Outcomes for intermediate risk prostate cancer: are there advantages for surgery, external radiation, or brachytherapy?

Role of radiomic analysis of [18F]fluoromethylcholine PET/CT in predicting biochemical recurrence in a cohort of intermediate and high risk prostate cancer patients at initial staging

AIM

To study the feasibility of radiomic analysis of baseline [18F]fluoromethylcholine positron emission tomography/computed tomography (PET/CT) for the prediction of biochemical recurrence (BCR) in a cohort of intermediate and high-risk prostate cancer (PCa) patients.

MATERIAL AND METHODS

Seventy-four patients were prospectively collected. We analyzed three prostate gland (PG) segmentations (i.e., PGwhole: whole PG; PG41%: prostate having standardized uptake value - SUV > 0.41*SUVmax; PG2.5: prostate having SUV > 2.5) together with three SUV discretization steps (i.e., 0.2, 0.4, and 0.6). For each segmentation/discretization step, we trained a logistic regression model to predict BCR using radiomic and/or clinical features.

RESULTS

The median baseline prostate-specific antigen was 11 ng/mL, the Gleason score was > 7 for 54% of patients, and the clinical stage was T1/T2 for 89% and T3 for 9% of patients. The baseline clinical model achieved an area under the receiver operating characteristic curve (AUC) of 0.73. Performances improved when clinical data were combined with radiomic features, in particular for PG2.5 and 0.4 discretization, for which the median test AUC was 0.78.

CONCLUSION

Radiomics reinforces clinical parameters in predicting BCR in intermediate and high-risk PCa patients. These first data strongly encourage further investigations on the use of radiomic analysis to identify patients at risk of BCR.

CLINICAL RELEVANCE STATEMENT

The application of AI combined with radiomic analysis of [18F]fluoromethylcholine PET/CT images has proven to be a promising tool to stratify patients with intermediate or high-risk PCa in order to predict biochemical recurrence and tailor the best treatment options.

KEY POINTS

• Stratification of patients with intermediate and high-risk prostate cancer at risk of biochemical recurrence before initial treatment would help determine the optimal curative strategy. • Artificial intelligence combined with radiomic analysis of [18F]fluorocholine PET/CT images allows prediction of biochemical recurrence, especially when radiomic features are complemented with patients' clinical information (highest median AUC of 0.78). • Radiomics reinforces the information of conventional clinical parameters (i.e., Gleason score and initial prostate-specific antigen level) in predicting biochemical recurrence.

A new tumorgraft panel to accelerate precision medicine in prostate cancer

Background

Despite the significant advances in the management of advanced prostate cancer (PCa), metastatic PCa is currently considered incurable. For further investigations in precision treatment, the development of preclinical models representing the complex prostate tumor heterogeneity are mandatory. Accordingly, we aimed to establish a resource of patient-derived xenograft (PDX) models that exemplify each phase of this multistage disease for accurate and rapid evaluation of candidate therapies.

Methods

Fresh tumor samples along with normal corresponding tissues were obtained directly from patients at surgery. To ensure that the established models reproduce the main features of patient's tumor, both PDX tumors at multiple passages and patient's primary tumors, were processed for histological characteristics. STR profile analyses were also performed to confirm patient identity. Finally, the responses of the PDX models to androgen deprivation, PARP inhibitors and chemotherapy were also evaluated.

Results

In this study, we described the development and characterization of 5 new PDX models of PCa. Within this collection, hormone-naïve, androgen-sensitive and castration-resistant (CRPC) primary tumors as well as prostate carcinoma with neuroendocrine differentiation (CRPC-NE) were represented. Interestingly, the comprehensive genomic characterization of the models identified recurrent cancer driver alterations in androgen signaling, DNA repair and PI3K, among others. Results were supported by expression patterns highlighting new potential targets among gene drivers and the metabolic pathway. In addition, in vivo results showed heterogeneity of response to androgen deprivation and chemotherapy, like the responses of patients to these treatments. Importantly, the neuroendocrine model has been shown to be responsive to PARP inhibitor.

Conclusion

We have developed a biobank of 5 PDX models from hormone-naïve, androgen-sensitive to CRPC primary tumors and CRPC-NE. Increased copy-number alterations and accumulation of mutations within cancer driver genes as well as the metabolism shift are consistent with the increased resistance mechanisms to treatment. The pharmacological characterization suggested that the CRPC-NE could benefit from the PARP inhibitor treatment. Given the difficulties in developing such models, this relevant panel of PDX models of PCa will provide the scientific community with an additional resource for the further development of PDAC research.

Basic Science and Molecular Genetics of Prostate Cancer Aggressiveness

Androgen receptor function, tumor cell plasticity, loss of tumor suppressors, and defects in DNA repair genes affect aggressive features of prostate cancer. Prostate cancer development, progression, and aggressive behavior are often attributable to function of the androgen receptor. Tumor cell plasticity, neuroendocrine features, and loss of tumor suppressors lend aggressive behavior to prostate cancer cells. DNA repair defects have ramifications for prostate cancer cell behavior.

YAP1 overexpression contributes to the development of enzalutamide resistance by induction of cancer stemness and lipid metabolism in prostate cancer

Metastatic castration-resistant prostate cancer (mCRPC) is a malignant and lethal disease caused by relapse after androgen-deprivation (ADT) therapy. Since enzalutamide is innovated and approved by US FDA as a new treatment option for mCRPC patients, drug resistance for enzalutamide is a critical issue during clinical usage. Although several underlying mechanisms causing enzalutamide resistance were previously identified, most of them revealed that drug resistant cells are still highly addicted to androgen and AR functions. Due to the numerous physical functions of AR in men, innovated AR-independent therapy might alleviate enzalutamide resistance and prevent production of adverse side effects. Here, we have identified that yes-associated protein 1 (YAP1) is overexpressed in enzalutamide-resistant (EnzaR) cells. Furthermore, enzalutamide-induced YAP1 expression is mediated through the function of chicken ovalbumin upstream promoter transcription factor 2 (COUP-TFII) at the transcriptional and the post-transcriptional levels. Functional analyses reveal that YAP1 positively regulates numerous genes related to cancer stemness and lipid metabolism and interacts with COUP-TFII to form a transcriptional complex. More importantly, YAP1 inhibitor attenuates the growth and cancer stemness of EnzaR cells in vitro and in vivo. Finally, YAP1, COUP-TFII, and miR-21 are detected in the extracellular vesicles (EVs) isolated from EnzaR cells and sera of patients. In addition, treatment with EnzaR-EVs induces the abilities of cancer stemness, lipid metabolism and enzalutamide resistance in its parental cells. Taken together, these results suggest that YAP1 might be a crucial factor involved in the development of enzalutamide resistance and can be an alternative therapeutic target in prostate cancer.

