Body size and composition and prostate cancer risk: systematic review and meta-regression analysis

Predicted body fat percentage, fat mass and lean body mass in relation to risk of prostate cancer: Results from the NHANES 1999 to 2010

The purpose of this study is to examine the relationship between fat mass (FM), body fat percentage (BF%), lean body mass (LM), and prostate cancer (PCa), and evaluate their potential impact on the risk of PCa. Data from the National Health and Nutrition Examination Survey (NHANES) of the United States were utilized. Adult male participants from 6 survey cycles between 1999 and 2010 were selected as the study sample. Multivariable logistic regression analysis was conducted to explore the association between BF%, LM, and PCa, while controlling for potential confounding variables. Among the 8440 participants, 359 cases of PCa were diagnosed. The relationship between BF%, LM, and PCa was nonlinear. In the multivariable logistic regression analysis, there was an independent association between BF% and PCa risk (OR: 1.04, 95% CI: 1.02-1.06), suggesting that higher BF% levels are associated with an increased risk of PCa. Conversely, higher LM levels were associated with a decreased risk of PCa (OR: 0.96, 95% CI: 0.95-0.98). The findings of this study demonstrate a correlation between BF% and LM with PCa, but do not provide direct evidence of a causal relationship. Higher BF% levels are associated with an increased risk of PCa, while higher LM levels are associated with a decreased risk. These results provide valuable insights for understanding and potentially preventing PCa, although further research is needed to fully comprehend the underlying mechanisms.

Excess weight, weight gain, and prostate cancer risk and prognosis: the PROCA-life study

BACKGROUND

Studies of excess weight and weight changes throughout adult life for prostate cancer (PCa) risk and prognosis have shown inconsistent results.

METHODS

In a population-based cohort, the Prostate Cancer Study throughout life (PROCA-life), 16,960 healthy men from the prospective cohort Tromsø Study (1994-2016) were included. Body mass index (BMI) and weight were measured at all four attendings, and weight change was calculated as the difference between the first and last of either Tromsø4, Tromsø5 or Tromsø6. Overall, 904 men developed PCa during 16 years of follow-up, and Poisson regression with fractional polynomials was used to investigate trends in incidence. Cox proportional hazard and logistic regression models were used to study associations between measurements of BMI and weight change and PCa risk, severity, and mortality.

RESULTS

At study entry, 46% of the participants (median age 44 years) were overweight, and 14% were obese (BMI > 30 kg/m2). We observed a 127% increase in overall age adjusted PCa incidence in the cohort during 1995 through 2019. No overall associations between BMI or weight change and PCa risk were observed. However, in sub-group analysis, weight gain among obese men was associated with a three-fold higher PCa risk (HR 3.03, 95% CI 1.39-6.58) compared with obese men with stable weight. Overweight was associated with lower risk of metastatic cancer (OR 0.48, 95% CI 0.30-0.75) at diagnosis. Men with obesity had higher risk of PCa-specific death (HR 1.72, 95% CI 1.03-2.88), while nonsmoking obese PCa cases had two times higher PCa-specific mortality compared with normal weighted PCa cases (HR 2.10, 95% CI 1.11-3.70).

INTERPRETATION

In our cohort, weight gain among obese men was associated with higher risk of PCa, and obesity was associated with higher PCa-specific mortality, especially among nonsmokers. The relationship between weight and risk for PCa remains complicated, and future studies are needed to determine clinical implications.

Obesity and prostate cancer screening, incidence, and mortality in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial

BACKGROUND

Though obesity, measured by body mass index (BMI), is an established risk factor for several cancer sites, there is conflicting evidence on whether obesity increases prostate cancer risk or mortality and, if it does, whether it increases risk directly or indirectly by affecting prostate cancer screening efficacy.

METHODS

We examined associations between BMI and prostate cancer screening outcomes, incidence, and mortality in men randomly assigned to the intervention arm of the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (n = 36 756) between 1993 and 2001. Participants received annual screening with the prostate-specific antigen test and digital rectal exam. Associations between baseline BMI and screening outcomes were assessed via multinomial logistic regression, and associations with prostate cancer incidence and mortality were assessed via Cox proportional hazards regression.

RESULTS

Individuals with higher BMI were less likely to screen positive via the prostate-specific antigen test and/or digital rectal exam and more likely to have an inadequate screen (all Ptrend < .01). Higher BMI was inversely associated with prostate cancer incidence (per 5 kg/m2 BMI increase: hazard ratio [HR] = 0.94, 95% confidence interval [CI] = 0.91 to 0.97), including incidence of early stage (HR = 0.94, 95% CI = 0.90 to 0.97) and advanced-stage (HR = 0.91, 95% CI = 0.82 to 1.02) disease, but positively associated with prostate cancer mortality (HR = 1.21, 95% CI = 1.06 to 1.37). The association with mortality was not modified by screening outcome (Pinteraction = .13).

CONCLUSIONS

Within this screened population, individuals with higher BMI had lower risk of prostate cancer diagnosis but higher risk of prostate cancer mortality. As higher BMI was not positively associated with advanced-stage prostate cancer risk, the increased mortality is unlikely to be due to delayed prostate cancer detection.

Association between body mass index, metabolic syndrome and common urologic conditions: a cross-sectional study using a large multi-institutional database from the United States

INTRODUCTION

The study aims to determine whether body mass index (BMI), metabolic syndrome (MS) or its individual components (primary hypertension, type 2 diabetes mellitus and dyslipidemias) are risk factors for common urological diseases.

MATERIALS AND METHODS

Cross-sectional study with data collected on February 28, 2022 from the TriNetX Research Network. Patients were divided in cohorts according to their BMI, presence of MS (BMI > 30 kg/m2, type 2 diabetes mellitus, primary hypertension and disorders of lipoprotein metabolism) and its individual components and its association with common urological conditions was determined. For each analysis, odds ratio (OR) with 95% confidence intervals were calculated. Statistical significance was assessed at p < .05.

RESULTS

BMI > 30 kg/m2 was associated with increased risk of lithiasis, kidney cancer, overactive bladder, male hypogonadism, benign prostatic hyperplasia, and erectile dysfunction (p < .05). On the contrary, BMI was inversely associated with ureteral, bladder and prostate cancer (p < .05). In all urological diseases, MS was the strongest risk factor, with prostate cancer (OR = 2.53) showing the weakest and male hypogonadism the strongest (OR = 13.00) associations.

CONCLUSIONS

MS and its individual components were significant risk factors for common urological conditions. Hence holistic approaches with lifestyle modification might prevent common urological disease.Key messagesOverall, metabolic syndrome is the strongest risk factor for all the analysed urological diseases.Abnormally high body mass index can be a risk or protective factor depending on the threshold and urological disease that are being evaluated.Metabolic syndrome and increased BMI should be considered important factors associated to the prevalence of common urological diseases.

Long-term outcomes of laparoscopic sleeve gastrectomy in those with class I obesity: safety, efficacy, and quality of life

BACKGROUND

Class I obesity carries significant morbidity and mortality risk similar to higher grades of obesity, and persons with class I obesity have a high risk of progression to class II and III obesity. While bariatric surgery has made strides in safety and efficacy, it remains inaccessible for persons with class I obesity (body mass index [BMI] of 30-35 kg/m2).

OBJECTIVES

To assess safety, weight loss durability, co-morbidity resolution, and quality of life after laparoscopic sleeve gastrectomy (LSG) in persons with class I obesity.

SETTING

Multidisciplinary medical center that specializes in obesity management.

METHODS

A longitudinal prospective single-surgeon registry was queried for data pertaining to persons with class I obesity who underwent primary LSG. Primary endpoint was weight loss. Secondary endpoints included change in obesity-related co-morbidities, adverse events, and post hoc analysis of symptoms of gastroesophageal reflux disease (GERD) and Bariatric Analysis and Reporting Outcome System results. Follow-up was divided into short- (1-3 yr), intermediate- (4-7 yr), and long-term (8-12 yr). We evaluated percent excess weight loss (%EWL) using linear mixed models adjusting for age, sex, years since operation, and baseline BMI. Least-squares means estimates and 95% confidence intervals (CI) were generated.

RESULTS

Of 13,863 bariatric procedures, a total of 1851 patients were included. Mean baseline BMI, age, and male:female ratio were 32.6 ± 2.1 kg/m2, 33.7 ± 9.2 years, and 1:5, respectively. Adjusted mean %EWL (95% CI) at short-, intermediate-, and long-term follow-up were 111% (95% CI, 91%-131%), 110% (95% CI, 89%-131%), and 141% (95% CI, 57%-225%), respectively. Of 195 patients with type 2 diabetes, 59% experienced complete remission, and of 168 patients with hypertension, 43% experienced complete remission. Being on oral antidiabetes medication was a significant predictor of sustained remission compared with being on insulin or combination therapy (P < .001). Sixty-nine patients had symptoms of GERD before surgery, which improved in 55 (79.7%). Thirty-three patients developed de novo symptoms of GERD. The average Bariatric Analysis and Reporting Outcome System score was 4.5 ± 1.7, with 83% of participants rating their quality of life after surgery as good, very good, or excellent.

