EFFECT OF THE DUAL 5α-REDUCTASE INHIBITOR DUTASTERIDE ON MARKERS OF TUMOR REGRESSION IN PROSTATE CANCER

Subchronic intake of arsenic at environmentally relevant concentrations causes histological lesions and oxidative stress in the prostate of adult Wistar rats

The prostate gland is one of the main sites of hyperplasia and cancer in elderly men. Numerous factors have been demonstrated to disrupt prostate homeostasis, including exposure to environmental pollutants. Arsenic is a metalloid found ubiquitously in soil, air, and water, which favors human poisoning through the involuntary intake of contaminated drinking water and food and has harmful effects by increasing the oxidative stress response. This study aimed to investigate the effects of prolonged exposure to arsenic at environmentally relevant concentrations on the prostate biology of adult Wistar rats. Thirty 80-day-old male rats were divided into three experimental groups. Rats from the control group received filtered water, whereas animals from the arsenic groups ingested 1 mg L-1 and 10 mg L-1 of arsenic, in the form of sodium arsenite, daily. The arsenic solutions were provided ad libitum in the drinking water for eight weeks. Our results showed that 1 mg L-1 and 10 mg L-1 of arsenic made the prostate susceptible to evolving benign and premalignant histopathological changes. While the ingestion of 1 mg L-1 of arsenic reduced SOD activity only, 10 mg L-1 diminished SOD and CAT activity in the prostate tissue, culminating in high MDA production. These doses, however, did not affect the intraprostatic levels of DHT and estradiol. In conclusion, exposure to arsenic at environmentally relevant concentrations through drinking water induces histological and oxidative stress-related changes in the prostate of adult rats, strengthening the between arsenic exposure and prostate disorders.

Phytochemicals With Anti 5-alpha-reductase Activity: A Prospective For Prostate Cancer Treatment

Prostate cancer (CaP) is one of the leading causes of death in men worldwide. Much attention has been given on its prevention and treatment strategies, including targeting the regulation of 5-alpha-Reductase (5αR) enzyme activity, aimed to limit the progression of CaP by inhibiting the conversion of potent androgen dihydrotestosterone from testosterone that is thought to play a role in pathogenesis of CaP, by using the 5-alpha-Reductase inhibitors (5αRis) such as finasteride and dutasteride. However, 5αRis are reported to exhibit numerous adverse side effects, for instance erectile dysfunction, ejaculatory dysfunction and loss of libido. This has led to a surge of interest on plant-derived alternatives that might offer favourable side effects and less toxic profiles. Phytochemicals from plants are shown to exhibit numerous medicinal properties in various studies targeting many major illnesses including CaP. Therefore, in this review, we aim to discuss the use of phytochemicals namely phytosterols, polyphenols and fatty acids, found in various plants with proven anti-CaP properties, as an alternative herbal CaP medicines as well as to outline their inhibitory activities on 5αRs isozymes based on their structural similarities with current 5αRis as part of CaP treatment approaches.

Five-alpha reductase inhibitors in men undergoing active surveillance for prostate cancer: impact on treatment and reclassification after 6 years follow-up

OBJECTIVES

To evaluate the impact of 5-alpha reductase inhibitors (5-ARIs) on definitive treatment (DT) and pathological progression (PP) in patients on active surveillance (AS) for prostate cancer.

METHODS

We identified 361 consecutive patients, from an IRB-approved database, on AS for prostate cancer with minimum 2 years follow-up. Patients were grouped into two cohorts, those using 5-ARIs (5-ARI; n = 119) or not using 5-ARIs (no 5-ARI; n = 242). Primary and secondary endpoints were treatment-free survival (TFS) and PP-free survival (PPFS), which were evaluated by Kaplan-Meier analysis. Univariate and multivariable cox regression analysis were used to identify predictors for PP and DT. A p value < 0.05 was considered statistically significant.

RESULTS

Baseline characteristics and the prostate biopsy rate were similar between the two groups. Median (range) follow-up was 5.7 (2.0-17.2) years. Five-year and 10-year TFS was 92% and 59% for the 5-ARI group versus 80% and 51% for the no 5-ARI group (p = 0.005), respectively. Five-year and 10-year PPFS was 77% and 41% for the 5-ARI group versus 70% and 32% for the no 5-ARI group (p = 0.04), respectively. Independent predictors for treatment and PP were not taking 5-ARIs (p = 0.005; p = 0.02), entry PSA > 2.5 ng/mL (p = 0.03; p = 0.01) and Gleason pattern 4 on initial biopsy (p < 0.001; p < 0.001), respectively. The main limitation is the retrospective study design.

CONCLUSIONS

5-ARIs reduces reclassification and cross-over to treatment in men on active surveillance for prostate cancer. Further, taking 5-ARIs was an independent predictor for prostate cancer progression and definitive treatment.

Azasteroids from diosgenin: Synthesis and evaluation of their antiproliferative activity

In this work, we report the synthesis of two new azasteroids through the modification of the A and B rings of diosgenin 1. The 4-azasteroid derivative 12 was prepared in three steps using the α,β-insaturated-3-keto compound 11 as a precursor, which was first oxidized with KMnO4/KIO4 followed by an oxidative cleavage of ring A, and subsequently cyclized with an ammonium salt, under focused microwave irradiation for a short time of 3 min. A second azasteroid was synthesized, for which the key step was the Beckmann rearrangement of ring B of the oxime 16, affording the lactam-type enamide 17 in good yield. The methodologies developed for the synthesis of the precursors derivatives 10 and 11 contribute to improved yields, compared to those reported in the literature. The biological activity of the azasteroidal compounds 12 and 17 and their precursors has been evaluated in cervical cancer cells (HeLa), colon (HCT-15), and triple negative breast cancer (MDA-MB-231) lines.

ARe we there yet? Understanding androgen receptor signaling in breast cancer

The role of androgen receptor (AR) activation and expression is well understood in prostate cancer. In breast cancer, expression and activation of AR is increasingly recognized for its role in cancer development and its importance in promoting cell growth in the presence or absence of estrogen. As both prostate and breast cancers often share a reliance on nuclear hormone signaling, there is increasing appreciation of the overlap between activated cellular pathways in these cancers in response to androgen signaling. Targeting of the androgen receptor as a monotherapy or in combination with other conventional therapies has proven to be an effective clinical strategy for the treatment of patients with prostate cancer, and these therapeutic strategies are increasingly being investigated in breast cancer. This overlap suggests that targeting androgens and AR signaling in other cancer types may also be effective. This manuscript will review the role of AR in various cellular processes that promote tumorigenesis and metastasis, first in prostate cancer and then in breast cancer, as well as discuss ongoing efforts to target AR for the more effective treatment and prevention of cancer, especially breast cancer.

