Finasteride for prostatic disease: an updated and comprehensive review

Mendelian randomization analyses identified bioavailable testosterone mediates the effect of sex hormone-binding globulin on prostate cancer

OBJECTIVE

A better knowledge of the hormonal etiology of prostate cancer is essential for its prevention and treatment. The goal of this study was to provide causal estimates of the connection between sex hormone-binding globulin and prostate cancer and investigate the possible mediating function of other modifiable risk indicators.

METHODS

We used two-step, two-sample multivariable Mendelian randomization using single-nucleotide polymorphisms as instrumental variables for exposure and mediators. Single-nucleotide polymorphisms associated with sex hormone-binding globulin and bioavailable testosterone were screened via a genome-wide association study enrolling European-descent adult male individuals. Summary-level data for prostate cancer (79,148 cases and 61,106 controls) were extracted from the PRACTICAL consortium. The total effect of sex hormone-binding globulin on prostate cancer risk was decomposed into direct and indirect effects through the mediator, bioavailable testosterone. An inverse-variance-weighted method was the primary Mendelian randomization analysis method. Sensitivity analyses were performed via Mendelian randomization-Egger regression, heterogeneity test, pleiotropy test, and leave-one-out test. The directionality that exposure causes the outcome was verified using Mendelian randomization-Steiger test.

RESULTS

In the univariable Mendelian randomization analysis, genetically predicted higher sex hormone-binding globulin levels had a causal association with lower prostate cancer risk (odds ratio = 0.944, 95% confidence interval = 0.897-0.993, p = 0.027) and an inverse association with bioavailable testosterone level (odds ratio = 0.945, 95% confidence interval = 0.926-0.965, p = 1.62E-07) without controlling for other factors. Moreover, an increase of one standard deviation (59.5 pmol/L) in genetically predicted bioavailable testosterone level was significantly associated with a 22.0% increase in the overall prostate cancer risk (odds ratio = 1.220, 95% confidence interval = 1.064-1.398, p = 0.004) after adjusting for sex hormone-binding globulin level. The effect size ratio of bioavailable testosterone-mediated sex hormone-binding globulin to prostate cancer was further analyzed to clarify the importance of the mediating effect. Notably, the mediator bioavailable testosterone explained 19.28% (95% confidence interval = 10.76%, 73.78%) of the total effect of sex hormone-binding globulin level on prostate cancer risk.

CONCLUSION

The results support the potentially protective causal effect of genetically predicted higher sex hormone-binding globulin levels against prostate cancer with mediation by the modifiable risk factor, bioavailable testosterone. More research is needed to determine how this possible sex hormone-binding globulin-bioavailable testosterone-prostate cancer link works. Targeting sex hormone-binding globulin and bioavailable testosterone traits may be a valuable strategy for preventing prostate cancer.

[Medical treatment of male lower urinary tract symptoms: what's new?]

Decades after the introduction of 5α-reductase inhibitors and α1-adrenoceptor antagonists, new data of practical relevance related to their desired and adverse effects continues to emerge. Some of these novel findings are to be taken seriously but are insufficiently established, for instance associations between drug use and depression or dementia. Multiple combination treatments have been tested. While combination treatment was often statistically superior to monotherapy, the difference was mostly in the range of 1 IPSS point, which raises doubts on the clinical relevance of the findings at the group level. The new evidence enables further personalisation of the treatment of male lower urinary tract dysfunction, but also makes individual risk-benefit considerations more complex.

Differential diagnosis of uncommon prostate diseases: combining mpMRI and clinical information

The differential diagnosis of abnormalities in the prostate is broad, covering common (acinar adenocarcinoma, benign prostatic hyperplasia, chronic prostatitis, hemorrhage, cysts, calcifications, atrophy and fibrosis) and less common conditions (tumors other than acinar adenocarcinoma, granulomatous prostatitis containing tuberculosis, abscesses and other conditions, and idiopathic disorders such as amyloidosis and exophytic benign prostatic hyperplasia). Recent advances in magnetic resonance imaging (MRI) of the prostate gland and imaging guidelines, such as the Prostate Imaging Reporting and Data System version 2.1 (PI-RADS v2.1), have dramatically improved the ability to distinguish common abnormalities, especially the ability to detect clinically significant prostate cancer (csPCa). Overlap can exist in the clinical history and imaging features associated with various common/uncommon prostate abnormalities, and biopsy is often required but is invasive. Prostate abnormalities can be divided into two categories: category 1, diseases for which PI-RADS scores are suitable for use, and category 2, diseases for which PI-RADS scores are unsuitable for use. Radiologists must have an intimate knowledge of other diseases, especially uncommon conditions. Past relevant history, symptoms, age, serum prostate-specific antigen (PSA) levels, MRI manifestations, and the applicability of the PI-RADS assessment should be considered when diagnosing prostate abnormalities.