Targeting androgen receptor signaling with MicroRNAs and Curcumin: a promising therapeutic approach for Prostate Cancer Prevention and intervention

Prostate cancer (PC) is a multifactorial disease characterized by the abrogation of androgen receptor signaling. Advancement in microbiology techniques has highlighted the significant role of microRNAs (miRNAs) in the progression of PC cells from an androgen-dependent to an androgen-independent state. At that stage, prostate tumors also fail to respond to currently practiced hormone therapies. So, studies in recent decades are focused on investigating the anti-tumor effects of natural compounds in PC. Curcumin is widely recognized and now of huge prestige for its anti-proliferative abilities in different types of cancer. However, its limited solubility, compatibility, and instability in the aqueous phase are major hurdles when administering. Nanoformulations have proven to be an excellent drug delivery system for various drugs and can be used as potential delivery platforms for curcumin in PC. In this review, a shed light is given on the miRNAs-mediated regulation of androgen receptor (AR) signaling and miRNA-curcumin interplay in PC, as well as on curcumin-based nanoformulations that can be used as possible therapeutic solutions for PC.

125I low-dose-rate prostate brachytherapy and radical prostatectomy in patients with prostate cancer

Radical prostatectomy (RP) and low-dose-rate prostate brachytherapy (LDR) are two widely used treatment options for patients with T1c-T3a prostate cancer. In the present study, the efficacy of the two treatments was compared. A total of 429 patients who underwent either LDR (n=218) or RP (n=211) between January 2010 and June 2015 were retrospectively reviewed. Biochemical relapse-free survival time (bRFS) and clinical relapse-free survival time (cRFS) were assessed. The log-rank test compared bRFS between the two modalities, and Cox regression identified factors associated with bRFS. The median follow-up time and patient age were 46.6 months and 71 years, respectively. The bRFS at 1, 2 and 5 years was 89.4, 87.2 and 79.9% for LDR, respectively, and 91.0, 82.8 and 72.2% for RP, respectively (P=0.077). The cRFS at 1, 2 and 5 years was 99.1, 97.7 and 94.9% for LDR, respectively, and 99.0, 96.2 and 94.5% for RP, respectively (P=0.630). It was indicated that LDR produced equivalent bRFS and cRFS rates compared with RP. The risk of biochemical failure (bF) was higher for the RP group compared with the LDR group in patients with a Gleason score ≤3+4 (P=0.022) or initial prostate specific antigen ≤10 ng/ml (P=0.002). Based on the univariate and multivariate logistic regression analysis of all 429 patients, T stage ≥T2b was an independent predictor for bF.

Endoplasmic reticulum stress, autophagic and apoptotic cell death, and immune activation by a natural triterpenoid in human prostate cancer cells

Though the current therapies are effective at clearing an early stage prostate cancer, they often fail to treat late-stage metastatic disease. We aimed to investigate the molecular mechanisms underlying the anticancer effects of a natural triterpenoid, ganoderic acid DM (GA-DM), on two human prostate cancer cell lines: the androgen-independent prostate carcinoma (PC-3), and androgen-sensitive prostate adenocarcinoma (LNCaP). Cell viability assay showed that GA-DM was relatively more toxic to LNCaP cells than to PC-3 cells (IC₅₀ s ranged 45-55 µM for PC-3, and 20-25 µM for LNCaP), which may have occurred due to differential expression of p53. Hoechst DNA staining confirmed detectable nuclear fragmentation in both cell lines irrespective of the p53 status. GA-DM treatment decreased Bcl-2 proteins while it upregulated apoptotic Bax and autophagic Beclin-1, Atg5, and LC-3 molecules, and caused an induction of both early and late events of apoptotic cell death. Biochemical analyses of GA-DM-treated prostate cancer cells demonstrated that caspase-3 cleavage was notable in GA-DM-treated PC-3 cells. Interestingly, GA-DM treatment altered cell cycle progression in the S phase with a significant growth arrest in the G2 checkpoint and enhanced CD4 ⁺ T cell recognition of prostate tumor cells. Mechanistic study of GA-DM-treated prostate cancer cells further demonstrated that calpain activation and endoplasmic reticulum stress contributed to cell death. These findings suggest that GA-DM is a candidate for future drug design for prostate cancer as it activates multiple pathways of cell death and immune recognition.

Randomised Phase II Feasibility Trial of Image-guided External Beam Radiotherapy With or Without High Dose Rate Brachytherapy Boost in Men with Intermediate-risk Prostate Cancer (CCTG PR15/ NCT01982786)

AIMS

We conducted a multicentre feasibility study to assess the ability to randomise patients between image-guided radiotherapy (IGRT) and IGRT + high dose rate (HDR) brachytherapy boost and to adhere to appropriate radiation quality assurance standards.

MATERIALS AND METHODS

The primary end point was to determine the ability to randomise 60 patients over an 18 month period. Arm 1 (IGRT) patients received 78 Gy in 39 fractions or 60 Gy in 20 fractions (physician's preference), whereas arm 2 (IGRT + HDR) received 37.5 Gy in 15 fractions with HDR boost of 15 Gy. The secondary end points included >grade 3 acute genitourinary and gastrointestinal toxicity, using Common Terminology Criteria for Adverse Events version 4.0 at 3 months, validation of a prospectively defined radiation oncology quality assurance to assess treatment compliance. All analyses were descriptive; no formal comparisons between treatment arms were carried out.

RESULTS

Between April 2014 and September 2015, 57 National Comprehensive Cancer Network (NCCN)-defined intermediate-risk prostate cancer patients were randomised between IGRT alone (arm 1; n = 29) and IGRT plus HDR brachytherapy boost (arm 2; n = 28). Overall, 93% received the treatment as randomised. There were four patients (one on IGRT arm 1 and three patients on the IGRT + HDR arm 2) who were treated differently from randomisation assignment. For the 29 patients receiving IGRT (arm 1), there were 14 cases reported with minor deviations and three with major deviations. For patients on IGRT + HDR (arm 2), there were 18 cases reported with minor deviations and two with major deviations. At 3 months in the IGRT group (arm 1), one patient reported grade 3 diarrhoea, whereas in the IGRT + HDR group (arm 2), two patients reported grade 3 haematuria. No other gastrointestinal and genitourinary toxicities were reported.

CONCLUSION

The pilot study showed the feasibility of randomisation between treatment with IGRT alone versus IGRT + HDR boost. Treatment compliance was good, including adherence to quality assurance standards.

A population-based study examining the influence of a specialized rapid-access cancer clinic on initial treatment choice in localized prostate cancer

INTRODUCTION

Treatment decisions in localized prostate cancer are complicated by the available choices. A rapid-access cancer clinic (RAC) has been unique to Calgary, AB, since 2007. This RAC offers multidisciplinary prostate cancer education by a urologist, medical oncologist, and radiation oncologist. It is hypothesized that treatment utilization data from decisions taken at RAC may serve to benchmark the appropriateness of treatment decisions on a population level.

METHODS

Records of patients with clinically localized prostate cancer in Alberta between October 1, 2007 and September 30, 2009 were reviewed with ethics approval. Records were linked to the Alberta Cancer Registry database. Clinical, treatment, and health services characteristics pertaining to patients attending RAC were compared to the general population. The primary endpoint was utilization rates of each initial treatment.

RESULTS

During this two-year period, 2838 patients were diagnosed with localized prostate cancer; 375 attended RAC. The utilization rates among RAC patients vs. the whole Alberta population were: prostatectomy 60.3% (95% confidence interval [CI] 55.3-65.2) vs. 48.0% (95% CI 47.1-50.7; χ² p<0.001); active surveillance 16.0% (95% CI 12.3-19.7%) vs. 13.5% (95% CI 12.2-15.8; χ² p=0.214); radiotherapy 11.7% (95% CI 8.5-15.0) vs. 18.0% (95% CI 16.9-20.5; χ² p=0.002); and hormone therapy 8.0% (95% CI 5.2-10.8) vs. 17.4% (95% CI 16.1-18.9; χ² p<0.001).