CONCLUSION

Those with class I obesity who undergo LSG experience normalization of weight, sustained remission of co-morbidity, and good quality of life without significant risk of morbidity or mortality.

Targeting lipid metabolism in metastatic prostate cancer

Despite key advances in the treatment of prostate cancer (PCa), a proportion of men have de novo resistance, and all will develop resistance to current therapeutics over time. Aberrant lipid metabolism has long been associated with prostate carcinogenesis and progression, but more recently there has been an explosion of preclinical and clinical data which is informing new clinical trials. This review explores the epidemiological links between obesity and metabolic syndrome and PCa, the evidence for altered circulating lipids in PCa and their potential role as biomarkers, as well as novel therapeutic strategies for targeting lipids in men with PCa, including therapies widely used in cardiovascular disease such as statins, metformin and lifestyle modification, as well as novel targeted agents such as sphingosine kinase inhibitors, DES1 inhibitors and agents targeting FASN and beta oxidation.

Pathogenic Role of Adipose Tissue-Derived Mesenchymal Stem Cells in Obesity and Obesity-Related Inflammatory Diseases

Adipose tissue-derived mesenchymal stem cells (ASCs) are adult stem cells, endowed with self-renewal, multipotent capacities, and immunomodulatory properties, as mesenchymal stem cells (MSCs) from other origins. However, in a pathological context, ASCs like MSCs can exhibit pro-inflammatory properties and attract inflammatory immune cells at their neighborhood. Subsequently, this creates an inflammatory microenvironment leading to ASCs' or MSCs' dysfunctions. One such example is given by obesity where adipogenesis is impaired and insulin resistance is initiated. These opposite properties have led to the classification of MSCs into two categories defined as pro-inflammatory ASC1 or anti-inflammatory ASC2, in which plasticity depends on the micro-environmental stimuli. The aim of this review is to (i) highlight the pathogenic role of ASCs during obesity and obesity-related inflammatory diseases, such as rheumatoid arthritis, multiple sclerosis, psoriasis, inflammatory bowel disease, and cancer; and (ii) describe some of the mechanisms leading to ASCs dysfunctions. Thus, the role of soluble factors, adhesion molecules; TLRs, Th17, and Th22 cells; γδ T cells; and immune checkpoint overexpression will be addressed.

Correlations between salivary- and blood-derived gonadal hormone assessments and implications for inclusion of female participants in research studies

Even in the 21st century, female participants continue to be underrepresented in human physiology research. This underrepresentation is attributable in part to the perception that the inclusion of females is more time consuming, less convenient, and more expensive relative to males because of the need to account for the menstrual cycle in cardiovascular study designs. Accounting for menstrual cycle-induced fluctuations in gonadal hormones is important, given established roles in governing vascular function and evidence that failure to consider gonadal hormone fluctuations can result in misinterpretations of biomarkers of cardiovascular disease. Thus, for cardiovascular researchers, the inclusion of females in research studies implies a necessity to predict, quantify, and/or track indexes of menstrual cycle-induced changes in hormones. It is here that methodologies are lacking. Gold standard measurement requires venous blood samples, but this technique is invasive and can become both expensive and technically preclusive when serial measurements are required. To this end, saliva-derived measures of gonadal hormones provide a means of simple, noninvasive hormone tracking. To investigate the feasibility of this technique as a means of facilitating research designs that take the menstrual cycle into account, the purpose of this review was to examine literature comparing salivary and blood concentrations of the primary gonadal hormones that fluctuate across the menstrual cycle: estradiol and progesterone. The data indicate that there appear to be valid and promising applications of salivary gonadal hormone monitoring, which may aid in the inclusion of female participants in cardiovascular research studies.

Body composition and pelvic fat distribution are associated with prostate cancer aggressiveness and can predict biochemical recurrence

This study evaluated the effect of body composition and pelvic fat distribution on the aggressiveness and prognosis of localized prostate cancer. This study included patients who underwent robot-assisted radical prostatectomy with positive surgical margins. Clinicodemographic data were collected from patients' medical reports. Pretreatment magnetic resonance images (MRI) obtained for cancer staging were reviewed by a single radiologist to calculate pelvic fat distribution and body composition. We correlated these body composition parameters with initial prostate-specific antigen (iPSA), Gleason score, extracapsular tumor extension, and biochemical recurrence (BCR)-free survival. The iPSA was significantly associated with body mass index (BMI; P = .027), pelvic fat volume (P = .004), and perirectal fat volume (P = .001), whereas the Gleason score was significantly associated with BMI only (P = .011). Tumor extracapsular extension was significantly associated with increased periprostatic fat volume (P = .047). Patients with less subcutaneous fat thickness (<2.4 cm) had significantly poor BCR-free survival (P = .039). Pelvic fat distribution, including pelvic fat volume, perirectal fat volume, and periprostatic fat volume, were significantly correlated with prostate cancer aggressiveness. Patients with less subcutaneous fat had an increased risk of BCR after radical prostatectomy.

[Prostate and breast cancer: similarities and differences]

Prostate and breast carcinomas are amongst the most common new diseases in men and women, with steadily rising incidences. In addition to the significant health consequences, both diseases also lead to a significantly reduced quality of life due to their influence on sexual function. The aim of this work is to identify scientific approaches and research priorities that in the future might lead to synergies in both disciplines by specifically considering the similarities and differences between the two diseases. For this purpose, clinically relevant aspects such as risk factors, treatment options, as well as scientific similarities and differences that offer direct joint research approaches in the areas of cultivation and modeling of both tumor entities were analyzed. Through this approach, we were able to demonstrate that due to the comparable biology of the two diseases and the underlying mechanisms, scientific synergies may certainly lead to targeted research. Clinical similarities also indicate that close collaboration between the two disciplines could lead to improved treatment of our patients. Evidence deficiencies in both diseases (e.g. the metastasis mechanisms of both tumor entities) and controversially discussed aspects such as risk factors clearly show that further scientific projects for a more detailed understanding of both diseases are necessary to ensure future success in the treatment of our patients.

Bone Health Management in the Continuum of Prostate Cancer Disease

Prostate cancer (PCa) is the second-leading cause of cancer-related deaths in men. PCa cells require androgen receptor (AR) signaling for their growth and survival. Androgen deprivation therapy (ADT) is the preferred treatment for patients with locally advanced and metastatic PCa disease. Despite their initial response to androgen blockade, most patients eventually will develop metastatic castration-resistant prostate cancer (mCRPC). Bone metastases are common in men with mCRPC, occurring in 30% of patients within 2 years of castration resistance and in >90% of patients over the course of the disease. Patients with mCRPC-induced bone metastasis develop lesions throughout their skeleton; the 5-year survival rate for these patients is 47%. Bone-metastasis-induced early changes in the bone that proceed the osteoblastic response in the bone matrix are monitored and detected via modern magnetic resonance and PET/CT imaging technologies. Various treatment options, such as targeting osteolytic metastasis with bisphosphonates, prednisone, dexamethasone, denosumab, immunotherapy, external beam radiation therapy, radiopharmaceuticals, surgery, and pain medications are employed to treat prostate-cancer-induced bone metastasis and manage bone health. However, these diagnostics and treatment options are not very accurate nor efficient enough to treat bone metastases and manage bone health. In this review, we present the pathogenesis of PCa-induced bone metastasis, its deleterious impacts on vital organs, the impact of metastatic PCa on bone health, treatment interventions for bone metastasis and management of bone- and skeletal-related events, and possible current and future therapeutic options for bone management in the continuum of prostate cancer disease.

Body Composition and Prostate Cancer Risk: A Systematic Review of Observational Studies

Body composition parameters are not captured by measures of body mass, which may explain inconsistent associations between body weight and prostate cancer (PC) risk. The objective of this systematic review was to characterize the association between fat mass (FM) and fat-free mass (FFM) parameters and PC risk. A search of PubMed, Embase, and Web of Science identified case-control and cohort studies that measured body composition in relation to PC risk. Methodological quality was assessed using the Newcastle-Ottawa Scale (NOS). Thirteen observational studies were included, of which 8 were case-control studies (n = 1572 cases, n = 1937 controls) and 5 were prospective cohort studies (n = 7854 incident cases with PC). The NOS score was 5.9 ± 1.1 for case-control studies and 8.4 ± 1.3 for cohort studies. The most common body composition technique was bioelectrical impedance analysis (n = 9 studies), followed by DXA (n = 2), computed tomography (n = 2), air displacement plethysmography (n = 1), and MRI (n = 1). No case-control studies reported differences in %FM between PC cases and controls and no consistent differences in FM or FFM (in kilograms) were observed. Two out of 5 cohort studies reported that higher %FM was associated with lower PC risk. Conversely, 3 cohort studies reported a greater risk of being diagnosed with advanced/aggressive PC with higher FM (expressed in kilograms, %FM, or fat distribution). Two out of 4 studies (both case-control and cohort) found that higher abdominal adipose tissue was associated with increased PC risk. In conclusion, although results were inconsistent, there is some evidence that FM may be negatively associated with total PC risk but positively associated with the risk of advanced/aggressive PC; modest evidence suggests that abdominal adipose tissue may increase the risk of PC. Future work should elucidate unique patterns of FM distribution and PC risk to triage men at risk for developing PC. This study protocol was registered in the International Prospective Register of Systematic Reviews (PROSPERO) database as CRD42019133388.

