The effects of 5alpha-reductase inhibitors on the natural history, detection and grading of prostate cancer: current state of knowledge

Prostate changes related to therapy: with special reference to hormone therapy

Hormone and radiation therapy have traditionally been used in prostate cancer (PCa). Morphological effects are often identified in needle biopsies and surgical specimens. A range of histological changes are seen in the non-neoplastic prostate and in the pre-neoplastic and neoplastic areas. Other ablative therapies, including cryotherapy, and emerging focal therapies, such as high-intensity focused ultrasound, photodynamic therapy and interstitial laser thermotherapy, may induce changes on the prostate. As new compounds are developed for prostate cancer treatment, it is important to document their effects on benign and neoplastic prostate tissue.

Finasteride inhibits human prostate cancer cell invasion through MMP2 and MMP9 downregulation

Introduction

The use of the 5-alpha reductase inhibitors (5-ARIs) finasteride and dutasteride for prostate cancer prevention is still under debate. The FDA recently concluded that the increased prevalence of high-grade tumors among 5-ARI-treated patients must not be neglected, and they decided to disallow the use of 5-ARIs for prostate cancer prevention. This study was conducted to verify the effects of finasteride on prostate cell migration and invasion and the related enzymes/proteins in normal human and tumoral prostatic cell lines.

Materials and Methods

RWPE-1, LNCaP, PC3 and DU145 cells were cultivated to 60% confluence and exposed for different periods to either 10 µM or 50 µM finasteride that was diluted in culture medium. The conditioned media were collected and concentrated, and MMP2 and MMP9 activities and TIMP-1 and TIMP-2 protein expression were determined. Cell viability, migration and invasion were analyzed, and the remaining cell extracts were submitted to androgen receptor (AR) detection by western blotting techniques. Experiments were carried out in triplicate.

Results

Cell viability was not significantly affected by finasteride exposure. Finasteride significantly downregulated MMP2 and MMP9 activities in RWPE-1 and PC3 cells and MMP2 in DU145 cells. TIMP-2 expression in RWPE-1 cells was upregulated after exposure. The cell invasion of all four tested cell lines was inhibited by exposure to 50 µM of finasteride, and migration inhibition only occurred for RWPE-1 and LNCaP cells. AR was expressed by LNCaP, RWPE-1 and PC3 cells.

Conclusions

Although the debate on the higher incidence of high-grade prostate cancer among 5-ARI-treated patients remains, our findings indicate that finasteride may attenuate tumor aggressiveness and invasion, which could vary depending on the androgen responsiveness of a patient’s prostate cells.

Detection rate of clinically insignificant prostate cancer increases with repeat prostate biopsies

To analyze if clinically insignificant prostate cancer (CIPC) is more frequently detected with repeat prostate biopsies, we retrospectively analyzed the records of 2146 men diagnosed with prostate cancer after one or more prostate biopsies. The patients were divided into five groups according to the number of prostate biopsies obtained, e.g. group 1 had one biopsy, group 2 had two biopsies and group 3 had three biopsies. Of the 2146 patients diagnosed with prostate cancer, 1956 (91.1%), 142 (6.6%), 38 (1.8%), 9 (0.4%) and 1 (0.1%) men were in groups 1, 2, 3, 4 and 5, respectively. Groups 4 and 5 were excluded because of the small sample sizes. The remaining three groups (groups 1, 2 and 3) were statistically analyzed. There were no differences in age or prostate-specific antigen level among the three groups. CIPC was detected in 201 (10.3%), 28 (19.7%) and 9 (23.7%) patients in groups 1, 2 and 3, respectively (P<0.001). A multivariate analysis showed that the number of biopsies was an independent predictor to detect CIPC (OR=2.688 for group 2; OR=4.723 for group 3). In conclusion, patients undergoing multiple prostate biopsies are more likely to be diagnosed with CIPC than those who only undergo one biopsy. However, the risk still exists that the patient could have clinically significant prostate cancer. Therefore, when counseling patients with regard to serial repeat biopsies, the possibility of prostate cancer overdiagnosis and overtreatment must be balanced with the continued risk of clinically significant disease.

