Does Finasteride Alter the Pathology of the Prostate and Cancer Grading?

Prostate cancer in transgender women: considerations for screening, diagnosis and management

Transgender individuals represent 0.55% of the US population, equivalent to 1.4 million transgender adults. In transgender women, feminisation can include a number of medical and surgical interventions. The main goal is to deprive the phenotypically masculine body of androgens and simultaneously provide oestrogen therapy for feminisation. In gender-confirming surgery (GCS) for transgender females, the prostate is usually not removed. Due to limitations of existing cohort studies, the true incidence of prostate cancer in transgender females is unknown but is thought to be less than the incidence among cis-gender males. It is unclear how prostate cancer develops in androgen-deprived conditions in these patients. Six out of eleven case reports in the literature presented with metastatic disease. It is thought that androgen receptor-mediated mechanisms or tumour-promoting effects of oestrogen may be responsible. Due to the low incidence of prostate cancer identified in transgender women, there is little evidence to drive specific screening recommendations in this patient subpopulation. The treatment of early and locally advanced prostate cancer in these patients warrants an individualised thoughtful approach with input from patients' reconstructive surgeons. Both surgical and radiation treatment for prostate cancer in these patients can profoundly impact the patient's quality of life. In this review, we discuss the evidence surrounding screening and treatment of prostate cancer in transgender women and consider the current gaps in our knowledge in providing evidence-based guidance at the molecular, genomic and epidemiological level, for clinical decision-making in the management of these patients.

Tumor-derived OBP2A promotes prostate cancer castration resistance

Androgen deprivation therapy (ADT) is a systemic therapy for advanced prostate cancer (PCa); although most patients initially respond to ADT, almost all cancers eventually develop castration-resistant PCa (CRPC). Currently, most research focuses on castration-resistant tumors, and the role of tumors in remission is almost completely ignored. Here, we report that odorant-binding protein (OBP2A) released from tumors in remission during ADT catches survival factors, such as CXCL15/IL8, to promote PCa cell androgen-independent growth and enhance the infiltration of myeloid-derived suppressor cells (MDSCs) into tumor microenvironment, leading to the emergence of castration resistance. OBP2A knockdown significantly inhibits CRPC and metastatic CRPC development and improves therapeutic efficacy of CTLA-4/PD-1 antibodies. Treatment with OBP2A-binding ligand α-pinene interrupts the function of OBP2A and suppresses CRPC development. Furthermore, α-pinene-conjugated doxorubicin/docetaxel can be specifically delivered to tumors, resulting in improved anticancer efficacy. Thus, our studies establish a novel concept for the emergence of PCa castration resistance and provide new therapeutic strategies for advanced PCa.

5-alpha reductase inhibitors induce a prostate luminal to club cell transition in human benign prostatic hyperplasia

Benign prostatic hyperplasia (BPH) is a progressive expansion of peri-urethral prostate tissue common in aging men. Patients with enlarged prostates are treated with 5-alpha reductase inhibitors (5ARIs) to shrink prostate volume by blocking the conversion of testosterone to dihydrotestosterone (DHT). A reduction in DHT levels can elicit atrophy and apoptosis of prostate secretory luminal cells, which results in a favorable clinical response characterized by improved lower urinary tract symptoms. However, the histologic response to 5ARI treatment is often heterogeneous across prostate acini and lower urinary tract symptoms can persist to require surgical intervention. We used two spatial profiling approaches to characterize gene expression changes across histologically normal and atrophied regions in prostates from 5ARI-treated men. Objective transcriptomic profiling using the Visium spatial gene expression platform showed that 5ARI-induced atrophy of prostate luminal cells correlated with reduced androgen receptor signaling and increased expression of urethral club cell genes including LTF, PIGR, OLFM4, SCGB1A1 and SCGB3A1. Prostate luminal cells within atrophied acini adapted to decreased DHT conditions by increasing NF-κB signaling and anti-apoptotic BCL2 expression, which may explain their survival. Using GeoMx digital spatial profiling with a probe set to assess ~18,000 RNA targets, we confirmed that atrophied acini expressing SCGB3A1 displayed higher levels of club cell markers compared to histologically normal acini with NKX3-1 expression. In addition, club-like cells within regions of 5ARI-induced atrophy closely resembled true club cells from the prostatic urethra. A comparison of histologically normal regions from 5ARI-treated men and histologically normal regions from untreated men revealed few transcriptional differences. Taken together, our results describe a heterogeneous response to 5ARI treatment where cells in atrophied acini undergo an adaptation from a prostate secretory luminal to a club cell-like state in response to 5ARI treatment. This article is protected by copyright. All rights reserved.

Cancer Targeting Potential of 99mTc-Finasteride in Experimental Model of Prostate Carcinogenesis

This study aimed to radiolabel finasteride, a novel 5α-reductase inhibitor, to evaluate its cancer targeting potential in experimental model of prostate carcinogenesis. Finasteride was effectively radiolabeled with ^99mTc and showed >90% labeling efficiency. The radiopharmaceutical was found to be stable up to 6 hours in rat serum at 37°C. The blood kinetics of the ^99mTc-finasteride followed a biphasic release pattern, whereby fast-release phase was observed at 15 seconds and a slow-release phase was observed after 30 minutes of administration. The plasma protein binding of the radio complex observed was 83.89%. For biodistribution studies, the rats were divided into two groups. Group I served as normal controls, while group II was subjected to carcinogen N-methyl-N-nitrosourea (MNU) and hormone testosterone propionate (T) for induction of prostate carcinogenesis, which was confirmed histopathologically. The biodistribution studies on control and carcinogen-treated rats revealed a significant percent-specific uptake in prostate, which was found to be increased significantly as a function of time. The most significant finding of the study was an increase in the percent-specific uptake in prostate of carcinogen-treated animals when compared to the percent-specific uptake in prostate of normal rats after 2 and 4 hours postinjection. The study concludes that ^99mTc-finasteride possesses selectively toward prostate cancer tissue and can be explored further for its role in detection of prostate cancer.

Side Effects of 5-Alpha Reductase Inhibitors: A Comprehensive Review

INTRODUCTION

5α-reductase inhibitors (5ARI) include finasteride and dutasteride, and are commonly prescribed in the treatment of benign prostatic hyperplasia and androgenic alopecia. 5ARIs are associated with several known adverse effects (AEs), with varying reported prevalence rates.

AIM

The aim was to review and summarize findings from published literature detailing AEs associated with 5ARI use. A secondary aim was to review potential mechanisms of action, which may account for these observed and reported AEs.

METHODS

A PubMed search was conducted on articles published from 1992 to 2012, which reported AEs with 5ARIs. Priority was given to randomized, placebo-controlled trials. Studies investigating potential mechanisms of action for 5ARIs were included for review.

MAIN OUTCOME MEASURES

AE data reported from available trials were summarized and reviewed.