Non-Alcoholic Fatty Liver Disease and Extrahepatic Cancers: A Wolf in Sheep’s Clothing?

Non-alcoholic fatty liver disease (NAFLD) is now considered the main driver and leading cause of chronic liver disease globally. The umbrella term NAFLD describes a range of liver conditions closely related to insulin resistance, metabolic syndrome, diabetes mellitus, obesity, and dyslipidemia. At the same time, several malignancies, including hepatocellular carcinoma and colorectal cancer, are considered to be common causes of death among patients with NAFLD. At first, our review herein aims to investigate the role of NAFLD in developing colorectal neoplasms and adenomatous polyps based on the current literature. We will also explore the connection and the missing links between NAFLD and extrahepatic cancers. Interestingly, any relationship between NAFLD and extrahepatic malignancies could be attributable to several shared metabolic risk factors. Overall, obesity, insulin resistance, metabolic syndrome, and related disorders may increase the risk of developing cancer. Therefore, early diagnosis of NAFLD is essential for preventing the progression of the disease and avoiding its severe complications. In addition, cancer screening and early detection in these patients may improve survival and reduce any delays in treatment.

Association between obesity and frequency of high‑grade prostate cancer on biopsy in men: A single‑center retrospective study

The present study aimed to investigate the relationship between BMI and the prostate cancer (PCa) risk at biopsy in Italian men. Retrospective analyses of the clinical data of 2,372 consecutive men undergoing ultrasound-guided multicore (≥10) prostate biopsy transrectally between May 2010 and December 2018 were performed. BMIs were categorized, according to Western countries' classification of obesity, as follows: <18.5 kg/m² (underweight), 18.5-24.99 kg/m² (normal weight), 25-30 kg/m² (overweight) and >30 kg/m² (obese). The distribution of patients undergoing biopsy was compared with a model population from the official survey data. Patient characteristics and the relationships between characteristics were investigated using correlation analysis, ANOVA, Kruskal-Wallis and Dunn's tests. The present study estimated the influence on cancer incidence not only of BMI but also of other patient characteristics using multi-variable logistic modelling and compared, using the models, the expected outcomes for patients who differed only in BMI. From a sample of 2,372 men, the present study enrolled 1,079 men due to a lack of clinical data [such as prostate specific antigen (PSA) and BMI data] in the other patients undergoing prostate biopsy. Their distribution was significantly different from the model distribution with the probability of undergoing biopsy increasing with increasing BMI. The median age was 69.4 years. The median BMI was 26.4 kg/m², while the median PSA level was 7.60 ng/ml. In total, the biopsies detected PCa in 320 men (29.7%) and high-grade PCa (HGPCa) in 218 men (20.2%). Upon applying the aforementioned Western countries' criteria for BMI categories, there were 4 (0.4%) underweight, 318 (29.5%) of normal weight, 546 (50.6%) overweight, and 211 (19.6%) obese patients. ANOVA/Kruskal-Wallis tests revealed that overweight and obese men were younger than the normal-weight men, while there was no statistical difference in their PSA values. Furthermore, 29.3% of normal-weight men, 29.5% of overweight men and 29.9% of obese men were diagnosed with PCa, while 19.5% of normal-weight men, 20.1% of overweight men and 21.8% of obese men were affected by severe cancer. BMI was found to be positively correlated with PCa risk and negatively correlated with both age and PSA level. Age and PSA level were both positively correlated with PCa risk, while digital rectal examination (DRE) outcome was strongly indicative of PCa discovery if the test outcome was positive. Logistics models attributed a positive coefficient to BMI when evaluated against both PCa risk and HGPCa risk. In patients having a negative DRE outcome who differed only in BMI, logistic regression showed a 60% increased risk of PCa diagnosis in obese patients compared with in normal-weight patients. This risk difference increased when other characteristics were less indicative of PCa (younger age/lower PSA), while it decreased when patient characteristics were more indicative (older age/higher PSA, positive DRE). In conclusion, the present study demonstrated that, in men with higher BMIs, the risk of PCa is higher. The relative difference in risk between low and high BMI is most pronounced in younger patients having a lower PSA level and a negative DRE outcome.

Cholesterol and saturated fatty acids synergistically promote the malignant progression of prostate cancer

The excessive accumulation of saturated fatty acids and cholesterol have been linked to prostate cancer (Pca). Here, we found that lipoproteins, apolipoproteins, triglycerides and free fatty acids are significantly higher in the peripheral blood of prostate cancer patients than in non-cancer patients. Furthermore, the expression of ACC1, FASN and HMGCR is significantly higher in prostate cancer tissues than that in non-cancer tissues, and positively correlated with the gleason score. Using genetically engineered mouse models, we found that in a mouse model of high grade prostatic intraneoplasia (HGPIN), a combination of fatty acid synthase (FASN) overexpression and cholesterol efflux pump (Abca1) knockout resulted in the progression of prostatic intraneoplasia (PIN) to invasive PCa with 100% penetrance, as well as an increase in prostate cancer stem cell (PCSC)population, accompanied by activation of PGE2 and TGF-β signaling pathway. Our study suggests that the steady rise in prostate cancer incidence and mortality among Chinese population during the last several decades may be attribute to a combinational effect of fatty acid and cholesterol, and reduction in dietary fat and cholesterol intake could slow down the progression from occult lesions to prostate cancer.

Effectiveness of cognitive behavioural therapy on quality of life in patients with prostate cancer after androgen deprivation therapy: a protocol for systematic review and meta-analysis

INTRODUCTION

Prostate cancer (PCa), as a malignant tumour with rapid development in recent years, significantly affects men's health, work, life and economy. Androgen deprivation therapy (ADT) plays an important role in the treatment of PCa and can be used as a complementary therapy in the late stage of castration-resistant prostate cancer. Though ADT targeting PCa shows an effective therapeutic effect, the underlying side effects (cognitive disorder, hot flashes, a decrease in sexuality) cannot be ignored. At present, cognitive behavioural therapy (CBT) has been widely used for patients with PCa after ADT due to its confirmed efficacy, fewer side effects and lower economic burden. However, the effectiveness of CBT for patients with PCa after ADT is still controversial. Therefore, we will conduct a systematic review and meta-analysis of the effectiveness of CBT for patients with PCa after ADT.

METHODS AND ANALYSIS

Literatures will be searched from establishment of the database to 31 May 2021 with the language restrictions of English and Chinese in eight online databases (PubMed, Embase, the Web of Science, Cochrane Library, VIP, CNKI, CBM, and WAN FANG). This study will include RCTs that performed CBT as the main method of the experimental group for patients with PCa after ADT. Two or more reviewers will independently conduct the selection of studies, data extraction and data analysis. The risk ratios with 95% CIs will be used to present the data synthesis result of dichotomous data, while weighted mean differences or standardised mean differences with 95% CIs will be used to present the data synthesis result of continuous data. Meanwhile, evidence quality of outcome will be assessed by using the Grading of Recommendations Assessment, Development and Evaluation method. Stata V.13.0 and Review Manager software V.5.3 will be used for analysis and synthesis.

ETHICS AND DISSEMINATION

This protocol is a second study based on a completed randomised controlled study. Thus, ethical approval is not required, and no additional data are available.

OSF REGISTRATION NUMBER

DOI 10.17605/OSF.IO/FUVEA.

Fatty Acid Metabolism Reprogramming in Advanced Prostate Cancer

Prostate cancer (PCa) is a carcinoma in which fatty acids are abundant. Fatty acid metabolism is rewired during PCa development. Although PCa can be treated with hormone therapy, after prolonged treatment, castration-resistant prostate cancer can develop and can lead to increased mortality. Changes to fatty acid metabolism occur systemically and locally in prostate cancer patients, and understanding these changes may lead to individualized treatments, especially in advanced, castration-resistant prostate cancers. The fatty acid metabolic changes are not merely reflective of oncogenic activity, but in many cases, these represent a critical factor in cancer initiation and development. In this review, we analyzed the literature regarding systemic changes to fatty acid metabolism in PCa patients and how these changes relate to obesity, diet, circulating metabolites, and peri-prostatic adipose tissue. We also analyzed cellular fatty acid metabolism in prostate cancer, including fatty acid uptake, de novo lipogenesis, fatty acid elongation, and oxidation. This review broadens our view of fatty acid switches in PCa and presents potential candidates for PCa treatment and diagnosis.