Endocrine prevention and treatment of prostate cancer

The major androgen within the prostate is dihydrotestosterone (DHT). DHT and 5α-reductase are highly associated with prostate cancer. It has been hypothesised that inhibition of 5α-reductase activity might reduce the risk of prostate cancer development, slow tumour progression and even treat the existing disease. The basis for endocrine treatment of prostate cancer is to deprive the cancer cells of androgens. Every type of endocrine treatment carries adverse events which influence quality of life in different ways. 5α-Reductase inhibitors (5-ARI) reduce risk of being diagnosed with prostate cancer but they do not eliminate it. By suppressing PSA from BPH and indolent prostate cancers 5-ARI enhances the ability of a rising PSA to define a group of men at increased risk of clinically significant prostate cancer. Also fewer high-grade cancers are missed because biopsy is more accurate in smaller prostates. Androgen deprivation is an effective treatment for patients with advanced prostate cancer. However, it is not curative, and creates a spectrum of unwanted effects that influence quality of life. Castration remains the frontline treatment for metastatic prostate cancer, where orchiectomy, oestrogen agonists, GnRH agonists and antagonists produce equivalent clinical responses. MAB is not significantly more effective than single agent GnRH agonist or orchiectomy. Nonsteroidal antiandrogen monotherapy is as effective as castration in treatment of locally advanced prostate cancer offering quality of life benefits. Neoadjuvant endocrine treatment has its place mainly in the external beam radiotherapy setting. Increasing data suggest IAD is as effective as continuous ADT. The decision regarding the type of androgen deprivation should be made individually after informing the patient of all available treatment options, including watchful waiting, and on the basis of potential benefits and adverse effects. There are new promising secondary or tertiary forms of endocrine therapies under evaluation, like CTP17A1 inhibitors and more potent antiandrogens including MDV3100, which give new hope for patients developing castration resistant prostate cancer.

Association of 5α-reductase inhibitor use and pathological features of prostate cancer in men undergoing radical prostatectomy

BACKGROUND

We investigated the association of 5α-reductase inhibitor (5-ARI) treatment with pathologic and biochemical outcome among the contemporary prostate cancer (PCa) patients undergoing radical prostatectomy.

METHODS

We reviewed records of 1,204 men who underwent radical prostatectomy from 2003 to 2010. We estimated association of 5-ARI use with high (≥7) pathologic Gleason score and pathologically nonorgan-confined disease (≥pT3) via logistic regression, and biochemical outcome via Cox proportional hazards regression.

RESULTS

Of 1,204 patients, 50 (4.2%) reported having history 5-ARI treatment before radical prostatectomy. Median duration of 5-ARI treatment among the 50 patients was 23.0 months. When adjusted for various factors including age, body mass index, prostate-specific antigen, clinical stage, biopsy Gleason, and prostate volume, history of 5-ARI treatment was revealed to be significantly associated with high (≥7) pathologic Gleason score (P = 0.015). Also, 5-ARI use was observed to significantly associated with higher rates of extraprostatic extension of tumor (P = 0.005) and seminal vesicle invasion (P = 0.003), respectively, when adjusted for same variables. However, 5-ARI use was not demonstrated to be a significant preoperative predictor of biochemical recurrence-free survival in multivariate analysis (P = 0.528).

CONCLUSIONS

Our results showed 5-ARI treatment may be associated with more aggressive PCa demonstrating higher pathologic Gleason score and advanced pathologic tumor stage in men undergoing radical prostatectomy. However, further investigations via larger-scale, prospective studies would be needed on the actual effect of 5-ARI treatment on PCa-specific morbidity and mortality.

Prostate size as a predictor of Gleason score upgrading in patients with low risk prostate cancer

PURPOSE

Gleason score upgrading between biopsy and surgical pathological specimens occurs in 30% to 50% of cases. Predicting upgrading in men with low risk prostate cancer may be particularly important since high grade disease influences management decisions and impacts prognosis. We determined whether prostate size predicts Gleason score upgrading in patients with low risk prostate cancer.

