Obesity is associated with castration-resistant disease and metastasis in men treated with androgen deprivation therapy after radical prostatectomy: results from the SEARCH database

Adiposity assessed close to diagnosis and prostate cancer prognosis in the EPIC study

BACKGROUND

Adiposity has been characterized as a modifiable risk factor for prostate cancer. Its association with outcomes after prostate cancer diagnosis, however, must be better understood, and more evidence is needed to facilitate the development of lifestyle guidance for patients with prostate cancer.

METHODS

We investigated the associations between adiposity indices close to prostate cancer diagnosis (up to 2 years before or up to 5 years after diagnosis) and mortality in 1968 men of the European Prospective Investigation into Cancer and Nutrition cohort. Men were followed up for a median of 9.5 years. Cox proportional hazards models were adjusted for age and year of diagnosis, disease stage and grade, and smoking history and stratified by country.

RESULTS

Each 5-unit increment in prediagnosis or postdiagnosis body mass index combined was associated with a 30% higher rate of all-cause mortality and a 49% higher rate of prostate cancer-specific mortality. Similarly, each 5-unit increment in prediagnosis body mass index was associated with a 35% higher rate of all-cause mortality and a 51% higher rate of prostate cancer-specific mortality. The associations were less strong for postdiagnosis body mass index, with a lower number of men in analyses. Less clear positive associations were shown for waist circumference, hip circumference, and waist to hip ratio, but data were limited.

CONCLUSIONS

Elevated levels of adiposity close to prostate cancer diagnosis could lead to higher risk of mortality; therefore, men are encouraged to maintain a healthy weight. Additional research is needed to confirm whether excessive adiposity after prostate cancer diagnosis could worsen prognosis.

Metabolic Response to Androgen Deprivation Therapy of Prostate Cancer

Prostate cancer (PC) stands as the most frequently diagnosed non-skin cancer and ranks as the second highest cause of cancer-related deaths among men in the United States. For those facing non-metastatic PC necessitating intervention, solely local treatments may not suffice, leading to a possible transition toward systemic therapies, including androgen deprivation therapy (ADT), chemotherapy, and therapies targeting androgen. Yet, these systemic treatments often bring about considerable adverse effects. Additionally, it is observed that overweight men are at a higher risk of developing aggressive forms of PC, advancing to metastatic stages, and succumbing to the disease. Consequently, there is a pressing demand for new treatment options that carry fewer side effects and enhance the current standard treatments, particularly for the majority of American men who are overweight or obese. In this article, we will review the metabolic response to ADT and how lifestyle modulation can mitigate these ADT-associated metabolic responses with a particular focus on the two clinical trials, Carbohydrate and Prostate Study 1 (CAPS1) and Carbohydrate and Prostate Study 2 (CAPS2), which tested the effects of low-carbohydrate diets on the metabolic side effects of ADT and PC progression, respectively. Furthermore, we will summarize the findings of serum metabolomic studies to elucidate the potential mechanisms by which ADT and low-carbohydrate diets can affect the metabolic response to mitigate the metabolic side effects while maximizing therapeutic efficacy.

MMP11 and MMP14 contribute to the interaction between castration-resistant prostate cancer and adipocytes

Previous studies have demonstrated that adipocytes promote prostate cancer (PCa) cell progression, which facilitates the development of PCa into castration-resistant prostate cancer (CRPC); however, the underlying mechanisms are still not fully understood. Matrix metalloproteinases (MMPs) are a group of proteases responsible for the degradation of extracellular matrix (ECM) and the activation of latent factors. In our study, we detected that MMP11 expression was increased in PCa patients and that a high level of MMP11 was correlated with poor prognosis. Furthermore, siRNA knockdown of MMP11 in CRPC cells not only blocked the delipidation and dedifferentiation of mature adipocytes but also reduced the lipid uptake and utilization of CRPC cells in a cell co-culture model. The number of mitophagosomes and the expression level of Parkin were increased in MMP11-silenced CRPC cells. Moreover, we found that simultaneous downregulation of MMP14 and MMP11 expression may benefit patient survival. Indeed, MMP11/14 knockdown in CRPC cells significantly decreased lipid metabolism and cell invasion, at least partly through the mTOR/HIF1α/MMP2 signaling pathway. Importantly, MMP11/14 knockdown dramatically delayed tumor growth in a xenograft mouse model. Consistently, the decreased lipid metabolism, Ki67 and MMP2 expression, as well as the increased Parkin level were also confirmed in in vivo experiments, further demonstrating the mechanisms responsible for the tumor-promoting effects of MMP11/14. Collectively, our study elucidated the role of MMP11 and MMP14 in the bidirectional crosstalk between adipocytes and CRPC cells and provided the rationale of targeting MMP11/14 for the treatment of CRPC patients.

Obesity and prostate cancer - microenvironmental roles of adipose tissue

Obesity is known to have important roles in driving prostate cancer aggressiveness and increased mortality. Multiple mechanisms have been postulated for these clinical observations, including effects of diet and lifestyle, systemic changes in energy balance and hormonal regulation and activation of signalling by growth factors and cytokines and other components of the immune system. Over the past decade, research on obesity has shifted towards investigating the role of peri-prostatic white adipose tissue as an important source of locally produced factors that stimulate prostate cancer progression. Cells that comprise white adipose tissue, the adipocytes and their progenitor adipose stromal cells (ASCs), which proliferate to accommodate white adipose tissue expansion in obesity, have been identified as important drivers of obesity-associated cancer progression. Accumulating evidence suggests that adipocytes are a source of lipids that are used by adjacent prostate cancer cells. However, results of preclinical studies indicate that ASCs promote tumour growth by remodelling extracellular matrix and supporting neovascularization, contributing to the recruitment of immunosuppressive cells, and inducing epithelial-mesenchymal transition through paracrine signalling. Because epithelial-mesenchymal transition is associated with cancer chemotherapy resistance and metastasis, ASCs are considered to be potential targets of therapies that could be developed to suppress cancer aggressiveness in patients with obesity.