Discovery and development of azasteroids as anticancer agents

Cancer is the second leading cause of death worldwide following cardiovascular diseases. Cancer can be treated by a variety of techniques including surgery, radiation therapy, immunotherapy, and chemotherapy. Choice of the method can be made based on type, physiologic location and the stage of disease progression. Among chemical methods, steroids find broad applications. Azasteroids have N- substitutions in steroidal rings. This structural modification renders azasteroids advantageous in increased effectiveness and reduced side effects. Numerous accounts of cancer efficacy of this family of compounds are available in literature. The progress made in the discovery, synthetic efforts and development of azasteroids as anticancer agents is broadly outlined in this review.

Design, synthesis, and biological evaluation of novel androst-17β-amide structurally related compounds as dual 5α-reductase inhibitors and androgen receptor antagonists

Prostate cancer (PCa) is the second leading cause of death in men. Apart from androgen receptor, 5α-reductase has also been recognized as a potential target. In this study, a series of androst-17β-amide compounds have been designed and synthesized targeting both AR and 5α-reductase. Their anti-proliferation activities were evaluated in AR + cell line 22RV1 and AR - cell line PC-3. The results indicated that most of the synthesized compounds inhibited the testosterone-stimulated cell proliferation with good selectivity and safety. Among all the compounds, androst[3,2-c]pyrazole derivatives (9a-9d) displayed the best inhibition activity comparable with flutamide. Moreover, most of the synthesized compounds displayed good 5α-reductase inhibitory activities with IC₅₀ lower than 1 μM. The docking result of 9d-AR indicated that AR was forced to expands its binding cavity and maintain an antagonistic conformation since the steric hindrance of 9d impeded H12 transposition. Overall, compound 9d can be identified as a potential dual 5α-reductase inhibitor and AR antagonist, which might be of therapeutic importance for PCa treatment.

The effects of Pueraria mirifica extract, diadzein and genistein in testosterone-induced prostate hyperplasia in male Sprague Dawley rats

Pueraria mirifica (PM) is a medicinal plant native to Thailand contained high amount of phytoestrogen and possesses anticancer activity. This study reports the effect of P. mirifica extract, phytoestrogen of diadzein and genistein for its benign prostate hyperplasia properties in testosterone-induced prostate hyperplasia in male Sprague Dawley rats. The P. mirifica extract was evaluated for its total phenols, flavonoid and antioxidant activity using DPPH, FRAP and metal chelating assay. The assessment of P. mirifica, diadzein and genistein against benign prostate hyperplasia was determined in testosterone-induced prostate hyperplasia in male Sprague Dawley rats. The total phenol was higher than flavonoid but showed low antioxidant activity of DPPH, FRAP and metal chelating. The aqueous PM extract at 1000 mg/kg significantly increased testosterone levels in testosterone-induced rats by 13% while diadzein and genistein increased it by 11% and 17% respectively. However, levels of FSH, LH, triglyceride and HDL are not affected by the oral administration of PM, diadzein and genistein to the rats. Similarly, total protein, albumin, globulin, total bilirubin, conjugated bilirubin, alkaline phosphatase, alanine aminotransferase, AST, and G-glutamyltransferase showed no significant difference as compared with negative control rats. The body weight of the rats, testis, kidney and liver showed no toxic effect. The zinc content increased significantly and the zinc transporter gen of ZnT4 and ZIP4 highly expressed suggesting that the PM, diadzein and genistein plays essential role in modulating prostate zinc homeostasis. Similarly, the expression of IL-6, AR and ER was significantly reduced indicating functioning in regulation of prostate growth and acts as anti-inflammatory role in preventing BPH. In conclusion, the results indicated that PM reduced BPH and contributed to the regulation in the zinc transport expression of the prostate cells in the benign prostate hyperplasia (BPH).

Sex steroids in serum and prostatic tissue of human cancerous prostate (STERKPROSER trial)

BACKGROUND

Currently, there is no consensus regarding the expected concentration levels of intra-prostatic sex steroids in patients with Prostate Cancer (PCa). Our objective was to assess the concentration levels of sex steroids in prostatic tissue and serum, in two cohorts of patients with localized PCa or benign prostatic hyperplasia (BPH).

METHODS

Between September 2014 and January 2017, men selected for radical cystectomy (for bladder cancer) or open prostatectomy (for BPH), and men selected for radical prostatectomy for localized PCa were included. Blood samples were collected at baseline before surgery, and steroid concentrations were assessed following the recommendations of the Endocrine Society. Intra-prostatic samples were collected from fresh surgical samples, and assessed by gas chromatography and mass spectrometry (GC/MS). Permanova analysis was performed. Analyses were adjusted for age, prostate weight, and prostate-specific antigen (PSA) level.

RESULTS

A total of 73 patients (41 patients with PCa and 32 patients with BPH) were included in this study. Patients with PCa were younger, and had smaller prostate volumes with higher levels of PSA. The levels of Total Testosterone (TT), Di-Hydro-Testosterone (DHT), and Estradiol (E2) in the serum were not significantly different between PCa and BPH. In PCa tissue, TT concentrations were significantly lower (0.11 ng/g vs 0.47 ng/g, P = 0.0002), however its derivative E2 had significantly higher concentrations (31.0 ng/g vs 22.3 ng/g, P = 0.01). DHT tissue concentrations were not significantly different between the two groups (5.55 ng/g vs 5.42 ng/g, P = 0.70). Intra-prostatic TT concentrations were significantly lower in the peripheral zone than in the central zone for the CaP group (0.07 ng/g vs 0.15 ng/g, P = 0.004).

CONCLUSIONS

Patients with PCa had lower intra-prostatic TT and higher E2 concentrations levels compared to the patients with BPH. PCa seem to consume more TT and produce more E2, especially in the peripheral zone.

Change of the 5α/5β ratio of urinary steroid metabolites in benign prostatic hyperplasia patients treated with dutasteride

BACKGROUND

The effects of the administration of dutasteride (DUT) on steroid metabolite pathways in BPH patients have not been examined.

METHODS

Urine and blood samples as well as clinical parameters were prospectively collected after the administration of DUT to 60 BPH patients, and after its withdrawal in another set of 25 BPH patients. Urine samples were assessed using gas chromatography/mass spectrometry for the urinary steroid profile (USP), which simultaneously measures 63 steroid metabolites. We examined pharmacological changes in the 5α/5β ratio of urinary metabolites and their relationships with clinical parameters in patients treated with DUT.

RESULTS

The mean urinary androsterone/etiocholanolone (An/Et) ratio in sex-steroid pathways significantly decreased from 1.39 to 0.02 (p < 0.01). Urinary metabolites in other steroid pathways such as 5αTHF/5βTHF in the glucocorticoid pathway and 5αTHB/5βTHB in the mineralocorticoid pathway also significant decreased after the DUT treatment. As compared to baseline level, the mean An/Et ratios in patients with the withdrawal of DUT were 0.7%, 1.4%, 12.6%, and 82.4% at just before, one month, 3 months, and 6 months after the withdrawal of DUT, respectively. All other steroid pathways changed in a similar manner without the aggravation of urinary symptoms. The recovery ratio of An/Et in USP before and 3 months after the withdrawal of DUT correlated with the recovery ratio of serum PSA levels (ρ = 0.61, p < 0.01).