MATERIALS AND METHODS

A total of 1,251 consecutive patients with D'Amico low risk disease and complete data available underwent radical prostatectomy at our institution between January 2000 and June 2008. Patients were divided into 3 groups by pathological Gleason score, including no, minor (3 + 4 = 7) and major (4 + 3 = 7 or greater) Gleason score upgrading. We developed bivariate and multivariate models to determine whether prostate size was an important predictor of upgrading while controlling for clinical and biopsy characteristics.

RESULTS

Of 1,251 cases 387 (31.0%) were upgraded, including 324 (26%) and 63 (5%) with minor and major upgrading, respectively. As expected, Gleason score upgrading was associated with worse pathological and cancer control outcomes. On multivariate analysis smaller prostate size was an independent predictor of any and major upgrading (OR 0.58, 95% CI 0.48-0.69, p <0.01 and OR 0.67, 95% CI 0.49-0.96, p = 0.03, respectively). Men with prostate volume at the 25th percentile (36 cm(3)) were 50% more likely to experience upgrading than men with prostate volume at the 75th percentile (58 cm(3)).

CONCLUSIONS

Of low risk cases 31% were upgraded at final pathology. Smaller prostate size predicts Gleason score upgrading in men with clinically low risk prostate cancer. This is important information when counseling patients on management and prognosis.

Optimizing prostate cancer detection during biopsy by standardizing the amount of tissue examined per core

OBJECTIVE

To investigate the effect on cancer detection by varying the number of cores taken for prostate biopsy according to the size of the prostate.

PATIENTS AND METHODS

A retrospective review of a prospectively registered prostate biopsy database identified 3040 consecutive patients undergoing prostate biopsy at a Veterans Administration Hospital between 1994 and 2008. Of 2224 biopsies, 681 (31%) were found to have cancer and 1540 (69%) had negative biopsies. Prostate volume to biopsy core ratios (volume/number of cores) were derived and a comparative analysis was performed to determine the impact on cancer detection rates.

RESULTS

The median prostate volume was significantly smaller for those patients diagnosed with prostate cancer than for those with negative biopsies (33 vs 43 cc, P= 0.01). The median number of cores was the same for both groups of patients (median 12, P= 0.66). The median transrectal ultrasonography TRUS size/core ratio was 3.5 [interquartile range (IQR) 2.5] for patients with identified cancer as compared with 4.7 (IQR = 3.9) for those with negative biopsies (P= 0.000). On multivariable logistic regression analysis TRUS size/core ratio had a significant impact on cancer detection with a relative risk ratio of 1.29 (95% confidence interval, 1.1-1.5, P= 0.001) even when controlled for age, race, prostate volume, digital rectal examination and prostate-specific antigen level.

CONCLUSIONS

Prostate cancer detection can be enhanced by individualizing the number of cores performed to a real-time prostate volume sampling. The present study emphasizes that optimal cancer detection rates were observed when a ratio of 3.5 cc per tissue core was achieved. Proper prospectively designed studies must be performed to further validate these findings.

Association of Polymorphisms in the Prostate-Specific Antigen (PSA) Gene Promoter with Serum PSA Level and PSA Changes after Dutasteride Treatment in Korean Men with Benign Prostatic Hypertrophy

Purpose

Studies of genetic variation in the prostate-specific antigen (PSA) gene have improved the diagnostic accuracy of PSA for diagnosing prostate diseases in Caucasians. However, the reference ranges and pharmacokinetics of PSA differ significantly according to race. Therefore, we evaluated the association between genetic variations in the PSA promoter area and benign prostatic hyperplasia (BPH) phenotypes in Korean BPH patients.

Materials and Methods

One hundred twenty-one men were enrolled. The initial serum PSA level, prostate size, and PSA changes at 3 months after treatment with dutasteride were determined. We amplified the promoter region of the PSA gene (nucleotide positions -158 to -356 and -5217 to -5429) and sequenced the products.

Results

Three relatively well characterized single-nucleotide polymorphisms (SNPs; rs3760722, rs266867, and rs266868), six uncharacterized SNPs (rs17554958, rs266882, rs4802754, rs2739448, rs2569733, and rs17526278), and one novel SNP (nucleotide position -5402) were found. There were no statistically significant correlations between any of the SNPs of the PSA promoter area and age-adjusted prostate sizes, initial PSA levels, or PSA variations after 3 months of dutasteride treatment.