Post-diagnostic health behaviour scores and risk of prostate cancer progression and mortality

BACKGROUND

Individual behaviours are associated with prostate cancer (PC) progression. Behavioural scores, comprised of multiple risk factors, allow assessment of the combined impact of multiple behaviours.

METHODS

We examined the association between six a priori scores and risk of PC progression and mortality among 2156 men with PC in the Cancer of the Prostate Strategic Urologic Research Endeavor (CaPSURE) cohort: two scores developed based on the PC survivorship literature ('2021 Score [+ Diet]'); a score developed based on pre-diagnostic PC literature ('2015 Score'); and three scores based on US recommendations for cancer prevention ('WCRF/AICR Score') and survival ('ACS Score [+ Alcohol]'). Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated for progression and PC mortality via parametric survival models (interval censoring) and Cox models, respectively.

RESULTS

Over a median (IQR) of 6.4 (1.3, 13.7) years, we observed 192 progression and 73 PC mortality events. Higher (i.e., healthier) 2021 Score + Diet and WCRF/AICR Scores were inversely associated with risk of PC progression (2021 + Diet: HRcontinuous = 0.76, 95% CI: 0.63-0.90.

WCRF/AICR

HRcontinuous = 0.83, 95% CI: 0.67-1.02) and mortality (2021 + Diet: HRcontinuous = 0.65, 95% CI: 0.45-0.93.

WCRF/AICR

HRcontinuous = 0.71; 95% CI: 0.57-0.89). The ACS Score + Alcohol was only associated with progression (HRcontinuous = 0.89, 95% CI: 0.81-0.98) while the 2021 Score was only associated with PC mortality (HRcontinuous = 0.62, 95% CI: 0.45-0.85). The 2015 was not associated with PC progression or mortality.

CONCLUSION

Findings strengthen the evidence that behavioural modifications following a prostate cancer diagnosis may improve clinical outcomes.

Association between adiposity after diagnosis of prostate cancer and mortality: systematic review and meta-analysis

Objective

To explore the associations between adiposity indices, assessed at or after a diagnosis of prostate cancer, and mortality.

Design

Systematic review and meta-analysis.

Data sources

PubMed and Embase, from inception to 16 November 2022.

Eligibility criteria for selecting studies

Cohort studies or randomised controlled trials of men with a diagnosis of prostate cancer that investigated the associations between adiposity (body mass index, waist and hip circumference, waist-to-hip ratio, and subcutaneous and visceral adipose tissue) after diagnosis and mortality outcomes. A modified version of the risk of bias for nutrition observational studies tool was used to assess risk of bias.

Results

79 studies were identified that investigated adiposity indices after a diagnosis of prostate cancer in relation to mortality. No randomised controlled trials were found. A non-linear dose-response meta-analysis indicated a J shaped association between body mass index and all cause mortality (33 910 men, 11 095 deaths, 17 studies). The highest rate of all cause mortality was found at the lowest and upper range of the distribution: 11-23% higher rate for a body mass index of 17-21 and 4-43% higher rate for a body mass index of 30-40. The association between body mass index and mortality specific to prostate cancer was flat until body mass index reached 26-27, and then increased linearly by 8-66% for a body mass index of 30-40 (33 137 men, 2947 deaths, 13 studies), but the 95% confidence intervals were wide. These associations did not differ in most predefined subgroups by study design, number of deaths, anthropometric assessment, follow-up time, geographical location, prostate cancer risk group, and adjustment variables. No associations were found in meta-analyses between 10 cm increases in waist circumference and all cause mortality or mortality specific to prostate cancer, but only three studies were available. The few studies with data on change in weight, waist-to-hip ratio, and subcutaneous and visceral adipose tissue reported conflicting results.

Conclusions

This review suggests that patients with prostate cancer might benefit from maintaining a healthy weight and avoiding obesity. Future studies should investigate adiposity across different stages of cancer survivorship and use various parameters for distribution of adipose tissue.

Systematic review registration

Open Science Framework https://osf.io/qp3c4.

Mechanisms of Prostate Cancer Cells Survival and Their Therapeutic Targeting

Prostate cancer (PCa) is today the second most common cancer in the world, with almost 400,000 deaths annually. Multiple factors are involved in the etiology of PCa, such as older age, genetic mutations, ethnicity, diet, or inflammation. Modern treatment of PCa involves radical surgical treatment or radiation therapy in the stages when the tumor is limited to the prostate. When metastases develop, the standard procedure is androgen deprivation therapy, which aims to reduce the level of circulating testosterone, which is achieved by surgical or medical castration. However, when the level of testosterone decreases to the castration level, the tumor cells adapt to the new conditions through different mechanisms, which enable their unhindered growth and survival, despite the therapy. New knowledge about the biology of the so-called of castration-resistant PCa and the way it adapts to therapy will enable the development of new drugs, whose goal is to prolong the survival of patients with this stage of the disease, which will be discussed in this review.