RESULTS

Reported AEs with 5ARIs include sexual dysfunction, infertility, mood disorders, gynecomastia, high-grade prostate cancer, breast cancer, and cardiovascular morbidity/risk factors, although their true association, prevalence, causality, and clinical significance remain unclear. A pooled summary of all randomized, placebo-controlled trials evaluating 5ARIs (N = 62,827) revealed slightly increased rates over placebo for decreased libido (1.5%), erectile dysfunction (ED) (1.6%), ejaculatory dysfunction (EjD) (3.4%), and gynecomastia (1.3%). The limited data available on the impact of 5ARIs on mood disorders demonstrate statistically significant (although clinically minimal) differences in rates of depression and/or anxiety. Similarly, there are limited reports of reversible, diminished fertility among susceptible individuals. Post-marketing surveillance reports have questioned the actual prevalence of AEs associated with 5ARI use and suggest the possibility of persistent symptoms after drug discontinuation. Well-designed studies evaluating these reports are needed.

CONCLUSIONS

5ARIs are associated with slightly increased rates of decreased libido, ED, EjD, gynecomastia, depression, and/or anxiety. Further studies directed at identifying prevalence rates and persistence of symptoms beyond drug discontinuation are required to assess causality. Trost L, Saitz TR, and Hellstrom WJG. Side effects of 5-alpha reductase inhibitors: A comprehensive review. Sex Med Rev 2013;1:24-41.

Five-alpha reductase inhibitor influences expression of androgen receptor and HOXB13 in human hyperplastic prostate tissue

OBJECTIVES

Five-alpha reductase inhibitors (5ARIs) are known as chemopreventive agents in prostate cancer with a risk of high-grade disease. This study evaluated the effects of 5ARI on androgen receptor (AR) and proteins involved in prostate cell growth such as HOXB13 expression in human prostate tissue and LNCaP prostate cancer cells.

MATERIALS AND METHODS

We retrospectively selected 21 patients who underwent TURP between March 2007 and February 2010 for previously confirmed BPH by prostate biopsy. They were grouped into control (group 1, n = 9) and 5ARI treatment (group 2, n = 12) before TURP. AR and HOXB13 expression in prostate tissue was evaluated by immunohistochemical staining. We tested the effect of 5ARI on the expression of AR, prostate specific antigen (PSA) and HOXB13 in LNCaP cells. Cells were assessed by Western blot analysis, MTT in vitro proliferation assay, and ELISA.

RESULTS

Group 2 showed stronger reactivity for AR and HOXB13 than those of the group 1. MTT assay showed death of LNCaP cells at 25uM of 5ARI. At the same time, ELISA assay for PSA showed that 5ARI inhibited secretion of PSA in LNCaP cells. Western blot analysis showed that 5ARI did not greatly alter AR expression but it stimulated the expression of HOXB13.

CONCLUSIONS

These results demonstrated that 5ARI influences AR and HOXB13 expression in both LNCaP cells and human prostate tissue. In order to use 5ARI in chemoprevention of prostate cancer, we still need to clarify the influence of 5ARI in ARs and oncogenic proteins and its regulation pathway.

Finasteride Increases the Expression of Hemoxygenase-1 (HO-1) and NF-E2-Related Factor-2 (Nrf2) Proteins in PC-3 Cells: Implication of Finasteride-Mediated High-Grade Prostate Tumor Occurrence

A number of naturally-occurring or synthetic chemicals have been reported to exhibit prostate chemopreventive effects. Synthetic 5α-reductase (5-AR) inhibitors, e.g. finasteride and durasteride, gained special interests as possible prostate chemopreventive agents. Indeed, two large-scale epidemiological studies have demonstrated that finasteride or durasteride significantly reduced the incidence of prostate cancer formation in men. However, these studies have raised an unexpected concern; finasteride and durasteride increased the occurrence of aggressive prostate tumor formation. In the present study, we have observed that treatment of finasteride did not affect the growth of androgen-refractory PC-3 prostate cancer cells. Finasteride also failed to induce apoptosis or affect the expression of proto-oncogenes in PC-3 cells. Interestingly, we found that treatment of finasteride induced the expression of Nrf2 and HO-1 proteins in PC-3 cells. In particular, basal level of Nrf2 protein was higher in androgen-refractory prostate cancer cells, e.g. DU-145 and PC-3 cells, compared with androgen-responsive prostate cancer cells, e.g. LNCaP cells. Also, treatment of finasteride resulted in a selective induction of Nrf2 protein in DU-145 and PC-3 cells, but not in LNCaP cells. In view of the fact that upregulation of Nrf2-mediated phase II cytoprotective enzymes contribute to attenuating tumor promotion in normal cells, but, on the other hand, confers a selective advantage for cancer cells to proliferate and survive against chemical carcinogenesis and other forms of toxicity, we propose that finasteride-mediated induction of Nrf2 protein might be responsible, at least in part, for an increased risk of high-grade prostate tumor formation in men.

Use of 5α-reductase inhibitors for lower urinary tract symptoms and risk of prostate cancer in Swedish men: nationwide, population based case-control study

OBJECTIVE

To assess the association between 5α-reductase inhibitor (5-ARI) use in men with lower urinary tract symptoms and prostate cancer risk.

DESIGN

Nationwide, population based case-control study for men diagnosed with prostate cancer in 2007-09 within the Prostate Cancer data Base Sweden 2.0.

SETTING

The National Prostate Cancer Register, National Patient Register, census, and Prescribed Drug Register in Sweden, from which we obtained data on 5-ARI use before date of prostate cancer diagnosis.

PARTICIPANTS

26,735 cases and 133,671 matched controls; five controls per case were randomly selected from matched men in the background population. 7815 men (1499 cases and 6316 controls) had been exposed to 5-ARI. 412 men had been exposed to 5-ARI before the diagnosis of a cancer with Gleason score 8-10.

MAIN OUTCOME MEASURES

Risk of prostate cancer calculated as odds ratios and 95% confidence intervals by conditional logistic regression analyses.

RESULTS

Risk of prostate cancer overall decreased with an increasing duration of exposure; men on 5-ARI treatment for more than three years had an odds ratio of 0.72 (95% confidence interval 0.59 to 0.89; P<0.001 for trend). The same pattern was seen for cancers with Gleason scores 2-6 and score 7 (both P<0.001 for trend). By contrast, the risk of tumours with Gleason scores 8-10 did not decrease with increasing exposure time to 5-ARI (for 0-1 year of exposure, odds ratio 0.96 (95% confidence interval 0.83 to 1.11); for 1-2 years, 1.07 (0.88 to 1.31); for 2-3 years, 0.96 (0.72 to 1.27); for >3 years, 1.23 (0.90 to 1.68); P=0.46 for trend).

CONCLUSIONS

Men treated with 5-ARI for lower urinary tract symptoms had a decreased risk of cancer with Gleason scores 2-7, and showed no evidence of an increased risk of cancer with Gleason scores 8-10 after up to four years' treatment.

