The biology and natural history of prostate cancer: a short introduction

Cardiovascular outcomes among patients with castration-resistant prostate cancer: A comparative safety study using US administrative claims data

BACKGROUND

Cardiovascular conditions are the most prevalent comorbidity among patients with prostate cancer, regardless of treatment. Additionally, cardiovascular risk has been shown to increase following exposure to certain treatments for advanced prostate cancer. There is conflicting evidence on risk of overall and specific cardiovascular outcomes among men treated for metastatic castrate resistant prostate cancer (CRPC). We, therefore, sought to compare incidence of serious cardiovascular events among CRPC patients treated with abiraterone acetate plus predniso(lo)ne (AAP) and enzalutamide (ENZ), the two most widely used CRPC therapies.

METHODS

Using US administrative claims data, we selected CRPC patients newly exposed to either treatment after August 31, 2012, with prior androgen deprivation therapy (ADT). We assessed incidence of hospitalization for heart failure (HHF), ischemic stroke, and acute myocardial infarction (AMI) during the period 30-days after AAP or ENZ initiation to discontinuation, outcome occurrence, death, or disenrollment. We matched treatment groups on propensity-scores (PSs) to control for observed confounding to estimate the average treatment effect among the treated (AAP) using conditional Cox proportional hazards models. To account for residual bias, we calibrated our estimates against a distribution of effect estimates from 124 negative-control outcomes.

RESULTS

The HHF analysis included 2322 (45.1%) AAP initiators and 2827 (54.9%) ENZ initiators. In this analysis, the median follow-up times among AAP and ENZ initiators (after PS matching) were 144 and 122 days, respectively. The empirically calibrated hazard ratio (HR) estimate for HHF was 2.56 (95% confidence interval [CI]: 1.32, 4.94). Corresponding HRs for AMI and ischemic stroke were 1.94 (95% CI: 0.90, 4.18) and 1.25 (95% CI: 0.54, 2.85), respectively.

CONCLUSIONS

Our study sought to quantify risk of HHF, AMI and ischemic stroke among CRPC patients initiating AAP relative to ENZ within a national administrative claims database. Increased risk for HHF among AAP compared to ENZ users was observed. The difference in myocardial infarction did not attain statistical significance after controlling for residual bias, and no differences were noted in ischemic stroke between the two treatments. These findings confirm labeled warnings and precautions for AAP for HHF and contribute to the comparative real-world evidence on AAP relative to ENZ.

Glucose, lipids and gamma-glutamyl transferase measured before prostate cancer diagnosis and secondly diagnosed primary tumours: a prospective study in the Swedish AMORIS cohort

Background

Improvements in detection and treatment of prostate cancer (PCa) translate into more men living with PCa, who are therefore potentially at risk of a secondly diagnosed primary tumour (SDPTs). Little is known about potential biochemical mechanisms linking PCa with the occurrence of SDPTs. The current study aims to investigate serum biomarkers of glucose and lipid metabolism and gamma-glutamyl transferase (GGT) measured prior to PCa diagnosis and their association with the occurrence of SDPTS.

Methods

From the Swedish AMORIS cohort, we selected all men diagnosed with PCa between 1996 and 2011, with at least one of the five biomarkers of interest (glucose, fructosamine, triglycerides, total cholesterol (TC), GGT) measured on average 16 years before PCa diagnosis (n = 10,791). Multivariate Cox proportional hazards models were used to determine hazard ratios (HR) for risk of SDPTs (overall and subtypes) by levels of the five biomarkers. Effect modification of treatment was assessed.

Results

811 SDPTS were diagnosed during a median follow-up time of 5 years. Elevated levels of triglycerides (HR: 1.37, 95%CI: 1.17–1.60), TC (HR: 1.22, 95%CI: 1.04–1.42) and GGT (HR: 1.32, 95%CI: 1.02–1.71) were associated with an increased risk of SDPTs. Risk of SDPTs subtypes varied by biomarkers.