CONCLUSION

Urinary 5α/5β metabolites in all pathways were strongly suppressed after the administration of DUT for one month and the pharmacological effect of DUT prolonged even after withdrawal of DUT.

Prognostic influence of 5 alpha reductase inhibitors in patients with localized prostate cancer under active surveillance

Objective

The incidence of prostate adenocarcinoma (PCa) is increased with the use of prostate-specific antigen (PSA). In the current study, we aimed to investigate the impact of 5- alpha- reductase inhibitors (5-ARI) on pathological progression in patients followed by active surveillance (AS).

Material and methods

Records of 69 patients with localized prostate cancer under AS (PSA ≤15 ng/mL, PSAD ≤0.20, ≤cT2c, Gleason sum ≤3+3, the number of cancer positive cores ≤3) were evaluated retrospectively. Patients were followed-up with quarterly PSA testing and semiannual digital rectal examination during the first 2 years, and semiannual PSA testing thereafter. Repeat biopsies were done annually and whenever indicated by clinical findings. Pathological progression was defined as increasing Gleason grade, number of cancer-positive cores, and/or increasing percentage of cancer in any core.

Results

Patients using (29/69: 42%) and not using (40/69: 58%) 5-ARI were followed for a median of 39 (IQR: 23-45) and 23.5 (IQR: 17-37.5) months, respectively. Pathological progression was observed in 32% (22/69) of the patients at a median of 25 (IQR: 18-39) months. Pathological progression was observed in 34.5% (10/29) and 30% (12/40) of the patients using and not using 5-ARI, respectively (Log-rank p=0.4151). Definitive treatment was done in 31% (9/29) and 47.5% (19/40) of the patients using and not using 5-ARI, respectively. Patients who did not use 5-ARI received definitive treatment earlier than 5-ARI users (Log-rank p=0.0342). On multivariate analysis, more than 2 cancer-positive cores (HR: 11.62) and age (HR: 0.94) were independently associated with pathological progression (p<0.05), rather than 5-ARI use (p=0.148).

Conclusion

More than 2 cancer- positive cores at the initial biopsy was the strongest covariate associated with pathological progression; these patients should not be offered AS. There was no impact of 5-ARI use on pathological progression in AS.

Prostate-Specific Antigen Kinetics Following 5α-Reductase Inhibitor Treatment May Be a Useful Indicator for Repeat Prostate Biopsy

PURPOSE

To evaluate parameters for determining repeat prostate biopsy in patients with 5α-reductase inhibitor (5ARI) treatment after initial negative biopsy.

MATERIALS AND METHODS

From January 2007 to December 2015, patients who underwent a repeat prostate biopsy after an initial negative biopsy were enrolled from multiple institutions. Serial prostate-specific antigen (PSA) levels after the initial biopsy were analyzed for PSA kinetics. Clinicopathologic variables were evaluated according to the use of 5ARIs after the initial negative biopsy.

RESULTS

Of 419 patients with initial negative biopsies (median age=67.0 years, median PSA=6.31 ng/mL), 101 patients (24.1%) were diagnosed with prostate cancer at the repeat biopsy. An increase in PSA level at 18 months, compared to that at 6 months, was a predictor of a positive repeat biopsy. However, the use of 5ARIs was not identified as a predictor. Of 126 patients receiving 5ARI treatment after the initial biopsy, 30 (23.8%) were diagnosed with prostate cancer at the repeat biopsy. Increase in PSA level at more than two time points after 6 months of 5ARI treatment (odds ratio=4.84, p=0.005) was associated with cancer detection at the repeat biopsy. There were no significant 5ARI group-related differences in the detection rates of prostate and high-grade cancers (Gleason score ≥7).

CONCLUSION

The effects of 5ARIs on prostate cancer detection and chemoprevention remain uncertain. However, more than two increases in PSA level after 6 months of 5ARI treatment may indicate the presence of prostate cancer.

Dehydroepiandrosterone (DHEA)-SO4 Depot and Castration-Resistant Prostate Cancer

Dehydroepiandrosterone (DHEA)-SO₄ of adrenal origin is the major C19 steroid in the serum. It is a precursor of intratumoral androgen biosynthesis in patients with advanced prostate cancer following chemical or surgical castration. DHEA is a product of the P450c17 (17α-hydroxylase-17,20-lyase) enzyme. Despite inhibition of P450c17 with new agents, e.g., Abiraterone acetate, Orterenol, and Galeterone, the level of enzyme inhibition rarely exceeds 90% leaving behind a significant depot for androgen biosynthesis within the tumor. For DHEA-SO₄ to be utilized there is uptake by organic anion transporter polypeptides, deconjugation catalyzed by steroid sulfatase, and adaptive upregulation of prostate steroidogenic enzymes that will convert DHEA into either testosterone or dihydrotestosterone. The depot of DHEA-SO₄ that remains after P450c17 inhibition and the adaptive responses that occur within the tumor to promote DHEA utilization contribute to mechanisms of drug resistance observed with P450c17 inhibitors. Knowledge of these mechanisms identify new targets for therapeutics that could be used to surmount drug resistance in prostate cancer.

Computer vision detects subtle histological effects of dutasteride on benign prostate

OBJECTIVE

To determine whether a computer vision-based approach applied to haematoxylin and eosin (H&E) prostate biopsy images can distinguish dutasteride-treated tissue from placebo, and identify features associated with degree of responsiveness to 5α-reductase inhibitor (5ARI) therapy.

SUBJECTS AND METHODS

Our study population comprised 100 treatment-adherent men without prostate cancer assigned to dutasteride or placebo in the REDUCE trial, who had slides available from mandatory year-4 biopsies. Half of the men also provided slides from a year-2 biopsy. We obtained 20× whole-slide images and used specialized software to generate a library of 1 300 epithelial and stromal features from objects comprising superpixels and several types of nuclei, including spatial relations among objects between and within each hierarchical level. We used penalized logistic regression and fivefold cross-validation to find optimal combinations of histological features in the year-4 biopsies. Feature data from the year-2 biopsies were fitted to a final model for independent validation. Two pathologists, blinded to treatment, scored each image for focal atrophy and histological features previously linked to 5AR1 treatment.

RESULTS

Consensus classification by pathologists obtained a discrimination accuracy equivalent to chance. A 21-feature computer vision model gave a cross-validation area under the curve of 0.97 (95% confidence interval [CI] 0.95-0.99) in the year-4 biopsies and 0.79 (95% CI: 0.65-0.92) in the set-aside year-2 biopsies. Histology scores were not correlated with change in prostate-specific antigen level, serum dihydrotestosterone level or gland volume. Key features associated with dutasteride treatment included greater shape and colour uniformity in stroma, irregular clustering of epithelial nuclei, and greater variation in lumen shape.

