Stephen J. Freedland

Prostate Cancer-Specific Survival Following Salvage Radiotherapy vs Observation in Men With Biochemical Recurrence After Radical Prostatectomy

CONTEXT Biochemical disease recurrence after radical prostatectomy often prompts salvage radiotherapy, but no studies to date have had sufficient numbers of patients or follow-up to determine whether radiotherapy improves survival, and if so, the subgroup of men most likely to benefit. OBJECTIVES To quantify the relative improvement in prostate cancer-specific survival of salvage radiotherapy vs no therapy after biochemical recurrence following prostatectomy, and to identify subgroups for whom salvage treatment is most beneficial. DESIGN, SETTING, AND PATIENTS Retrospective analysis of a cohort of 635 US men undergoing prostatectomy from 1982-2004, followed up through December 28, 2007, who experienced biochemical and/or local recurrence and received no salvage treatment (n = 397), salvage radiotherapy alone (n = 160), or salvage radiotherapy combined with hormonal therapy (n = 78). MAIN OUTCOME MEASURE Prostate cancer-specific survival defined from time of recurrence until death from disease. RESULTS With a median follow-up of 6 years after recurrence and 9 years after prostatectomy, 116 men (18%) died from prostate cancer, including 89 (22%) who received no salvage treatment, 18 (11%) who received salvage radiotherapy alone, and 9 (12%) who received salvage radiotherapy and hormonal therapy. Salvage radiotherapy alone was associated with a significant 3-fold increase in prostate cancer-specific survival relative to those who received no salvage treatment (hazard ratio [HR], 0.32 [95% confidence interval {CI}, 0.19-0.54]; P<.001). Addition of hormonal therapy to salvage radiotherapy was not associated with any additional increase in prostate cancer-specific survival (HR, 0.34 [95% CI, 0.17-0.69]; P = .003). The increase in prostate cancer-specific survival associated with salvage radiotherapy was limited to men with a prostate-specific antigen doubling time of less than 6 months and remained after adjustment for pathological stage and other established prognostic factors. Salvage radiotherapy initiated more than 2 years after recurrence provided no significant increase in prostate cancer-specific survival. Men whose prostate-specific antigen level never became undetectable after salvage radiotherapy did not experience a significant increase in prostate cancer-specific survival. Salvage radiotherapy also was associated with a significant increase in overall survival. CONCLUSIONS Salvage radiotherapy administered within 2 years of biochemical recurrence was associated with a significant increase in prostate cancer-specific survival among men with a prostate-specific antigen doubling time of less than 6 months, independent of other prognostic features such as pathological stage or Gleason score. These preliminary findings should be validated in other settings, and ultimately, in a randomized controlled trial.

Active Surveillance for Prostate Cancer: A Systematic Review of the Literature

CONTEXT Prostate cancer (PCa) remains an increasingly common malignancy worldwide. The optimal management of clinically localized, early-stage disease remains unknown, and profound quality of life issues surround PCa interventions. OBJECTIVE To systematically summarize the current literature on the management of low-risk PCa with active surveillance (AS), with a focus on patient selection, outcomes, and future research needs. EVIDENCE ACQUISITION A comprehensive search of the PubMed and Embase databases from 1980 to 2011 was performed to identify studies pertaining to AS for PCa. The search terms used included prostate cancer and active surveillance or conservative management or watchful waiting or expectant management. Selected studies for outcomes analysis had to provide a comprehensive description of entry characteristics, criteria for surveillance, and indicators for further intervention. EVIDENCE SYNTHESIS Data from seven large AS series were reviewed. Inclusion criteria for surveillance vary among studies, and eligibility therefore varies considerably (4-82%). PCa-specific mortality remains low (0-1%), with the longest published median follow-up being 6.8 yr. Up to one-third of patients receive secondary therapy after a median of about 2.5 yr of surveillance. Surveillance protocols and triggers for intervention vary among institutions. Most patients are treated for histologic reclassification (27-100%) or prostate-specific antigen doubling time <3 yr (13-48%), while 7-13% are treated with no evidence of progression. Repeat prostate biopsy with a minimum of 12 cores appears to be important for monitoring patients for changes in tumor histology over time. CONCLUSIONS AS for PCa offers an opportunity to limit intervention to patients who will likely benefit the most from radical treatment. This approach confers a low risk of disease-specific mortality in the short to intermediate term. An early, confirmatory biopsy is essential for limiting the risk of underestimating tumor grade and amount.