Conclusion

Elevated levels of biomarkers of lipid metabolism and GGT measured prior to PCa diagnosis were associated with an increased risk of SDPTs, suggesting a potential common biochemical background for development of PCa and SDPTs.

Serum inflammatory markers in relation to prostate cancer severity and death in the Swedish AMORIS study

Inflammation is a well-documented driver of cancer development and progression. However, little is known about its role in prostate carcinogenesis. Thus, we examined the association of C-reactive protein (CRP), haptoglobin, albumin and white blood cells (WBC) with prostate cancer (PCa) severity (defined by PCa risk category and clinicopathological characteristics) and progression (defined by PCa death). We selected 8,471 Swedish men with newly diagnosed PCa who had exposure measurements taken approximately 14 years prior to diagnosis. We calculated odds ratio (OR) and 95% confidence interval (CI) for the associations between the inflammatory markers and PCa severity using logistic regression, while Cox proportional hazard regression was used for the associations with overall and PCa death. Serum CRP levels were associated with increased odds of high risk and metastatic PCa, and high PSA levels (≥20 µg/L) (OR: 1.29; 95% CI: 1.06-1.56, 1.32; 1.05-1.65 and 1.51; 1.26-1.81, respectively). Similarly, higher haptoglobin levels were associated with increased odds of metastatic PCa, high PSA level and possibly high grade PCa (1.38; 1.10-1.74, 1.50; 1.17-1.93 and 1.25; 1.00-1.56, respectively). Albumin was positively associated with Gleason 4 + 3 tumour (1.38; 1.02-1.86) and overall death (HR_{unit increase in log} : 1.60; 95% CI: 1.11-2.30), but inversely associated with high risk PCa and high PSA levels (≥20 µg/L) (0.71; 0.56-0.89 and 0.72; 0.5 9-0.90). WBC was associated with increased odds of T3-T4 PCa. Except for albumin, none of these markers were associated with PCa death or overall death. Systemic inflammation as early as 14 years prior to diagnosis may influence prostate cancer severity.

Role of vitamin D receptor gene Cdx2 and Apa1 polymorphisms in prostate cancer susceptibility: a meta-analysis

BACKGROUND

Vitamin D receptor (VDR) gene polymorphisms affect the risk of prostate cancer. However, studies investigating the relationship between VDR gene polymorphisms (Cdx2 and ApaI) and prostate cancer risk are equivocal. Therefore, we conducted a meta-analysis of all the studies to review the evidence available.

METHODS

A comprehensive search of PubMed, EMBASE, and ISI Web of Science for studies published until September 2015 was conducted. Odds ratios (ORs) and 95 % confidence intervals (CIs) were analyzed to determine the association between VDR Cdx2 and ApaI polymorphisms, and prostate cancer risk.

RESULTS

The meta-analysis included 10 studies involving 4979 cases and 4380 controls to analyze the VDR Cdx2 polymorphism. An additional 11 studies involving 2837 cases and 2884 controls were analyzed for the VDR ApaI polymorphism. Evidence failed to support the role of VDR Cdx2 and ApaI polymorphisms in prostate cancer. For Cdx2, the pooled OR was 1.11 (95 % CI = 0.93-1.33) for AA vs. GG genotypes, 0.97 (95 % CI = 0.88-1.06) for GA vs. AA genotypes, 0.99 (95 % CI = 0.91-1.08) for AA + GA vs. GG, and 1.12 (95 % CI = 0.95-1.31) for AA vs. GA + GG. No significant relationship was observed in any subgroup analysis based on ethnicity, controls, and Hardy-Weinberg equilibrium (HWE). ORs for the ApaI polymorphism were similar.

CONCLUSIONS

VDR Cdx2 and ApaI polymorphisms are not associated with prostate cancer. Additional evidence is required to confirm this conclusion.