Research progress on the relationship between sex hormone-binding globulin and male reproductive system diseases

Sex hormone-binding globulin, also known as testosterone-estradiol-binding globulin, is a multifunctional protein synthesised by hepatocytes. Sex hormone-binding globulin specifically binds and transports sex hormones to regulate plasma bioactive sex hormone levels and affects their bioavailability. As male sex hormone expression is dominated by testosterone, the binding of sex hormone-binding globulin with testosterone leads to the reduction in bioavailable testosterone, which cannot fulfil its physiological roles, thereby resulting in male infertility, erectile and gonadal dysfunction, prostate cancer and other male reproductive system diseases. Sex hormone-binding globulin may be involved in the pathogenesis of male reproductive system diseases, seriously affecting the quality of life of men. In this article, we review the association between sex hormone-binding globulin and male reproductive system diseases.

Serum levels of sex hormone binding globulin (SHBG) are not predictive of prostate cancer diagnosis and aggressiveness: results from an Italian biopsy cohort

PURPOSE

To explore the association between serum levels of Sex Hormone Binding Globulin (SHBG) and the risk of developing prostate cancer (PCa) as well as high grade disease in men undergoing prostate biopsy.

MATERIALS AND METHODS

Between 2006 and 2012, we prospectively enrolled 740 patients with no history of PCa undergoing prostate biopsy. Before biopsy general data of the patient DRE, PSA and BMI were recorded. The risk of detecting cancer and high grade cancer was assessed as a function of SHBG using crude and adjusted logistic regressions.

RESULTS

Serum levels of SHBG were not associated with an increased risk of PCa or high grade disease. Age (OR 1.027 95% CI 1.003-1.052 p = 0.027), DRE (OR 3.391 95% CI 2.258-5.092 p = 0.000) and PSA (OR 1.078 95% CI 1.037-1.120 p = 0.000) were found to be independent predictors of prostate cancer risk. Age (OR 1.051 95% CI 1.009-1.095 p = 0.016), DRE (OR 2.519 95% CI 1.384-4.584 p = 0.000), BMI (OR 1.098 95% CI 1.011-1.193 p = 0.027) and PSA (OR 1.074 95% CI 1.014-1.137 p = 0.015) were found to be independent predictors of high grade disease.

CONCLUSIONS

In our cohort of patients, serum levels of SHBG are not predictive of PCa or high grade disease. According to our experience SHBG should not be considered a biomarker in PCa diagnosis neither a marker for high grade disease.

α-Spinasterol from Melandrium firmum attenuates benign prostatic hyperplasia in a rat model

Spinasterol, a biologically active compound, exhibits a number of pharmacological activities, including antitumor, antiulcerogenic and anticarcinogenic activity, and originates from the aerial parts of Aster scaber Thunb (Asteraceae). The present study investigated whether α-spinasterol isolated from Melandrium firmum Rohrbach could prevent benign prostatic hyperplasia (BPH) induced by testosterone propionate (TP) in rats. Male Wistar rats were randomly divided into four groups of eight rats following castration. A negative control group received subcutaneous injections of corn oil. Treatments were administered orally 1 h prior to TP injection. All the rats were sacrificed at the scheduled termination time and their prostates were removed, cleaned and weighed. The prostate size ratio (prostate weight/rat body weight) was then calculated. Additional histopathological examinations were conducted, and the levels of TP and dihydrotestosterone (DHT) in the serum and prostate were measured. TP significantly increased the prostate size ratio (P<0.01), and DHT and testosterone levels in the serum and prostate. The TP-induced increase was significantly inhibited in α-spinasterol-treated rats when compared with the negative controls (P<0.05). In addition, histopathological examination demonstrated that α-spinasterol treatment suppressed TP-induced prostatic hyperplasia. It is concluded that α-spinasterol can prevent TP-induced prostatic hyperplasia and may be beneficial in the management of BPH.

Serum levels of 17-β-estradiol are not predictive of prostate cancer diagnosis and aggressiveness: results from an Italian biopsy cohort

OBJECTIVES

To explore the association between serum levels of 17-β-estradiol (17BE) and prostate cancer (PCa) risk in men undergoing prostate biopsy.

METHODS AND MATERIALS

Between 2006 and 2012, we prospectively enrolled 894 patients, with no history of PCa, undergoing prostate biopsy. Before biopsy was performed, general data, digital rectal examination (DRE), body mass index, 17BE, and prostate-specific antigen (PSA) were recorded. The risk of detecting cancer and high-grade cancer was assessed as a function of 17BE using crude and adjusted logistic regressions.

RESULTS

Serum levels of 17BE were not associated with an increased risk of PCa or high-grade disease. Age (odds ratio [OR] 1.05; 95% confidence interval [CI]: 1.03-1.07; P = 0.000), DRE(OR 2.81; 95% CI: 1.98-4.00; P = 0.000), and PSA(OR 1.07; 95% CI: 1.04-1.10; P = 0.000) were found to be independent predictors of PCa risk. Age (OR 1.05; 95% CI: 1.01-1.09; P = 0.007), DRE (OR 3.04; 95% CI: 1.79-5.17; P = 0.000), body mass index (OR 1.07; 95% CI: 1.01-1.150; P = 0.040), and PSA (OR 1.08; 95% CI: 1.03-1.12; P = 0.000) were found to be independent predictors of high-grade disease.