Current perspectives on Gleason grading of prostate cancer

The 5-tier Gleason grading system for prostate cancer, introduced in 1966, has been proven to be one of the main independent predictors of prostate cancer outcome. This review addresses interobserver concordance in Gleason grading; the persistence of grading discrepancies with frequent upgrading from the biopsy to the prostatectomy specimen; the 2005 International Society of Urologic Pathologists' modifications to Gleason grading; the impact of this modified grading on grade migration and outcome prediction; and molecular correlates of cancer morphology. Data from the most recent years are emphasized.

Finasteride upregulates expression of androgen receptor in hyperplastic prostate and LNCaP cells: implications for chemoprevention of prostate cancer

BACKGROUND

Although finasteride is recognized for its role as a chemopreventive agent for prostate cancer, higher grades of malignancy have been reported. It is questioned whether blocking of testosterone conversion to dihydrotestosterone (DHT) by finasteride in prostate tissue will change expression of androgen receptor (AR). Therefore, this study evaluated the effects of finasteride on AR expression in prostate tissue and in the LNCaP cell line.

METHODS

Between January and December 2006, we retrospectively selected and evaluated 47 cases of benign prostatic hyperplasia treated with variable duration of finasteride (5 mg QD) before transurethral resection of the prostate. AR expression in prostate tissue was semiquantified by immunostaining and compared with duration of finasteride treatment. An androgen-dependent prostate cancer cell line (LNCaP) was cultured in charcoal/dextran-treated FBS with DHT or testosterone, and treated with finasteride for 1-3 weeks. Samples of total RNA were collected to analyze expression of AR by real-time quantitative reverse transcription polymerase chain reaction.

RESULTS

Immunohistochemical study revealed significant upregulation of ARs by finasteride treatment for 30-180 days. In cell line study, quantitative real-time reverse transcription polymerase chain reaction revealed significant upregulation of ARs treated by finasteride.

CONCLUSIONS

In our study, finasteride influenced AR expression in benign prostate tissue and prostate cancer cell. Before we can use finasteride in chemoprevention with confidence, we still need to clarify the influence of finasteride in ARs and its regulation pathway.

Maximizing outcomes in genitourinary cancers across the treatment continuum

Key controversies concerning the management of genitourinary cancers across the treatment continua were discussed at the second annual Interactive Genitourinary Cancer Conference (IGUCC) held in February 2010 in Athens, Greece. Prostate cancer is the most common form of cancer among western men and prevention strategies are needed. Trials evaluating 5α-reductase inhibitors have reported beneficial and clinically meaningful results, but uptake remains low for primary prostate cancer prevention. Prostate cancer detection programmes are also important as curative treatments for advanced disease are unavailable. Two large landmark randomized controlled trials reported conflicting results concerning screening efficacy and uncovered high levels of over-diagnosis and potential over-treatment. Tailored management strategies after diagnosis are important and predictive markers that distinguish between aggressive and indolent tumours are needed. The majority of newly diagnosed cases of prostate cancer are clinically localized. Active surveillance of favourable risk patients may be beneficial in the intermediate term, while an integrated approach of multi-modality therapy in patients with adverse features is recommended. The benefits of new technologies such as high-intensity focused ultrasound (HIFU) and robotic prostatectomy have not been established in prospective randomized trials vs current standards of care. A multidisciplinary approach is essential to evolving the management of advanced prostate cancer into a chronic disease paradigm. Docetaxel plus prednisone is the standard first-line chemotherapy for patients with metastatic castration-resistant prostate cancer (mCRPC), but the optimal timing of chemotherapy initiation has not been addressed in randomized clinical trials. Retrospective analyses suggest that asymptomatic patients with adverse prognostic factors for survival may also benefit from receiving chemotherapy. Bladder cancer is a common malignancy and the most expensive cancer per patient. Non-muscle-invasive bladder cancer is a heterogenous disease that requires dynamic multidisciplinary management. Aggressive early intervention may be beneficial in some cases. Platinum-based therapies represent the first-line standard of care for advanced bladder cancer, but the maximum benefit may have been reached for conventional chemotherapies and new strategies are needed. Several ongoing clinical trials are assessing combination chemotherapy and targeted therapy.

Combination therapy with dutasteride and tamsulosin for the treatment of symptomatic enlarged prostate

Benign prostatic hyperplasia (BPH) is a frequent cause of lower urinary symptoms, with a prevalence of 50% by the sixth decade of life. Hyperplasia of stromal and epithelial prostatic elements that surround the urethra cause lower urinary tract symptoms (LUTS), urinary tract infection and acute urinary retention. Medical treatments of symptomatic BPH include; 1) the 5α-reductase inhibitors, 2) the α1-adrenergic antagonists, and 3) the combination of a 5α-reductase inhibitor and a α1-adrenergic antagonist. Selective α1-adrenergic antagonists relax the smooth muscle of the prostate and bladder neck without affecting the detrussor muscle of the bladder wall, thus decreasing the resistance to urine flow without compromising bladder contractility. Clinical trials have shown that α1-adrenergic antagonists decrease LUTS and increase urinary flow rates in men with symptomatic BPH, but do not reduce the long-term risk of urinary retention or need for surgical intervention. Inhibitors of 5α-reductase decrease production of dihydrotestosterone within the prostate resulting in decreased prostate volumes, increased peak urinary flow rates, improvement of symptoms, and decreased risk of acute urinary retention and need for surgical intervention. Interim results of the ongoing Combination of Avodart and Tamsulosin (CombAt) study have shown combination therapy with the 5α-reductase inhibitor dutasteride and the α1-adrenergic antagonist tamsulosin offer significant improvements from baseline compared with either drug alone.

5alpha-Reductase inhibitor treatment of prostatic diseases: background and practical implications

This literature review discusses the theoretical background of 5alpha-reductase inhibitor (5ARI) treatment and the resulting clinical implications. A Medline-based search for peer-reviewed articles addressing 5ARIs, benign prostatic hyperplasia and prostate cancer was performed. The 5ARIs Finasteride and Dutasteride, which specifically inhibit the production of dihydrotestosterone by acting as competitive inhibitors of 5alpha-reductase, are clinically well tolerated and represent an effective treatment option for benign prostatic obstruction. Finasteride is the first compound which has a proven efficacy in chemoprevention of prostate cancer. The aim of this review was to elucidate, if there are sufficient data available to point out clinically relevant differences between the drugs. Both compounds achieve a significant reduction of prostate volume, an improvement of symptoms and a lower risk of acute urinary retention. Whether the different pharmacokinetic and pharmacodynamic properties of Finasteride and Dutasteride are of clinical importance cannot be judged at this time.