Emerging Hallmarks of Metabolic Reprogramming in Prostate Cancer

Prostate cancer (PCa) is the most common male malignancy and the fifth leading cause of cancer death in men worldwide. Prostate cancer cells are characterized by a hybrid glycolytic/oxidative phosphorylation phenotype determined by androgen receptor signaling. An increased lipogenesis and cholesterogenesis have been described in PCa cells. Many studies have shown that enzymes involved in these pathways are overexpressed in PCa. Glutamine becomes an essential amino acid for PCa cells, and its metabolism is thought to become an attractive therapeutic target. A crosstalk between cancer and stromal cells occurs in the tumor microenvironment because of the release of different cytokines and growth factors and due to changes in the extracellular matrix. A deeper insight into the metabolic changes may be obtained by a multi-omic approach integrating genomics, transcriptomics, metabolomics, lipidomics, and radiomics data.

Post-diagnostic health behaviour scores in relation to fatal prostate cancer

BACKGROUND

Individual health behaviours have been associated with fatal prostate cancer (PCa). Their combined association with fatal PCa after diagnosis is unknown.

METHODS

This prospective cohort included 4518 men diagnosed with nonmetastatic PCa from the Health Professionals Follow-up Study. Exposures included a three-factor score integrating post-diagnostic fatal PCa risk factors ("2021 PCa Behaviour Score"), six-factor score integrating incident aggressive PCa risk factors ("2015 PCa Behaviour Score"), and two scores integrating recommendations for cancer prevention and survival, respectively. Multivariable Cox models estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for fatal PCa.

RESULTS

Over a median 10.2 years, we observed 219 PCa deaths. Each additional point of one of the PCa-specific health behaviour scores (2015 PCa Behaviour Score) was associated with a 19% reduced fatal PCa risk (HR: 0.81, 95%CI: 0.68-0.97). The 2021 PCa Behaviour Score and scores integrating national recommendations were not associated with fatal PCa.

CONCLUSIONS

While a PCa-specific health behaviour score was associated with a reduced risk of fatal PCa, we did not otherwise observe strong evidence of associations between post-diagnostic scores and fatal PCa. Avoiding tobacco, healthy body size, and physical activity may decrease PCa death risk, but further research is needed to inform cancer survivorship recommendations.

Circadian Rhythm Disruption as a Contributor to Racial Disparities in Prostate Cancer

In the United States, African American (AA) men have a 2.4 times higher mortality rate due to prostate cancer than White men. The multifactorial causes of the racial disparities in prostate cancer involve various social determinants of health, socioeconomic status, and access to healthcare. However, emerging evidence also suggests that circadian rhythm disruption (CRD) contributes to prostate cancer, and AA men may be more susceptible to developing CRDs. Circadian rhythms play a significant role in metabolism, hormone secretion, and sleep/wake cycles. Disruption in these circadian rhythms can be caused by airplane travel/jetlag, night shift work, exposure to light, and neighborhood noise levels, which can contribute to sleep disorders and chronic conditions such as obesity, diabetes, cardiovascular disease, and depression. The drivers of the racial disparities in CRD include night shift work, racial discrimination, elevated stress, and residing in poor neighborhoods characterized by high noise pollution. Given the increased vulnerability of AA men to CRDs, and the role that CRDs play in prostate cancer, elucidating the clock-related prostate cancer pathways and their behavior and environmental covariates may be critical to better understanding and reducing the racial disparities in prostate cancer.

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.

Leptin modulated microRNA-628-5p targets Jagged-1 and inhibits prostate cancer hallmarks

MicroRNAs (miRNAs) are single-stranded non-coding RNA molecules that play a regulatory role in gene expression and cancer cell signaling. We previously identified miR-628-5p (miR-628) as a potential biomarker in serum samples from men with prostate cancer (PCa) (Srivastava et al. in Tumour Biol 35:4867–4873, 10.1007/s13277-014-1638-1, 2014). This study examined the detailed cellular phenotypes and pathways regulated by miR-628 in PCa cells. Since obesity is a significant risk factor for PCa, and there is a correlation between levels of the obesity-associated hormone leptin and PCa development, here we investigated the functional relationship between leptin and miR-628 regulation in PCa. We demonstrated that exposure to leptin downregulated the expression of miR-628 and increased cell proliferation/migration in PCa cells. We next studied the effects on cancer-related phenotypes in PCa cells after altering miR-628 expression levels. Enforced expression of miR-628 in PCa cells inhibited cell proliferation, reduced PCa cell survival/migration/invasion/spheroid formation, and decreased markers of cell stemness. Mechanistically, miR-628 binds with the JAG1-3′UTR and inhibits the expression of Jagged-1 (JAG1). JAG1 inhibition by miR-628 downregulated Notch signaling, decreased the expression of Snail/Slug, and modulated epithelial-mesenchymal transition and invasiveness in PC3 cells. Furthermore, expression of miR-628 in PCa cells increased sensitivity towards the drugs enzalutamide and docetaxel by induction of cell apoptosis. Collectively our data suggest that miR-628 is a key regulator of PCa carcinogenesis and is modulated by leptin, offering a novel therapeutic opportunity to inhibit the growth of advanced PCa.

Energy Metabolism-Related Gene Prognostic Index Predicts Biochemical Recurrence for Patients With Prostate Cancer Undergoing Radical Prostatectomy

Background

We aimed to construct and validate an energy metabolism-related gene prognostic index (EMRGPI) to predict biochemical recurrence (BCR) in patients undergoing radical prostatectomy.