CONCLUSIONS

A specialized clinic for localized prostate cancer may be associated with a higher likelihood of receiving surgery or active surveillance as initial treatment compared to the prostate cancer population in Alberta.

Androgen receptor dampens tissue factor expression via nuclear factor-κB and early growth response protein 1

Essentials Androgen deprivation increases the rate of venous thromboembolism in prostate cancer patients. We characterized androgen receptor-mediated tissue factor regulation in prostate epithelial cells. Androgen receptor is dampening tissue factor expression in prostate epithelial cells. Androgen deprivation could enhance tissue factor expression and raise venous thromboembolism rates.

SUMMARY

Background Prostate cancer is one of the leading causes of cancer death in men. Advanced prostate cancer is usually treated by androgen deprivation therapy (ADT), which is aimed at reducing circulating testosterone levels to reduce cancer growth. There is growing evidence that ADT can increase the rate of venous thromboembolism (VTE) in prostate cancer patients. The tissue factor (TF) gene is one of the most important mediators of coagulation and VTE, but, so far, there are limited data on androgen receptor (AR)-mediated TF gene expression. Objectives To characterize AR-mediated TF regulation in vitro and in vivo. Methods We used the androgen-dependent prostate cancer cell lines LNCaP and MyC-CaP to test whether TF expression is regulated by AR. Furthermore, we cloned the TF gene promoter into a luciferase reporter vector to identify the transcription factor-binding sites that mediate TF regulation downstream of AR. Finally, we used castration experiments in mice to characterize AR-mediated TF regulation in vivo. Results TF is directly regulated by AR. In LNCaP cells, nuclear factor-κB signaling and EGR1 mediate TF expression. By using castration experiments in mice, we could detect upregulation of TF and early growth response protein 1 mRNA and protein expression in prostate epithelial cells. Conclusion AR is crucial for dampening TF expression, which could be important for increased TF expression and TF-positive microvesicle release in androgen-deprived prostate cancer patients.

Prostate cancer as a paradigm of multidisciplinary approach? Highlights from the Italian young radiation oncologist meeting

Aims and background

The diagnostic and therapeutic approach to prostate cancer has evolved rapidly in last decades. Young professionals need an update about these recent developments in order to improve the care of patients treated in their daily clinical practice.

Methods

On May 18, 2013, AIRO Giovani (the young section of the Italian Association of Radiation Oncology) organized a multidisciplinary meeting involving, as speakers, several young physicians from many parts of Italy actively involved in the diagnostic and therapeutic approach to prostate cancer. The meeting was specifically addressed to young physicians (radio-oncologists, urologists, medical oncologists) and presented the state-of-the-art of the diagnostic/therapeutic approach based on the latest evidence on the issue. Highlights of the congress are summarized and presented in this report.

Results

The large participation in the meeting (more than 120 participants were present) confirmed the interest of young radiation oncologists in improving their skills in prostate cancer management. The contributions of the speakers confirmed the need for regular updates, considering the promising results of recently published studies and the many new ongoing trials, on the diagnostic and therapeutic approaches to prostate cancer.

Conclusions

Multidisciplinary meetings are helpful to improve the skills of young professionals.

Validation of the French-Canadian version of the Expanded Prostate Cancer Index Composite (EPIC) in a French-Canadian population

INTRODUCTION

This study aims to empirically validate the French-Canadian version of the Expanded Prostate Cancer Index Composite (EPIC), a measure of health-related quality of life for prostate cancer patients.

METHODS

Two hundred fifty-one participants completed a battery of self-report scales, including the French-Canadian version of the EPIC, after having received radiation therapy or radical prostatectomy for prostate cancer.

RESULTS

The internal consistency for the urinary incontinence, bowel, and sexual domains of the EPIC-26 was high (Cronbach's alpha coefficients from 0.80-0.92), while coefficients for the urinary irritation/obstruction (0.59) and hormonal (0.67) domains were lower. Item-total correlations (rs=0.15-0.85), and temporal stability (rs=0.72-0.93) generally supported the reliability of the instrument. The five-factor structure of the EPIC-26 was confirmed for the most part. The construct validity of the instrument was also supported by high correlations obtained between each domain and measures assessing similar constructs (rs=-0.56-0.83). The EPIC also showed an excellent sensitivity to change with significant differences obtained on EPIC scores (all p<0.05) between pre- and post-prostate cancer treatment.

CONCLUSIONS

The psychometric qualities of the French-Canadian version of the EPIC are well-supported, thus providing a valid tool to assess health-related quality of life in prostate cancer patients.

Novel small molecule guanidine Sigma1 inhibitors for advanced prostate cancer

Prostate cancer is the most frequently diagnosed malignancy and the leading cause of cancer related death in men. First line therapy for disseminated disease relies on androgen deprivation, leveraging the addiction of these tumors on androgens for both growth and survival. Treatment typically involves antagonizing the androgen receptor (AR) or blocking the synthesis of androgens. Recurrence is common and within 2-3years patients develop castration resistant tumors that become unresponsive to AR-axis targeted therapies. In order to provide a more effective treatment, we are utilizing an approach that targets a key scaffolding protein, Sigma1 (also known as sigma-1 receptor), a unique 26-kilodalton integral membrane protein that is critical in stabilizing the AR. Herein we report on a new series of Sigma1 compounds for lead optimization derived from a hybrid pharmacophore approach.

Evaluation of biochemical recurrence in patients with high-risk prostate cancer treated with radical prostatectomy and radiotherapy plus androgen deprivation therapy

Objective

The aim of this study was to evaluate the biochemical recurrence (BCR) in patients with high-risk prostate cancer (PCa) treated with radical prostatectomy (RP) or radiotherapy (RT) plus androgen deprivation therapy (ADT).

Methods

Subjects were patients with National Comprehensive Cancer Network-defined high-risk PCa treated with either RP or RT plus ADT. We calculated BCR-free survival in patients with those treatments and evaluated risk factor against BCR.

Results

A total of 114 patients, 71 RP and 43 RT plus ADT, were evaluated. A total of 59 and 20.9% of patients experienced BCR in the RP and RT treatment groups, respectively. The 5-year BCR-free survival probabilities improved significantly for patients who received RT compared to those who received RP (81.3 vs 37.3%, P<0.001). According to the number of risk factors, 59.2% of patients in the RP and 51.2% of patients in the RT treatment groups were classified with one risk factor (P<0.014). The 5-year BCR-free survival probabilities for patients treated with RP were 46.6 and 21.7% for one and multiple risk factors, respectively (P=0.008). On univariate analysis, only the number of risk factors had a significant impact on the risk of BCR. Meanwhile, there were no significant differences in the 5-year BCR-free survival probabilities between one and multiple risk factors in patients treated with RT.

Conclusion

Among patients treated with RP, a marked heterogeneity existed in the oncological outcomes. Based on these findings, the number of risk factors should be emphasized to decide the optimal treatments for patients with high-risk PCa.