Could Reducing Body Fatness Reduce the Risk of Aggressive Prostate Cancer via the Insulin Signalling Pathway? A Systematic Review of the Mechanistic Pathway

Excess body weight is thought to increase the risk of aggressive prostate cancer (PCa), although the biological mechanism is currently unclear. Body fatness is positively associated with a diminished cellular response to insulin and biomarkers of insulin signalling have been positively associated with PCa risk. We carried out a two-pronged systematic review of (a) the effect of reducing body fatness on insulin biomarker levels and (b) the effect of insulin biomarkers on PCa risk, to determine whether a reduction in body fatness could reduce PCa risk via effects on the insulin signalling pathway. We identified seven eligible randomised controlled trials of interventions designed to reduce body fatness which measured insulin biomarkers as an outcome, and six eligible prospective observational studies of insulin biomarkers and PCa risk. We found some evidence that a reduction in body fatness improved insulin sensitivity although our confidence in this evidence was low based on GRADE (Grading of Recommendations, Assessment, Development and Evaluations). We were unable to reach any conclusions on the effect of insulin sensitivity on PCa risk from the few studies included in our systematic review. A reduction in body fatness may reduce PCa risk via insulin signalling, but more high-quality evidence is needed before any conclusions can be reached regarding PCa.

Association of Anthropometric Measures With the Risk of Prostate Cancer in the Multiethnic Cohort

In studies of anthropometric measures and prostate cancer risk, conducted primarily in White men, positive associations with advanced disease have been reported. We assessed body size in relation to incident prostate cancer risk in 79,950 men from the Multiethnic Cohort, with 8,819 cases identified over 22 years (1993-2015). Height was associated with increased risk of advanced prostate cancer (≥68 inches (≥ 173 cm) vs. < 66 inches (168 cm); hazard ratio (HR) = 1.24, 95% confidence interval (CI): 1.04, 1.48) and high-grade disease (HR = 1.15, 95% CI: 1.02, 1.31). Compared with men of normal weight, men overweight at baseline were at higher risk of high-grade cancer (HR = 1.15, 95% CI: 1.04, 1.26). Greater weight was positively associated with localized and low-grade disease in Blacks and Native Hawaiians (by race, P for heterogeneity = 0.0002 and 0.008, respectively). Weight change since age 21 years was positively associated with high-grade disease (for ≥ 40 pounds (18 kg) vs. 10 pounds (4.5 kg), HR = 1.20, 95% CI: 1.05, 1.37; P for trend = 0.005). Comparing highest versus lowest quartile, waist-to-hip ratio was associated with a 1.78-fold increase (95% CI: 1.28, 2.46) in the risk of advanced prostate cancer. Positive associations with the majority of anthropometric measures were observed in all 5 racial/ethnic groups, suggesting a general impact of anthropometric measures on risk across populations.

Increased Body Mass Index Is a Risk Factor for Poor Clinical Outcomes after Radical Prostatectomy in Men with International Society of Urological Pathology Grade Group 1 Prostate Cancer Diagnosed with Systematic Biopsies

INTRODUCTION

The association between obesity and clinically significant prostate cancer (PCa) is still a matter of debate. In this study, we evaluated the effect of body mass index (BMI) on the prediction of pathological unfavorable disease (UD), positive surgical margins (PSMs), and biochemical recurrence (BCR) in patients with clinically localized (≤cT2c) International Society of Urological Pathology (ISUP) grade group 1 PCa at biopsy.

METHODS

427 patients with ISUP grade group 1 PCa who have undergone radical prostatectomy and BMI evaluation were included. The outcome of interest was the presence of UD (defined as ISUP grade group ≥3 and pT ≥3a), PSM, and BCR.

RESULTS

Statistically significant differences resulted in comparing BMI with prostate-specific antigen (PSA) and serum testosterone levels (both p < 0.0001). Patients with UD and PSM had higher BMI values (p < 0.0001 and p = 0.006, respectively). BCR-free survival was significantly decreased in patients with higher BMI values (p < 0.0001). BMI was an independent risk factor for BCR and PSM. Receiver-operating characteristic analysis testing PSA accuracy in different BMI groups, showed that PSA had a reduced predictive value (area under the curve [AUC] = 0.535; 95% confidence interval [CI] = 0.422-0.646), in obese men compared to overweight (AUC = 0.664; 95% CI = 0.598-0.725) and normal weight patients (AUC = 0.721; 95% CI = 0.660-0.777).

CONCLUSION

Our findings show that increased BMI is a significant predictor of UD and PSM at RP in patients with preoperative low-to intermediate-risk diseases, suggesting that BMI evaluation may be useful in a clinical setting to identify patients with favorable preoperative disease characteristics harboring high-risk PCa.

Effect of pre-operative internal obturator muscle mass index in MRI on biochemical recurrence of prostate cancer patients after radical prostatectomy: a multi-center study

Background

Recent reports show that the pre-operative or post-operative skeletal mass index (sarcopenia) affects survival rates for various cancers; however, the link between prostate cancer survival and sarcopenia is unclear. Therefore, this study examined the effect of the pre-operative internal obturator muscle (IOM) mass index on biochemical recurrence (BCR) of prostate cancer (PCa) patients who underwent radical prostatectomy.

Methods

In total, 222 patients, who underwent open, laparoscopic, or robot-assisted radical prostatectomy at seven centers in 2011 and were followed up for 5 years, were enrolled. BCR was examined in the context of pre-operative IOM mass index and BMI.

Results

The mean age of the patients was 67.82 ± 6.23 years, and the mean pre-operative prostate-specific antigen (PSA) level was 11.61 ± 13.22 ng/ml. There was no significant difference in baseline characteristics between the low and high IOM mass index groups (p > 0.05). Age, pre-op PSA level, ECE, and T-stage were associated with BCR (p = 0.049, p < 0.001, p = 0.001, p = 0.004, respectively). BMI, prostate volume, Gleason score, resection margin, N-stage, M-stage and IOM mass index was not associated with BCR (p > 0.05).

Conclusions

Pre-operative IOM mass index was not associated with BCR; however, long-term follow-up is necessary to evaluate cancer-specific and overall survival of PCa patients.

Skeletal Muscle-Adipose Tissue-Tumor Axis: Molecular Mechanisms Linking Exercise Training in Prostate Cancer

Increased visceral adiposity may influence the development of prostate cancer (PCa) aggressive tumors and cancer mortality. White adipose tissue (WAT), usually referred to as periprostatic adipose tissue (PPAT), surrounds the prostatic gland and has emerged as a potential mediator of the tumor microenvironment. Exercise training (ET) induces several adaptations in both skeletal muscle and WAT. Some of these effects are mediated by ET-induced synthesis and secretion of several proteins, known as myo- and adipokines. Together, myokines and adipokines may act in an endocrine-like manner to favor communication between skeletal muscle and WAT, as they may work together to improve whole-body metabolic health. This crosstalk may constitute a potential mechanism by which ET exerts its beneficial role in the prevention and treatment of PCa-related disorders; however, this has not yet been explored. Therefore, we reviewed the current evidence on the effects of skeletal muscle–WAT–tumor crosstalk in PCa, and the potential mediators of this process to provide a better understanding of underlying ET-related mechanisms in cancer.

Mechanistic Insights into the Link between Obesity and Prostate Cancer

Obesity is a pandemic of increasing worldwide prevalence. There is evidence of an association between obesity and the risk of prostate cancer from observational studies, and different biologic mechanisms have been proposed. The chronic low-level inflammation within the adipose tissue in obesity results in oxidative stress, activation of inflammatory cytokines, deregulation of adipokines signaling, and increased circulating levels of insulin and insulin-like growth factors (IGF). These mechanisms may be involved in epithelial to mesenchymal transformation into a malignant phenotype that promotes invasiveness, aggressiveness, and metastatic potential of prostate cancer. A thorough understanding of these mechanisms may be valuable in the development of effective prostate cancer prevention strategies and treatments. This review provides an overview of these mechanisms.

Associating the risk of three urinary cancers with obesity and overweight: an overview with evidence mapping of systematic reviews

BACKGROUND

The relationship between cancer with overweight and obesity has been extensively reported. However, the association between urinary cancers with these risk factors remains unclear, with existing reports showing conflicting findings. The current review, therefore, sought to clarify the latter association by assessing the methodological and reporting quality of existing systematic reviews on the subject.

METHODS

We first screened PubMed, EMBASE, and Cochrane Library databases for relevant literature and subjected the resulting articles to meta-analysis. We adopted the AMSTAR-2 and PRISMA checklists for assessing methodological and reporting quality, respectively, then performed meta-analyses to determine the relationship between incidence and mortality of three types of urinary cancers with obesity and overweight. Indirect comparisons were also done across subgroups.