Diabetes and Cardiovascular Disease During Androgen Deprivation Therapy: Observational Study of Veterans With Prostate Cancer

BACKGROUND Previous studies indicate that androgen deprivation therapy for prostate cancer is associated with diabetes and cardiovascular disease among older men. We evaluated the relationship between androgen deprivation therapy and incident diabetes and cardiovascular disease in men of all ages with prostate cancer. METHODS We conducted an observational study of 37,443 population-based men who were diagnosed with local or regional prostate cancer in the Veterans Healthcare Administration from January 1, 2001, through December 31, 2004, with follow-up through December 31, 2005. Cox proportional hazards models were used to assess whether androgen deprivation therapy with gonadotropin-releasing hormone (GnRH) agonists, oral antiandrogens, the combination of the two (ie, combined androgen blockade), or orchiectomy was associated with diabetes, coronary heart disease, myocardial infarction, sudden cardiac death, or stroke, after adjustment for patient and tumor characteristics. All statistical tests were two-sided. RESULTS Overall, 14,597 (39%) of the 37,443 patients were treated with androgen deprivation therapy. Treatment with GnRH agonists was associated with statistically significantly increased risks of incident diabetes (for GnRH agonist therapy, 159.4 events per 1000 person-years vs 87.5 events for no androgen deprivation therapy, difference = 71.9, 95% confidence interval [CI] = 71.6 to 72.2; adjusted hazard ratio [aHR] = 1.28, 95% CI = 1.19 to 1.38), incident coronary heart disease (aHR = 1.19, 95% CI = 1.10 to 1.28), myocardial infarction (12.8 events per 1000 person-years for GnRH agonist therapy vs 7.3 for no androgen deprivation therapy, difference = 5.5, 95% CI = 5.4 to 5.6; aHR = 1.28, 95% CI = 1.08 to 1.52), sudden cardiac death (aHR = 1.35, 95% CI = 1.18 to 1.54), and stroke (aHR = 1.22, 95% CI = 1.10 to 1.36). Combined androgen blockade was statistically significantly associated with an increased risk of incident coronary heart disease (aHR = 1.27, 95% CI = 1.05 to 1.53), and orchiectomy was associated with coronary heart disease (aHR = 1.40, 95% CI = 1.04 to 1.87) and myocardial infarction (aHR = 2.11, 95% CI = 1.27 to 3.50). Oral antiandrogen monotherapy was not associated with any outcome studied. CONCLUSION Androgen deprivation therapy with GnRH agonists was associated with an increased risk of diabetes and cardiovascular disease.