Comparison of biochemical recurrence in prostate cancer patients treated with radical prostatectomy or radiotherapy

Purpose

We evaluated the biochemical recurrence (BCR) of prostate cancer patients treated by radical prostatectomy (RP) or radiotherapy (RT).

Materials and Methods

Patients who underwent RP or RT as primary definitive treatment from 2007 were enrolled for this study. They were divided into two groups; the low-intermediate risk group and the high risk group according to the National Comprehensive Cancer Network guidelines. We compared differences such as age, prostate specific antigen, Gleason score, follow-up duration, clinical T staging, and BCR. Their BCR-free survival rates were analyzed.

Results

A total of 165 patients were enrolled. There were 115 patients in the low-intermediate risk. Among them, 88 received RP and 27 underwent RT. BCR occurred in 9 of the RP patients (10.2%) and 3 of the RT patients (11.1%). For the high risk group, 50 patients were included. RP was performed in 25 patients and RT in 25 patients. BCR was observed in 4 of the RP patients (16%) and 12 of the RT patients (48%). There were no differences in BCR-free survival for the low-intermediate group (p=0.765). For the high risk group, the RP group had a higher BCR free survival rate (p=0.032).

Conclusions

No difference of BCR and BCR-free survival was seen in the low-intermediate risk group but lower BCR and better BCR-free survival were observed for patients that received RP in the high risk group. RP should be a more strongly considered option when deciding the treatment method for selected high risk patients.

PEG spacer gel and adaptive planning vs single plan in external prostate radiotherapy--clinical dosimetry evaluation

OBJECTIVE

Spacer gel is used to reduce the rectal dose in prostate radiotherapy. It is injected to increase the distance between the prostate and rectum. During the course of external radiotherapy treatment, physiological changes in rectal volume exist. When using polyethylene glycol material, such as DuraSeal(®) (Covidien, Mansfield, MA), gel resorption also occurs. Together, these factors alter the original dose plan distribution.

METHODS

External dose planning and calculations were simulated using images acquired from 10 patients who were treated with brachytherapy and gel. The CT series was taken relative to gel injection: pre 1 day, post 1 day, post 1 month and post 2 months. Adaptive planning was compared with a single plan.

RESULTS

Adaptive planning shows better results compared with the single plan used in the total treatment course; however, the effect is minor.

CONCLUSION

Gel usage is clearly favourable to rectal DVH. Using adaptive planning with gel improves rectal DVH but is not necessary according to this study.

ADVANCES IN KNOWLEDGE

Spacer gel is used in prostate radiotherapy to increase distance between the prostate and the rectum, thus reducing the rectal doses. During the treatment course, gel resorption exists which affects the rectal doses. The usefulness of adaptive planning to compensate this resorption effect has not been studied before.

Differences in practice patterns between urologists and radiation oncologists in the management of localized prostate cancer: a cross-sectional survey

INTRODUCTION

Through a cross-sectional survey, we tried to assess whether practices of urologists and radiation oncologists are uniform when faced with similar clinical situations.

MATERIALS AND METHODS

A self-administered questionnaire was mailed to all French urologists and radiation oncologists. Respondents were asked about their practices through 11 case scenarios. The scenarios cover most of localized prostate cancer situations and were gradually organized depending on prostate cancer progression risk and the age of the patient. The eight first scenarios address the situation of treatment-naive patients, and the last cases were about the management of patients after radical prostatectomy. Physicians were asked to choose a treatment modality for each case. The responses were first stratified according to the intention to treat: either curative-intent treatment or palliative. The curative-treatment modality chosen were afterward assessed. The responses to clinical scenarios were compared between the two specialties.

RESULTS

Concerning the intention to treat, practice patterns were overall consistent except in one case. Indeed, a higher rate of radiation oncologists prefer curative-intent treatment for intermediate-risk prostate cancer in aged patients: 57.4 versus 14.6 % (p < 0.001). Each medical specialist prefers the treatment that he himself delivers (p < 0.005). For intermediate-risk prostate cancer in 65-year-old patient: 96.5 % of urologists chose radical prostatectomy versus 37.7 % of radiation oncologists (p < 0.001). Fewer urologists (almost 14 %) compared to radiation oncologists (47.5 %) would prescribe adjuvant treatment after radical prostatectomy for T3a R0 prostate cancer with post-operative PSA undetectable (p < 0.001).

CONCLUSION

Significant differences were found in therapeutic approach between the two main specialties that deal with localized prostate cancer.

Clinical and biochemical outcomes of men undergoing radical prostatectomy or radiation therapy for localized prostate cancer

Purpose

We analyzed outcomes of patients with prostate cancer undergoing either radical retropubic prostatectomy (RRP) +/- salvage radiation or definitive radiation therapy (RT) +/- androgen deprivation.

Materials and Methods

From 2003-2010 there were 251 patients who underwent RRP and 469 patients who received RT (≥7,560 cGy) for prostate cancer. Kaplan-Meier analysis was performed with the log-rank test to compare biochemical control (bCR), distant metastatic-free survival (DMPFS), and prostate cancer-specific survival (PCSS) between the two groups.

Results

The median follow-up was 70 months and 61.3% of the men were African American. For low risk disease the 6-year bCR were 90.3% for RT and 85.6% for RRP (p = 0.23) and the 6-year post-salvage bCR were 90.3% vs. 90.9%, respectively (p = 0.84). For intermediate risk disease the 6-year bCR were 82.6% for RT and 59.7% for RRP (p < 0.001) and 82.6% vs. 74.0%, respectively, after including those salvaged with RT (p = 0.06). For high risk disease, the 6-year bCR were 67.4% for RT and 41.3% for RRP (p < 0.001) and after including those salvaged with RT was 67.4% vs. 43.1%, respectively (p < 0.001). However, there were no significant differences between the two groups in regards to DMPFS or PCSS.

Conclusion

Treatment approaches utilizing RRP +/- salvage radiation or RT +/- androgen deprivation yielded equivalent DMPFS and PCSS outcomes. Biochemical control rates, using their respective definitions, appeared equivalent or better in those who received treatment with RT.

AR function in promoting metastatic prostate cancer

Prostate cancer (PCa) remains a leading cause of cancer-related death in the USA. While localized lesions are effectively treated through radical prostatectomy and/or radiation therapy, treatment for metastatic disease leverages the addiction of these tumors on the androgen receptor (AR) signaling axis for growth and disease progression. Though initially effective, tumors resistant to AR-directed therapeutics ultimately arise (a stage of the disease known as castration-resistant prostate cancer) and are responsible for PCa-specific mortality. Importantly, an abundance of clinical and preclinical evidence strongly implicates AR signaling cascades in the development of metastatic disease in both early and late stages, and thus a concerted effort has been made to delineate the AR-specific programs that facilitate progression to metastatic PCa. A multitude of downstream AR targets as well as critical AR cofactors have been identified which impinge upon both the AR pathway as well as associated metastatic phenotypes. This review will highlight the functional significance of these pathways to disseminated disease and define the molecular underpinnings behind these unique, AR-driven, metastatic signatures.