Unemployment and prostate cancer mortality in the OECD, 1990-2009

The global economic downturn has been associated with increased unemployment in many countries. Insights into the impact of unemployment on specific health conditions remain limited. We determined the association between unemployment and prostate cancer mortality in members of the Organisation for Economic Co-operation and Development (OECD). We used multivariate regression analysis to assess the association between changes in unemployment and prostate cancer mortality in OECD member states between 1990 and 2009. Country-specific differences in healthcare infrastructure, population structure, and population size were controlled for and lag analyses conducted. Several robustness checks were also performed. Time trend analyses were used to predict the number of excess deaths from prostate cancer following the 2008 global recession. Between 1990 and 2009, a 1% rise in unemployment was associated with an increase in prostate cancer mortality. Lag analysis showed a continued increase in mortality years after unemployment rises. The association between unemployment and prostate cancer mortality remained significant in robustness checks with 46 controls. Eight of the 21 OECD countries for which a time trend analysis was conducted, exhibited an estimated excess of prostate cancer deaths in at least one of 2008, 2009, or 2010, based on 2000-2007 trends. Rises in unemployment are associated with significant increases in prostate cancer mortality. Initiatives that bolster employment may help to minimise prostate cancer mortality during times of economic hardship.

Functional status declines among cancer survivors: trajectory and contributing factors

OBJECTIVE

This study aimed to quantify functional status (FS) trajectories pre- and post-diagnosis of cancer, FS trajectories among cancer-free individuals, and factors affecting FS.

MATERIALS AND METHODS

Self-reported FS, scored from 0 (worst) to 100 (best), of Atherosclerosis Risk in Communities (ARIC) Study cohort participants diagnosed with incident cancer (lung (N=303), breast (N=374), prostate (N=529), colorectal (N=228)), and cancer-free participants (N=11,155) over 15 years was examined. FS was evaluated in two ways: 1) until death or follow-up year 15 (Model 1) and 2) same as survivorship model except that a FS value of zero was used for assessments after death to follow-up year 15 (Model 2). Mean FS at discrete time points were used to generate FS trajectories. Differences in repeated measures of FS were assessed using linear growth models.

RESULTS

Within one year after diagnosis, FS scores declined compared to the cancer-free group, except for prostate cancer. FS continued to decline beyond one year after lung or colorectal cancer diagnosis. FS was lower in all cancer groups, except prostate, compared to the cancer-free group (Model 1: lung -4.76, breast -2.28, colorectal -2.55; Model 2: lung -2.36, breast -2.46, colorectal -2.31). Predictors of decreased FS score independent of cancer diagnosis included low education, comorbidities, obesity, smoking, lack of health insurance, and age.

CONCLUSION

FS in all incident cancer groups declined during the first year post-diagnosis, which could be due to intensive treatments. Targeting factors related to FS declines could improve health outcomes for patients with cancer.

The role of biomarkers in the assessment of prostate cancer risk prior to prostate biopsy: which markers matter and how should they be used?

Prostate cancer (PCa) screening has been substantially influenced by the clinical implementation of serum prostate-specific antigen (PSA). In this context, improvement of early PCa detection and stage migration as well as reduced PCa mortality were achieved, and up-to-date PSA represents the gold standard biomarker of PCa diagnosis together with clinical findings. Nonetheless, PSA shows weakness in discriminating between malign and benign prostatic disease or indolent and aggressive cancers. As a result, the expansion of PSA screening is extensively debated with regard to overdetection and ultimately overtreatment, keeping in mind that PCa is still the third leading cause of cancer-specific mortality in the Western male population. Consequently, today's task is to increase the accuracy of PCa detection and furthermore to allow stratification for indolent PCa that might permit active surveillance and to filter out aggressive cancers necessitating treatment. Thus, novel biomarkers, especially in combination with approved clinical risk factors (e.g., age or family history of PCa), within multivariable prediction models carry the potential to improve many aspects of PCa diagnosis and to enable risk classification in clinical practice. Multivariable models lead to superior accuracy for PCa prediction instead of the use of a single risk factor. The aim of this article was to present an overview of known risk factors for PCa together with new promising blood- and urine-based biomarkers and their application within risk models that may allow risk stratification for PCa prior to prostate biopsy. Risk models may optimize PCa detection and classification with regard to improved PCa risk assessment and avoidance of unnecessary prostate biopsies.