CONCLUSION

The present findings show that a computer vision approach can detect subtle histological effects attributable to dutasteride, resulting in a continuous measure of responsiveness to the drug that could eventually be used to predict individual patient response in the context of BPH treatment or cancer chemoprevention.

Targeting phenotypic heterogeneity in benign prostatic hyperplasia

Benign prostatic hyperplasia and associated lower urinary tract symptoms remain difficult to treat medically, resulting in hundreds of thousands of surgeries performed annually in elderly males. New therapies have not improved clinical outcomes since alpha blockers and 5 alpha reductase inhibitors were introduced in the 1990s. An underappreciated confounder to identifying novel targets is pathological heterogeneity. Individual patients display unique phenotypes, composed of distinct cell types. We have yet to develop a cellular or molecular understanding of these unique phenotypes, which has led to failure in developing targeted therapies for personalized medicine. This review covers the strategic experimental approach to unraveling the cellular pathogenesis of discrete BPH phenotypes and discusses how to incorporate these findings into the clinic to improve outcomes.

The impact of finasteride and dutasteride treatments on proliferation, apoptosis, androgen receptor, 5α-reductase 1 and 5α-reductase 2 in TRAMP mouse prostates

BACKGROUND

Previously, we studied the effect of finasteride- or dutasteride-containing diets in male C57BL/6 TRAMP x FVB mice. Pre (6 weeks of age) and post (12 weeks of age) groups received finasteride or dutasteride to determine the efficacy of these pharmaceuticals on prostate cancer (PCa) development in male C57BL/6 TRAMP x FVB mice. Post-Dutasteride treatment was more effective than Pre-Dutasteride treatment, and dutasteride treatments were more effective than finasteride treatments in decreasing prostatic intraepithelial neoplasia (PIN) progression and PCa development. Finasteride and Pre-Dutasteride treatments significantly decreased high-grade PIN incidence, but increased poorly differentiated PCa incidence. In this study, molecular changes in prostates of these mice were characterized in an effort to elucidate the discordant response in Pre-Dutasteride and finasteride groups, and determine why Post-Dutasteride treatment was more effective.

METHOD/PRINCIPAL FINDINGS

Ki-67 (proliferation marker) and androgen receptor (AR) protein, apoptotic DNA fragmentation (TUNEL assay), 5α-reductase 1 (5αR1) and 5α-reductase 2 (5αR2) mRNA were quantified in male TRAMP mice prostate tissues with genitourinary weight < 1 and > 1 gram. Overall, proliferation and AR were decreased and apoptosis was increased in most tumors versus prostate epithelium and hyperplasia. Proliferation and AR were increased notably in hyperplasia versus prostate epithelium and tumor. There were no clear trends or differences in 5α-reductase 1 and 5α-reductase 2 levels between large and small tumors. The discordant response in Pre-Finasteride and Pre-Dutasteride groups may be due to upregulated 5αR1 levels in large versus small tumors. It is not clear what the mechanism is for the different response in the Post-Finasteride group. Post-Dutasteride treatment was more effective than Pre-Dutasteride treatment in decreasing 5αR1 in large tumors. Therefore, this may be why this treatment was more effective in decreasing PIN progression and PCa development.

CONCLUSION

The effect of finasteride and dutasteride on these biomarkers did not clearly elucidate their mechanism of action, but tumor 5αR1 levels were significantly positively correlated with adjusted prostate severe lesion score.

Testosterone and dihydrotestosterone levels in the transition zone correlate with prostate volume

BACKGROUND

There is still no consensus regarding intraprostatic androgen levels and the accumulation of androgens in the hyperplastic prostatic tissue. The current opinion is that intraprostatic dihydrotestosterone (DHT) concentrations are maintained but not elevated in benign prostatic hyperplasia (BPH), while there is no similar data concerning intraprostatic testosterone (T).

METHODS

Tissue T (tT) and tissue DHT (tDHT) concentration were determined in 93 patients scheduled for initial prostate biopsy. The criteria for biopsy were abnormal DRE and/or PSA > 4 ng/mL. Total prostate volume (TPV) was determined by transrectal ultrasound (TRUS). During TRUS- guided prostate biopsy, 10-12 samples were collected from the peripheral zone (PZ) and two additional samples were collected from the transition zone (TZ). The samples from the TZ were immediately frozen in liquid nitrogen at -70°C, and transported for tissue androgen determination, using liquid chromatography mass spectrometry (LC-MS).

RESULTS

Pathological analysis revealed that prostate cancer (PCa) was present in 45 and absent in 48 patients. In the whole group, there were 42 men with small prostate (TPV < 30 mL) and 51 with enlarged prostate (TPV ≥ 31 mL). The overall average tT level was 0.79 ± 0.66 ng/g, while the average tDHT level was 10.27 ± 7.15 ng/g. There were no differences in tT and tDHT level in prostates with and without PCa. However, tT and tDHT levels were significantly higher in larger, than in smaller prostates (tT: 1.05 ± 0.75 and 0.46 ± 0.29 ng/g, and tDHT: 15.0 ± 6.09 and 4.51 ± 2.75 ng/g, respectively). There were strong correlations between tT and TPV (r = 0.71), and tDHT and TPV (r = 0.74).

CONCLUSIONS

The present study confirmed that both T and DHT accumulated in the stroma of enlarged prostates; the degree of accumulation correlated with prostate volume.

Early dutasteride monotherapy in men with detectable serum prostate-specific antigen levels following radical prostatectomy: A prospective trial

Purpose

To investigate the effects of early administration of dutasteride in patients with detectable serum prostate-specific antigen (PSA) levels after radical prostatectomy (RP).

Materials and Methods

A prospective open-label study, with a cumulative analysis of asymptomatic increase in PSA following RP, was conducted from January 2005 to December 2013. An early increase in PSA level was defined as detectable serum PSA level> 0.04 ng/mL. Patients with PSA level>0.04 ng/mL were treated with dutasteride 0.5 mg daily. Serum PSA level and biochemical recurrence (BCR) were monitored. We divided the patients into 2 groups based on the serum PSA response after dutasteride treatment.

Results

Eighty patients were included in the study. At the median follow-up of 51.8 months, 56 patients (70.0%) showed a decrease of greater than 10% in serum PSA level, and 24 showed increased PSA levels. Twelve of the 56 patients with PSA response showed subsequently increased PSA. Intergroup differences in preoperative PSA levels, PSA nadir levels, and Gleason score of 6 or less were significant (p=0.028, p=0.030, and p=0.035, respectively). A multivariate analysis revealed that Gleason score of 6 or less (p=0.018) and PSA nadir levels (p=0.011) were predictive factors for PSA response after early dutasteride treatment in men with increased PSA levels following RP.

Conclusions

Early monotherapy of dutasteride showed a decline in serum PSA levels in men with lower nadir PSA levels, and a Gleason score 6, when the serum PSA was detected after RP.