Brachytherapy improves biochemical failure-free survival in low- and intermediate-risk prostate cancer compared with conventionally fractionated external beam radiation therapy: a propensity score matched analysis

PURPOSE

To compare, in a retrospective study, biochemical failure-free survival (bFFS) and overall survival (OS) in low-risk and intermediate-risk prostate cancer patients who received brachytherapy (BT) (either low-dose-rate brachytherapy [LDR-BT] or high-dose-rate brachytherapy with external beam radiation therapy [HDR-BT+EBRT]) versus external beam radiation therapy (EBRT) alone.

METHODS AND MATERIALS

Patient data were obtained from the ProCaRS database, which contains 7974 prostate cancer patients treated with primary radiation therapy at four Canadian cancer institutions from 1994 to 2010. Propensity score matching was used to obtain the following 3 matched cohorts with balanced baseline prognostic factors: (1) low-risk LDR-BT versus EBRT; (2) intermediate-risk LDR-BT versus EBRT; and (3) intermediate-risk HDR-BT+EBRT versus EBRT. Kaplan-Meier survival analysis was performed to compare differences in bFFS (primary endpoint) and OS in the 3 matched groups.

RESULTS

Propensity score matching created acceptable balance in the baseline prognostic factors in all matches. Final matches included 2 1:1 matches in the intermediate-risk cohorts, LDR-BT versus EBRT (total n=254) and HDR-BT+EBRT versus EBRT (total n=388), and one 4:1 match in the low-risk cohort (LDR-BT:EBRT, total n=400). Median follow-up ranged from 2.7 to 7.3 years for the 3 matched cohorts. Kaplan-Meier survival analysis showed that all BT treatment options were associated with statistically significant improvements in bFFS when compared with EBRT in all cohorts (intermediate-risk EBRT vs LDR-BT hazard ratio [HR] 4.58, P=.001; intermediate-risk EBRT vs HDR-BT+EBRT HR 2.08, P=.007; low-risk EBRT vs LDR-BT HR 2.90, P=.004). No significant difference in OS was found in all comparisons (intermediate-risk EBRT vs LDR-BT HR 1.27, P=.687; intermediate-risk EBRT vs HDR-BT+EBRT HR 1.55, P=.470; low-risk LDR-BT vs EBRT HR 1.41, P=.500).

CONCLUSIONS

Propensity score matched analysis showed that BT options led to statistically significant improvements in bFFS in low- and intermediate-risk prostate cancer patient populations.

Low-dose rate brachytherapy for patients with low- or intermediate-risk prostate cancer: A systematic review

INTRODUCTION

We review the current evidence for the role of low-dose rate brachytherapy (PB) in patients with low- or intermediate-risk prostate cancer using a systematic review of the literature.

METHODS

We searched MEDLINE and EMBASE (from January 1996 to October 2011), the Cochrane Library, relevant guideline web-sites, and websites for meetings specific for genitourinary diseases.

RESULTS

Ten systematic reviews and 55 single-study papers met the pre-planned study selection criteria. In the end, 36 articles were abstracted and analyzed for this systematic review. There is no evidence for a difference in efficacy between PB and external beam radiation therapy (EBRT), or between PB and radical prostatectomy (RP). During the 6 months to 3 years after treatment, PB was associated with less urinary incontinence and sexual impotency than RP, and RP was associated with less urinary irritation and rectal morbidity than PB. However, these differences diminished over time. PB conferred less risk of impotency and rectal morbidity in the three years after treatment than EBRT. Iodine-125 and alladium-103 did not differ with respect to biochemical relapse-free survival and patient-reported outcomes.

CONCLUSIONS

PB alone is a treatment option with equal efficacy to EBRT or RP alone in patients with newly diagnosed low- or intermediate-risk prostate cancer who require or choose active treatment.

A hormone-DNA repair circuit governs the response to genotoxic insult

Alterations in DNA repair promote tumor development, but the impact on tumor progression is poorly understood. Here, discovery of a biochemical circuit linking hormone signaling to DNA repair and therapeutic resistance is reported. Findings show that androgen receptor (AR) activity is induced by DNA damage and promotes expression and activation of a gene expression program governing DNA repair. Subsequent investigation revealed that activated AR promotes resolution of double-strand breaks and resistance to DNA damage both in vitro and in vivo. Mechanistically, DNA-dependent protein kinase catalytic subunit (DNAPKcs) was identified as a key target of AR after damage, controlling AR-mediated DNA repair and cell survival after genotoxic insult. Finally, DNAPKcs was shown to potentiate AR function, consistent with a dual role in both DNA repair and transcriptional regulation. Combined, these studies identify the AR-DNAPKcs circuit as a major effector of DNA repair and therapeutic resistance and establish a new node for therapeutic intervention in advanced disease.

SIGNIFICANCE

The present study identifies for the fi rst time a positive feedback circuit linking hormone action to the DNA damage response and shows the significant impact of this process on tumor progression and therapeutic response. These provocative findings provide the foundation for development of novel nodes of therapeutic intervention for advanced disease.

[Comparative study of radical prostatectomy versus external beam radiotherapy (75.6 Gy) combined with hormone therapy for prostate cancer of intermediate D'Amico risk classification]

INTRODUCTION

Thirty-three percent of the localized cancers belongs initially to the group of intermediate risk of D'Amico. The standard treatments validated by the French Association of Urology are the radical prostatectomy and the external beam radiotherapy.

OBJECTIVES

We retrospectively compared the carcinologic results of the radical prostatectomy±adjuvant treatment (RP) and the external beam radiotherapy combining high dose (75.6 Gy) and short hormonotherapy (RH), in the treatment of intermediate risk prostate cancer. The series consisted of 143 patients treated between 2000 and 2006 in the department of Urology and Kidney transplantation of the Conception Hospital, Marseilles. The main assessment criteria was the survival without biological recurrence (SBR).

RESULTS

The median follow-up was 90 months [59-51]. The 5 years and 8 years SBR were 85% and 73% in the RH group, versus 74% and 65% with RP (P=0.196). There was a significant difference between the series: on the age of diagnosis (63.9 versus 73.3 years, P<0.001), the Charlson score of comorbidity (2 versus 3, P<0.001) and the number of intermediate criteria per patients (one intermediate criteria: RP 74% versus 57%, P<0.01).

CONCLUSION

According to our study, there was no superiority of the radical prostatectomy±adjuvant treatment or the external radiotherapy combining high dose and concomitant short hormonotherapy on the survival without biological recurrence at 5 and 8 years. Many studies confirm that a concomitant hormonotherapy increases the carcinologic control, even with a high rate external beam radiotherapy.

Upregulation of miR-96 enhances cellular proliferation of prostate cancer cells through FOXO1

Aberrant expression of miR-96 in prostate cancer has previously been reported. However, the role and mechanism of action of miR-96 in prostate cancer has not been determined. In this study, the diagnostic and prognostic properties of miR-96 expression levels were investigated by qRT-PCR in two well documented prostate cancer cohorts. The miR-96 expression was found to be significantly higher in prostate cancer patients and correlate with WHO grade, and decreased overall survival time; patients with low levels of miR-96 lived 1.5 years longer than patients with high miR-96 levels. The therapeutic potential was further investigated in vitro, showing that ectopic levels of miR-96 enhances growth and cellular proliferation in prostate cancer cells, implying that miR-96 has oncogenic properties in this setting. We demonstrate that miR-96 expression decreases the transcript and protein levels of FOXO1 by binding to one of two predicted binding sites in the FOXO1 3'UTR sequence. Blocking this binding site completely inhibited the growth enhancement conveyed by miR-96. This finding was corroborated in a large external prostate cancer patient cohort where miR-96 expression inversely correlated to FOXO1 expression. Taken together these findings indicate that miR-96 plays a key role in prostate cancer cellular proliferation and can enhance prostate cancer progression. This knowledge might be utilized for the development of novel therapeutic tools for prostate cancer.