Methods

We used Lasso and COX regression analysis to orchestrate the EMRGPI in the TCGA database, and the prognostic value of EMRGPI was further validated externally using the GSE46602. All analyses were conducted with R version 3.6.3 and its suitable packages.

Results

SDC1 and ADH1B were finally used to construct the risk formula. We classified the 430 tumor patients in the TCGA database into two groups, and patients in the high-risk group had a higher risk of BCR than those in the low-risk group (HR: 1.98, 95%CI: 1.18-3.32, p=0.01). Moreover, in the GSE46602, we confirmed that the BCR risk in the high-risk group was 3.86 times higher than that in the low-risk group (95%CI: 1.61-9.24, p=0.001). We found that patients in the high-risk group had significantly higher proportions of residual tumor, older age, and T stage. SDC1 and ADH1B were significantly expressed low in the normal tissues when compared to the tumor tissues, which were opposite at the protein level. The spearman analysis showed that EMRGPI was significantly associated with B cells, CD4+ T cells, CD8+ T cells, neutrophils, macrophages, dendritic cells, stromal score, immune score, and estimate score. In addition, the EMRGPI was positively associated with the 54 immune checkpoints, among which CD80, ADORA2A, CD160, and TNFRSF25 were significantly related to the BCR-free survival of PCa patients undergoing RP.

Conclusions

The EMRGPI established in this study might serve as an independent risk factor for PCa patients undergoing radical prostatectomy.

Serum metabolomic analysis of men on a low-carbohydrate diet for biochemically recurrent prostate cancer reveals the potential role of ketogenesis to slow tumor growth: a secondary analysis of the CAPS2 diet trial

BACKGROUND

Systemic treatments for prostate cancer (PC) have significant side effects. Thus, newer alternatives with fewer side effects are urgently needed. Animal and human studies suggest the therapeutic potential of low carbohydrate diet (LCD) for PC. To test this possibility, Carbohydrate and Prostate Study 2 (CAPS2) trial was conducted in PC patients with biochemical recurrence (BCR) after local treatment to determine the effect of a 6-month LCD intervention vs. usual care control on PC growth as measured by PSA doubling time (PSADT). We previously reported the LCD intervention led to significant weight loss, higher HDL, and lower triglycerides and HbA1c with a suggested longer PSADT. However, the metabolic basis of these effects are unknown.

METHODS

To identify the potential metabolic basis of effects of LCD on PSADT, serum metabolomic analysis was performed using baseline, month 3, and month 6 banked sera to identify the metabolites significantly altered by LCD and that correlated with varying PSADT.

RESULTS

LCD increased the serum levels of ketone bodies, glycine and hydroxyisocaproic acid. Reciprocally, LCD reduced the serum levels of alanine, cytidine, asymmetric dimethylarginine (ADMA) and 2-oxobutanoate. As high ADMA level is shown to inhibit nitric oxide (NO) signaling and contribute to various cardiovascular diseases, the ADMA repression under LCD may contribute to the LCD-associated health benefit. Regression analysis of the PSADT revealed a correlation between longer PSADT with higher level of 2-hydroxybutyric acids, ketone bodies, citrate and malate. Longer PSADT was also associated with LCD reduced nicotinamide, fructose-1, 6-biphosphate (FBP) and 2-oxobutanoate.

CONCLUSION

These results suggest a potential association of ketogenesis and TCA metabolites with slower PC growth and conversely glycolysis with faster PC growth. The link of high ketone bodies with longer PSADT supports future studies of ketogenic diets to slow PC growth.

Lipid Metabolism and Epigenetics Crosstalk in Prostate Cancer

Prostate cancer (PCa) is the most commonly diagnosed malignant neoplasm in men in the Western world. Localized low-risk PCa has an excellent prognosis thanks to effective local treatments; however, despite the incorporation of new therapeutic strategies, metastatic PCa remains incurable mainly due to disease heterogeneity and the development of resistance to therapy. The mechanisms underlying PCa progression and therapy resistance are multiple and include metabolic reprogramming, especially in relation to lipid metabolism, as well as epigenetic remodelling, both of which enable cancer cells to adapt to dynamic changes in the tumour. Interestingly, metabolism and epigenetics are interconnected. Metabolism can regulate epigenetics through the direct influence of metabolites on epigenetic processes, while epigenetics can control metabolism by directly or indirectly regulating the expression of metabolic genes. Moreover, epidemiological studies suggest an association between a high-fat diet, which can alter the availability of metabolites, and PCa progression. Here, we review the alterations of lipid metabolism and epigenetics in PCa, before focusing on the mechanisms that connect them. We also discuss the influence of diet in this scenario. This information may help to identify prognostic and predictive biomarkers as well as targetable vulnerabilities.

Maintaining Weight Loss in Obese Men with Prostate Cancer Following a Supervised Exercise and Nutrition Program-A Pilot Study

Simple Summary

More than 50% of prostate cancer patients will receive androgen deprivation therapy (ADT) and 70% will experience ADT-induced weight gain. Supervised exercise and nutrition interventions are viable strategies to mitigate or reverse ADT-induced body composition changes; however, the ability to preserve these benefits when supervision is no longer available is unclear. Our study examined the effects of a home-based weight maintenance program on body composition and physical function in obese men with prostate cancer on ADT who had previously completed a supervised weight loss intervention. We demonstrated that a home-based weight maintenance program can preserve body composition and physical function for at least 12 weeks following a supervised intervention. This study provides insight into the prospect of home-based programs to preserve benefits gained within a supervised environment for patients remaining on ADT when ongoing in-person services are no longer viable.