[Histological modifications observed in prostate after preserving treatments for prostate cancer and their impact on Gleason score interpretation]

Total prostatectomy remains the main treatment for intermediate risk prostate cancer with a life expectancy greater than 10 years. In other cases non-surgical treatments can be proposed: external radiotherapy (exclusive or combined anti-androgen therapy), brachytherapy with permanent implants, high frequency ultrasounds (HIFU, Ablatherm), cryotherapy or exclusive hormonal treatment. For such patients in case of biological recurrence, prostate biopsies are usually performed in order to affirm the local recurrence. The histological confirmation of persistent tumor is usually required before any treatment: salvage surgery, cryotherapy, and brachytherapy or high intensity focused ultrasound (HIFU). Pathologists must be aware of the histological modifications induced by these different treatments in order to ensure an optimal interpretation of the biopsies. In this review, we describe the modifications observed in the normal prostate and in cancers after these various therapeutic methods, and also after alpha reductase inhibitors proposed as treatment of benign prostate hypertrophy and prostate cancer chemoprevention.

[The pathologist's perspective on the PCPT trial]

The PCPT (Prostate Cancer Prevention Trial) trial which compared 5 mg/d of finastéride to placebo in men over 55 years old showed that active treatment reduced the incidence of prostate cancer from 24.4 to 18.4%. Paradoxically, the incidence of high grade cancers (Gleason score > or = 7) was higher in the finasteride group (6.4%) than in the placebo group (5.1%). Histological interpretation of the radical prostatectomy specimens showed an overestimation of Gleason score on biopsy both in the finasteride and placebo group. The high grade cancers on total prostatectomy specimens were not more aggressive in the finasteride arm than in the placebo arm. There is no argument to suggest that long term finasteride may promote the development of highly aggressive cancer. Urologists must clearly be aware that finasteride treatment may result in morphological changes in order to inform the pathologist that this drug is being taken. If a prostate cancer with a Gleason score > or = 7 is diagnosed in a treated patient, the pathologist will perform a double reading of the slides to confirm the score.

Is there a relationship between prostate volume and Gleason score?

OBJECTIVES

To review the relationship between the Gleason grade and prostate volume in biopsy and radical prostatectomy (RP) specimens, and thus assess the hypothesis that smaller prostates have a greater incidence of high-grade tumours.

PATIENTS AND METHODS

We selected 390 patients who had RP at our institution, with a prostate-specific antigen (PSA) level of < 10 ng/mL and who had not had hormonal therapy. We retrospectively reviewed the data for transrectal ultrasonography (TRUS)-guided prostate biopsies from these patients and the RP specimens. Indications for biopsy included a PSA level of > or = 4 ng/mL or an abnormal digital rectal examination. High-grade tumours were defined as having a Gleason score of > or = 7.

RESULTS

The TRUS volume was statistically related to the rate of high-grade tumours at biopsy and RP. On multivariate analyses, TRUS volume was a significant predictor of high-grade tumour for biopsy and RP specimens, with an inverse relationship between high-grade tumours and prostate volume for biopsy and RP specimens.

CONCLUSIONS

Our data suggest that there is a relationship between the rate of high-grade tumours and prostate volume even in biopsy and RP specimens and it is not an artefact related to the biopsy.

5alpha-reductase inhibitors in benign prostatic hyperplasia and prostate cancer risk reduction

Androgens play an essential role in prostatic development and function, but are also involved in prostate disease pathogenesis. The primary prostatic androgen, dihydrotestosterone (DHT), is synthesized from testosterone by 5alpha-reductase types 1 and 2. Inhibition of the 5alpha-reductase isoenzymes therefore has potential therapeutic benefit in prostate disease. The two currently approved 5alpha-reductase inhibitors (5ARIs), finasteride and dutasteride, have demonstrated long-term efficacy and safety in the treatment of benign prostatic hyperplasia. Finasteride, a type-2 5ARI, has also been studied for its ability to reduce the incidence of biopsy-detectable prostate cancer in the Prostate Cancer Prevention Trial. Treatment with dutasteride, a dual 5ARI, has been shown to result in a greater degree and consistency of DHT suppression compared with finasteride. Two large-scale studies of dutasteride are currently investigating the role of near-maximal DHT suppression in the settings of prostate cancer risk reduction and expectant management of localized prostate cancer.

Prevention of Prostate Cancer: What We Know and Where We Are Going

As one of the most prevalent cancers, prostate cancer has enormous public health importance and its prevention seems to be a rational approach to attenuate the economic, emotional, physical, and social impact of this disease. This review discusses some of the options available to clinicians worldwide under the broad headings of chemoprevention and dietary modification including lifestyle issues. From the review of available literature, it is appreciated that although many exciting options such as androgen inhibitors, vitamin E, and selenium are being actively considered, they are far from being included in clinical practice. So until large randomized trials confirm the benefit of chemopreventives and dietary modifications, patients may be advised to pursue a diet and lifestyle that ensures overall fitness.

Update on the use of dutasteride in the management of benign prostatic hypertrophy

Benign prostatic hyperplasia (BPH) is a frequent cause of lower urinary symptoms, with a prevalence of 50% by the sixth decade of life. Hyperplasia of stromal and epithelial prostatic elements that surround the urethra cause lower urinary tract symptoms (LUTS), urinary tract infection, and acute urinary retention. Medical treatments of symptomatic BPH include; 1) the 5alpha-reductase inhibitors, 2) the alpha1-adrenergic antagonists, and 3) the combination of a 5alpha-reductase inhibitor and a alpha1-adrenergic antagonist. Selective alpha1-adrenergic antagonists relax the smooth muscle of the prostate and bladder neck without affecting the detrussor muscle of the bladder wall, thus decreasing the resistance to urine flow without compromising bladder contractility. Clinical trials have shown that alpha1-adrenergic antagonists decrease LUTS and increase urinary flow rates in men with symptomatic BPH, but do not reduce the long-term risk of urinary retention or need for surgical intervention. Inhibitors of 5alpha-reductase decrease production of dihydrotestosterone within the prostate resulting in decreased prostate volumes, increased peak urinary flow rates, improvement of symptoms, and decreased risk of acute urinary retention and need for surgical intervention. The combination of a 5alpha-reductase inhibitor and a alpha1-adrenergic antagonist reduces the clinical progression of BPH over either class of drug alone.

Das „Prostate Cancer Prevention Trial“ (PCPT)

The Prostate Cancer Prevention Trial (PCPT) has been the first interventional trial directly aimed at the prevention of prostate cancer. A total of 18,882 men over 55 years with a PSA serum level less than 3.0 ng/ml were randomized to receive either the 5-alpha-reductase inhibitor finasteride 5 mg/day or placebo for 7 years. Despite a 25% reduction of prostate cancers in the treatment arm the results were discussed controversially. This criticism was mainly due to the observation of significantly more high-grade cancers in the finasteride group. Meanwhile, results of extensive follow-up analyses have been published suggesting that this finding is most likely due to optimized tumor detection in smaller glands. Further work-up demonstrated that PSA diagnosis and the histopathological examination were not compromised by finasteride. Furthermore, in addition to a decrease of prostate cancer the amount of prostatic intraepithelial dysplasia (PIN) was also reduced under finasteride. Future research must now aim at defining high-risk groups specifically profiting from chemoprevention with a 5-alpha-reductase inhibitor.