Evidence-based guideline recommendations on low-dose rate brachytherapy in patients with low- or intermediate-risk prostate cancer

OBJECTIVE

The Genitourinary Cancer Disease Site Group (GU DSG) and Cancer Care Ontario's Program in Evidence-Based Care (PEBC) in Ontario, Canada developed a guideline on low-dose rate brachytherapy (LDR-BT) in patients with early-stage low-grade prostate cancer in 2001. The current updated guideline focuses on the research questions regarding the effect of LDR-BT alone, the effect of LDR-BT with external beam radiation therapy (EBRT) and the selection of an isotope.

METHODS

This guideline was developed by using the methods of the Practice Guidelines Development Cycle and the core methodology was a systematic review. MEDLINE and EMBASE (from January 1996 to October 2011), the Cochrane Library, main guideline websites, and main annual meeting abstract websites specific for genitourinary diseases were searched. Internal and external reviews of the draft guideline were conducted.

RESULTS

The draft guideline was developed according to a total of 10 systematic reviews and 55 full text articles that met the pre-planned study selection criteria. The quality of evidence was low to moderate. The final report reflects integration of the feedback obtained through the internal review (two oncologists and a methodologist) and external review (five target reviewers and 48 professional consultation reviewers) process, with final approval given by the GU DSG and the PEBC.

CONCLUSION

THE MAIN RECOMMENDATIONS ARE: (1) For patients with newly diagnosed low-risk or intermediate-risk prostate cancer who require or choose active treatment, LDR-BT alone is a treatment option as an alternative to EBRT alone or RP alone; and (2) I-125 and Pd-103 are each reasonable isotope options.

Impact of experience and technical changes on acute urinary and rectal morbidity in low-dose prostate brachytherapy using loose seeds real-time implantation

PURPOSE

To assess the impact of experience and technical changes on morbidity during the first year after permanent prostate brachytherapy.

METHODS AND MATERIALS

From July 2003 to May 2010, 150 patients with prostate cancer underwent low-dose iodine-125 prostate brachytherapy as a monotherapy by the same medical team (one urologist and one radiation oncologist). Patients were divided into three periods: P1 (n = 64), P2 (n = 45), and P3 (n = 41) according to technical changes: use of an automatic stepper from P2, use of a high-frequency ultrasound probe in P3. Urinary toxicity was analyzed according to the incidence of acute urinary retention (AUR), Delta International Prostate Symptom Score (Δ IPSS) defined as IPPS maximal - IPSS at baseline, and proportion of patients with Δ IPSS ≥5 and IPSS total >15. The Radiation Therapy Oncology Group classification was used to evaluate the rectal morbidity.

RESULTS

The incidence of AUR (6% overall) decreased significantly with time: 12.5% (8/64) during P1, 2.2% (1/45) in P2, and 0% in P3 (p = 0.014). Mean Δ IPSS (11.6) remained stable during the three periods. Patients with Δ IPSS ≥5 and IPSS total >15 were 58.7%, 58.1%, and 56.1% for P1, P2, and P3 (p = 0.96), respectively. Grade 1 and 2 proctitis were observed in 15.3% and 9.3% of the patients without any significant difference between the three periods.

CONCLUSION

The incidence of AUR decreased significantly with time. This was probably because of the experience of the practitioner and the use of an automatic stepper that allowed reducing prostatic traumatism. Experience and technical changes did not seem to affect rectal morbidity.

RhoA as a mediator of clinically relevant androgen action in prostate cancer cells

Recently, we have identified serum response factor (SRF) as a mediator of clinically relevant androgen receptor (AR) action in prostate cancer (PCa). Genes that rely on SRF for androgen responsiveness represent a small fraction of androgen-regulated genes, but distinguish benign from malignant prostate, correlate with aggressive disease, and are associated with biochemical recurrence. Thus, understanding the mechanism(s) by which SRF conveys androgen regulation to its target genes may provide novel opportunities to target clinically relevant androgen signaling. Here, we show that the small GTPase ras homolog family member A (RhoA) mediates androgen-responsiveness of more than half of SRF target genes. Interference with expression of RhoA, activity of the RhoA effector Rho-associated coiled-coil containing protein kinase 1 (ROCK), and actin polymerization necessary for nuclear translocation of the SRF cofactor megakaryocytic acute leukemia (MAL) prevented full androgen regulation of SRF target genes. Androgen treatment induced RhoA activation, increased the nuclear content of MAL, and led to MAL recruitment to the promoter of the SRF target gene FHL2. In clinical specimens RhoA expression was higher in PCa cells than benign prostate cells, and elevated RhoA expression levels were associated with aggressive disease features and decreased disease-free survival after radical prostatectomy. Overexpression of RhoA markedly increased the androgen-responsiveness of select SRF target genes, in a manner that depends on its GTPase activity. The use of isogenic cell lines and a xenograft model that mimics the transition from androgen-stimulated to castration-recurrent PCa indicated that RhoA levels are not altered during disease progression, suggesting that RhoA expression levels in the primary tumor determine disease aggressiveness. Androgen-responsiveness of SRF target genes in castration-recurrent PCa cells continued to rely on AR, RhoA, SRF, and MAL and the presence of intact SRF binding sites. Silencing of RhoA, use of Rho-associated coiled-coil containing protein kinase 1 inhibitors, or an inhibitor of SRF-MAL interaction attenuated (androgen-regulated) cell viability and blunted PCa cell migration. Taken together, these studies demonstrate that the RhoA signaling axis mediates clinically relevant AR action in PCa.

mTOR is a selective effector of the radiation therapy response in androgen receptor-positive prostate cancer

Ionizing radiation (IR) is used frequently in the management of multiple tumor types, including both organ-confined and locally advanced prostate cancer (PCa). Enhancing tumor radiosensitivity could both reduce the amount of radiation required for definitive treatment and improve clinical outcome. Androgen suppression therapy improves clinical outcomes when combined with radiation therapy but is associated with significant acute and chronic toxicities; hence, there is a clear need for alternative means to increase the therapeutic window of radiotherapy. Herein, it is demonstrated that the mammalian target of rapamycin (mTOR) inhibitors rapamycin (sirolimus) and temsirolimus limit both hormone therapy (HT)-sensitive and castration-resistant PCa (CRPC) cell proliferation as single agents and have a profound radiosensitization effect when used in combination with IR. Importantly, the observed radiosensitization was influenced by the treatment schedule, in which adjuvant administration of mTOR inhibitors was most effective in limiting PCa cell population doubling. This schedule-dependent influence on in vitro treatment outcome was determined to be the result of relative effects on the cell cycle kinetics. Finally, adjuvant administration of either mTOR inhibitor tested after IR significantly decreased clonogenic cell survival of both HT-sensitive and CRPC cells compared with IR alone. Taken together, these data demonstrate that inhibition of mTOR confers a radiosensitization phenotype that is dependent on relative cell cycle kinetics and provide a foundation for clinical assessment.