Conclusions

SNPs in the PSA promoter area were not associated with BPH phenotypes. We could not predict serum PSA changes after dutasteride treatment on the basis of PSA promoter genotype in Korean patients with BPH.

Are men on 5α-reductase inhibitors appropriately referred to urology? A survey of primary care physicians

OBJECTIVE

• To investigate among general practitioners (GPs) their level of awareness and indications for urological consultations in patients treated with 5α-reductase inhibitors (5ARIs).

SUBJECTS AND METHODS

• We conducted a survey of GPs in Quebec. • Questions covered GPs' preferred benign prostatic hyperplasia (BPH) management, knowledge of 5ARIs, their role in prostate cancer prevention, and triggers for urology consultation.

RESULTS

• Of the surveys mailed, 599 were returned (15.7% response rate). • Therapy with 5ARIs was initiated by GPs in 34.3%, with 20% and 12% preferring 5ARIs alone and combined with an α-blocker as first-line therapy for BPH, respectively. • Once on therapy, 74% did not refer to a urologist if the PSA level did not decline after 6-12 months. • Finally, 40.7% would not advocate 5ARI chemoprevention for prostate cancer, regardless of risk reduction. • Findings were not associated with GP gender, experience or geographic location of practice (urban versus rural).

CONCLUSIONS

• There was a preference amongst GP to use α-blockers over 5ARIs for BPH and hesitancy to use them in prostate cancer chemoprevention. • There is a lack of awareness of 5ARI effects on PSA kinetics and a reluctance to refer to a urologist. • Further education in Quebec is needed about 5ARIs to optimize their usage and avoid delaying cancer detection.

Biology and natural history of prostate cancer and the role of chemoprevention

Androgens not only play an important role in the development and function of the prostate but they are also intimately involved in the development and progression of prostate cancer (PCa). Within the prostate, testosterone is converted to the more potent androgen dihydrotestosterone (DHT) via the action of 5α-reductase enzymes. DHT is the primary prostatic androgen and promotes the growth and survival of normal, hyperplastic and malignant prostate tissues. Throughout the different stages of PCa [prostatic intraepithelial neoplasia (PIN), localised, recurrent, and metastatic] there is an increase in expression of 5α-reductase enzymes, particularly in localised high-grade carcinoma. Specifically inhibiting 5α-reductase may reduce the production of DHT in the prostate while maintaining other endogenous hormone levels. Clinical studies have shown significant PCa risk reduction by blocking this pathway with 5α-reductase inhibitors (5ARIs). However, this comes at a risk, albeit low, with sexual side effects, gynaecomastia and cardiac failure. In addition, one study has shown a slight, but significant, risk of high-grade PCa. The currently available evidence does not support the routine use of 5α-reductase inhibitors to prevent PCa in the general population. It could, however, be considered as an individual option for high-risk or concerned patients with appropriate education from the prescribing provider.

Understanding the epidemiology, natural history, and key pathways involved in prostate cancer

Prostate cancer accounts for about 25% of all the newly diagnosed cancers in American men and was projected to cause >28,000 deaths in 2008. Black men are disproportionately affected; their incidence rate is about 1.6 times greater than the rate for white men. As the population ages, the number of new cases per year is expected to increase by >60% and reach 300,000 by 2015. This high incidence, coupled with the protracted onset of the disease, makes PCa a particularly appropriate candidate for prevention and early intervention strategies. Potential disease precursors, particularly high-grade prostatic intraepithelial neoplasia, might help identify men at high risk of developing PCa. Dihydrotestosterone, a product converted from testosterone by 5alpha-reductases, plays an important role in normal prostate growth and in the development of PCa. The 5alpha-reductase levels, particularly type 1, appear to increase during the disease course of prostatic intraepithelial neoplasia and PCa, with greater expression occurring as the disease progresses. Therefore, the inhibition of 5alpha-reductase could potentially reduce the risk of PCa development, slow or prevent disease progression, and/or treat existing disease. A substantial research effort has recently focused on understanding the pathways involved in the disease's emergence and progression, particularly the 5alpha-reductase pathway.