Abstract

Supervised exercise and nutrition programs can mitigate or reverse androgen deprivation therapy (ADT) induced fat mass (FM) gain, lean mass (LM) loss, and impaired physical function. It is unclear whether these benefits are retained following transition to self-management. This study examined the effect of a home-based weight maintenance program on body composition and physical function in obese men with prostate cancer (PCa) on ADT following a 12-week supervised weight loss intervention. Eleven obese PCa patients (74 ± 5 years, 40.0 ± 4.9% body fat) on ADT (>6 months) completed a 12-week self-managed home-based weight maintenance program consisting of 150 min/week of aerobic and resistance training while maintaining a healthy balanced diet. Body composition (DXA), muscle strength (1RM), and cardiorespiratory fitness (400 m walk) were assessed. Significant reductions in weight (−2.8 ± 3.2 kg) and FM (−2.8 ± 2.6 kg), preservation of LM (−0.05 ± 1.6 kg), and improvements in muscle strength and VO_2max were achieved across the supervised intervention. Across the home-based program, no significant changes were observed in weight (−0.6 ± 2.8 kg, p = 0.508), FM (0.2 ± 1.4 kg, p = 0.619), LM (−0.8 ± 1.6 kg, p = 0.146), muscle strength (−0.2 to 4.1%, p = 0.086–0.745), or estimated VO_2max (0.3 ± 2.1 mL/min/kg, p = 0.649). Self-managed, home-based exercise and nutrition programs are a viable strategy to promote maintenance of body composition and physical function following a supervised intervention in obese PCa patients on ADT.

The Role of Inflammation in Breast and Prostate Cancer Metastasis to Bone

Tumor metastasis to bone is a common event in multiple forms of malignancy. Inflammation holds essential functions in homeostasis as a defense mechanism against infections and is a strategy to repair injured tissue and to adapt to stress conditions. However, exaggerated and/or persistent (chronic) inflammation may eventually become maladaptive and evoke diseases such as autoimmunity, diabetes, inflammatory tissue damage, fibrosis, and cancer. In fact, inflammation is now considered a hallmark of malignancy with prognostic relevance. Emerging studies have revealed a central involvement of inflammation in several steps of the metastatic cascade of bone-homing tumor cells through supporting their survival, migration, invasion, and growth. The mechanisms by which inflammation favors these steps involve activation of epithelial-to-mesenchymal transition (EMT), chemokine-mediated homing of tumor cells, local activation of osteoclastogenesis, and a positive feedback amplification of the protumorigenic inflammation loop between tumor and resident cells. In this review, we summarize established and evolving concepts of inflammation-driven tumorigenesis, with a special focus on bone metastasis.

Canadian Urological Association guideline on androgen deprivation therapy: Adverse events and management strategies

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Post-Diagnostic Dietary and Lifestyle Factors and Prostate Cancer Recurrence, Progression, and Mortality

PURPOSE OF REVIEW

This study aimed to summarize evidence published between 1999 and June 2020 examining diet and lifestyle after prostate cancer (PC) diagnosis in relation to risk of biochemical recurrence, PC progression, and PC-specific mortality.

RECENT FINDINGS

Secondary prevention is an important research area in cancer survivorship. A growing number of studies have reported associations between post-diagnostic modifiable behaviors and risk of PC outcomes. Evidence on modifiable lifestyle factors and PC remains limited. Where multiple studies exist, findings are often mixed. However, studies consistently suggest that smoking and consumption of whole milk/high-fat dairy are associated with higher risk of PC recurrence and mortality. In addition, physical activity and ½ to 1 glass of red wine/day have been associated with lower risk of recurrence and PC-specific mortality. Greater inclusion of racially/ethnically diverse groups in future research is necessary to understand these relationships in populations most impacted by adverse PC outcomes.

Weight Loss for Obese Prostate Cancer Patients on Androgen Deprivation Therapy

PURPOSE

Excess fat mass (FM) contributes to poor prostate cancer (PCa) prognosis and comorbidity. However, FM gain is a common side effect of androgen deprivation therapy (ADT). We examined the efficacy of a 12-wk weight loss intervention to reduce FM and maintain lean mass (LM) in ADT-treated obese PCa patients.

METHODS

Fourteen ADT-treated obese PCa patients (72 ± 9 yr, 39.7% ± 5.4% body fat) were recruited for a self-controlled prospective study, with 11 completing the 6-wk control period, followed by a 12-wk intervention comprising 300 min·wk-1 of exercise including supervised resistance training and home-based aerobic exercise, and dietitian consultations advising a daily energy deficit (2100-4200 kJ) and protein supplementation. Body composition was assessed by dual x-ray absorptiometry. Secondary outcomes included muscle strength (one-repetition maximum), cardiorespiratory fitness (maximal oxygen consumption), and blood biomarkers.