Application of transrectal ultrasound-guided repeat needle biopsy in the diagnosis of prostate cancer in Chinese population: A retrospective study

BACKGROUND

Transrectal ultrasound-guided repeat needle biopsy (TUGRNB) is widely used for diagnosis of prostate cancer (PCa). However, significance of TUGRNB in Chinese population was rarely reported. A retrospective study was conducted to evaluate the significance of TUGRNB applied in prediction of PCa in Chinese population.

MATERIALS AND METHODS

A total of 960 from January 2009 to December 2012 were included. Repeat needle biopsy rate and PCa positive detection rate were evaluated. Relationship between prostate specific antigen (PSA) levels and PCa positive rates was analyzed.

RESULTS

PCa positive detection rate after initial needle biopsy was 28.4%, which was lower than the rate of repeat needle biopsy (40%). The rate for immediate transurethral resection (TUR), surgery after initial needle biopsy, was 27.1%, however with a low PCa positive detection rate (0.66%). The repeat needle biopsy rate was lower compared with the initial biopsy rate (P < 0.05). Meanwhile, immediate TUR rate was significantly higher than that of the repeat needle biopsy rate (P < 0.05). Among the three groups, the PCa positive detection rate in repeat needle biopsy group was the highest. In subgroups with different PSA levels, the PCa positive rate increased with the elevation of PSA level. In cases with PSA > 20 ng/ml, PCa positive rate was significantly higher than those with PSA < 20 ng/ml (P < 0.05).

CONCLUSION

PCa positive detection rate following repeat needle biopsy in Chinese population was higher, although the repeated needle biopsy rate was still in a low level. TUGRNB should attract more attention in the diagnosis of PCa.

Is There a Future for Chemoprevention of Prostate Cancer?

The outcome of the Selenium and Vitamin E Cancer Prevention Trial, demonstrating harm and no preventive activity of selenomethionine and α-tocopherol for prostate cancer, and the lack of approval by the FDA for the use of 5α-reductase inhibitors to prevent prostate cancer have cast doubt about the future of chemoprevention of prostate cancer. This article attempts to critically assess whether the notion that chemoprevention of prostate cancer has no future is warranted. Risk of prostate cancer is modifiable and chemoprevention of prostate cancer, particularly fatal/lethal cancer, is both needed and possible. However, the approach to prostate cancer-chemopreventive agent development has not followed a rational and systematic process. To make progress, the following steps are necessary: (i) identification of intermediate biomarkers predictive of fatal/lethal disease; (ii) development of a rational approach to identification of candidate agents, including high-throughput screening and generation of information on mechanism and biology of candidate agents and potential molecular targets; and (iii) systematic evaluation of the predictive value of preclinical models, phase II trials, and intermediate biomarkers for the outcome of phase III trials. New phase III trials should be based on adequate preclinical and phase II studies. Cancer Prev Res; 9(8); 642-7. ©2016 AACR.

Tissue Effects in a Randomized Controlled Trial of Short-term Finasteride in Early Prostate Cancer

BACKGROUND

In the Prostate Cancer Prevention Trial, finasteride selectively suppressed low-grade prostate cancer and significantly reduced the incidence of prostate cancer in men treated with finasteride compared with placebo. However, an apparent increase in high-grade disease was also observed among men randomized to finasteride. We aimed to determine why and hypothesized that there is a grade-dependent response to finasteride.

METHODS

From 2007 to 2012, we randomized dynamically by intranet-accessible software 183 men with localized prostate cancer to receive 5mg finasteride or placebo daily in a double-blind study during the 4-6weeks preceding prostatectomy. As the primary end point, the expression of a predefined molecular signature (ERβ, UBE2C, SRD5A2, and VEGF) differentiating high- and low-grade tumors in Gleason grade (GG) 3 areas of finasteride-exposed tumors from those in GG3 areas of placebo-exposed tumors, adjusted for Gleason score (GS) at prostatectomy, was compared. We also determined androgen receptor (AR) levels, Ki-67, and cleaved caspase 3 to evaluate the effects of finasteride on the expression of its downstream target, cell proliferation, and apoptosis, respectively. The expression of these markers was also compared across grades between and within treatment groups. Logistic regression was used to assess the expression of markers.

FINDINGS

We found that the predetermined molecular signature did not distinguish GG3 from GG4 areas in the placebo group. However, AR expression was significantly lower in the GG4 areas of the finasteride group than in those of the placebo group. Within the finasteride group, AR expression was also lower in GG4 than in GG3 areas, but not significantly. Expression of cleaved caspase 3 was significantly increased in both GG3 and GG4 areas in the finasteride group compared to the placebo group, although it was lower in GG4 than in GG3 areas in both groups.

INTERPRETATION

We showed that finasteride's effect on apoptosis and AR expression is tumor grade dependent after short-term intervention. This may explain finasteride's selective suppression of low-grade tumors observed in the PCPT.

Risk of Fractures and Falls during and after 5-α Reductase Inhibitor Use: A Nationwide Cohort Study

Background

Lower urinary tract symptoms are common among older men and 5-α reductase inhibitors (5-ARI) are a group of drugs recommended in treating these symptoms. The effect on prostate volume is mediated by a reduction in dihydrotestosterone; however, this reduction is counterbalanced by a 25% rise in serum testosterone levels. Therefore, 5-ARI use might have systemic effects and differentially affect bone mineral density, muscular mass and strength, as well as falls, all of which are major determinants of fractures in older men.

Methods

We conducted a nationwide cohort study of all Swedish men who used 5-ARI by comparing their risk of hip fracture, any type of fracture and of falls with matched control men randomly selected from the population and unexposed to 5-ARI.

Results

During 1 417 673 person-years of follow-up, 10 418 men had a hip fracture, 19 570 any type of fracture and 46 755 a fall requiring hospital care. Compared with unexposed men, current users of 5-ARI had an adjusted hazard ratio (HR) of 0.96 (95% CI 0.91–1.02) for hip fracture, an HR of 0.94 (95% CI 0.90–0.98) for all fracture and an HR of 0.99 (95% CI 0.96–1.02) for falls. Former users had an increased risk of hip fractures (HR 1.10, 95% CI 1.01–1.19).

Conclusion

5-ARI is safe from a bone health perspective with an unaltered risk of fractures and falls during periods of use. After discontinuation of 5-ARI, there is a modest increase in the rate of fractures and falls.

A synopsis of drugs currently in preclinical and early clinical development for the treatment of benign prostatic hyperplasia

INTRODUCTION

Benign prostatic hyperplasia (BPH) is a common disease among men and significantly impacts quality of life by causing lower urinary tract symptoms (LUTS). Current medical therapies are not always adequate in controlling LUTS or slowing disease progression, and there is unmet need for new effective therapeutic options.