Autonomic Nerve Development Contributes to Prostate Cancer Progression

Introduction Cancer cells usurp the healthy tissue microenvironment to promote their survival, proliferation, and dissemination. The role of angiogenesis, the formation of new blood vessels, in solid tumor growth is well established. Whether neurogenesis, the formation of new nerve fibers, likewise contributes to tumor development and progression remains unclear. Here, studying mouse models and human tumor samples, we examined the role of the autonomic nervous system in prostate cancer growth and dissemination. The parasympathetic nervous system promotes prostate cancer dissemination in mice. Image shows bone metastases (arrowheads) detected by Na18F-PET scanning of Hi-Myc mice, a model of prostate cancer. Such metastases are not detected when the Hi-Myc mice are genetically deficient in muscarinic cholinergic receptor type 1, an essential signaling component of the parasympathetic branch of the autonomic nervous system. Methods To track tumor growth and dissemination, we studied (i) mice bearing PC-3 prostate tumor xenografts that expressed luciferase and (ii) transgenic mice expressing the c-Myc oncogene under the control of the probasin promoter (Hi-Myc mice), which develop prostatic intraepithelial neoplasia that progresses to invasive adenocarcinoma. Tumors were monitored by bioluminescence, positron emission tomography (PET), and histological analyses. Sympathetic (adrenergic) and parasympathetic (cholinergic) nerve functions were assessed using chemical or surgical neural ablation, pharmacological agonists or antagonists, and genetically engineered mice. We also determined the adrenergic and cholinergic nerve densities in radical prostatectomy tissues from a cohort of 43 patients with prostate cancer. Results Quantitative bioluminescence and immunofluorescence analyses, combined with histological examinations, revealed that sympathetic adrenergic nerve outgrowth was critical in the early phases of cancer development. Prostate tumor xenografts developed poorly in mice that had been pretreated by chemical or surgical sympathectomy of the prostate gland, or when stromal β2- and β3-adrenergic receptors were genetically deleted. Prostate tumors were also infiltrated by parasympathetic cholinergic fibers that promoted cancer dissemination. Cholinergic-induced tumor invasion and metastasis in mice were inhibited by pharmacological blockade or genetic disruption of the stromal type 1 muscarinic receptor. Quantitative confocal microscopy analysis of radical prostatectomy specimens from patients with low-risk (n = 30) or high-risk (n = 13) prostate adenocarcinoma revealed higher overall nerve densities in high-risk tumors relative to low-risk tumors. Adrenergic fibers were increased in normal prostate tissues surrounding the human tumors, whereas cholinergic fibers infiltrated the tumor tissue. Higher densities of adrenergic and cholinergic nerve fibers were associated with poor clinical outcome, including higher preoperative levels of prostate-specific antigen (PSA), extension beyond the prostatic capsule, and biochemical recurrence. Discussion These results suggest that the formation of new nerve fibers within and around prostate tumors can alter tumor behavior. The autonomic nervous system appears to exert dual functions in prostate cancer: Sympathetic neonerves promote early stages of tumorigenesis, whereas parasympathetic nerve fibers promote cancer dissemination. Conceivably, drugs targeting both branches of the autonomic nervous system could provide therapeutic benefit. Cancer Hits a Nerve Solid tumors sculpt their microenvironment to maximize their growth and metastatic potential. This concept is illustrated most famously by tumor angiogenesis, a process whereby tumors induce the growth of new blood vessels to boost their supply of oxygen and blood-borne nutrients. Magnon et al. (p. 10.1126/science.1236361; see the Perspective by Isaacs) now highlight the important contribution made by another microenvironmental component—developing autonomic nerve fibers—to tumor growth and metastasis. In mouse models of prostate cancer, surgical or chemical destruction of sympathetic nerves prevented early-stage growth of tumors, whereas pharmacological inhibition of parasympathetic nerves inhibited tumor dissemination. In a small study of human prostate cancer specimens, the presence of a high density of nerve fibers in and around the tumor tissue was found to correlate with poor clinical outcome. These results raise the possibility that drugs targeting the autonomic nervous system may have therapeutic potential for prostate cancer. Prostate cancer is more aggressive when certain types of nerves form near and within the tumor. [Also see Perspective by Isaacs] Nerves are a common feature of the microenvironment, but their role in tumor growth and progression remains unclear. We found that the formation of autonomic nerve fibers in the prostate gland regulates prostate cancer development and dissemination in mouse models. The early phases of tumor development were prevented by chemical or surgical sympathectomy and by genetic deletion of stromal β2- and β3-adrenergic receptors. Tumors were also infiltrated by parasympathetic cholinergic fibers that promoted cancer dissemination. Cholinergic-induced tumor invasion and metastasis were inhibited by pharmacological blockade or genetic disruption of the stromal type 1 muscarinic receptor, leading to improved survival of the mice. A retrospective blinded analysis of prostate adenocarcinoma specimens from 43 patients revealed that the densities of sympathetic and parasympathetic nerve fibers in tumor and surrounding normal tissue, respectively, were associated with poor clinical outcomes. These findings may lead to novel therapeutic approaches for prostate cancer.

Body Mass Index, Weight Change, and Risk of Prostate Cancer in the Cancer Prevention Study II Nutrition Cohort