RESULTS

There were no significant changes during the control period. Patients attended 89% of supervised exercise sessions and 100% of dietitian consultations. No changes in physical activity or energy intake were observed. During the intervention, patients experienced significant reductions in weight (-2.8 ± 3.2 kg, P = 0.016), FM (-2.8 ± 2.6 kg, P < 0.001), and trunk FM (-1.8 ± 1.4 kg, P < 0.001), with LM preserved (-0.05 ± 1.6 kg, P = 0.805). Muscle strength (4.6%-24.7%, P < 0.010) and maximal oxygen consumption (3.5 ± 4.7 mL·min-1·kg-1, P = 0.041) significantly improved. Leptin significantly decreased (-2.2 (-2.7 to 0.5) ng·mL-1, P = 0.016) with no other changes in blood biomarkers such as testosterone and lipids (P = 0.051-0.765); however, C-reactive protein (rs = -0.670, P = 0.024) and triglycerides (r = -0.667, P = 0.025) were associated with individual changes in LM.

CONCLUSIONS

This study shows preliminary efficacy for an exercise and nutrition weight loss intervention to reduce FM, maintain LM, and improve muscle strength and cardiorespiratory fitness in ADT-treated obese PCa patients. The change in body composition may affect blood biomarkers associated with obesity and PCa progression; however, further research is required.

Obesity, Inflammation, and Advanced Prostate Cancer

Obesity is associated with high-grade and advanced prostate cancer. While this association may be multi-factorial, studies suggest that obesity-induced inflammation may play a role in the progression of advanced prostate cancer. The microenvironment associated with obesity increases growth factors and pro-inflammatory cytokines which have been implicated mechanistically to promote invasion, metastasis, and androgen-independent growth. This review summarizes recent findings related to obesity-induced inflammation which may be the link to advanced prostate cancer. In addition, this review while introduce novel targets to mitigate prostate cancer metastasis to the bone. Specific emphasis will be placed on the role of the pro-inflammatory cytokines interleukin (IL)-6, tumor necrosis factor (TNF)α, and IL-1β.

Caprylic acid (C8:0) promotes bone metastasis of prostate cancer by dysregulated adipo-osteogenic balance in bone marrow

Prostate cancer (PCa) continues to be the most common, noncutaneous cancer in men. Bone is the most frequent site of PCa metastases, and up to 90% of patients with advanced PCa develop bone metastases. An altered bone marrow microenvironment, induced by obesity, is a significant mediator for the bone tropism of PCa. However, the specific molecular mechanisms by which obesity causes changes in the bone marrow microenvironment, leading to PCa bone metastasis, are not fully understood. Our results demonstrate that a high‐fat diet (HFD) leads to dyslipidemia and changes in bone marrow of nude mice: an increase in the area and number of adipocytes and a reduction in the area and number of osteoblasts. Moreover, a HFD promoted cyclooxygenase 2 (COX2) expression and inhibited osteoprotegerin (OPG) expression in the bone microenvironment. Additionally, the total level of free fatty acids (FFAs) and caprylic acid (C8:0) was significantly higher in PCa patients with bone metastases. In vitro, caprylic acid (C8:0) promoted bone mesenchymal stem cell (MSC)‐derived adipocytic differentiation, COX2 expression, and prostaglandin E2 (PGE2) secretion, whereas osteoblastic differentiation and OPG expression were reduced. Furthermore, caprylic acid (C8:0)‐treated adipocytes promoted the invasion and migration of PCa cells. Taken together, our findings suggest caprylic acid (C8:0) promotes bone metastasis of PCa by dysregulated adipo‐osteogenic balance of bone marrow.

A Randomized Controlled Trial of a 6-Month Low-Carbohydrate Intervention on Disease Progression in Men with Recurrent Prostate Cancer: Carbohydrate and Prostate Study 2 (CAPS2)

PURPOSE

Both weight loss and low-carbohydrate diets (LCD) without weight loss prolong survival in prostate cancer models. Few human trials have tested weight loss or LCD on prostate cancer.

EXPERIMENTAL DESIGN

We conducted a multi-site randomized 6-month trial of LCD versus control on PSA doubling time (PSADT) in patients with prostate cancer with biochemical recurrence (BCR) after local treatment. Eligibility included body mass index (BMI) ≥ 24 kg/m² and PSADT 3 to 36 months. The LCD arm was instructed to eat [Formula: see text]20 g/carbs/day; the control arm instructed to avoid dietary changes. Primary outcome was PSADT. Secondary outcomes included weight, lipids, glucose metabolism, and diet.

RESULTS

Of 60 planned patients, the study stopped early after an interim analysis showed futility. Twenty-seven LCD and 18 control patients completed the study. At 6 months, although both arms consumed similar protein and fats, the LCD arm reduced carbohydrates intake (-117 vs. 8 g, P < 0.001) and lost weight (-12.1 vs. -0.50 kg, P < 0.001). The LCD arm reduced HDL, triglycerides, and HbA1c with no difference in total cholesterol or glucose. Mean PSADT was similar between LCD (21 months) and control (15 months, P = 0.316) arms. In a post hoc exploratory analysis accounting for prestudy PSADT, baseline PSA, primary treatment, and hemoconcentration, PSADT was significantly longer in LCD versus control (28 vs. 13 months, P = 0.021) arms. Adverse events were few, usually mild, and returned to baseline by 6 months.

CONCLUSIONS

Among BCR patients, LCD induced weight loss and metabolic benefits with acceptable safety without affecting PSADT, suggesting LCD does not adversely affect prostate cancer growth and is safe. Given exploratory findings of longer PSADT, larger studies testing LCD on disease progression are warranted.

