Early versus delayed hormonal therapy for prostate specific antigen only recurrence of prostate cancer after radical prostatectomy

Time without PSA recurrence after radical prostatectomy as a predictor of future biochemical recurrence, metastatic disease and prostate cancer death: a prospective Scandinavian cohort study

OBJECTIVE

Although surveillance after radical prostatectomy routinely includes repeated prostate specific antigen (PSA)-testing for many years, biochemical recurrence often occurs without further clinical progression. We therefore hypothesised that follow-up can be shortened for many patients without increasing the risk of prostate cancer death. We investigated the long-term probabilities of PSA recurrence, metastases and prostate cancer death in patients without biochemical recurrence five and 10 years after radical prostatectomy.

DESIGN

Prospective cohort study. Stratification by Gleason score (≤3+4=7 or ≥4+3=7), pathological tumour stage (pT2 or ≥pT3) and negative or positive surgical margins.

SETTING

Between 1989 and 1998, 14 urological centres in Scandinavia randomised patients to the Scandinavian Prostate Cancer Group study number 4 (SPCG-4) trial.

PARTICIPATION

All 306 patients from the SPCG-4 trial who underwent radical prostatectomy within 1 year from inclusion were eligible. Four patients were excluded due to surgery-related death (n=1) or salvage radiotherapy or hormonal treatment within 6 weeks from surgery (n=3).

PRIMARY OUTCOME MEASURES

Cumulative incidences and absolute differences in metastatic disease and prostate cancer death.

RESULTS

We analysed 302 patients with complete follow-up during a median of 24 years. Median preoperative PSA was 9.8 ng/mL and median age was 65 years. For patients without biochemical recurrence 5 years after radical prostatectomy the 20-year probability of biochemical recurrence was 25% among men with Gleason score ≤3+4=7 and 57% among men with Gleason score ≥4+3=7; the probabilities for metastases were 0.8% and 17%; and for prostate cancer death 0.8% and 12%, respectively. The long-term probabilities were higher for pT ≥3 versus pT2 and for positive versus negative surgical margins. Limitations include small size of the cohort.

CONCLUSION

Many patients with favourable histopathology without biochemical recurrence 5 years after radical prostatectomy could stop follow-up earlier than 10 years after radical prostatectomy.

Development of machine learning classifiers to predict compound activity on prostate cancer cell lines

Prostate cancer is the most common type of cancer in men. The disease presents good survival rates if treated at the early stages. However, the evolution of the disease in its most aggressive variant remains without effective therapeutic answers. Therefore, the identification of novel effective therapeutics is urgently needed. On these premises, we developed a series of machine learning models, based on compounds with reported highly homogeneous cell-based antiproliferative assay data, able to predict the activity of ligands towards the PC-3 and DU-145 prostate cancer cell lines. The data employed in the development of the computational models was finely-tuned according to a series of thresholds for the classification of active/inactive compounds, to the number of features to be implemented, and by using 10 different machine learning algorithms. Models’ evaluation allowed us to identify the best combination of activity thresholds and ML algorithms for the classification of active compounds, achieving prediction performances with MCC values above 0.60 for PC-3 and DU-145 cells. Moreover, in silico models based on the combination of PC-3 and DU-145 data were also developed, demonstrating excellent precision performances. Finally, an analysis of the activity annotations reported for the ligands in the curated datasets were conducted, suggesting associations between cellular activity and biological targets that might be explored in the future for the design of more effective prostate cancer antiproliferative agents.

Post-prostatectomy adjuvant androgen deprivation therapy- Current opinions and practices of Canadian urologists

INTRODUCTION

Despite the proven benefit of adjuvant androgen deprivation therapy (ADT) for patients receiving primary radiation, there are few studies evaluating adjuvant ADT after prostatectomy. In the absence of evidence, opinions and practice patterns vary. We surveyed Canadian prostate cancer surgeons about their use of adjuvant ADT and their opinions on the design of a potential adjuvant ADT trial.

METHODS

An electronic survey was devised and distributed using a modified Dillman approach. The survey was sent to 38 Canadian urologists that perform radical prostatectomy and representing all 17 major academic institutions in Canada and all 10 Canadian provinces. Reminders were sent three and four weeks following the original request. In addition to demographic information, we asked surgeons about their current use of postoperative adjuvant ADT and their opinion about the need for a clinical trial. To inform trial design, we asked respondents their opinions about which patients should be eligible, what duration of ADT was most appropriate, and which outcomes are clinically meaningful. The survey was sent in February 2020 and all responses were received by March 2020.