Background: Obesity has been associated with aggressive prostate cancer. The extent of this association, which varies by stage and grade, remains unclear. The role of recent weight change had not been previously examined. Methods: We examined body mass index (BMI) and weight change in relation to incident prostate cancer by disease stage and grade at diagnosis among 69,991 men in the Cancer Prevention Study II Nutrition Cohort. Participants provided information on height and weight in 1982, and again at enrollment in 1992. During follow-up through June 30, 2003 (excluding the first 2 years of follow-up), we documented 5,252 incident prostate cancers. Cox proportional hazards models were used to estimate rate ratios (RR) and 95% confidence intervals (95% CI). Results: The association between BMI in 1992 and risk of prostate cancer differed by stage and grade at diagnosis. BMI was inversely associated with risk of nonmetastatic low-grade prostate cancer (RR, 0.84; 95% CI, 0.66-1.06), but BMI was positively associated with risk of nonmetastatic high-grade prostate cancer (RR, 1.22; 95% CI, 0.96-1.55) and risk of metastatic or fatal prostate cancer (RR, 1.54; 95% CI, 1.06-2.23). Compared with weight maintenance, men who lost >11 pounds between 1982 and 1992 were at a decreased risk of nonmetastatic high-grade prostate cancer (RR, 0.58; 95% CI, 0.42-0.79). Conclusion: Obesity increases the risk of more aggressive prostate cancer and may decrease either the occurrence or the likelihood of diagnosis of less-aggressive tumors. Men who lose weight may reduce their risk of prostate cancer. (Cancer Epidemiol Biomarkers Prev 2007;16(1):63–9)

Obesity and Prostate Cancer: Weighing the Evidence

CONTEXT Obesity and prostate cancer (PCa) affect substantial proportions of Western society. Mounting evidence, both epidemiologic and mechanistic, for an association between the two is of public health interest. An improved understanding of the role of this modifiable risk factor in PCa etiology is imperative to optimize screening, treatment, and prevention. OBJECTIVE To consolidate and evaluate the evidence for an epidemiologic link between obesity and PCa, in addition to examining the proposed underlying molecular mechanisms. EVIDENCE ACQUISITION A PubMed search for relevant articles published between 1991 and July 2012 was performed by combining the following terms: obesity, BMI, body mass index and prostate cancer risk, prostate cancer incidence, prostate cancer mortality, radical prostatectomy, androgen-deprivation therapy, external-beam radiation, brachytherapy, prostate cancer and quality of life, prostate cancer and active surveillance, in addition to obesity, BMI, body mass index and prostate cancer and insulin, insulin-like growth factor, androgen, estradiol, leptin, adiponectin, and IL-6. Articles were selected based on content, date of publication, and relevancy, and their references were also searched for relevant articles. EVIDENCE SYNTHESIS Increasing evidence suggests obesity is associated with elevated incidence of aggressive PCa, increased risk of biochemical failure following radical prostatectomy and external-beam radiotherapy, higher frequency of complications following androgen-deprivation therapy, and increased PCa-specific mortality, although perhaps a lower overall PCa incidence. These results may in part relate to difficulties in detecting and treating obese men. However, multiple molecular mechanisms could explain these associations as well. Weight loss slows PCa in animal models but has yet to be fully tested in human trials. CONCLUSIONS Obesity appears to be linked with aggressive PCa. We suggest clinical tips to better diagnose and treat obese men with PCa. Whether reversing obesity slows PCa growth is currently unknown, although it is an active area of research.

The Correlation Between Metabolic Syndrome and Prostatic Diseases

CONTEXT Metabolic syndrome (MetS), a cluster of several metabolic abnormalities with a high socioeconomic cost, is considered a worldwide epidemic. Recent epidemiologic and clinical data suggest that MetS is involved in the pathogenesis and progression of prostatic diseases such as benign prostatic hyperplasia (BPH) and prostate cancer (PCa). OBJECTIVE This review evaluates the available evidence of the role of MetS in BPH and PCa development and progression and discusses possible clinical implications for the management, prevention, and treatment of these diseases. EVIDENCE ACQUISITION A National Center for Biotechnology Information (NCBI) PubMed search for relevant articles published between 1995 and September 2011 was performed by combining the following Patient population, Intervention, Comparison, Outcome (PICO) terms: male, metabolic syndrome, prostate, benign prostatic hyperplasia, prostate cancer, prevention, diagnosis, treatment, and prognosis. Additional references were obtained from the reference list of full-text manuscripts. EVIDENCE SYNTHESIS MetS is a complex, highly prevalent disorder and a worldwide epidemic. Central obesity, insulin resistance, dyslipidemia, and hypertension are the main components of MetS. Notwithstanding all the attempts made to correctly define MetS, a major problem related to most definitions remains the applicability to different populations and ethnic groups. Although there is growing evidence of the association of MetS with the initiation and clinical progression of BPH and PCa, molecular mechanisms and effects on treatment efficacy remain unclear. Further research is required to better understand the role of MetS in BPH and PCa. CONCLUSIONS Data from the peer-reviewed literature suggest an association of MetS with BPH and PCa, although the evidence for a causal relationship remains missing. MetS should be considered a new domain in basic and clinical research in patients with prostatic disorders.