[Treatment of LUTS in BPS. When and when not to administer pills?]

Benign prostatic syndrome (BPS) is considered a diagnosis of exclusion and needs a thorough work-up. One of the pitfalls for a tailored medical treatment scheme is the objective evaluation of benign prostatic obstruction. Characteristics of the various medical therapy options and the multifactorial origin of LUTS in BPH patients imply an individualized approach. LUTS involving mostly urine storage disorders and a small prostate are suitably managed with alpha(1)-receptor antagonists, which may be combined with antimuscarinics if OAB symptoms predominate. Long-term treatment addressing clinical progression may favor combination therapy of alpha(1)-receptor antagonists with 5alpha-reductase inhibitors if prostate size is sufficient. Age, symptom severity at baseline, a large prostate volume, or a high PSA value are indicative of progression. However, combination therapy aggravates side effects, and thus a risk-benefit analysis is essential. The potential of any medication for BPS to treat obstruction is rather low. If deobstruction is the main aim of therapy, medical treatment is not suitable.

[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.

Significance of chemoprevention for prostate cancer development: experimental in vivo approaches to chemoprevention

Prostate cancer is the most common tumor in men in Western countries and mortality in Asian countries from the disease appears to be constantly increasing. Characteristics include (i) frequent discovery of latent carcinoma, even in countries with low incidences of clinical cancer; (ii) very long time to clinically significant cancer; (iii) few patients under 50 years of age (primarily a disease of elderly men); (iv) strong influences of environmental factors such as food; (v) temporal effectiveness of androgen deprival therapy; and (vi) no effective therapeutic approaches once hormone-refractory neoplasms have developed. Therefore prostate cancer is particularly indicated for preventive efforts, especially chemoprevention. Several large-scale chemoprevention trials have in fact been conducted and some have found suppressive effects. However, not all have been proven to have benefit. Experimental preclinical investigations, particularly using animal models, are recommended to find better chemopreventive agents with less adverse effects. Data using rat models have generated very interesting findings from which mechanism-based strategies can be proposed. In the present report the importance of chemoprevention of prostate cancer will be discussed using the data on human and rat prostate cancer development.

Therapeutic effect of ACTICOA powder, a cocoa polyphenolic extract, on experimentally induced prostate hyperplasia in Wistar-Unilever rats

Benign prostatic hyperplasia (BPH) is a non-malignant enlargement of the prostate that results in obstructive lower urinary tract symptoms. Plant extracts are frequently used to treat BPH rather than therapeutics that can cause severe side effects. ACTICOA() (Ba0rry Callebaut France, Louviers, France) powder (AP) is a cocoa polyphenolic extract, and we have shown in a previous study that oral treatment with AP prevented prostate hyperplasia. This study investigated whether AP could improve established prostate hyperplasia using the same testosterone propionate (TP)-induced prostate hyperplasia model in rats. Male Wistar-Unilever rats were randomly divided in four groups of 12 rats: one group injected with corn oil and orally treated with the vehicle (negative control) and three groups injected subcutaneously with TP and orally treated with the vehicle (positive control) or AP at 24 (AP24) and 48 (AP48) mg/kg/day. Treatments started 1 week after the start of the induction of prostate hyperplasia and lasted for 2 weeks. The influence of TP and AP on body weights, food and water consumptions, plasma polyphenolic concentration, and serum dihydrotestoterone (DHT) level of rats was examined. At completion of the study, rats were sacrificed, and the prostates were removed, cleaned, and weighed. The prostate size ratio (prostate weight/rat body weight) was then calculated. TP significantly influenced the body weight gain of the rats and their food and water consumptions, while AP reduced significantly these differences in a dose-dependent manner. AP significantly reduced serum DHT level and prostate size ratio in comparison with positive controls also dose-dependently. In conclusion, AP orally administered was effective for reducing established prostate hyperplasia, especially at the dose of 48 mg/kg/day.