Detection bias due to the effect of finasteride on prostate volume: a modeling approach for analysis of the Prostate Cancer Prevention Trial

BACKGROUND

The Prostate Cancer Prevention Trial (PCPT) demonstrated a 24.8% reduction in the 7-year prevalence of prostate cancer among patients treated with finasteride (5 mg daily) compared with that among patients treated with placebo; however, a 25.5% increase in the prevalence of high-Gleason grade tumors was observed, the clinical significance of which is unknown. One hypothesized explanation for this increase is that finasteride reduced prostate volume, leading to detection of more high-grade tumors due to increased sampling density. This possibility was investigated in an observational reanalysis of the PCPT data, with adjustment for sampling density.

METHODS

A logistic model for the association of high-grade (Gleason score 7-10) prostate cancer with baseline covariates and/or baseline covariates plus prostate volume and number of cores obtained at biopsy was developed using the placebo group (n = 4775) of the PCPT. This model was then applied to the finasteride group (n = 5123) to compare the predicted and observed numbers of high-grade tumors in that group. In a second approach, odds ratios (ORs) for prostate cancer in the finasteride versus placebo groups calculated from binary and polytomous logistic regression models that contained or excluded covariates for gland volume and number of needle cores were compared.

RESULTS

Median prostate volume was 25% lower in the finasteride group (median = 25.1 cm3) than in the placebo group (median = 33.5 cm3). The logistic model developed in the placebo group showed that the likelihood of detection of high-grade prostate cancer decreased as volume increased (for each 10 cm3 increase in prostate volume, OR = 0.81, 95% confidence interval [CI] = 0.74 to 0.90). Based on this model, 239 high-grade prostate cancers were predicted in the finasteride group, whereas 243 were observed, a non-statistically significant difference. Among all participants, the odds ratios for high-grade cancer in the finasteride versus placebo groups decreased from 1.27 (95% CI = 1.05 to 1.54) with adjustment for baseline covariates to 1.03 (95% CI = 0.84 to 1.26) following additional adjustment for gland volume and number of biopsy cores in binary outcome models and from 1.14 (95% CI = 0.94 to 1.38) to 0.88 (95% CI = 0.72 to 1.09) following these adjustments in the polytomous models.

CONCLUSIONS

Although analyses using postrandomization data require cautious interpretation, these results suggest that sampling density bias alone could explain the excess of high-grade cancers among the finasteride-assigned participants in the PCPT.

Finasteride and high-grade prostate cancer in the Prostate Cancer Prevention Trial

BACKGROUND

The Prostate Cancer Prevention Trial (PCPT) reported a decreased incidence of prostate cancer overall but an increase in the incidence of high-grade prostate cancer with finasteride compared with placebo. We assessed whether the increased high-grade prostate cancer associated with finasteride in the PCPT was due to finasteride's potential effects on tumor morphology or prostate size.

METHODS

Prostate biopsies with Gleason score 8-10 (n = 90, finasteride; n = 52, placebo) were examined histologically for hormonal effects, and those with Gleason score 7-10 (n = 282, finasteride; n = 244, placebo) were examined for pathologic surrogates of disease extent. Prostate volumes were measured at biopsy. Samples from radical prostatectomies (n = 222, finasteride; n = 306, placebo) were examined for tumor grade and extent, and, where possible, grades at biopsy and prostatectomy were compared between the groups. Logistic regression was used to analyze differences between treatment groups with respect to pathologic criteria. All statistical tests were two-sided.

RESULTS

Degenerative hormonal changes in high-grade biopsies were equivalent between the finasteride and placebo groups, but prostate volumes were lower in the finasteride group (median = 25.1 versus 34.4 cm3, P<.001). Pathologic surrogates for tumor extent were lower with finasteride than with placebo, including mean percentage of positive cores (34% versus 38%, P = .016), mean tumor linear extent (greatest [4.4 versus 4.8 mm, P = .19] and aggregate [7.6 versus 9.2 mm, P = .13]), bilaterality (22.8% versus 30.6%, P = .046), and perineural invasion (14.2% versus 20.3%, P = .07). Among patients who had prostatectomy, the finasteride-associated increase in high-grade disease (Gleason score > or = 7) at biopsy (42.7% finasteride versus 25.4% placebo, P<.001) was diminished at prostatectomy (46.4% finasteride versus 38.6% placebo, P = .10). Biopsy identified a greater proportion of patients with high-grade disease present at prostatectomy in the finasteride group than in the placebo group (69.7% versus 50.5%, P = .01). The rate of upgrading (from low-grade cancer at biopsy to high-grade cancer at prostatectomy) and pathologic stage at prostatectomy were similar in both groups.

CONCLUSIONS

Effects of finasteride on prostate volume and selective inhibition of low-grade cancer, rather than effects on tumor morphology, may have contributed to the increase in high-grade cancers with finasteride in the PCPT. Although induction of high-grade cancer cannot be excluded, the results suggest that high-grade cancer was detected earlier and was less extensive in the finasteride group than in the placebo group.

Cellular Changes in Prostate Cancer Cells Induced by Intermittent Androgen Suppression

OBJECTIVES

This study used tumour specimens from a clinical trial on intermittent androgen suppression (IAS) to study the effects of castration on tissue morphology, cell proliferation, apoptosis, and the expression of androgen receptor (AR).

METHODS

A total of 113 representative needle biopsy specimens were available from 29 patients for evaluation of the Gleason score as well as Ki-67, cleaved caspase-3, and AR immunostaining.

RESULTS

At 6 mo from the beginning of the first androgen withdrawal, cell proliferation activity was significantly (p = 0.002) reduced, whereas no effect on apoptosis was found. A nonsignificant trend to an increase in Gleason score after castration was found. Subsequent cycles of withdrawals had no significant effect on any of the measured parameters. The Gleason score, proliferation activity, and apoptosis rate showed only heterogeneous, nonsignificant changes after the first progression. Strong nuclear AR staining was evident in all cancer specimens.

CONCLUSIONS

The findings suggest that the long-term (months) effect of androgen withdrawal on tumour growth is due to the inhibition of proliferation. Because the tumours seem to become resistant to castration at the first cycle of treatment withheld, it is possible that IAS does not postpone the emergence of ablation-resistant tumours. There was no consistent sign of increased proliferation or Gleason score during the treatment, suggesting that the biologic aggressiveness of a particular tumour is defined already at an early stage of disease. The constant nuclear expression of AR in cancer cells indicates that the AR signalling remains active despite of the androgen withdrawal.

Prostate cancer prevention

PURPOSE OF REVIEW

Prostate cancer, a common cause of morbidity and mortality in the developed world, ought to be a preventable disease. This review focuses on prostate cancer prevention in the context of new mechanistic insights into human prostatic carcinogenesis.