RESULTS

All 38 (100%) invited urologists completed the survey. Only 3 (7%) respondents currently offer postoperative adjuvant ADT as an option for patients without metastases. 35 (92%) urologists believed that a trial is needed before short-term adjuvant treatment should be offered to prevent recurrence. 15 (45%) urologists believed an adjuvant ADT trial was most appropriate for patients with an estimated PSA recurrence risk of >25% and 16 (42%) believed a recurrence risk of >50% was most appropriate. 25 (66%) respondents believed 12-month was the optimal duration of treatment with adjuvant ADT for a randomized trial. 37 (97%) respondents felt that prolonging the time to PSA recurrence and/or pelvic radiation was a clinically important outcome. The majority (20; 53%) of respondents would recommend 12 months of adjuvant ADT in their practice if a randomized trial showed a 50% relative risk reduction in PSA recurrence at 5-year postoperative.

CONCLUSION

The vast majority of Canadian prostate cancer surgeons do not offer adjuvant ADT following prostatectomy in patients without metastases. Based on the results from this survey, a randomized trial was considered warranted and feasible, and would influence patient care.

Efficacy and safety of combined androgen blockade with antiandrogen for advanced prostate cancer

Background

Combined androgen blockade (cab) is a promising treatment modality for prostate cancer (pca). In the present meta-analysis, we compared the efficacy and safety of first-line cab using an antiandrogen (aa) with castration monotherapy in patients with advanced pca.

Methods

PubMed, embase, Cochrane, and Google Scholar were searched for randomized controlled trials (rcts) published through 12 December 2016. Hazard ratios (hrs) with 95% confidence intervals (cis) were determined for primary outcomes: overall survival (os) and progression-free survival (pfs). Subgroup analyses were performed for Western compared with Eastern patients and use of a nonsteroidal aa (nsaa) compared with a steroidal aa (saa).

Results

Compared with castration monotherapy, cab using an aa was associated with significantly improved os (n = 14; hr: 0.90; 95% ci: 0.84 to 0.97; p = 0.003) and pfs (n = 13; hr: 0.89; 95% ci: 0.80 to 1.00; p = 0.04). No significant difference in os (p = 0.71) and pfs (p = 0.49) was observed between the Western and Eastern patients. Compared with castration monotherapy, cab using a nsaa was associated with significantly improved os (hr: 0.88; 95% ci: 0.82 to 0.95; p = 0.0009) and pfs (hr: 0.85; 95% ci: 0.73 to 0.98; p = 0.007)-a result that was not achieved with cab using a saa. The safety profiles of cab and monotherapy were similar in terms of adverse events, including hot flushes, impotence, and grade 3 or 4 events, with the exception of risk of diarrhea and liver dysfunction or elevation in liver enzymes, which were statistically greater with cab using an aa.

Conclusions

Compared with castration monotherapy, first-line cab therapy with an aa, especially a nsaa, resulted in significantly improved os and pfs, and had an acceptable safety profile in patients with advanced pca.

First off-time treatment prostate-specific antigen kinetics predicts survival in intermittent androgen deprivation for prostate cancer

BACKGROUND

Prostate-specific antigen (PSA) doubling time is relying on an exponential kinetic pattern. This pattern has never been validated in the setting of intermittent androgen deprivation (IAD). Objective is to analyze the prognostic significance for PCa of recurrent patterns in PSA kinetics in patients undergoing IAD.

METHODS

A retrospective study was conducted on 377 patients treated with IAD. On-treatment period (ONTP) consisted of gonadotropin-releasing hormone agonist injections combined with oral androgen receptor antagonist. Off-treatment period (OFTP) began when PSA was lower than 4 ng/ml. ONTP resumed when PSA was higher than 20 ng/ml. PSA values of each OFTP were fitted with three basic patterns: exponential (PSA(t) = λ.e(αt)), linear (PSA(t) = a.t), and power law (PSA(t) = a.t(c)). Univariate and multivariate Cox regression model analyzed predictive factors for oncologic outcomes.

RESULTS

Only 45% of the analyzed OFTPs were exponential. Linear and power law PSA kinetics represented 7.5% and 7.7%, respectively. Remaining fraction of analyzed OFTPs (40%) exhibited complex kinetics. Exponential PSA kinetics during the first OFTP was significantly associated with worse oncologic outcome. The estimated 10-year cancer-specific survival (CSS) was 46% for exponential versus 80% for nonexponential PSA kinetics patterns. The corresponding 10-year probability of castration-resistant prostate cancer (CRPC) was 69% and 31% for the two patterns, respectively. Limitations include retrospective design and mixed indications for IAD.

CONCLUSION

PSA kinetic fitted with exponential pattern in approximately half of the OFTPs. First OFTP exponential PSA kinetic was associated with a shorter time to CRPC and worse CSS.