Small transrectal ultrasound volume predicts clinically significant Gleason score upgrading after radical prostatectomy: results from the SEARCH database

PURPOSE

Needle biopsy Gleason scores are often upgraded after pathological examination of the prostate following radical prostatectomy. It has been suggested that larger prostates would be associated with a greater risk of upgrading since a smaller percentage of the gland is sampled and, thus, the highest grade disease would more likely be missed, assuming an equal number of cores is taken from similar locations. We examined the likelihood of clinically relevant upgrading after radical prostatectomy as a function of transrectal ultrasound volume.

MATERIALS AND METHODS

We examined the association between transrectal ultrasound volume and upgrading (higher Gleason score category in the radical prostatectomy specimen than in the biopsy) in 586 men treated with radical prostatectomy between 1995 and 2006 in the SEARCH database who underwent at least a sextant biopsy using multivariate logistic regression. Transrectal ultrasound volume was categorized as 20 or less (in 71), 21 to 40 (in 334), 41 to 60 (in 123) and greater than 60 cm(3) (in 58). Gleason score was examined as a categorical variable of 2-6, 3 + 4 and 4 + 3 or greater.

RESULTS

Overall 138 cases (24%) were upgraded, 80 (14%) were downgraded, and 368 (62%) had identical biopsy and pathological Gleason sum groups. Larger transrectal ultrasound volume was significantly associated with decreased likelihood of upgrading (p trend <0.001). For transrectal ultrasound volumes greater than 60, 41 to 60, 21 to 40 and 20 cm(3) or less, the estimated multivariate adjusted probability of upgrading was 12.6%, 27.5%, 36.4% and 45.5% for Gleason 2-6 tumors, and 6.1%, 8.5%, 18.9% and 20.9% for Gleason 3 + 4 tumors, respectively.

CONCLUSIONS

Larger transrectal ultrasound volumes were at decreased risk for clinically significant upgrading after radical prostatectomy. This fact should be kept in mind when deciding on treatment decisions for men with apparently low grade prostate cancer on biopsy.

SRD5A2 and HSD3B2 polymorphisms are associated with prostate cancer risk and aggressiveness

BACKGROUND

Dihydrotestosterone (DHT) is believed to play an important role in prostate carcinogenesis. Five alpha reductase type II (SRD5A2) and 3 beta-hydroxysteroid dehydrogenase type II (HSD3B2) are responsible for the biosynthesis and degradation of DHT in the prostate. Two polymorphisms, a valine (V) for leucine (L) substitution at the 89 codon of the SRD5A2 gene and a (TG)n,(TA)n,(CA)n repeat polymorphism within the third intron of the HSD3B2 gene were evaluated with regard to prostate cancer risk.

METHODS

Blood samples were collected for 637 prostate cancer cases and 244 age and race frequency matched controls. In analysis, the SRD5A2 VL and LL genotypes were combined into one group and the HSD3B2 repeat polymorphism was dichotomized into short (<283) and long (> or =283) alleles.

RESULTS

The SRD5A2 V89L polymorphism was not independently associated with prostate cancer risk. Carriage of at least one HSD3B2 intron 3 intron 3 short allele was associated with a significant increased risk for prostate cancer among all subjects (OR = 2.07, 95% CI = 1.08-3.95, P = 0.03) and Caucasians (OR = 2.80, CI = 2.80-7.43, P = 0.04), but not in African Americans (OR = 1.50, CI = 0.62-3.60, P = 0.37). Stratified analyses revealed that most of the prostate cancer risk associated with the intron 3 HSD3B2 short allele was confined to the SRD5A2 89L variant subgroup and indicated that in combination these polymorphisms may be associated with increased risk of aggressive (Gleason >7) disease (Gleason >7).

CONCLUSIONS

In Caucasians, the HSD3B2 (TG)n,(TA)n,(CA)n intron 3 length polymorphism is associated with both prostate cancer risk and aggressiveness and the SRD5A2 V89L polymorphism may modify the risk conferred by this polymorphism.

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.

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.

Medical treatment of benign prostatic hyperplasia

Pharmaceutical preparations are commonly used for benign prostate hyperplasia. This article reviews the current understanding of the natural history of the condition and the literature regarding medical treatment.