AREAS COVERED

The authors review the standard current medical therapies for BPH which include the use of α-1 blockers, 5-α reductase inhibitors, combination therapy and PDE inhibitors. Following this, the authors then discuss new therapies that are currently undergoing preclinical and clinical investigation.

EXPERT OPINION

Existing preclinical and clinical trials have highlighted many promising therapies to treat BPH. Further investigation with larger clinical trials is needed to establish these drugs as standard therapies. As the number of drugs in the arsenal against BPH continues to grow, providers and patients will have to engage in a discussion that weighs the risks and benefits of each therapy.

5-Alpha reductase inhibitors in active surveillance

PURPOSE OF REVIEW

Active surveillance is now one of the recommended treatment options for low-risk prostate cancer (PCa). However, about 10-30% of men on active surveillance will progress and require definitive therapy. In this review, we examine the role of 5-alpha reductase inhibitors (5-ARIs) in secondary prevention among men with low-risk PCa who opted to be managed by active surveillance.

RECENT FINDINGS

Three retrospective studies and one randomized controlled trial have evaluated the role of 5-ARIs in preventing clinical progression among men followed by active surveillance. These studies largely support the role of 5-ARIs for secondary chemoprevention, although the drugs do not have an indication for this setting.

SUMMARY

5-ARIs have been shown to play an important role in preventing clinical progression among men with low-risk PCa on active surveillance. However, in light of the US Food and Drug Administration recommendation against 5-ARIs for primary chemoprevention, these findings should be interpreted with caution. Patients should be made aware of this warning label before starting the drug.

5ARI and PSA: open questions

No consensus has ever been reached on the predictive value of serum prostate specific antigen (PSA) for the diagnosis of prostate cancer. Limitations of PSA testing in clinical practice have been often discussed in the peer-reviewed literature following data derived from clinical trials such as the Prostate Cancer Prevention Trial (PCPT) and the Reduction by Dutasteride of Prostate Cancer Events (REDUCE) study that showed a linear rise in the risk of prostate cancer with increasing PSA levels. Benign prostatic hyperplasia is a known confounding factor for the use of PSA as a marker of prostate cancer. Increased prostate volume observed with ageing, urinary retention, acute and chronic inflammatory conditions of the prostate, sexual activity and digital rectal examination may all cause an increase of PSA values. Both finasteride and dutasteride, 5-alpha reductase inhibitors (5ARI) used in the treatment of BPH, are known to induce a significant decrease of serum PSA levels close to 50%. The observed change in PSA values following 5ARI treatment has raised questions about the accuracy of PSA testing for the early diagnosis of prostate cancer in patients on finasteride/dutasteride treatment. Careful analysis of data from various clinical trials on pharmacological treatment of LUTS due to BPH suggested that the accuracy of PSA testing is not just maintained but rather increased following 5ARI use. Then, the question of PSA accuracy during 5ARI treatment can be considered closed.

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.

5α-reductase type 3 enzyme in benign and malignant prostate

BACKGROUND

Currently available 5α-reductase inhibitors are not completely effective for treatment of benign prostate enlargement, prevention of prostate cancer (CaP), or treatment of advanced castration-recurrent (CR) CaP. We tested the hypothesis that a novel 5α-reductase, 5α-reductase-3, contributes to residual androgen metabolism, especially in CR-CaP.

METHODS

A new protein with potential 5α-reducing activity was expressed in CHO-K1 cellsandTOP10 E. coli for characterization. Protein lysates and total mRNA were isolated from preclinical and clinical tissues. Androgen metabolism was assessed using androgen precursors and thin layer chromatography or liquid chromatography tandem mass spectrometry.

RESULTS

The relative mRNA expression for the three 5α-reductase enzymes in clinical samples of CR-CaP was 5α-reductase-3 ≫ 5α-reductase-1> 5α-reductase-2. Recombinant 5α-reductase-3 protein incubations converted testosterone, 4-androstene-3,17-dione (androstenedione) and 4-pregnene-3,20-dione (progesterone) to dihydrotestosterone, 5α-androstan-3,17-dione, and 5α-pregnan-3,20-dione, respectively. 5α-Reduced androgen metabolites were measurable in lysates from androgen-stimulated (AS) CWR22 and CR-CWR22 tumors and clinical specimens of AS-CaP and CR-CaP pre-incubated with dutasteride (a bi-specific inhibitor of 5α-reductase-1 and 2).

CONCLUSION

Human prostate tissues contain a third 5α-reductase that was inhibited poorly by dutasteride at high androgen substrate concentration in vitro, and it may promote DHT formation in vivo, through alternative androgen metabolism pathways when testosterone levels are low.

Prostate cancer cells differ in testosterone accumulation, dihydrotestosterone conversion, and androgen receptor signaling response to steroid 5α-reductase inhibitors

BACKGROUND

Blocking 5α-reductase-mediated testosterone conversion to dihydrotestosterone (DHT) with finasteride or dutasteride is the driving hypothesis behind two prostate cancer prevention trials. Factors affecting intracellular androgen levels and the androgen receptor (AR) signaling axis need to be examined systematically in order to fully understand the outcome of interventions using these drugs.

METHODS

The expression of three 5α-reductase isozymes, as determined by immunohistochemistry and qRT-PCR, was studied in five human prostate cancer cell lines. Intracellular testosterone and DHT were analyzed using mass spectrometry. A luciferase reporter assay and AR-regulated genes were used to evaluate the modulation of AR activity.

RESULTS

Prostate cancer cells were capable of accumulating testosterone to a level 15-50 times higher than that in the medium. The profile and expression of 5α-reductase isozymes did not predict the capacity to convert testosterone to DHT. Finasteride and dutasteride were able to depress testosterone uptake in addition to lowering intracellular DHT. The inhibition of AR activity following drug treatment often exceeded the expected response due to reduced availability of DHT. The ability to maintain high intracellular testosterone might compensate for the shortage of DHT.

CONCLUSIONS

The biological effect of finasteride or dutasteride appears to be complex and may depend on the interplay of several factors, which include testosterone turnover, enzymology of DHT production, ability to use testosterone and DHT interchangeably, and propensity of cells for off-target AR inhibitory effect.

A dual 5α-reductase inhibitor dutasteride caused reductions in vascular density and area in benign prostatic hyperplasia

Objectives. Dutasteride, a dual 5α-reductase inhibitor, is used to treat benign prostatic hyperplasia. Nevertheless, its histopathological effects on the morphometrics of blood vessels and glands are still controversial. The aim here was to assess the histopathological effects of dutasteride in cases of benign prostatic hyperplasia in a retrospective study. Methods. Patients with benign prostatic hyperplasia more than 40 cm(3) in prostatic volume were administered 0.5 mg of dutasteride daily or left untreated prior to receiving a transurethral resection of the prostate. Images of sections stained with hematoxylin/eosin and with anti-CD31 antibody were analyzed. Results. In the dutasteride-treated group, the duration of administration was 16.3 ± 8.1 weeks. Artery/arteriole density and vein/venule density in benign prostatic tissue were both lower in the dutasteride-treated group than in the control group. The vein/venule area as a percentage of the whole area was also lower in the dutasteride-treated group, while the artery/arteriole area did not show a significant difference. Glandular/CD31-expressing vessel densities as well as glandular/CD31-expressing vessel areas were comparable between the two groups. Conclusions. Dutasteride reduced the artery/arteriole and vein/venule densities and the proportion of vein/venule area in the tissue of patients with benign prostatic hyperplasia.