RECENT FINDINGS

Evidence is accumulating to implicate infection and inflammation as contributors to prostate cancer development. Inherited prostate cancer susceptibility genes discovered thus far encode participants in host responses to infection. Proliferative inflammatory atrophy, a prostate cancer precursor lesion, ties inflammatory responses to prostatic carcinogenesis. Somatic epigenetic alterations, present in all prostate cancers, appear to arise in the setting of inflammation. Finally, a newly identified somatic genome change, involving a fusion between an androgen-regulated gene, TMPRSS2, and genes encoding members of the ETS family of transcription factors, may provide a clue as to why prostate cancer cells exhibit androgen dependence for growth and survival.

SUMMARY

The contributions of infection and inflammation to the early development of prostate cancer suggest prevention strategies featuring prevention or eradication of infection, amelioration of inflammation, or attenuation of genome-damaging reactive oxygen and nitrogen species. The acquisition of androgen dependence later during prostate cancer pathogenesis suggests the use of approaches targeting androgen signaling, including inhibitors of 5alpha-reductase.

Diagnosis of prostatic carcinoma after therapy

CONTEXT

Prostate cancer is the most common cancer of men in the United States and is third only to lung and colon cancer as a cause of cancer death. In 2006, 27,350 Americans will die of prostate cancer, and 234,460 new cases will be diagnosed. Treatment changes in the benign and cancerous prostate create diagnostic challenges in pathologic interpretation, particularly in needle biopsy specimens and in evaluation of extraprostatic metastases.

OBJECTIVE

To summarize therapy-related pathologic findings in the prostate with emphasis on recognition of treated adenocarcinoma.

DATA SOURCES

Extensive review of published literature and the authors' experience.

CONCLUSIONS

Following therapy for prostate cancer, it is critical that the clinician provide the pertinent history of androgen deprivation or radiation therapy to assist the pathologist in rendering the correct diagnosis.

Hormonal interventions to prevent hormonal cancers: breast and prostate cancers

In 1998, the concept of breast cancer prevention became a reality with the approval of tamoxifen to reduce the risk of developing breast cancer in women at increased risk for the disease. This approval was based on decades of research on selective estrogen receptor modulators providing an understanding of the role of the estrogen receptor in breast cell growth, and an appreciation of the carcinogenic process. Although results from the Breast Cancer Prevention Trial demonstrated a 49% reduction in breast cancer in women at increased risk, there were associated toxicities related to the estrogenic effects of tamoxifen; that is, deep vein thrombosis, pulmonary embolism, and endometrial cancer. In an effort to improve its benefit-risk profile, tamoxifen is now being compared with raloxifene, a selective estrogen receptor modulator approved for the treatment and prevention of osteoporosis. This equivalency prevention Study of Tamoxifen and Raloxifene completed accrual of 19 747 high-risk postmenopausal women in November 2004. Meanwhile, another class of estrogen-directed drugs, the aromatase inhibitors, have shown efficacy in breast cancer adjuvant trials, spawning a number of prevention trials that have recently been initiated. As with breast cancer the hormonal contribution to prostate carcinogenesis was the basis for the Prostate Cancer Prevention Trial which showed that finasteride, an androgen antagonist, reduces the incidence of prostate cancer compared to placebo.

Successful Treatment of Metastatic Androgen-Independent Prostate Carcinoma in a Transsexual Patient

The occurrence of prostate carcinoma in transsexual patients has rarely been reported. These cases present a unique challenge in that such patients are effectively receiving androgen deprivation therapy. By definition, their disease is androgen-independent prostate cancer, and the role of local therapy is undefined. We report on a male-to-female transsexual patient with metastatic prostate cancer treated successfully with combination chemotherapy after previous standard therapy failed.

Optimierte Standards der Prostatastanzbiopsie

As individual risk assessment mainly depends on the correct prediction of the tumor's biological behavior, primary diagnosis plays a key role in the clinical management of prostate cancer patients. Prostate core needle biopsy, as a primary diagnostic tool, should not only confirm clinical suspicion but also supply the urologist with information which is necessary for risk-adapted therapy. The experience and competence of both the urologist and the pathologist are crucial for the quality of prostate core needle biopsy diagnosis. Optimized handling and submission of prostate core needle biopsy specimens by the urologist to the pathologist are of outstanding importance for improving the number of cancer cases detected. Increasing availability of molecular markers leads to the necessity of developing new tissue sampling procedures which allow prostate core needle biopsy specimens to be simultaneously studied histologically and by molecular approaches.

Novel techniques for the treatment of localized prostate cancer: Evidence of efficacy?

Radical retropubic prostatectomy and radiation therapy remain the mainstay of treatment for localized prostate cancer. However, with the advent of the Internet, more patients are arriving in physicians' offices questioning novel techniques for their treatment that they otherwise would not have discovered. This paper discusses several of these techniques, including focal cryotherapy, high-intensity focused ultrasound, robotic-assisted laparoscopic prostatectomy, diets, supplements, and hormonal therapy. We also render our opinion on their efficacy for treatment based on the available published studies.

Suppressive effects of antiandrogens, finasteride and flutamide on development of prostatic lesions in a transgenic rat model

Transgenic (TG) rats bearing a probasin promoter/simian virus 40 T antigen (SV40 Tag) construct were treated with antiandrogens to examine their ability to suppress prostate carcinogenesis. Finasteride and flutamide were administered to 10-week-old TG rats five times a week for 2, 5 and 7 weeks. Antiandrogen-treated prostates exhibited atrophic glandular structures with almost no expression of SV40 Tag and only weak signals for androgen receptors. Furthermore, quantitative data for ventral prostate adenocarcinomas showed significant decrease with antiandrogen treatment. Both finasteride and flutamide had the ability to suppress SV40 Tag-driven carcinogenesis through their different antiandrogenic mechanisms, suggesting that this TG model is suitable for exploring the potential of agents to inhibit prostate cancer development.

Looking Back at PCPT: Looking Forward to New Paradigms in Prostate Cancer Screening and Prevention

OBJECTIVES

Provide a critical summary of the latest interpretation of findings from the Prostate Cancer Prevention Trial (PCPT).

METHODS

Findings from PCPT and recently published post-hoc analyses are reviewed.

RESULTS

PCPT demonstrated that finasteride can reduce the prevalence of prostate cancer, permitted the first large-scale assessment of the performance characteristics of prostate-specific antigen for prostate cancer screening, and identified new-onset erectile dysfunction as an early predictor of cardiovascular events.

CONCLUSIONS

PCPT has and will continue to yield valuable information regarding future strategies for prostate cancer prevention and detection, benign prostatic hyperplasia, and other matters of public health importance.

Finasteride as a chemopreventive agent in prostate cancer: impact of the PCPT on urologic practice

Prostate cancer chemoprevention involves the use of natural and/or synthetic agents that inhibit or reverse the development of precancerous lesions or delay progression of these lesions to invasive disease. The recent completion of the first Phase III trial for prostate cancer prevention, the Prostate Cancer Prevention Trial (PCPT) using the drug finasteride, has provided the urologic community with the first evidence that a chemopreventive agent can reduce the risk of developing prostate cancer. The enthusiasm for the clear relative risk reduction in the finasteride arm of the trial has been tempered by the observation that the incidence of high-grade tumors was higher in men receiving finasteride compared to those on placebo. A question remains about whether the observed higher incidence in high-grade tumors is real or whether it is related to a pathologic or sampling artifact. The PCPT has instigated a great deal of debate, resulting in the larger urologic community being reluctant to recommend the widespread use of finasteride as a chemopreventive agent. This review summarizes the PCPT, analyzes its controversial results, and describes future prostate cancer chemoprevention studies.