A critical analysis of the long-term impact of radical prostatectomy on cancer control and function outcomes

CONTEXT

The optimal management strategy for men with newly diagnosed clinically localized prostate cancer remains a matter of debate. Numerous series have reported cancer control and quality-of-life (QoL) outcomes following treatment with radical prostatectomy (RP).

OBJECTIVE

Critically review published oncologic and functional outcomes after RP, and evaluate factors associated with these outcome measures.

EVIDENCE ACQUISITION

A review of the literature was performed using the Medline and Web of Sciences databases. Relevant reports published between 1980 and 2011 identified using the keywords prostate cancer, radical prostatectomy, prostate-specific antigen, biochemical recurrence, incontinence, and erectile dysfunction were reviewed and summarized.

EVIDENCE SYNTHESIS

Cancer control rates following RP largely depend on the definition of treatment efficacy. While up to 40% of men have been reported to experience postoperative biochemical recurrence on long-term follow-up, death from prostate cancer has been noted in <10% of men at 15 yr after surgery in contemporary series. For men with high-risk disease, surgery affords pathologic staging, thereby facilitating the selective application of secondary therapies, and has been associated with decreased mortality risk versus radiation in retrospective series. Reported functional outcomes after surgery, particularly urinary continence and erectile dysfunction, have varied greatly to date. These assessments have been limited by nonstandardized reporting methodology. The use of robot-assisted radical prostatectomy has increased in recent years, and while follow-up is thus far short, available data do not suggest the superiority of either approach in terms of functional or oncologic outcomes.

CONCLUSIONS

RP is associated with excellent long-term cancer control. Continued efforts to conduct prospective assessments of postoperative functional outcomes are necessary using validated QoL instruments. The importance of surgical approach will also require further study, incorporating comparative oncologic, functional, and economic data.

High dose brachytherapy as monotherapy for intermediate risk prostate cancer

PURPOSE

We evaluated our retrospective, single institution experience with high dose rate brachytherapy as monotherapy for intermediate risk prostate cancer.

MATERIALS AND METHODS

Our cohort included 284 patients with intermediate risk prostate cancer, defined as clinical stage T2b/T2c, Gleason score 7 and/or prostate specific antigen 10 to 20 ng/ml, and 1-year minimum followup. Treatment was 2 high dose rate brachytherapy sessions at 3 fractions of 6.5 Gy each for a mean of 19 days. Prostate specific antigen failure was defined as nadir +2 ng/ml.

RESULTS

Mean followup was 35.1 months (median 31.9). Actuarial 5-year cause specific survival and clinical local control were 100%, distant-metastasis-free survival 98.8% and biochemical disease-free survival 94.4%. Clinical stage predicted biochemical disease-free survival. For stage T2a or less 5-year biochemical disease-free survival was 95.1% vs 100% for stage T2b and 77.4% for T2c (p = 0.012). Percent positive biopsy cores and prostate specific antigen nadir were also predictive. International Prostate Symptom Score results remained stable and potency was maintained in 82.6% of patients at 2 years. Pads were used for the first time after brachytherapy in 22 patients (7.7%), mostly for grade 1 incontinence (occasionally or less per week). Excluding patients with prior transurethral prostatectomy, stroke or tremor 2.5% used pads for the first time after treatment. No patient had urethral stricture. Radiation Therapy Oncology Group grade 1 rectal toxicity developed in 12 patients (4.2%) but not beyond grade 1.

CONCLUSIONS

High dose rate brachytherapy as monotherapy is safe and effective for patients with intermediate risk prostate cancer. We recommend caution for percent positive biopsy cores exceeding 75% or clinical stage T2c. Excluding such patients the 5-year biochemical disease-free survival rate was 97.5%.

Androgen receptor signaling in prostate cancer development and progression

The androgen receptor (AR) signaling axis plays a critical role in the development, function and homeostasis of the prostate. The classical action of AR is to regulate gene transcriptional processes via AR nuclear translocation, binding to androgen response elements on target genes and recruitment of, or crosstalk with, transcription factors. Prostate cancer initiation and progression is also uniquely dependent on AR. Androgen deprivation therapy remains the standard of care for treatment of advanced prostate cancer. Despite an initial favorable response, almost all patients invariably progress to a more aggressive, castrate-resistant phenotype. Considerable evidence now supports the concept that development of castrate-resistant prostate cancer (CRPC) is causally related to continued transactivation of AR. Understanding the critical events and complexities of AR signaling in the progression to CRPC is essential in developing successful future therapies. This review provides a synopsis of AR structure and signaling in prostate cancer progression, with a special focus on recent findings on the role of AR in CRPC. Clinical implications of these findings and potential directions for future research are also outlined.

Comparison of tumor control and toxicity outcomes of high-dose intensity-modulated radiotherapy and brachytherapy for patients with favorable risk prostate cancer

OBJECTIVES

To compare the long-term, prostate-specific antigen relapse-free survival outcome and incidence of toxicity for patients with low-risk prostate cancer who underwent brachytherapy or intensity-modulated radiotherapy (RT).

METHODS

A total of 729 consecutive patients underwent brachytherapy (n = 448; prescription dose 144 Gy) or intensity-modulated RT alone (n = 281; prescription dose 81 Gy). The prostate-specific antigen relapse-free survival using the nadir plus 2 ng/mL definition and late toxicity using the National Cancer Institute's Common Terminology Criteria for Adverse Events were determined.

RESULTS

The 7-year prostate-specific antigen relapse-free survival rate for the brachytherapy and intensity-modulated RT groups was 95% and 89% for low-risk patients, respectively (P = .004). Cox regression analysis demonstrated that brachytherapy was associated with improved prostate-specific antigen relapse-free survival, even after adjustment for other variables. The incidence of metastatic disease between treatment sessions was low for both treatment groups. Late grade 2 gastrointestinal toxicity was observed in 5.1% and 1.4% of the brachytherapy and intensity-modulated RT groups, respectively (P = .02). No significant differences were seen between treatment groups for late grade 3 or greater rectal complications (brachytherapy 1.1% and intensity-modulated RT 0%; P = .19). Late grade 2 urinary toxicity occurred more often in the brachytherapy group than in the intensity-modulated RT group (15.6% and 4.3%, respectively; P < .0001). No significant differences were seen between the 2 treatment groups for late grade 3 urinary toxicity (brachytherapy 2.2% and intensity-modulated RT 1.4%; P = .62).

CONCLUSIONS

Among low-risk prostate cancer patients, the 7-year biochemical tumor control was superior for intraoperatively planned brachytherapy compared with high-dose intensity-modulated RT. Although significant toxicities were minimal for both groups, modest, but significant, increases in grade 2 urinary and rectal symptoms were noted for brachytherapy compared with intensity-modulated RT.