Overcoming castration resistance in prostate cancer

PURPOSE OF REVIEW

Recent advances in our understanding of the androgen axis signaling pathway have led to the development of therapeutic strategies to overcome the state of 'castration resistance' in prostate cancer. In this review, we examine the mechanisms of castration resistance, as well as recently reported and ongoing clinical studies, which will further identify therapeutic opportunities for novel therapeutics targeting the androgen-signaling axis in advanced prostate cancer.

RECENT FINDINGS

As evidenced by recently reported positive phase III clinical trials, secondary hormonal agents such as abiraterone and MDV3100 may still be very effective in the treatment of castration-resistant prostate cancer, even after the use of docetaxel chemotherapy.

SUMMARY

Novel agents targeting this pathway have demonstrated a proof of principle that overcoming castration resistance is possible, leading to significant changes in the landscape of treatment in this disease. The optimal combination, sequence, and pattern of use in these novel therapies will be the focus of clinical research in the near future.

The 5 alpha-reductase isozyme family: a review of basic biology and their role in human diseases

Despite the discovery of 5 alpha-reduction as an enzymatic step in steroid metabolism in 1951, and the discovery that dihydrotestosterone is more potent than testosterone in 1968, the significance of 5 alpha-reduced steroids in human diseases was not appreciated until the discovery of 5 alpha-reductase type 2 deficiency in 1974. Affected males are born with ambiguous external genitalia, despite normal internal genitalia. The prostate is hypoplastic, nonpalpable on rectal examination and approximately 1/10th the size of age-matched normal glands. Benign prostate hyperplasia or prostate cancer does not develop in these patients. At puberty, the external genitalia virilize partially, however, secondary sexual hair remains sparse and male pattern baldness and acne develop rarely. Several compounds have been developed to inhibit the 5 alpha-reductase isozymes and they play an important role in the prevention and treatment of many common diseases. This review describes the basic biochemical properties, functions, tissue distribution, chromosomal location, and clinical significance of the 5 alpha-reductase isozyme family.

Effect of Discontinuation of Tamsulosin in Korean Men with Benign Prostatic Hyperplasia Taking Tamsulosin and Dutasteride: An Open-Label, Prospective, Randomized Pilot Study

OBJECTIVE

This study was conducted to examine the effect of discontinuing tamsulosin in patients with benign prostatic hyperplasia who had been receiving combination therapy with tamsulosin and dutasteride.

METHODS

The study sample consisted of 108 men with benign prostatic hyperplasia and lower urinary tract symptoms who visited our urology clinics between April 2008 and December 2010. All were assessed using the International Prostate Symptom Score (IPSS). The patients had IPSS of 8-19 and prostate volumes ≥25 mL by transrectal ultrasonography. They were put on tamsulosin and dutasteride, and the efficacy of this regimen was assessed every 12 weeks. After 48 weeks, patients were divided at random into a group continuing to take the same drug combination (group 1) and a group taking only dutasteride 0.5 mg (group 2).

RESULTS

Sixty-nine of the original 108 patients completed the study, 36 (52%) in group 1 and 33 (48%) in group 2. The mean age of all patients was 67.96 ± 7.88 years and mean prostatic volume was 40.45 ± 12.81 mL. Mean prostate-specific antigen was 3.31 (0.4-9.9) ng/mL at the outset. The IPSS scores of the two groups at first visit, 48 and 72 weeks were, respectively, 14.69 versus 15.85 (P = 0.322), 12.08 versus 12.85 (P = 0.582) and 10.89 versus 11.06 (P = 0.897.) There was a statistically significant difference between the baseline and 72-week IPSS scores in both groups (group 1: P < 0.001, group 2: P < 0.001).

CONCLUSION

In patients with moderate IPSS, discontinuing tamsulosin after 48 weeks of combined tamsulosin and dutasteride therapy has no significant effect on outcome.

Intraprostatic testosterone and dihydrotestosterone. Part I: concentrations and methods of determination in men with benign prostatic hyperplasia and prostate cancer

Owing to inconsistencies and methodological differences, the present peer-reviewed literature lacks conclusive data on the intraprostatic levels of androgens, in particular dihydrotestosterone (DHT), in untreated benign prostatic hyperplasia (BPH) and prostate cancer. To date, no difference has been shown between DHT concentrations in normal prostatic tissue and BPH, and nor has a difference been shown in DHT concentrations between the histologically distinct regions of the prostate. Recent literature has also failed to show a consistent difference in androgen level between BPH and prostate cancer. The role of intraprostatic DHT in the pathogenesis of BPH and in the initiation and progression of prostate cancer thus remains to be established. Increased knowledge of the mechanisms of the androgenic steroid pathways in prostatic diseases, with a special focus on intraprostatic androgen levels may lead to more optimized and more personalized forms of treatment, and probably new therapeutic targets as well.

Usefulness of prostate-specific antigen (PSA) rise as a marker of prostate cancer in men treated with dutasteride: lessons from the REDUCE study

OBJECTIVES

To determine if dutasteride-treated men can be monitored safely and adequately for prostate cancer based on data from the Reduction by Dutasteride in Prostate Cancer Events (REDUCE) study. To analyse whether the use of treatment-specific criteria for repeat biopsy maintains the usefulness of prostate-specific antigen (PSA) level for detecting high grade cancers.

PATIENTS AND METHODS

The REDUCE study was a randomized, double-blind, placebo-controlled investigation of whether dutasteride (0.5 mg/day) reduced the risk of biopsy-detectable prostate cancer in men with a previous negative biopsy. The usefulness of PSA was evaluated using biopsy thresholds defined by National Comprehensive Cancer Network guidelines in the placebo group and any rise in PSA from nadir (the lowest PSA level achieved while in the study) in the dutasteride group. The number of cancers detected on biopsy in the absence of increased/suspicious PSA level as well as sensitivity, specificity, positive predictive value and negative predictive value for high grade prostate cancer detection were analysed by treatment group. Prostate cancer pathological characteristics were compared between men who did and did not meet biopsy thresholds.