Prevention of benign prostatic hyperplasia disease

PURPOSE

We reviewed the evidence that benign prostatic hyperplasia is a progressive condition and men at risk for benign prostatic hyperplasia disease can be identified, treated and protected to a meaningful extent regardless of symptom status.

MATERIALS AND METHODS

The MEDLINE database was searched in 4 areas of interest relating to benign prostatic hyperplasia, including 1) progression of clinical manifestations with age, especially in regard to baseline symptom status, 2) the incidence of complications due to disease progression, 3) the use of predictive factors that may help identify men at risk for disease progression and 4) the prevention of benign prostatic hyperplasia disease with medical therapy.

RESULTS

Tissue changes in the prostate (benign prostatic hyperplasia) are inevitable consequences of aging. However, benign prostatic hyperplasia disease, which we define as a life altering urinary condition requiring medical intervention, is predictable and preventable. Benign prostatic hyperplasia disease progression is associated with increasing prostate volume, decreasing urinary flow, symptomatic deterioration often to the point of major life-style interference and serious complications, eg acute urinary retention and the need for surgery. The risk of benign prostatic hyperplasia disease progression was found to be directly related to prostate volume and its surrogate marker, serum prostate specific antigen, after prostate cancer is excluded. Other factors, eg baseline symptoms and the flow rate, were found to be less relevant compared with prostate specific antigen greater than 1.5 ng/ml for predicting benign prostatic hyperplasia disease morbidity.

CONCLUSIONS

Men at risk for benign prostatic hyperplasia disease can be identified using prostate specific antigen greater than 1.5 ng/ml as a surrogate marker of prostate volume. In men at risk with prostate specific antigen greater than 1.5 ng/ml 5alpha-reductase inhibitors have potential value for benign prostatic hyperplasia disease prevention regardless of symptom status.

Progress in chemoprevention drug development: the promise of molecular biomarkers for prevention of intraepithelial neoplasia and cancer--a plan to move forward

This article reviews progress in chemopreventive drug development, especially data and concepts that are new since the 2002 AACR report on treatment and prevention of intraepithelial neoplasia. Molecular biomarker expressions involved in mechanisms of carcinogenesis and genetic progression models of intraepithelial neoplasia are discussed and analyzed for how they can inform mechanism-based, molecularly targeted drug development as well as risk stratification, cohort selection, and end-point selection for clinical trials. We outline the concept of augmenting the risk, mechanistic, and disease data from histopathologic intraepithelial neoplasia assessments with molecular biomarker data. Updates of work in 10 clinical target organ sites include new data on molecular progression, significant completed trials, new agents of interest, and promising directions for future clinical studies. This overview concludes with strategies for accelerating chemopreventive drug development, such as integrating the best science into chemopreventive strategies and regulatory policy, providing incentives for industry to accelerate preventive drugs, fostering multisector cooperation in sharing clinical samples and data, and creating public-private partnerships to foster new regulatory policies and public education.

Use of 5α-reductase inhibitors to prevent benign prostatic hyperplasia disease

A histologic change in the prostate, benign prostatic hyperplasia (BPH), is a normal part of aging. However, BPH disease, defined here as a life-altering urinary condition caused by BPH requiring prompt medical intervention, is a serious medical disorder associated with major complications, surgical intervention, and severe lifestyle interference. BPH disease is preventable. The rationale for BPH disease prevention rests on four pillars of evidence: (1) BPH disease generally is a progressive disorder; (2) complications and severe lifestyle interference from BPH disease are common and serious; (3) men at greatest risk of BPH disease can be identified using prostate-specific antigen (PSA) level higher than 1.5 ng/mL as a surrogate marker for an enlarged prostate; and (4) 5alpha-reductase inhibitors (5ARIs) reduce the primary androgen responsible for prostate growth (dihydrotestosterone), shrink the prostate, and arrest the disease process regardless of symptom status. Thus, we now can identify men with an enlarged prostate at risk for BPH disease who may be candidates for preventive therapy with 5ARIs, regardless of urinary symptoms or bother.

Intermittent use of testosterone inactivating pharmaceuticals using finasteride prolongs the time off period

PURPOSE

Men with prostate cancer treated intermittently with TIP benefit from improved quality of life when TOP with recovered testosterone is prolonged. We examined factors influencing the duration of TOP.

MATERIALS AND METHODS

We retrospectively reviewed the charts of 101 men treated with intermittent TIP in a 9-year period. Men with positive bone scan, men in whom a PSA nadir of less than 0.1 ng/ml on TIP failed to be achieved and maintained and men in whom testosterone failed to recover to greater than 150 ng/dl during the first 12 months of TOP were excluded. Potential factors predicting prolonged TOP or accelerated time to AIPC were studied with Cox regression analysis.

RESULTS

Patient characteristics were clinical stage T1c-T2a in 51 and T2b-T3b in 11, PSA relapse in 29, and T3c, D0 or D1 in 10. Median PSA was 7.6 ng/ml, Gleason score was 3 + 4 = 7 and TIP duration was 15.8 months. The 60 group 1 patients received finasteride and the 41 in group 2 received no finasteride. Median TOP in groups 1 and 2 was 31 and 15 months, respectively, using Kaplan-Meier analysis. Cox regression analysis indicated that longer TIP, finasteride and increased age predicted longer TOP. A slow PSA decrease while on TIP, higher baseline PSA and increased Gleason score predicted shorter TOP. Cox regression analysis indicated that only higher clinical stage but not finasteride predicted the earlier onset of AIPC.

CONCLUSIONS

Finasteride doubles the duration of TOP. AIPC was not increased by finasteride after almost 9 years of observation.

Combination therapy for the pharmacological management of benign prostatic hyperplasia: rationale and treatment options

The management of symptomatic benign prostatic hyperplasia (BPH) continues to evolve, with new techniques and forms of medical management being introduced and traditional surgical techniques being used less frequently. Medical management of BPH has evolved from nonspecific alpha-adrenoceptor antagonists to uroselective alpha-adrenoceptor antagonists and 5-alpha reductase inhibitors. Traditionally, alpha-adrenoceptor antagonists have been used for relief of lower urinary tract symptoms (LUTS) as a result of BPH and are known for their quick onset of action. 5-alpha Reductase inhibitors have proven useful for the prevention of BPH progression as measured by prostate volume, disease progression, incidence of acute urinary retention and the need for subsequent BPH-related surgery. Recent studies have shown that the combination of an alpha-adrenoceptor antagonist and a 5-alpha reductase inhibitor has significantly better efficacy than either drug alone or placebo. Currently, alpha-adrenoceptor antagonists are used in the acute setting or for short-term relief of LUTS. The combination of an alpha-adrenoceptor antagonist and a 5-alpha reductase inhibitor is used for the longer term management of BPH symptoms and to prevent progression of BPH and perhaps avoid surgical intervention.