Lifestyle in urology: Cancer

The opportunity to prevent, to improve their prognosis, or even to cure uro-oncological diseases by modifying the lifestyle habits is a very modern topical subject and represents a great and fascinating challenge for the future. A PubMed and Web of Science databases search has been performed to review the published knowledge on most important lifestyle habits, such as smoking, physical activity, nutrition, sexual activity, and personal hygiene, highlighting modifiable factors influencing development and progression of urological cancers. Cigarette smoking has been historically established as risk factors for urothelial cancer, and an association with risk of renal cell carcinoma and worse prognosis of prostate cancer has been sufficiently demonstrated. Poor genital hygiene is a recognized risk factor for penile cancer. Furthermore, a convincing evidence has been found on the association between physical activity and both risk and prognosis of bladder and prostate cancer. Obesity is strongly associated with increased risk of developing lethal prostate cancer. An unequivocal evidence of a direct relationship between most of the other lifestyle habits and development of the uro-oncological diseases has not been found.

Relationship between body composition and hormone sensitivity for androgen deprivation therapy in patients with metastatic prostate cancer

Background

To evaluate the relationship between body composition and the oncological outcome of androgen deprivation therapy (ADT), we investigated whether body composition features including the psoas muscle may be predictive factors of ADT.

Methods

This study enrolled patients with hormone-naïve metastatic prostate cancer who were treated with primary ADT from April 1996 to November 2013 at Kyushu University Hospital and who underwent a computed tomography scan before primary ADT for calculating body fat percentage, psoas muscle ratio (psoas muscle, cm³/height, cm), and body mass index.

Results

Of the 178 patients enrolled, 60 patients died during follow-up. Median follow-up was 32 months, and progression-free survival and overall survival (OS) were 28 and 80 months, respectively. Multivariate analysis revealed that the psoas muscle ratio was correlated with OS (hazard ratio: 0.448; 95% confidence interval = 0.206–0.922; p = 0.028).

Conclusions

This study demonstrated that higher psoas muscle ratio predicts longer OS among patients with nonlocalized prostate cancer treated with primary ADT.

Contribution of Inherited DNA-Repair Gene Mutations to Hormone-Sensitive and Castrate-Resistant Metastatic Prostate Cancer and Implications for Clinical Outcome

PURPOSE

To compare the prevalence of germline mutations in metastatic hormone-sensitive prostate cancer (mHSPC) and metastatic castrate-resistant prostate cancer (mCRPC) and assess the impact of mutations on progression to castration resistance and overall survival.

METHODS

Targeted sequencing of germline DNA from 704 men (221 at the time of mHSPC and 483 at the time of mCRPC) enrolled in two advanced prostate cancer registries at Mayo Clinic between 2003 and 2013 was performed for 21 predisposition genes. Frequencies of pathogenic mutations were compared in patients and reference controls to identify genes enriched in metastatic prostate cancer. Multivariable Cox proportional hazards regression was used to identify predictors of progression to mCRPC and overall survival.

RESULTS

Sixty-eight germline mutations in 12 genes were identified in 66 men (9.4%). Mutations in ATM, BRCA2, CHEK2, FANCM, and TP53 were significantly enriched (odds ratio greater than 2.0) in the metastatic cohorts compared with reference controls. The frequency of germline mutations was similar for patients with mHSPC and mCRPC (11.8% v 8.3%; P = .16). The median time to progression from mHSPC to mCRPC was 23.1 and 32.5 months for patients with and without mutations, respectively (P = .96). Although older age at diagnosis, Gleason score greater than 7, elevated alkaline phosphatase level, and high volume of disease were associated with shorter duration of progression to mCRPC and poor overall survival, mutation status was not (progression to mCRPC hazard ratio, 0.81; 95% CI, 0.61 to 1.09; P = .17; overall survival hazard ratio, 1.00; 95% CI, 0.75 to 1.34; P = .98).

CONCLUSION

Similarly elevated rates of germline predisposition gene mutations in mHSPC and mCRPC suggest that germline genetic testing may help to guide medical management for all patients with advanced metastatic prostate cancer. Mutation status was not associated with shorter progression to mCRPC or poor overall survival.

Periprostatic Fat Thickness on MRI is an Independent Predictor of Time to Castration-resistant Prostate Cancer in Chinese Patients With Newly Diagnosed Prostate Cancer Treated With Androgen Deprivation Therapy

BACKGROUND

The aim of this study was to evaluate the association between periprostatic fat thickness (PPFT) and time to castration-resistant prostate cancer (CRPC) in newly diagnosed patients with prostate cancer (PCa) treated with androgen deprivation therapy (ADT).

PATIENTS AND METHODS

We retrospectively reviewed the medical records of 150 patients with PCa treated with ADT at our hospital between June 2011 and June 2017. PPFT measured on magnetic resonance imaging (MRI) and PPFT/periprostatic fat volume (PPFV) measured on computed tomography (CT) were evaluated. Kaplan-Meier curves and log-rank tests were used to assess significant differences in time to CRPC between the 2 groups (high PPFT vs. low PPFT, determined by PPFT > or < the median value, respectively). Univariable and multivariable Cox regression analyses were employed to identify the potential prognostic factors for survival.

RESULTS

The median value of PPFT measured on MRI was 0.555 cm. PPFT was significantly associated with PPFV measured on CT images (with a correlation coefficient of 0.825; P < .001). A total of 66 patients (44%) progressed to CRPC during the follow-up period. Patients with high PPFT (measured on MRI) showed a significantly shorter PFS than patients with low PPFT. Multivariable Cox analysis demonstrated that T stage, presence of distant metastasis, shorter time to prostate-specific antigen nadir, higher prostate-specific antigen nadir, Gleason score (greater than 4 + 4), and high PPFT were significantly associated with shorter PFS.