The effects of the dual 5alpha-reductase inhibitor dutasteride on localized prostate cancer--results from a 4-month pre-radical prostatectomy study

BACKGROUND

As dihydrotestosterone (DHT) is the most potent androgen in the prostate, inhibition of the 5alpha-reductase isoenzymes, which convert testosterone to DHT, could be an appropriate target for the treatment of prostate cancer.

METHODS

Eighty-one men with clinically localized prostate cancer received daily dutasteride 3.5 or 0.5 mg, or no therapy for 4 months before radical prostatectomy. Histopathological assessments were conducted on prostatectomy specimens.

RESULTS

Treatment with dutasteride was associated with reductions in serum and intraprostatic DHT of >or=90%, and a decrease in total prostate and tumor volumes. No effect of dutasteride was noted on Gleason grade. Histopathological effects on benign tissue were similar but less prominent than those seen with androgen ablation, whereas there was no significant difference in cancer histology among the groups.

CONCLUSIONS

Dutasteride treatment results in similar but less marked changes compared with androgen ablation.

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.

An update on chemoprevention strategies in prostate cancer for 2006

PURPOSE OF REVIEW

An increasing volume of research has been directed at the prevention of prostate cancer. This review proposes to summarize the large trials, novel approaches and molecular mechanisms of effect published in 2004 and 2005.

RECENT FINDINGS

The impact of the Prostate Cancer Prevention Trial continues and subsequent articles have addressed the increase of high-grade prostate cancers detected in the finasteride arm of the trial, as well as the potential costs and benefits of extrapolating the findings to a public health campaign. Studies of risk have been published warning of excessive vitamin E and cyclooxygenase-2 inhibitor use in chemoprevention. Growing evidence supports the concept of chemopreventative agent combinations and further data on the roles of selenium, lycopene, soy, green tea, anti-inflammatories and statins in prostate-cancer prevention are presented.

SUMMARY

Level one evidence exists for the preventative effects of finasteride in prostate cancer. The evidence for other agents is less conclusive but a number of large-scale, appropriately designed trials will hopefully address some of the relevant issues in prostate-cancer prevention over the next decade.

Association between the dihydrotestosterone level in the prostate and prostate cancer aggressiveness using the Gleason score

PURPOSE

To our knowledge the association between dihydrotestosterone in the prostate and prostate cancer aggressiveness has not yet been elucidated. We analyzed dihydrotestosterone levels in the prostate and Gleason score in patients diagnosed with clinically localized prostate cancer.

MATERIALS AND METHODS

A total of 81 patients with suspected prostate cancer underwent prostate biopsy. Serum samples were collected before biopsy. Dihydrotestosterone levels in prostatic tissue and serum were analyzed using liquid chromatography/electrospray ionization-mass spectrometry after polar derivatization.

RESULTS

A total of 47 patients were diagnosed with stages T1 to T3N0M0 prostate cancer and 34 were diagnosed with no malignancy. Of the 47 patients 32 had a Gleason score of 6 or less and 15 had a score of 7 to 10. Dihydrotestosterone in prostatic tissue in patients with Gleason score 7 to 10 disease was significantly lower than in those with Gleason score 6 or less disease (p = 0.025). Gleason score correlated with the testosterone-to-serum dihydrotestosterone ratio (rs = 0.329, p = 0.038).

CONCLUSIONS

Patients with Gleason score 7 to 10 prostate cancer have low dihydrotestosterone in the prostate, although there were no significant differences between patients with Gleason score 7 to 10 vs 6 or less prostate cancer with respect to serum androgens. Low dihydrotestosterone in cases of aggressive prostate cancer is probably sufficient to activate androgen receptor expression and propagate tumor growth.