Agents in development for prostate cancer prevention

Accumulated epidemiological evidence indicates that prostate cancer mortality should be preventable. As androgenic hormones have long been recognised to be required for normal prostatic development, and because androgen deprivation is an established treatment for advanced prostate cancer, androgen signalling has been an attractive target for prostate cancer prevention. Inhibitors of 5alpha-reductase, an enzyme necessary for the conversion of testosterone to the more potent androgen dihydrotestosterone, have reached pivotal clinical trials for prostate cancer prevention. In addition, new insights into the molecular pathogenesis of prostate cancer hint that chronic or recurrent prostate inflammation may contribute to the development of the disease. A variety of antioxidants and anti-inflammatory drugs, which are likely to be capable of attenuating pro-carcinogenic genome damage from reactive oxygen and nitrogen species, are also under current development for prostate cancer prevention. This review will consider the rational development of these and other new agents and approaches for prostate cancer prevention in the context of recent research progress in ascertaining the aetiology of prostate cancer.

Phase III prostate cancer prevention trials: are the costs justified?

One randomized, prospective clinical trial for chemoprevention of prostate cancer has been completed, and two additional trials are ongoing. The investment, time, and effort for these trials are substantial. We reviewed the outcomes of these trials to address the value of the investment. The outcomes of the Prostate Cancer Prevention Trial (testing finasteride) and the design of the Selenium and Vitamin E Cancer Prevention Trial (SELECT; testing vitamin E and selenium) trial as well as the Reduction by Dutasteride of Prostate Cancer Events (REDUCE) trial (testing dutasteride) were reviewed. From a public health standpoint, there is tremendous potential for benefit from large-scale cancer prevention trials. Because of the volume of data that are collected, potential discoveries related to the biology of the disease are substantial. Translational scientific efforts are direct outgrowths of these studies. Prospective, randomized chemoprevention trials for prostate and other cancers are expensive and require long periods of time to conduct, yet the rewards are on a par with the investment.

Effects of long-term finasteride treatment on prostate cancer morphology and clinical outcome

OBJECTIVES

To examine the morphologic alterations of finasteride therapy on prostate cancer compared with no treatment or treatment with a luteinizing hormone-releasing hormone (LHRH) agonist and the clinical outcomes of patients treated with finasteride.

METHODS

The data of 56 patients with prostate cancer who had taken finasteride for at least 6 months were reviewed. A central pathology review was performed in a blinded manner comparing these patients with 56 matched controls and 44 patients who received a 3-month course of LHRH agonist before radical prostatectomy. The histologic hormonal treatment effects included apoptosis, vacuolated cytoplasm, pyknotic nuclei, and small irregular glands. An overall consensus was scored using a three-tiered system: no apparent effect (score = 0), suspicious for hormonal effect (score = 1), and highly suggestive of hormonal treatment (score = 2). A Gleason score was assigned to all prostatectomy specimens.

RESULTS

The mean hormonal treatment score for the prostatectomy specimens was 0.4, 0.5, and 1.6 for the control, finasteride, and 3-month LHRH groups, respectively. Surprisingly, 20% of control patients had suspicious or highly suggestive hormonal effects and 26% of the finasteride-treated patients did so. For the LHRH-treated group, only 23% did not demonstrate classic features of hormonal treatment. Similar clinical outcomes were observed between the finasteride and control groups.

CONCLUSIONS

No consistent hormonal therapy effects with finasteride treatment were observed compared with LHRH agonists. The hormonal effect was observed in the control group. Therefore, although other aspects of the Prostate Cancer Prevention Trial design might account for the greater percentage of Gleason grade tumors in the study arm, morphologic changes due to long-term finasteride treatment were not a likely cause.

Assessing Benefit and Risk in the Prevention of Prostate Cancer: The Prostate Cancer Prevention Trial Revisited

Purpose

The Prostate Cancer Prevention Trial demonstrated a 25% reduction in period prevalence of prostate cancer in men randomly assigned to 5 mg/d of finasteride. However, widespread use of finasteride for prevention is inhibited by the observed increased risk of high-grade disease. We present a model of risk and benefit that estimates the potential effects of histologic artifact in the assignment of excess risk for high-grade disease and the possible effect of overdetection bias introduced by finasteride-induced volume reduction.

Methods

The absolute benefit/absolute risk ratio of finasteride use was estimated by calculating the ratio of absolute risk reduction in the finasteride arm to the absolute risk of excess high-grade cancers. This ratio was recalculated for assumptions that 10%, 25%, or 50% of the excess high-grade cancers were due to histologic artifact, and that there was a 25% overdetection bias in the finasteride arm.

Results

For all cancers the absolute benefit/absolute risk ratio increased from 4.6:1 to 5.1:1, 6.2:1, and 9.2:1 for assumptions of 10%, 25%, or 50% histologic artifact, respectively. The ratio increased from 4.6:1 to 8.2:1 for the assumption of 25% overdetection bias, and to 9.1:1, 10.9:1, and 16.3:1 for combined assumptions of 25% overdetection bias and 10%, 25%, or 50% histologic artifact, respectively.

Conclusion

The adoption of a prevention strategy hinges on potential benefits weighed against potential risks. This model demonstrates the magnitude of effect for a hypothesized range of histologic artifact and overdetection bias on the assessment of risk versus benefit for finasteride.

Chemoprevention using dutasteride: the REDUCE trial

PURPOSE OF REVIEW

This article will review the design and rationale of the dutasteride prostate cancer chemoprevention trial known as the REDUCE trial (Reduction by Dutasteride of Prostate Cancer Events) in the context of the recently completed Prostate Cancer Prevention Trial.

RECENT FINDINGS

The Prostate Cancer Prevention Trial used the 5alpha-reductase inhibitor finasteride to prevent prostate cancer in a prospective randomized trial. The trial demonstrated a nearly 25% reduction in the prevalence of prostate cancer compared with placebo. Finasteride is a type 2-specific 5alpha-reductase inhibitor, whereas dutasteride is an inhibitor of both type 1 and type 2 5alpha-reductase. Recent evidence suggests that there may be increased expression of the type 1 5alpha-reductase in prostate cancer versus benign prostate tissue making dutasteride an attractive agent to study.

SUMMARY

Proof of principle has been demonstrated by the Prostate Cancer Prevention Trial that a chemoprevention strategy using a hormonal agent such as a 5alpha-reductase inhibitor can be effective. The REDUCE trial will use the dual 5alpha-reductase inhibitor dutasteride in a group of men identified at increased risk of developing prostate cancer to determine if this will be an effective chemoprevention strategy.