RESULTS

All systematic reviews (SRs) were of critically low methodological quality. Seventeen SRs had minimal reporting flaws, and 11 SRs had minor reporting flaws. We found an association between obesity with an incidence of kidney (RR = 1.68, 95% CI 1.47-1.92), bladder (RR = 1.1, 95% CI 1.07-1.13), and prostate (RR = 1.02, 95% CI 0.91, 1.13) cancers. Similarly, overweight was associated with the incidence of the three types of cancer, recording RR values of 1.37 (95% CI 1.26-1.48), 1.07 (95% CI 1.03-1.1), and 1 (95% CI 0.93, 1.07) for kidney, bladder, and prostate cancers, respectively. With regard to the dose analysis, the RR of BMI (per 5 kg/m2 increase) was associated with kidney (RR = 1.24, 95% CI 1.2-1.28), bladder (RR = 1.03, 95% CI 1.02-1.05), and prostate (RR = 1.02, 95% CI 1.01, 1.03) cancers.

CONCLUSIONS

This comprehensive quantitative analysis provides an affirmation that overweight and obesity are strong risk factors for kidney cancer, owing to a strong association between them. Conversely, a weak association between overweight and obesity with bladder and prostate cancers confirms their status as mild risk factors for the 2 types of cancer. But due to the low quality of included SRs, the results need to be interpreted with caution.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42019119459.

Endotoxemia by Porphyromonas gingivalis Alters Endocrine Functions in Brown Adipose Tissue

Improvement of obesity is important for increasing longevity. The characteristics, size, and function of adipocytes are altered in patients with obesity. Adipose tissue is not only an energy storage but also an endocrine organ. Alteration of endocrine activities in adipose tissue, among them the functional decline of brown adipose tissue (BAT), is associated with obesity. Periodontal disease is a risk factor for systemic diseases since endotoxemia is caused by periodontal bacteria. However, the effect of periodontal disease on obesity remains unclear. Thus, this study aimed to investigate the effect of endotoxemia due to Porphyromonas gingivalis, a prominent cause of periodontal disease, on the BAT. Herein, endotoxemia was induced in 12-week-old C57BL/6J mice through intravenous injection of sonicated 10⁸ CFU of P. gingivalis (Pg) or saline (control [Co]) once. Eighteen hours later, despite no inflammatory M1 macrophage infiltration, inflammation-related genes were upregulated exclusively in the BAT of Pg mice compared with Co mice. Although no marked histological changes were observed in adipose tissues, expressions of genes related to lipolysis, Lipe and Pnpla2 were downregulated after P. gingivalis injection in BAT. Furthermore, expression of Pparg and Adipoq was downregulated only in the BAT but not in the white adipose tissues, along with downregulation of Ucp1 and Cidea expression, which are BAT-specific markers, in Pg mice. Microarray analysis of the BAT showed 106 differentially expressed genes between Co and Pg mice. Gene set enrichment analysis revealed that the cholesterol homeostasis gene set and PI3/Akt/mTOR signaling gene set in BAT were downregulated, whereas the TGF-β signaling gene set was enriched in Pg mice. Overall, intravenous injection of sonicated P. gingivalis altered the endocrine functions of the BAT in mice. This study indicates that endotoxemia by P. gingivalis potentially affects obesity by disrupting BAT function.

Circulating adiponectin and leptin and risk of overall and aggressive prostate cancer: a systematic review and meta-analysis

Obesity is associated with an increased risk of advanced, recurrent and fatal prostate cancer. Adipokines may mediate this relationship. We conducted a systematic review and meta-analysis of associations of leptin and adiponectin with overall and aggressive prostate cancer. Bibliographic databases were systematically searched up to 1st April 2017. Log Odds Ratios (ORs) per 2.5 unit increase in adiponectin or leptin levels were derived and pooled. All analyses were stratified by study type (cross-sectional/prospective). 746 papers were retrieved, 34 eligible studies identified, 31 of these could be included in the meta-analysis. Leptin was not consistently associated with overall prostate cancer (pooled OR 1.00, 95%CI 0.98-1.02, per 2.5 ng/ml increase, prospective study OR 0.97, 95%CI 0.95-0.99, cross-sectional study OR 1.19, 95%CI 1.13-1.26) and there was weak evidence of a positive association with aggressive disease (OR 1.03, 95%CI 1.00-1.06). There was also weak evidence of a small inverse association of adiponectin with overall prostate cancer (OR 0.96, 95%CI 0.93-0.99, per 2.5 µg/ml increase), but less evidence of an association with aggressive disease (OR 0.98, 95%CI 0.94-1.01). The magnitude of any effects are small, therefore levels of circulating adiponectin or leptin alone are unlikely to be useful biomarkers of risk or prognosis.

Differences in the prevalence of modifiable risk and protective factors for prostate cancer by race and ethnicity in the National Health and Nutrition Examination Survey

PURPOSE

Prostate cancer burden is disproportionate by race. Black men have the highest incidence and mortality rates. Rates for Hispanic men are significantly lower than for non-Hispanic Whites. Whether differences in prevalences of modifiable risk and protective factors for prostate cancer may explain these racial/ethnic differences remains unclear.

METHODS

We used data from the National Health and Nutrition Examination Surveys (NHANES), which are cross-sectional and nationally representative. We selected factors known or suspected to be associated with prostate cancer and calculated risk scores combining key factors. Age-adjusted means and proportions were calculated for each factor and risk score by race/ethnicity. We estimated odds ratios (OR) using polytomous logistic regression.

RESULTS

Prevalences of most factors are statistically significantly differed by race/ethnicity. In NHANES III, the prevalence of high risk score (i.e., > 25th percentile for all participants) was lower for all groups (non-Hispanic Black = 59.4%, non-US-born Mexican American = 51.4%, US-born Mexican American = 61.4%) vs. non-Hispanic White men (76.4%). Similar findings were observed for the fatal weighted risk score and for continuous NHANES.

CONCLUSIONS

Our findings from this nationally representative study suggest that a combination of multiple risk and protective factors may help to explain the lower rates of prostate cancer in Mexican Americans. However, variation in these factors did not explain the higher risk of prostate cancer in non-Hispanic Black men. No one lifestyle change can reduce prostate cancer equally across all racial/ethnic groups, and modifiable factors may not explain the increased risk in black men at all. Secondary prevention strategies may provide the most benefit for black men.

Does increased body mass index lead to elevated prostate cancer risk? It depends on waist circumference

Background

We examined the association between obesity and prostate cancer based on both body mass index (BMI) and waist circumference (WC) using the National Health Insurance System (NHIS) database for the entire male population of Korea.

Methods

A total of 1,917,430 men who underwent at least one health examination in 2009 without a previous diagnosis of any other cancer were tracked through December 2015. The hazard ratio (HR) and 95% confidence interval (CI) value for the association between prostate cancer and obesity were analyzed using multiple Cox regression model. Since there was a statistically significant interaction between WC and BMI, a multiple HR for prostate cancer was estimated with stratifying both WC and BMI to control the interaction between WC and BMI.

Results

Without considering WC as an adjustment factor, very weak association between BMI and prostate cancer development risk was observed. When WC was considered as an adjustment factor, no significant change in the HRs for prostate cancer development beyond the reference BMI was observed in the group with WC < 85 cm in the multivariable-adjusted models. However, in the group with WC ≥ 85 cm, the HRs for prostate cancer increased as the BMI increased beyond the reference BMI. In addition, there was a discrepancy in the trend of prostate cancer development according to BMI among the groups with different categories for WC.

Conclusion

In groups with abdominal obesity, a significant linear relationship was observed between increasing BMI and prostate cancer risk. Higher the WC category, the stronger was the association with BMI, signifying that the association of BMI with risk of prostate cancer development depends on abdominal obesity.

Assessment of expression levels of leptin and leptin receptor as potential biomarkers for risk of prostate cancer development and aggressiveness

Background

Prostate cancer (PCa) is one of the most frequently diagnosed cancers worldwide. Despite the growing evidence associating obesity and adipokines, particularly leptin and its receptors, with cancer development and progression, it is still a debatable matter in PCa.

Objectives

We aimed to assess the role of leptin and its receptors as potential biomarkers for the risk of PCa development and aggressiveness.

Methods

In this study, 176 men were included and categorized according to an established histopathological diagnosis into three age‐ and BMI‐matched groups. The PCa group included 56 patients while the BPH group and the control group comprised 60 men each. Serum levels of total PSA (tPSA) were assessed by ELISA and mRNA expression levels of leptin and leptin receptors were assessed by RT‐PCR.

Results

Leptin and leptin receptor mRNA expression levels were significantly higher in PCa patients relative to BPH and to healthy control men. Both were overexpressed in PCa patients with aggressive and distantly metastasizing tumors compared to patients with confined tumors. Leptin receptor mRNA was an independent predictor of high Gleason score ≥ 7, distant metastasis, LN, and seminal vesicles invasion.