Identification of a clinically relevant androgen-dependent gene signature in prostate cancer

The androgen receptor (AR) is the principal target for treatment of non-organ-confined prostate cancer (PCa). Androgen deprivation therapies (ADT) directed against the AR ligand-binding domain do not fully inhibit androgen-dependent signaling critical for PCa progression. Thus, information that could direct the development of more effective ADTs is desired. Systems and bioinformatics approaches suggest that considerable variation exists in the mechanisms by which AR regulates expression of effector genes, pointing to a role for secondary transcription factors. A combination of microarray and in silico analyses led us to identify a 158-gene signature that relies on AR along with the transcription factor SRF (serum response factor), representing less than 6% of androgen-dependent genes. This AR-SRF signature is sufficient to distinguish microdissected benign and malignant prostate samples, and it correlates with the presence of aggressive disease and poor outcome. The AR-SRF signature described here associates more strongly with biochemical failure than other AR target gene signatures of similar size. Furthermore, it is enriched in malignant versus benign prostate tissues, compared with other signatures. To our knowledge, this profile represents the first demonstration of a distinct mechanism of androgen action with clinical relevance in PCa, offering a possible rationale to develop novel and more effective forms of ADT.

Long-term survival after radical prostatectomy versus external-beam radiotherapy for patients with high-risk prostate cancer

BACKGROUND

The long-term survival of patients with high-risk prostate cancer was compared after radical prostatectomy (RRP) and after external beam radiation therapy (EBRT) with or without adjuvant androgen-deprivation therapy (ADT).

METHODS

In total, 1238 patients underwent RRP, and 609 patients received with EBRT (344 received EBRT plus ADT, and 265 received EBRT alone) between 1988 and 2004 who had a pretreatment prostate-specific antigen (PSA) level ≥ 20 ng/mL, a biopsy Gleason score between 8 and 10, or clinical tumor classification ≥ T3. The median follow-up was 10.2 years, 6.0 years, and 7.2 years after RRP, EBRT plus ADT, and EBRT alone, respectively. The impact of treatment modality on systemic progression, cancer-specific survival, and overall survival was evaluated using multivariate Cox proportional hazard regression analysis and a competing risk-regression model.

RESULTS

The 10-year cancer-specific survival rate was 92%, 92%, and 88% after RRP, EBRT plus ADT, and EBRT alone, respectively (P = .06). After adjustment for case mix, no significant differences in the risks of systemic progression (hazard ratio [HR], 0.78; 95% confidence interval [CI], 0.51-1.18; P = .23) or prostate cancer death (HR, 1.14; 95% CI, 0.68-1.91; P = .61) were observed between patients who received EBRT plus ADT and patients who underwent RRP. The risk of all-cause mortality, however, was greater after EBRT plus ADT than after RRP (HR, 1.60; 95% CI, 1.25-2.05; P = .0002).

CONCLUSIONS

RRP alone and EBRT plus ADT provided similar long-term cancer control for patients with high-risk prostate cancer. The authors concluded that continued investigation into the differing impact of treatments on quality-of-life and noncancer mortality will be necessary to determine the optimal management approach for these patients.

Partners in crime: deregulation of AR activity and androgen synthesis in prostate cancer

Prostate cancer remains a leading cause of cancer death, as there are no durable means to treat advanced disease. Treatment of non-organ-confined prostate cancer hinges on its androgen dependence. First-line therapeutic strategies suppress androgen receptor (AR) activity, via androgen ablation and direct AR antagonists, whereas initially effective, incurable, 'castration-resistant' tumors arise as a result of resurgent AR activity. Alterations of AR and/or associated regulatory networks are known to restore receptor activity and support resultant therapy-resistant tumor progression. However, recent evidence also reveals an unexpected contribution of the AR ligand, indicating that alterations in pathways controlling androgen synthesis support castration-resistant AR activity. In this report, the mechanisms underlying the lethal pairing of AR deregulation and aberrant androgen synthesis in prostate cancer progression will be discussed.

Five year biochemical recurrence free survival for intermediate risk prostate cancer after radical prostatectomy, external beam radiation therapy or permanent seed implantation

OBJECTIVE

To compare biochemical recurrence-free survival (bRFS) for patients with intermediate-risk prostate cancer treated by retropubic radical prostatectomy (RRP), laparoscopic radical prostatectomy (LRP), external beam radiation therapy (RT), or permanent seed implantation (PI).

METHODS

Patients treated for intermediate-risk prostate cancer per National Comprehensive Cancer Network guidelines from 1996 to 2005 were studied. Variables potentially affecting bRFS were examined using univariate and multivariate Cox regression analysis. Five-year bRFS rates were calculated by actuarial methods; bRFS was calculated using Kaplan-Meier analysis. Nadir +2 definition of biochemical failure was used for RT and PI patients; a PSA ≥ 0.4 ng/mL was used for radical prostatectomy (RP) patients. Time to initiation of salvage therapy was compared for each treatment group using the Kruskal-Wallis test.

RESULTS

Nine-hundred seventy-nine patients were analyzed with a median follow-up of 65 months. Five years bRFS rate was 82.8% for all patients (89.5% PI, 85.7% RT, 79.9% RRP, and 60.2% LRP). Patients treated by LRP had significantly worse bRFS than RT (P < .0001), PI (P < .0001), or RRP patients (P = .0038). Treatment modality (P < .0001) and average number of PSA tests per year (P < .0001) were the only independent predictors of bRFS on multivariate analysis. Median time to initiation of salvage therapy from time of treatment was 28.6 months for all patients (26.1 RP, 21.0 LRP, 47.4 PI, 47.8 RT; P < .0001).

CONCLUSIONS

Patients with intermediate-risk prostate cancer choosing PI, RT, or RRP appear to have improved 5-year bRFS and delayed salvage therapy compared with LRP.

Starving the addiction: new opportunities for durable suppression of AR signaling in prostate cancer

Clinical data and models of human disease indicate that androgen receptor (AR) activity is essential for prostate cancer development, growth, and progression. The dependence of prostatic adenocarcinoma on AR signaling at all stages of disease has thereby been exploited in the treatment of disseminated tumors, for which ablation of AR function is the goal of first-line therapy. Although these strategies are initially effective, recurrent tumors arise with restored AR activity, and no durable treatment has yet been identified to combat this stage of disease. New insights into AR regulation and the mechanisms underlying resurgent AR activity have provided fertile ground for the development of novel strategies to more effectively inhibit receptor activity and prolong the transition to therapeutic failure.

2-methoxyestradiol Prevents LNCaP Tumor Development in Nude Mice: Potential Role of G2/M Regulatory Proteins

Nontoxic naturally occurring metabolite of estrogen namely 2-methoxyestradial (2ME₂) found in serum and urine has been shown to be antitumorigenic in various tumor models including the prostate. A recent study conducted in breast cancer cells showed growth stimulatory effect of 2ME₂ when used at low concentrations (10–750 nM). Studies from our laboratory has demonstrated prostate tumor preventive ability of 50 mg/kg 2-ME₂. In this study we show that concentrations of 2-ME₂ as low as 1 µM is sufficient to inhibit proliferation and induce apoptosis in androgen responsive LNCaP cells. In addition oral administration of doses lower than 50 mg/kg prevented prostate tumor development in LNCaP xenograft model. The observed tumor growth inhibition was associated with induction of apoptosis, increased expression of Wee1 kinase and p34cdc2. In addition administration of 25 mg/kg 2-ME₂ prevented tumor development significantly that is associated with reduction in serum PSA levels.