The Contemporary Concept of Significant Versus Insignificant Prostate Cancer

CONTEXT The notion of insignificant prostate cancer (Ins-PCa) has progressively emerged in the past two decades. The clinical relevance of such a definition was based on the fact that low-grade, small-volume, and organ-confined prostate cancer (PCa) may be indolent and unlikely to progress to biologic significance in the absence of treatment. OBJECTIVE To review the definition of Ins-PCa, its incidence, and the clinical impact of Ins-PCa on the contemporary management of PCa. EVIDENCE ACQUISITION A review of the literature was performed using the Medline, Scopus, and Web of Science databases with no restriction on language up to September 2010. The literature search used the following terms: insignificant, indolent, minute, microfocal, minimal, low volume, low risk, and prostate cancer. EVIDENCE SYNTHESIS The most commonly used criteria to define Ins-PCa are based on the pathologic assessment of the radical prostatectomy specimen: (1) Gleason score ≤ 6 without Gleason pattern 4 or 5, (2) organ-confined disease, and (3) tumour volume<0.5 cm(3). Several preoperative criteria and prognostication tools for predicting Ins-PCa have been suggested. Nomograms are best placed to estimate the risk of progression on an individualised basis, but a substantial proportion of men with a high probability of harbouring Ins-PCa are at risk for pathologic understaging and/or undergrading. Thus, there is an ongoing need for identifying novel and more accurate predictors of Ins-PCa to improve the distinction between insignificant versus significant disease and thus to promote the adequate management of PCa patients at low risk for progression. CONCLUSIONS The exciting challenge of obtaining the pretreatment diagnostic tools that can really distinguish insignificant from significant PCa should be one of the main objectives of urologists in the following years to decrease the risk of overtreatment of Ins-PCa.

Castration-resistant prostate cancer: from new pathophysiology to new treatment targets.

CONTEXT Castration-resistant prostate cancer (CRPC) refers to patients who no longer respond to surgical or medical castration. Standard treatment options are limited. OBJECTIVE To review the concepts and rationale behind targeted agents currently in late-stage clinical testing for patients with CRPC. EVIDENCE ACQUISITION Novel targeted therapies in clinical trials were identified from registries. The MEDLINE database was searched for all relevant reports published from 1996 to October 2009. Bibliographies of the retrieved articles and major international meeting abstracts were hand-searched to identify additional studies. EVIDENCE SYNTHESIS Advances in our understanding of the molecular mechanisms underlying prostate cancer (PCa) progression has translated into a variety of treatment approaches. Agents targeting androgen receptor (AR) activation and local steroidogenesis, angiogenesis, immunotherapy, apoptosis, chaperone proteins, the insulin-like growth factor (IGF) pathway, RANK-ligand, endothelin receptors, and the Src family kinases are entering or have recently completed accrual to phase 3 trials for patients with CRPC. CONCLUSIONS A number of new agents targeting mechanisms of PCa progression with early promising results are in clinical trials and have the potential to provide novel treatment options for CRPC in the near future.

Exercise intolerance in cancer and the role of exercise therapy to reverse dysfunction

Exercise tolerance reflects the integrative capacity of components in the oxygen cascade to supply adequate oxygen for ATP resynthesis. Conventional cancer therapies can simultaneously affect one or more components of this cascade and reduce the bodys ability to deliver or utilise oxygen and substrate, leading to exercise intolerance. We propose that molecularly-targeted therapy is associated with a further, more subtle, negative effect on the components that regulate exercise limitation. We outline possible causes of exercise intolerance in patients with cancer and the role of exercise therapy to mitigate or prevent dysfunction. We also discuss possible implications for exercise-regulated gene expression for cancer biology and treatment efficacy. A better understanding of these issues might lead to more effective integration of exercise therapy to optimise the treatment and management of patients with cancer.