Conclusion

Leptin and its receptors are suggested to be potential biomarkers for PCa; leptin receptor mRNA might predict risk and aggressiveness of PCa.

Systematic review and meta-analysis of the associations between body mass index, prostate cancer, advanced prostate cancer, and prostate-specific antigen

PURPOSE

The relationship between body mass index (BMI) and prostate cancer remains unclear. However, there is an inverse association between BMI and prostate-specific antigen (PSA), used for prostate cancer screening. We conducted this review to estimate the associations between BMI and (1) prostate cancer, (2) advanced prostate cancer, and (3) PSA.

METHODS

We searched PubMed and Embase for studies until 02 October 2017 and obtained individual participant data from four studies. In total, 78 studies were identified for the association between BMI and prostate cancer, 21 for BMI and advanced prostate cancer, and 35 for BMI and PSA. We performed random-effects meta-analysis of linear associations of log-PSA and prostate cancer with BMI and, to examine potential non-linearity, of associations between categories of BMI and each outcome.

RESULTS

In the meta-analyses with continuous BMI, a 5 kg/m2 increase in BMI was associated with a percentage change in PSA of - 5.88% (95% CI - 6.87 to - 4.87). Using BMI categories, compared to normal weight men the PSA levels of overweight men were 3.43% lower (95% CI - 5.57 to - 1.23), and obese men were 12.9% lower (95% CI - 15.2 to - 10.7). Prostate cancer and advanced prostate cancer analyses showed little or no evidence associations.

CONCLUSION

There is little or no evidence of an association between BMI and risk of prostate cancer or advanced prostate cancer, and strong evidence of an inverse and non-linear association between BMI and PSA. The association between BMI and prostate cancer is likely biased if missed diagnoses are not considered.

Does Physical Activity Regulate Prostate Carcinogenesis and Prostate Cancer Outcomes? A Narrative Review

Background: Prostate cancer (PCa) represents a common disease in men aged >65 years. The role of physical activity (PA) in patients at risk or diagnosed with PCa represents an evolving issue. We aimed to summarize available evidences about the impact of PA on the pathophysiology and clinical outcomes of PCa. Methods: We performed a narrative review. Evidences about the role of PA in elderly patients in terms of PCa biology, epidemiology, oncological and functional outcomes, as well as in terms of impact on the outcomes of androgen deprivation therapy (ADT) were summarized. Results: Potential pathophysiological pathways hypothesized to explain the benefits of PA in terms of prostate carcinogenesis include circulating levels of Insulin-like growth factor-1 (IGF-1), oxidative stress, systemic inflammation, sex hormones, and myokines. Clinically, emerging evidences support the hypothesis that PA is associated with decreased PCa risk, improved PCa-related survival, improved functional outcomes, and reduced ADT-related adverse events.

Relationship of self-reported body size and shape with risk for prostate cancer: A UK case-control study

INTRODUCTION

Previous evidence has suggested a relationship between male self-reported body size and the risk of developing prostate cancer. In this UK-wide case-control study, we have explored the possible association of prostate cancer risk with male self-reported body size. We also investigated body shape as a surrogate marker for fat deposition around the body. As obesity and excessive adiposity have been linked with increased risk for developing a number of different cancers, further investigation of self-reported body size and shape and their potential relationship with prostate cancer was considered to be appropriate.

OBJECTIVE

The study objective was to investigate whether underlying associations exist between prostate cancer risk and male self-reported body size and shape.

METHODS

Data were collected from a large case-control study of men (1928 cases and 2043 controls) using self-administered questionnaires. Data from self-reported pictograms of perceived body size relating to three decades of life (20's, 30's and 40's) were recorded and analysed, including the pattern of change. The associations of self-identified body shape with prostate cancer risk were also explored.

RESULTS

Self-reported body size for men in their 20's, 30's and 40's did not appear to be associated with prostate cancer risk. More than half of the subjects reported an increase in self-reported body size throughout these three decades of life. Furthermore, no association was observed between self-reported body size changes and prostate cancer risk. Using 'symmetrical' body shape as a reference group, subjects with an 'apple' shape showed a significant 27% reduction in risk (Odds ratio = 0.73, 95% C.I. 0.57-0.92).

CONCLUSIONS

Change in self-reported body size throughout early to mid-adulthood in males is not a significant risk factor for the development of prostate cancer. Body shape indicative of body fat distribution suggested that an 'apple' body shape was protective and inversely associated with prostate cancer risk when compared with 'symmetrical' shape. Further studies which investigate prostate cancer risk and possible relationships with genetic factors known to influence body shape may shed further light on any underlying associations.

Physical activity in relation to risk of prostate cancer: a systematic review and meta-analysis

Background

Prostate cancer (PCa) is one of the most common cancers among men, yet little is known about its modifiable risk and protective factors. This study aims to quantitatively summarize observational studies relating physical activity (PA) to PCa incidence and mortality.

Materials and methods

Published articles pertaining to PA and PCa incidence and mortality were retrieved in July 2017 using the Medline and EMBASE databases. The literature review yielded 48 cohort studies and 24 case-control studies with a total of 151 748 PCa cases. The mean age of the study participants at baseline was 61 years.

Results

In random-effects models, comparing the highest versus the lowest level of overall PA showed a summary relative risk (RR) estimate for total PCa incidence close to the null [RR = 0.99, 95% confidence interval (CI) = 0.94-1.04]. The corresponding RRs for advanced and non-advanced PCa were 0.92 (95% CI = 0.80-1.06) and 0.95 (95% CI = 0.85-1.07), respectively. We noted a statistically significant inverse association between long-term occupational activity and total PCa (RR = 0.83, 95% CI = 0.71-0.98, n studies = 13), although that finding became statistically non-significant when individual studies were removed from the analysis. When evaluated by cancer subtype, an inverse association with long-term occupational activity was noted for non-advanced/non-aggressive PCa (RR = 0.51, 95% CI = 0.37-0.71, n studies = 2) and regular recreational activity was inversely related to advanced/aggressive PCa (RR = 0.75, 95% CI = 0.60-0.95, n studies = 2), although these observations are based on a low number of studies. Moreover, PA after diagnosis was related to reduced risk of PCa mortality among survivors of PCa (summary RR based on four studies = 0.69, 95% CI = 0.55-0.85).

Conclusions

Whether PA protects against PCa remains elusive. Further investigation taking into account the complex clinical and pathologic nature of PCa is needed to clarify the PA and PCa incidence relation. Moreover, future studies are needed to confirm whether PA after diagnosis reduces risk of PCa mortality.

Lower body mass index and higher height are correlated with increased varicocele risk

To evaluate the anthropometric indexes in subjects with varicocele compared to controls and the incidence of varicocele in different body mass index (BMI) groups for the purpose of exploring the association between varicocele and anthropometric indexes. A comprehensive literature search was conducted by using PubMed, MEDLINE, EMBASE databases and Cochrane Library up to February 2019. A systematic review and meta-analysis was conducted by STATA, and Newcastle-Ottawa Scale was utilised for assessing risk of bias. Ultimately, 13 articles containing seven case-control studies and six cross-sectional studies with 1,385,630 subjects were involved in our study. Pooled results demonstrated that varicocele patients had a lower BMI (WMD = -0.77, 95% CI = -1.03 to -0.51) and a higher height than nonvaricocele participants, especially in grade 3 varicocele patients. Subgroup analyses showed that normal BMI individuals had a higher risk of varicocele than obese or overweight individuals and a lower risk than underweight individuals. In conclusion, this study indicates that varicocele patients have a lower BMI and a higher height than nonvaricocele participants. Moreover, men with excess bodyweight have a lower incidence of varicocele compared to normal weight or underweight people. That is to say, high BMI and adiposity protect against varicocele and high BMI is associated with a decreased risk of varicocele.

Obesity at Diagnosis and Prostate Cancer Prognosis and Recurrence Risk Following Primary Treatment by Radical Prostatectomy

BACKGROUND

The association of obesity at diagnosis with prostate cancer progression is uncertain. This study aimed to examine the relationship between body mass index (BMI; 18.5-<25, 25-<30, 30-<35, ≥35 kg/m²) and prognostic risk at diagnosis, compare the concordance between prognostic risk assessed at diagnostic biopsy versus pathologic risk assessed at surgery across BMI categories, and investigate the association between obesity and prostate cancer recurrence and all-cause death.

METHODS

We examined men enrolled in CaPSURE who underwent radical prostatectomy between 1995 and 2017. Multiple imputation methods were used to handle missing data and reported along with complete case findings.

RESULTS

Participants (n = 5,200) were followed for a median of 4.5 years; 685 experienced recurrence. Obesity was associated with higher prognostic risk at time of diagnosis (OR_obese = 1.5; OR_{very obese} = 1.7) and upward reclassification of disease between biopsy and surgery, driven by change in tumor stage (OR_obese = 1.3; OR_{very obese} = 1.6). We observed an association between BMI and recurrence with adjustment for disease severity using diagnostic factors (HR_{very obese} = 1.7); this association disappeared when adjusting for disease severity factors obtained at surgery.