Epigenetics of prostate cancer: beyond DNA methylation

Epigenetic mechanisms permit the stable inheritance of cellular properties without changes in DNA sequence or amount. In prostate carcinoma, epigenetic mechanisms are essential for development and progression, complementing, amplifying and diversifying genetic alterations. DNA hypermethylation affects at least 30 individual genes, while repetitive sequences including retrotransposons and selected genes become hypomethylated. Hypermethylation of several genes occurs in a coordinate manner early in carcinogenesis and can be exploited for cancer detection, whereas hypomethylation and further hypermethylation events are associated with progression. DNA methylation alterations interact with changes in chromatin proteins. Prominent alterations at this level include altered patterns of histone modification, increased expression of the EZH2 polycomb histone methyltransferase, and changes in transcriptional corepressors and coactivators. These changes may make prostate carcinoma particularly susceptible to drugs targeting chromatin and DNA modifications. They relate to crucial alterations in a network of transcription factors comprising ETS family proteins, the androgen receptor, NKX3.1, KLF, and HOXB13 homeobox proteins. This network controls differentiation and proliferation of prostate epithelial cells integrating signals from hormones, growth factors and cell adhesion proteins that are likewise distorted in prostate cancer. As a consequence, prostate carcinoma cells appear to be locked into an aberrant state, characterized by continued proliferation of largely differentiated cells. Accordingly, stem cell characteristics of prostate cancer cells appear to be secondarily acquired. The aberrant differentiation state of prostate carcinoma cells also results in distorted mutual interactions between epithelial and stromal cells in the tumor that promote tumor growth, invasion, and metastasis.

Finasteride effects on hypoxia and angiogenetic markers in benign prostatic hyperplasia

OBJECTIVES

To assess the effects of finasteride on angiogenetic and hypoxia markers in benign prostatic hyperplasia.

METHODS

A total of 178 patients aged 51 to 85 years (mean 68.7) with benign prostatic hyperplasia and awaiting transurethral prostate resection were prospectively randomized into a group of patients receiving finasteride (group 1; 88 patients) and a group of patients who received no medication until transurethral prostate resection (group 2; 90 patients). Tissue specimens were immunohistochemically stained with monoclonal antibodies against CD34 for microvessel density (MVD), vascular endothelial growth factor (VEGF), and hypoxia inducible factor-1alpha (HIF-1alpha).

RESULTS

Blood loss during transurethral prostate resection was significantly higher in group 2 compared with group 1 (P <0.001). The distribution of CD34 immunostaining was mainly at the suburethral prostate. MVD, VEGF, and HIF-1alpha values were significantly lower statistically (P <0.001) in group 1 compared with group 2. In the finasteride group (group 1), the positive correlation of the immunoreactivity of CD34 and HIF-1alpha, VEGF and HIF-1alpha, and VEGF and CD34 was statistically significant (P <0.001). In the same group, MVD and VEGF and HIF-1alpha expression correlated statistically with the treatment duration.

CONCLUSIONS

Finasteride administration in benign prostatic hyperplasia results in statistically significant suppression of MVD, VEGF, and HIF-1alpha in a time-dependent manner.

Bicalutamide 50 mg monotherapy in patients with isolated high-grade PIN: findings in repeat biopsies at 6 months

OBJECTIVES

To evaluate morphological findings in repeat biopsies in patients with isolated high-grade prostatic intraepithelial neoplasia (HGPIN) after a 6-month course of bicalutamide (Casodex) 50 mg/day.

METHODS

20 consecutive patients with isolated HGPIN in prostate biopsies were treated for 6 months with bicalutamide 50 mg/day. After treatment, the patients were resubmitted to prostate biopsy mapping. The control group included 22 untreated consecutive patients with isolated high-grade PIN with repeat biopsies taken 6 months after the initial biopsies.

RESULTS

In the initial biopsies of the treated group, HGPIN was monofocal in 12 patients and plurifocal in 8. In the repeat biopsies HGPIN was present in 2 patients, monofocal in both, whereas prostate adenocarcinoma (PCa) was discovered in one. In the control group, HGPIN was monofocal in 15 and plurifocal in 7. In the repeat biopsies HGPIN was present in six patients, being monofocal in three and plurifocal in the other three. PCa was present in one.

CONCLUSIONS

There was a lower incidence of HGPIN (treated group vs control: 10% vs 27.2%) after 6 months of bicalutamide. Reduction in its extent was also observed (treated group vs control: monofocal 100% vs 50%). Treatment did not affect the incidence of cancer (treated vs control: 5% vs 4.5%).