RESULTS

Of 8231 men randomized, 3305 (dutasteride) and 3424 (placebo) underwent at least one prostate biopsy during the study and were included in the analysis. If only men meeting biopsy thresholds underwent biopsy, 25% (47/191) of Gleason 7 and 24% (7/29) of Gleason 8-10 cancers would have been missed in the dutasteride group, and 37% (78/209) of Gleason 7 and 22% (4/18) Gleason 8-10 cancers would have been missed in the placebo group. In both groups, the incidence of Gleason 7 and Gleason 8-10 cancers generally increased with greater rises in PSA. Sensitivity of PSA kinetics was higher and specificity was lower for the detection of Gleason 7-10 cancers in men treated with dutasteride vs placebo. Men with Gleason 7 and Gleason 8-10 cancer meeting biopsy thresholds had greater numbers of positive cores, percent core involvement, and biopsy cancer volume vs men not meeting thresholds.

CONCLUSION

Using treatment-specific biopsy thresholds, the present study shows that the ability of PSA kinetics to detect high grade prostate cancer is maintained with dutasteride compared with placebo in men with a previous negative biopsy. The sensitivity of PSA kinetics with dutasteride was similar to (Gleason 8-10) or higher than (Gleason 7-10) the placebo group; however, biopsy decisions based on a single increased PSA measurement from nadir in the dutasteride group resulted in a lower specificity compared with using a comparable biopsy threshold in the placebo group, indicating the importance of confirmation of PSA measurements.

Prostate cancer detection after a negative prostate biopsy: lessons learnt in the Cleveland Clinic experience

Urologists are often faced with the dilemma of managing patients with a negative initial prostate biopsy in whom clinical or pathological risk for prostate cancer still exists. Such real-life challenging scenarios might raise questions such as: Who should undergo further biopsies? What are the optimal predictors for prostate cancer on subsequent biopsies? What is the optimal biopsy protocol that should be used? When to stop the biopsy cascade? The last decade has witnessed numerous studies that have analyzed factors conferring a significant risk for cancer discovered on repeat biopsies. We and others have developed predictive models to aid decision-making regarding pursuing further biopsies. For decades, high-grade prostatic intraepithelial neoplasia has been considered a strong risk indicator for subsequent cancer. However, it has been recently shown that only through segmentation of this heterogeneous population does the real risk profile emerge. Biopsy templates underwent modification regarding the number and location of cores with emergence of the transrectal or brachytherapy grid transperineal saturation biopsy. However, the best biopsy protocol remains controversial. We have refined the initial biopsy template to a 14 core initial biopsy template that optimizes cancer detection, and have shown that transrectal saturation biopsy significantly improves cancer detection for repeat biopsy. Another concern is the overdiagnosis of clinically insignificant cancer on repeat biopsies, so we explored ways to limit this, and to deal with its ramifications. Through carrying out a Medline literature search, we critically evaluated pertinent articles together with emphasis of our own journey in this arena to assist in the decision-making process for repeat biopsy population.

Targeting 5α-reductase for prostate cancer prevention and treatment

Testosterone is the most abundant circulating androgen, and can be converted to dihydrotestosterone (DHT), a more potent androgen, by the 5α-reductase enzymes in target tissues. Current treatments for prostate cancer consist of reducing androgen levels by chemical or surgical castration or pure antiandrogen therapy that directly targets the androgen receptor (AR). Although these therapies reduce tumor burden and AR activity, the cancer inevitably recurs within 18-30 months. An approach targeting the androgen-AR axis at different levels could, therefore, improve the efficacy of prostate cancer therapy. Inhibition of 5α-reductase is one such approach; however, the two largest trials to investigate the use of the 5α-reductase inhibitors (5ARIs) finasteride and dutasteride in patients with prostate cancer have shown that, although the incidence of cancer was reduced by 5ARI treatment, those cancers that were detected were more aggressive than in patients treated with placebo. Thus, the best practice for using these drugs to prevent and treat prostate cancer remains unclear.

Old issues and new perspectives on prostate cancer hormonal therapy: the molecular substratum

Secondary hormonal therapy is a treatment option in patients with castration-resistant prostate cancer (CRPC); however, it is underutilized and is room for optimization and improvement. In this context, androgen receptor (AR) is the Achilles' heel, being critically important and various mechanisms ranging from receptor mutations to secondary signaling pathways are responsible for some of the biological heterogeneity, demanding a multimodal approach. A comprehensive review of the peer-reviewed literature is performed on the topic of molecular mechanisms supporting secondary hormonal therapies, including expanded alternative hormonal therapies for CRPC. Essential concepts in clinical treatment of patients with progression on primary hormonal therapy are maintaining the castrate state, accounting for the intermittency phenomenon and sequentially using oral antiandrogens and adrenolytics heading to androgen depletion microenvironment. Survival prolongation, pain relief or measurable improvement in tumor-related symptoms should be persecuted and are considered to be a tangible benefit of obvious worth to the patient. Understanding the underlying molecular substratum is of paramount importance to hormonal therapy optimization in this context once current androgen-depletion strategies are incomplete, and residual androgens as well as alternative routes contribute to sustained AR activity and disease progression to a lethal phenotype. One or many mechanisms may be playing a role, even within the same patient and lastly are potential targets for treatment. Five fundamental mechanisms mediated through the AR to promote tumor growth (three of which depend on ligand signaling) added to the stem cell pathway must be recognized in CRPC. They are persistence of intratumoral androgens as a result of in situ steroidogenesis or adrenal source; AR mutations that allow promiscuous activation by otherwise nonsignaling ligands; wild-type AR gene amplification; alterations in AR coactivator-to-corepressor ratio that impact transcription; outlaw AR pathways that bypass the need for androgens by signaling through crosstalk with other ligand-bound receptors, cytokines, or transactivation of activated tyrosine kinase receptors in the cytosol.

The different reduction rate of prostate-specific antigen in dutasteride and finasteride

Purpose

To compare and analyze the therapeutic effects and changes in the prostate-specific antigen (PSA) level with treatment with finasteride or dutasteride for benign prostatic hyperplasia (BPH) for 1 year.

Materials and Methods

We retrospectively investigated patients who suffered from BPH for 1 year between January 2005 and December 2008. For treatment groups, we divided the patients into two groups: one was treated with alfuzosin and finasteride and the other was treated with alfuzosin and dutasteride. At the beginning of treatment, the patients underwent transrectal ultrasonography and measurement of urine flow rate, residual urine volume, PSA, and International Prostate Symptom Score (IPSS). Patients with diseases affecting urinary function were excluded. We not only analyzed the data at the time of initial treatment, but also after 1 year of treatment. A total of 219 patients were able to be evaluated for 1 year.

Results

Both finasteride and dutasteride reduced PSA and prostate volume significantly. The comparison between groups showed a more significant reduction of PSA (p=0.020) and prostate volume (p=0.052) in the dutasteride group. Other parameters did not differ significantly between the groups.

Conclusions

5-α Reductase inhibitors for BPH treatment reduced PSA and prostate volume significantly when the patients were treated for 1 year. Administration of dutasteride is considered to be more effective in reducing PSA and prostate volume. Therefore, dutasteride should not be considered equivalent to finasteride in the reduction rate of PSA. The intensity of dutasteride must be reevaluated in comparison with finasteride.