CONCLUSIONS

Our findings suggest that residual confounding may partially explain the conflicting evidence regarding obesity's influence on prostate cancer progression. Assessing T-stage via digital rectal exam may be complicated in larger men, potentially affecting clinical treatment decisions. A strong association with all-cause mortality demonstrates healthier BMI at diagnosis may still improve overall survival.

IMPACT

Patients with greater BMI are prone to more advanced disease at diagnosis and may be more likely to have their tumor stage underestimated at diagnosis.

Epidemiology of Mortality Due to Prostate Cancer in Poland, 2000-2015

The aim of the study was to assess trends in mortality and years of life lost due to prostate cancer (PCa) in Poland in 2000–2015. The crude death rates (CDR), standardised death rates (SDR), standard expected years of life lost per living person (SEYLL_p) and per death (SEYLL_d) values were calculated. Joinpoint models were used to analyse time trends. In the study period, 61,928 men died of PCa. The values of mortality rates in 2000 (per 100,000) were: CDR = 16.97, SDR = 16.17, SEYLL_p = 332.1. In 2015, the values of all rates increased: CDR = 26.22, SDR = 16.69, SEYLL_p = 429.5. However, the SEYLL_d value decreased from 15.62 to one man who died due to PCa in 2000 to 13.78 in 2015. The highest SEYLL_p values occurred in the group of men with primary education (619.5 in 2000 and 700.7 in 2015). They were respectively 2.24 and 2.96 times higher than in men with higher education (275.7 and 237.1). SEYLL_p values increased in urban areas (from 295.7 to 449.4), slightly changed in the rural areas (from 391.5 to 400.2). Unfavorable trends in mortality due to PCa in Poland require explanation of the causes and implementation of appropriate actions aimed at mortality reducing.

Body mass index and prostate cancer risk in the Carotene and Retinol Efficacy Trial

The aim of this study was to investigate the association between BMI (kg/m) and prostate cancer risk. BMI is a modifiable lifestyle factor and may provide a unique opportunity for primary prevention of prostate cancer if a causal association exists. Data from 11 886 men from the Carotene and Retinol Efficacy Trial (CARET, 1985-1996 with active follow-up through 2005) comprising current and former heavy smokers were analyzed. CARET was a multicenter randomized, double-blind placebo-controlled chemoprevention trial testing daily supplementation of 30 mg β-carotene+25 000 IU retinyl palmitate for primary prevention of lung cancer. Prostate cancer was a secondary outcome. Nonaggressive disease was defined as Gleason less than 7 and stage I/II. Aggressive disease was primarily defined as at least Gleason 7 or stage III/IV, and secondarily by excluding Gleason 3+4 from the first definition. BMI was calculated from measured weight and height. Cox proportional hazards regression models were used to estimate hazard ratios (HRs) with 95% confidence intervals (CIs) for cancer incidence between BMI categories. During follow-up, 883 men were diagnosed with prostate cancer. In the analysis of aggressive disease when Gleason 3+4 was excluded, men with a BMI of at least 35 kg/m had an increased rate of prostate cancer (HR: 1.80, 95% CI: 1.04-3.11, Ptrend=0.04) compared with men with BMI 18-24.9 kg/m. No other differences were seen in risk estimates for overall, nonaggressive or aggressive prostate cancer including all Gleason 7 cases, between BMI categories. Our results show an association between having a BMI of at least 35 kg/m and an increased risk of aggressive prostate cancer (not including Gleason 3+4 tumors), but do not support an association between BMI and risk of overall, aggressive disease including all Gleason 7, or nonaggressive prostate cancer within a population of current and former heavy smokers.

Metabolomic profiling for the identification of novel diagnostic markers and therapeutic targets in prostate cancer: an update

INTRODUCTION

An altered metabolic regulation is involved in the development and progression of different cancer types. As well as this, many genes associated with tumors are shown to have an important role in control of the metabolism. The incidence of prostate cancer (PCa) is increased in men with metabolic disorders. In particular, obesity is an established risk factor for PCa. An increased body mass index correlates with aggressive disease, and a higher risk of biochemical recurrence and prostate cancer-specific mortality. Increased lipogenesis is also one of the most significant events in PCa metabolism reprogramming. Areas covered: In this article, we provide an updated review of the current understanding of the PCa metabolome and evaluate the possibility of unveiling novel therapeutic targets. Expert opinion: Obesity is an established risk factor for PCa, and an increased BMI correlates with aggressive disease, and a higher risk of biochemical recurrence and prostate cancer-specific mortality. PCa metabolome is characterized by the accumulation of metabolic intermediates and an increased expression of genes in the tricarboxylic acid cycle, the induction of de novo lipogenesis and cholesterogenesis. PCa cells can induce different alterations in their microenvironment by modulating the crosstalk between cancer and stromal cells.

Leptin-induced signaling pathways in cancer cell migration and invasion

BACKGROUND

Increasing evidence indicates that obesity is associated with tumor development and progression. Leptin is an adipocyte-related hormone with a key role in energy metabolism and whose circulating levels are elevated in obesity. The effect of leptin on cancer progression and metastasis and its underlying mechanisms are still unclear. Leptin can impact various steps in tumor metastasis, including epithelial-mesenchymal transition, cell adhesion to the extracellular matrix (ECM), and proteolysis of ECM components. To do so, leptin binds to its receptor (OB-Rb) to activate signaling pathways and downstream effectors that participate in tumor cell invasion as well as distant metastasis.

CONCLUSIONS

In this review, we describe metastasis steps in detail and characterize metastasis-related molecules activated by leptin, which may help to develop a roadmap that guides future work. In addition, we conclude that a profound understanding of the fundamental molecular processes that contribute to leptin-induced metastasis may pave the way for the development of new prognostic molecules and appropriate approaches to the treatment of obesity-related cancers.

CRTC2 as a novel prognostic biomarker for worse pathologic outcomes and biochemical recurrence after radical prostatectomy in patients with prostate cancer

Purpose

To identify the association between tumor metabolism and prostate cancer (PCa), we investigated the relationship between expression of metabolism-related genes and clinicopathologic outcomes in patients with localized PCa.

Materials and Methods

We prospectively collected periprostatic adipose tissue from 40 PCa patients and extracted the RNA of each sample. After cDNA was synthesized from the extracted RNA, we analyzed the expression of 18 metabolism-related genes using real-time polymerase chain reaction. We divided the subjects according to the pathologic Gleason score (pGS) and compared the expression of each gene. Subsequently, the clinicopathologic outcomes were also compared according to the expression of each gene.

Results

When we compared the expression of 18 metabolism-related genes between the high (≥4+3) and low pGS groups (3+4), there were significant differences in the expression of six genes (SREBP, SCD, FASN, ACLY, ECHS, and CRTC2; p<0.05). Among them, the subjects with low expression for CRTC2 showed significantly worse pathologic outcomes in terms of high pGS (≥4+3) (p=0.020) and higher rates of seminal vesicle invasion (p=0.017). The low CRTC2 group also showed significantly inferior biochemical recurrence-free survival than the high CRTC2 group (p=0.048).

Conclusions

We found that high pGS patients showed significant differences in expression of several metabolism-related genes compared with low pGS patients. Among those genes, CRTC2 showed the strongest association with pathologic outcome, as well as postoperative survival.

Incidence of Prostate Cancer according to Metabolic Health Status: a Nationwide Cohort Study

BACKGROUND

We assessed the association between metabolic health status and incidence of prostate cancer using the National Health Check-ups (NHC) database of Korea.

METHODS

A total of 11,771,252 men who participated in the NHC between 2009 and 2012 and 56,552 men who were newly diagnosed with prostate cancer were analyzed. Normal-weight and obesity were defined as body mass index (BMI) < 25 kg/m² and ≥ 25 kg/m², respectively. Metabolic obesity was defined as the presence ≥ 3 components of the metabolic syndrome. Participants were stratified into 4 groups: metabolically healthy, normal-weight; metabolically obese, normal-weight (MONW); metabolically healthy, obese (MHO); and metabolically obese, obese. Multivariate Cox regression analysis was performed to examine the relationship between metabolic health status and incidence of prostate cancer.

RESULTS

During a mean 5.4 ± 1.1 years of follow-up, 56,552 patients were registered with a diagnosis of prostate cancer. When analyzed according to metabolic health status classification, the multivariable-adjusted hazard ratio (HR) was 1.143 for the MONW group, 1.097 for the MHO group, showing the HR for the MONW group was higher than that for the MHO group. As the number of metabolic syndrome components increased, HR increased significantly. When stratified based on BMI, metabolically obese patients showed significantly higher HR than metabolically healthy patients in all BMI groups.

CONCLUSION

This population-based nationwide study revealed an association between metabolic health status and the incidence of prostate cancer, and the risk increased according to the number of components of the metabolic syndrome.