CONCLUSION

In our cohort of patients, serum levels of 17BE are not predictive of PCa or high-grade disease. In patients at risk of PCa, 17BE should not be considered a reliable marker to predict poorly differentiated PCa in the setting of initial prostate biopsy.

The impact of obesity on the predictive accuracy of PSA in men undergoing prostate biopsy

PURPOSE

Obese men have been reported to have lower serum PSA values relative to normal-weight men in population-based studies, screening cohorts, and in men with prostate cancer (CaP) treated with surgery. There are concerns that PSA may be less accurate in detecting prostate cancer in men with increased body mass index (BMI). We determine whether the diagnostic potential of PSA is negatively influenced by obesity by comparing its operating characteristics across BMI categories among men undergoing prostate biopsy.

METHODS

Demographic, clinical, and histopathological data on 917 men who underwent trans-rectal ultrasound-guided prostate needle biopsy from 2002 to 2010 at a University hospital in Italy were used in the study. Men were categorized for BMI as follows: <25 kg/m(2) (normal weight), 25-29.9 kg/m(2) (overweight), and ≥ 30 kg/m(2) (obese). Receiver operator characteristics (ROC) curves were used to assess PSA accuracy for predicting prostate cancer overall and then stratified according to digital rectal examination (DRE) findings using the area under the ROC curve (AUC).

RESULTS

The obesity rate of the study cohort was 21 %. There was no statistically significant difference in the overall AUCs of PSA for predicting CaP among normal-weight (AUC = 0.56), overweight (AUC = 0.60), and obese men (AUC = 0.60; p = 0.68) in either DRE-positive or negative men.

CONCLUSIONS

In a cohort of Italian men undergoing prostate biopsy, the performance accuracy of PSA as a predictor of CaP is not significantly altered by BMI. Obesity does not negatively impact the overall ability of PSA to discriminate between CaP and benign conditions.

Influence of dosing time on the efficacy and safety of finasteride in rats

Finasteride (FIN), a widely used medication for the treatment of androgen-dependent diseases, blocks the conversion of testosterone to a more potent androgen, dihydrotestosterone (DHT). In this study, we investigated a dosing time-dependent effect and safety of FIN in rats. Androgen receptor (AR) mRNA and nuclear protein levels exhibited clear daily rhythms with the peak during the dark period in the prostate and during the light period in the liver. Repeated oral administration of FIN (5 or 100 mg/kg) at 3 h after lights on (HALO) for 2 weeks decreased serum DHT concentration throughout a 24-h period, whereas the dosing of the agent at 15 HALO decreased its level only transiently even in the higher dose group. FIN caused laboratory abnormalities in the 3 HALO group but not in the 15 HALO group. However, the effect of FIN on the prostate weight was not influenced by the dosing time. These results suggest that the safety, but not effect, of FIN depends on its dosing time in rats. The dosing of FIN in the active period might be a rational dosage regimen, which is needed to be confirmed in human subjects.

Prostate cancer does not influence androgen levels: a radical prostatectomy cohort study

AIM

To investigate the relationship between androgens and prostate cancer in patients scheduled for radical prostatectomy.

SUBJECTS AND METHODS

Patients scheduled for open radical prostatectomy were enrolled. Blood samples were collected before prostate biopsy and 12 months later to evaluate testosterone, free testosterone, sex hormone-binding globulin (SHBG), PSA, calculated free and bioavailable testosterone.

RESULTS

44 patients were consecutively enrolled. 15 patients (34%) presented a Gleason score (GS) of 6, 24 patients GS 7 (54%), 1 patient (2%) GS 8, and 4 patients GS 9 (9%). Mean prostate cancer volume was 4.3 ± 5.7 cm(3). 24 patients presented a pT2 stage, 16 a pT3a stage, and 4 a pT3b stage. Positive surgical margins were detected in 12 patients (27.3%). No significant change of testosterone (4.21 ± 1.49 vs. 4.00 ± 1.48 ng/ml, p = 0.46), free testosterone (9.01 ± 3.64 vs. 8.85 ± 3.04 pg/ml, p = 0.83), SHBG (38 ± 14.39 vs. 38.5 ± 17.23 nmol/l, p = 0.71), calculated free testosterone (0.091 ± 0.13 vs. 0.067 ± 0.026, p = 0.563), and bioavailable testosterone (1.89 ± 0.722 vs. 1.88 ± 0.53, p = 0.912) was observed.

CONCLUSIONS

In our single-center study, prostate cancer does not impact on serum androgen levels, however our results should be confirmed in a larger study.

Breast and prostate cancer: more similar than different

Breast cancer and prostate cancer are the two most common invasive cancers in women and men, respectively. Although these cancers arise in organs that are different in terms of anatomy and physiological function both organs require gonadal steroids for their development, and tumours that arise from them are typically hormone-dependent and have remarkable underlying biological similarities. Many of the recent advances in understanding the pathophysiology of breast and prostate cancers have paved the way for new treatment strategies. In this Opinion article we discuss some key issues common to breast and prostate cancer and how new insights into these cancers could improve patient outcomes.