 patients (31.3%) who underwent prostate biopsy (prostate cancer group). The remaining patients had benign histopathological findings (prostate cancer-free group). The prostate cancer and benign histology groups were compared for age, total and free testosterone, PSA values, and testis volume. The patients with prostate cancer were found to have a higher mean age (p=0.04). There were no significant differences in serum PSA levels, free or total testosterone levels, or testis volumes between the two groups (p>0.05). A binary logistic regression analysis showed that neither free nor total testosterone was a predictor of prostate cancer (p=0.315 and p=0.213, respectively). Only age was found to be a significant risk factor for the development of prostate cancer (p=0.02).

CONCLUSION

Our study failed to show a relationship between total or free serum testosterone levels, testis volume, and the risk of prostate cancer. Therefore, monitoring serum testosterone levels for prostate cancer prediction does not appear to add an advantage over PSA screening.

Circulating sex steroids and prostate cancer: introducing the time-dependency theory

PURPOSE

We sought whether serum total testosterone (tT), estradiol (E2), tT/E2 ratio, and sex hormone-binding globulin (SHBG) significantly fluctuate throughout time in men with prostate cancer (PCa).

METHODS

Circulating hormones were measured in a cohort of 631 candidates for radical prostatectomy. Hormone levels were analyzed according to either patient age, stratified into quartiles, or body mass index (BMI). Linear regression analyses tested the association between sex steroids and continuously coded patient age and BMI values.

RESULTS

No significant differences were found among age quartiles regarding serum tT levels and tT/E2 ratio. Conversely, E2 and SHBG levels significantly increased throughout time (all, p ≤ 0.001). Total T did not linearly change according to continuously coded patient age; in contrast, E2 and SHBG linearly increased (all, p ≤ 0.001), whereas tT/E2 decreased (p = 0.016) with aging. Rate of hypogonadism significantly increased with aging (p = 0.04). Total T, T/E2 ratio, and SHBG linearly decreased along with BMI increases (all p ≤ 0.02), whereas serum E2 did not significantly change. Rate of hypogonadism significantly increased with BMI increases (p < 0.001).

CONCLUSIONS

In contrast with longitudinal studies in the general male population, these data indirectly suggest that serum tT levels could be stable over time in PCa patients. This finding led to formulation of a "time-dependency theory", which postulates that the endocrine biology of prostate tissue is dependent on the exposure time at a given concentration of sex steroid, which, in turn, fluctuates throughout the lifespan of the individual.