Total nut, tree nut, peanut, and peanut butter intake and the risk of prostate cancer in the Netherlands Cohort Study

BACKGROUND

The consumption of nuts has been associated with a reduction of cancer risk, but only a few studies have examined the effects of nuts on prostate cancer risk. The current study prospectively investigated the association between the consumption of total nuts, tree nuts, peanuts, and peanut butter and the risk of total, advanced, and non-advanced prostate cancer.

METHODS

The association between nuts and prostate cancer was evaluated in the Netherlands Cohort Study, which was conducted among 58,279 men aged 55-69 year at baseline. A case-cohort approach was used for data processing and analyses. After 20.3 years of follow-up, 3868 incident prostate cancer cases and 1979 subcohort members were available for multivariable Cox regression analyses.

RESULTS

For total, advanced, and non-advanced prostate cancer, no significant associations were found for total nuts (total prostate cancer: hazard ratio (HR) (95%CI) for 10+ g/day vs. non-consumers = 1.09 (0.92-1.29), P_trend = 0.409). No significant associations were observed for tree nuts and peanuts for total, advanced, and non-advanced prostate cancer risk. Peanut butter consumption was associated with a significantly increased risk of non-advanced prostate cancer (HR (95%CI) for 5+ g/day vs. non-consumers = 1.33 (1.08-1.63), P_trend = 0.008), but not with total or advanced prostate cancer.

CONCLUSIONS

No significant associations were found between total nut, tree nut, and peanut consumption and total, advanced, and non-advanced prostate cancer. Peanut butter might be associated with an increased non-advanced prostate cancer risk.

PAGE4 promotes prostate cancer cells survive under oxidative stress through modulating MAPK/JNK/ERK pathway

Background

Prostate cancer (PCa) is one of the most common cancers in male worldwide. Oxidative stress has been recognized as one of the driving signals pathologically linked to PCa progression. Nevertheless, the association of oxidative stress with PCa progression remains unclear.

Methods

Western blot, q-RT-PCR and bioinformatics analyses were used to examine PAGE4 expression. Comet assay and Annexin V/ PI dual staining assay were performed to investigate DNA damage and cell death under oxidative stress. Mouse xenograft model of PCa cells was established to verify the role of PAGE4 in vivo. Transcriptomic analysis was performed to investigate the underlying mechanism for the function of PAGE4 under oxidative stress. Western blot assay was conducted to determine the status of MAPK pathway. Immunohistochemistry was used to identify protein expression of PAGE4 in tumor tissues.

Results

In this study, we found that PAGE4 expression was increased in PCa cells under oxidative stress condition. PAGE4 overexpression protected PCa cells from oxidative stress-inducing cell death by reducing DNA damage. PAGE4 overexpression promoted PCa cells growth in vivo. Mechanistically, PAGE4 promoted the survival of prostate cancer cells through regulating MAPK pathway which reflected in decreasing the phosphorylation of MAP2K4, JNK and c-JUN but increasing phosphorylation of ERK1/2.

Conclusion

Our findings indicate that PAGE4 protects PCa cells from DNA damage and apoptosis under oxidative stress by modulating MAPK signalling pathway. PAGE4 expression may serve as a prognostic biomarker for clinical applications.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1032-3) contains supplementary material, which is available to authorized users.

The Epidemiology of Prostate Cancer

Prostate cancer is a major cause of disease and mortality among men, and each year 1.6 million men are diagnosed with and 366,000 men die of prostate cancer. In this review, we discuss the state of evidence for specific genetic, lifestyle, and dietary factors associated with prostate cancer risk. Given the biological heterogeneity of this cancer, we focus on risk factors for advanced or fatal prostate cancer. First, we provide descriptive epidemiology statistics and patterns for prostate cancer incidence and mortality around the world. This includes discussion of the impact of prostate-specific antigen screening on prostate cancer epidemiology. Next, we summarize evidence for selected risk factors for which there is strong or probable evidence of an association: genetics, obesity and weight change, physical activity, smoking, lycopene and tomatoes, fish, vitamin D and calcium, and statins. Finally, we highlight future directions for prostate cancer epidemiology research.

Abdominal obesity and prostate cancer risk: epidemiological evidence from the EPICAP study

Obesity is associated with an increased risk of several cancers, but inconsistent results have been observed between body mass index (BMI) and prostate cancer (PCa) risk. However, some associations have been reported with other indicators such as waist circumference (WC) and waist-hip ratio (WHR). We investigated the role of anthropometric indicators in PCa risk based on data from the Epidemiological study of Prostate Cancer (EPICAP).

EPICAP is a population-based case-control study that included 819 incident PCa in 2012–2013 and 879 controls frequency matched by age. Anthropometric indicators (weight, height, WC, and hip circumference) have been measured at interview. Logistic regression models were used to assess odds ratios (ORs) for the associations between anthropometric indicators (BMI, WC and WHR) and PCa risk.

We observed a slight, but not significant increased risk of PCa for men with a WC > 94 cm (OR 1.20, 95% CI 0.92–1.56) and for men with a WHR ≥ 0.95 (OR 1.30, 95% CI 1.00–1.70 between 0.95 and 1.00, OR 1.25, 95% CI 0.96–1.61 above 1.00). Associations were more pronounced after adjustment and stratification for BMI and in men with aggressive PCa.

Our results suggest that abdominal obesity may be associated with an increased risk of PCa, especially aggressive PCa.

Association of Anthropometric Measures with Prostate Cancer among African American Men in the NCI-Maryland Prostate Cancer Case-Control Study

Background: Obesity is a cancer risk factor. Although it does not increase the risk of localized prostate cancer, it raises the risk of the aggressive disease in men of European ancestry. Few studies investigated obesity as a prostate cancer risk factor in men of African ancestry. Findings from those studies were heterogeneous, but some reported an association of excess body fatness with aggressive disease.Methods: We examined the relationship of body mass index (BMI), waist circumference, and waist-hip ratio with prostate cancer in African American (AA) and European American (EA) men in the NCI-Maryland Prostate Cancer Case-Control Study consisting of 798 men with incident prostate cancer (402 AA and 496 EA) and 1,008 population-based controls (474 AA and 534 EA). BMI was self-reported. Waist circumference and waist-hip ratio were calculated from measurements at enrollment.Results: A high BMI either at enrollment or years prior to it was associated with a decreased risk of prostate cancer in AA men. In contrast, an elevated BMI tended to increase the disease risk in EA men. Waist circumference was inversely associated with prostate cancer in both AA and EA men, whereas a high waist-hip ratio did not associate with prostate cancer in AA men but tended to be associated with advanced/aggressive disease in EA men.Conclusions: Our findings reveal an obesity paradox among AA men in this study population, where a high BMI and waist circumference associated with a decreased disease risk.Impact: Our observations expand the knowledge of how obesity may affect prostate cancer risks in AAs. Cancer Epidemiol Biomarkers Prev; 27(8); 936-44. ©2018 AACR.

Concentrated sugars and incidence of prostate cancer in a prospective cohort

The association between consumption of added or concentrated sugars and prostate cancer risk is unclear. We examined the association between concentrated sugars in beverages and desserts and prostate cancer risk among 22 720 men in the usual-care arm of the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial, enrolled during 1993-2001. After a median follow-up of 9 years, 1996 men were diagnosed with prostate cancer. Cox proportional hazards regression models were used to estimate hazard ratios (HR) for prostate cancer risk and 95 % CI, adjusting for potential confounding factors. Increased consumption of sugars from sugar-sweetened beverages was associated with increased risk of prostate cancer for men in the highest quartile of sugar consumption (HR: 1·21; 95 % CI 1·06, 1·39), and there was a linear trend (P<0·01). There were no linear associations between prostate cancer risk and consumption of sugars from fruit juices or dessert foods. In conclusion, in this prospective substudy within the PLCO trial, consumption of sugars from sugar-sweetened beverages was associated with increased risk of prostate cancer among men receiving standard medical care. Our study suggests that limiting intake of sugars from beverages may be important in the prevention of prostate cancer.

Adiponectin as a Potential Therapeutic Target for Prostate Cancer

Adipokines are bioactive proteins that mediate proliferation, metabolism, inflammation, and angiogenesis. Adiponectin is an important adipokine that exerts multiple key functions via its anti-metabolic syndrome and anti-inflammatory properties. A number of adiponectin receptors, AdipoR1, AdipoR2 and T-cadherin, have been identified. Recent studies have suggested the involvement of adiponectin and receptors in several cancers, including prostate, breast, endometrial, brain, and colon cancer. Altered levels of adiponectin expression, or its interacting receptors, in cancers can lead to dysregulation of signaling pathways. Our current review describes the molecular mechanisms underlying the anti-tumorigenesis activity of adiponectin and the role of its receptors in prostate carcinogenesis, and provides perspectives of adiponectin-mediated signaling as a potential target for therapy.