Management of patients with biochemical recurrence after local therapy for prostate cancer

Nearly three-quarters of a million American men who have been treated with prostatectomy and/or radiation therapy experience an increasing prostate-specific antigen level known as biochemical recurrence. Although androgen-deprivation therapy remains a reasonable option for some men with biochemical recurrence, deferring androgen ablation or offering nonhormonal therapies may be appropriate in patients in whom the risk of clinical or metastatic progression and prostate cancer-specific death is low. A risk-stratified approach informed by the patient's prostate-specific antigen kinetics, comorbidities, and personal preferences is recommended to determine the best management approach.

Current status of immunological approaches for the treatment of prostate cancer

PURPOSE OF REVIEW

The recent Food and Drug Administration approval of sipuleucel-T for metastatic castration-resistant prostate cancer and of the anticytotoxic T-lymphocyte antigen 4 antibody (Ipilimumab) for metastatic melanoma has led to a renewed interest in immunotherapy for prostate and other cancers. Ipilimumab has entered phase III testing for prostate cancer, as has a viral-based anti-prostate-specific antigen vaccine (ProstVac-VF). Complementing these phase III studies are a number of innovative phase II studies, aimed at bringing immunotherapy forward in the setting of less advanced disease, as well as a number of interesting trials combining immunotherapy with conventional therapy for prostate cancer.

RECENT FINDINGS

Although a number of immunotherapy trials have been initiated, few mature results are available at the current time. These data are likely to mature in the setting of an increasingly complex treatment paradigm in which multiple hormonal and novel agents are available.

SUMMARY

Immunotherapy for prostate cancer represents an attractive treatment approach, with the currently available agent sipuleucel-T providing a significant survival benefit without appreciable toxicity. Novel approaches to improve the efficacy of this and other immune-active agents are currently under evaluation.

Individualized decision-making for older men with prostate cancer: balancing cancer control with treatment consequences across the clinical spectrum

Prostate cancer (PCa) is the most prevalent non-skin cancer among men and is the second leading cause of cancer death in men. PCa has an increased incidence and prevalence in older men. Age-associated incidence is on the rise due to increased screening in the older population. This has led to a sharp rise in the detection of early stage PCa. Given the indolent nature of many prostatic malignancies, a large proportion of older men with PCa will ultimately die from other causes. As a result, physicians and patients are faced with the challenge of identifying optimal treatment strategies for localized PCa, biochemically recurrent PCa and later-stage PCa. Age-related changes can impact tolerance of hormonal therapy and chemotherapy in men with metastatic disease and shift the risk-benefit ratio of these treatments. Tools such as the Comprehensive Geriatric Assessment (CGA) can help estimate remaining life expectancy and can help predict treatment-related morbidity and mortality in older men. Application of CGA in older men with PCa is important to help individualize and optimize treatment strategies. Research that integrates multidisciplinary and multidimensional assessment of PCa and the patient's overall health status is needed.

Molecular processes leading to aberrant androgen receptor signaling and castration resistance in prostate cancer

Hormone therapies targeting androgen receptor signaling are the mainstay of treatment for patients with advanced prostate cancer. The length of clinical remission induced by hormone therapies varies substantially among treated patients. Why some patients progress rapidly after treatment while others benefit with prolonged remission is a question that remains unsolved. The androgen receptor signaling pathway is the key molecular determinant of castration resistance, and a key target for prostate cancer drug design. Recent advances in characterizing molecular processes leading to the development of castration-resistant prostate cancer, including the discovery of multiple androgen receptor splicing variants, offer opportunities for rational development of new clinical tools or approaches to predict, monitor or control/prevent prostate cancer progression in the castrate setting.

Current status of immunological therapies for prostate cancer

PURPOSE OF REVIEW

Considerable progress has been made in prostate cancer immunotherapy over the last year, and two agents have completed phase III testing. This review will discuss the most promising immune-directed strategies in development for prostate cancer, outlining interventions that mitigate tumor-induced tolerance and highlighting several combination immunotherapy approaches.

RECENT FINDINGS

A pivotal phase III study using Sipuleucel-T, an autologous prostatic acid phosphatase (PAP)-loaded dendritic cell immunotherapy, in men with metastatic castration-resistant prostate cancer (CRPC) demonstrated a survival advantage over placebo. By contrast, two phase III studies of GVAX, an allogeneic tumor cell vaccine, in a similar patient population failed to show a survival benefit of GVAX or GVAX/docetaxel over standard docetaxel/prednisone. Other strategies currently in clinical development include the ProstVac poxviral vaccine, a PAP-encoding DNA vaccine, and immune checkpoint inhibitory approaches.

SUMMARY

Although Sipuleucel-T may receive FDA approval for patients with metastatic CRPC, challenges remain in identifying immunotherapy strategies that overcome immune tolerance, especially when disease burden is substantial. An emerging paradigm focuses on using immunotherapy together with checkpoint antagonists or in combination with conventional therapies in patients with early-stage disease. Such approaches are likely to yield optimal results, but must carefully be explored in well designed phase II studies before moving forward.