CONCLUSIONS

PPFT is significantly associated with PPFV measured on CT images. PPFT measured on MRI is a readily available and significant predictor of time to CRPC in patients with PCa receiving ADT as the primary treatment.

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.

First-year weight loss with androgen-deprivation therapy increases risks of prostate cancer progression and prostate cancer-specific mortality: results from SEARCH

PURPOSE

We aimed to study the associations between androgen-deprivation therapy (ADT)-induced weight changes and prostate cancer (PC) progression and mortality in men who had undergone radical prostatectomy (RP).

METHODS

Data from the Shared Equal Access Regional Cancer Hospital (SEARCH) cohort were used to study the associations between weight change approximately 1-year post-ADT initiation and metastases, castration-resistant prostate cancer (CRPC), all-cause mortality (ACM), and PC-specific mortality (PCSM) in 357 patients who had undergone RP between 1988 and 2014. We estimated hazard ratios (HR) and 95% confidence intervals (95% CI) using covariate-adjusted Cox regression models for associations between weight loss, and weight gains of 2.3 kg or more, and PC progression and mortality post-ADT.

RESULTS

During a median (IQR) follow-up of 81 (46-119) months, 55 men were diagnosed with metastases, 61 with CRPC, 36 died of PC, and 122 died of any cause. In multivariable analysis, weight loss was associated with increases in risks of metastases (HR 3.13; 95% CI 1.40-6.97), PCSM (HR 4.73; 95% CI 1.59-14.0), and ACM (HR 2.16; 95% CI 1.25-3.74) compared with mild weight gains of ≤ 2.2. Results were slightly attenuated but remained statistically significant in analyses that accounted for competing risks of non-PC death. Estimates for the associations between weight gains of ≥ 2.3 kg and metastases (HR 1.58; 95% CI 0.73-3.42), CRPC (HR 1.33; 95% CI 0.66-2.66), and PCSM (HR 2.44; 95% CI 0.84-7.11) were elevated, but not statistically significant.

CONCLUSIONS

Our results suggest that weight loss following ADT initiation in men who have undergone RP is a poor prognostic sign. If confirmed in future studies, testing ways to mitigate weight loss post-ADT may be warranted.

Comprehensive Lifestyle Improvement Program for Prostate Cancer (CLIPP): Protocol for a Feasibility and Exploratory Efficacy Study in Men on Androgen Deprivation Therapy

BACKGROUND

Androgen deprivation therapy (ADT) for prostate cancer is associated with adverse cardiometabolic effects such as reduced libido, hot flashes, metabolic syndrome, diabetes, myocardial infarction, and stroke. This reduces quality of life and potentially increases mortality. Several large clinical trials have demonstrated improvements in cardiometabolic risk with comprehensive multimodality lifestyle modification. However, there is a lack of data for such interventions in men on ADT for prostate cancer, and existing studies have used non-standardized interventions or lacked data on metabolic risk factors.

OBJECTIVE

The Comprehensive Lifestyle Improvement Project for Prostate Cancer (CLIPP) is designed to address these gaps by using an intervention modeled on the Diabetes Prevention Program, a standardized multicomponent intervention with demonstrated effectiveness in reducing cardiometabolic risk factors that has been successfully adapted for multiple disease types including breast cancer.

METHODS

A single-arm unblinded clinical trial will be conducted to determine the feasibility of conducting a 24-week comprehensive lifestyle modification intervention that targets weight loss and increased physical activity modeled on the Diabetes Prevention Program in 30 men on ADT for prostate cancer. Secondary aims are to determine the effect of the intervention on cardiometabolic markers and quality of life. The tertiary aim is to determine the effect of the intervention on markers of inflammation and angiogenesis, important mechanisms for prostate cancer progression. Participants will be recruited from the University of Arizona Cancer Center and the surrounding community. The intervention will be delivered weekly in person and over the phone for 16 weeks. For Weeks 16-24, participants receive weekly phone calls from the study health coach to motivate them to continue their lifestyle modification. Questionnaire and biological data are collected at baseline, 12 weeks, and 24 weeks. Body composition using dual-energy x-ray absorptiometry scans will be performed at baseline and end of study.

RESULTS

Based on a sample size of 30, the two-sided 95% confidence interval will not be wider than 0.373 standard deviations for the adherence rate and will not be wider than 0.374 for the retention rate. In addition, the study will have a power of 80% to detect a change of 0.47 standard deviations from baseline for each of the markers investigated in the secondary and tertiary aims assuming a within-subject correlation of 0.20 at a significance level of 5%. The recruitment period is from October 2018 to April 2019.

CONCLUSIONS

The aim of CLIPP is to determine the feasibility of conducting a Diabetes Prevention Program-style comprehensive lifestyle modification intervention in men with ADT for prostate cancer and its effects on cardiometabolic adverse effects, quality of life, as well as markers of inflammation and angiogenesis. Results will inform the development of future clinical trials in this population.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/12579.

Peri-prostatic Fat Volume Measurement as a Predictive Tool for Castration Resistance in Advanced Prostate Cancer

BACKGROUND

Obesity and aggressive prostate cancer (PC) may be linked, but how local peri-prostatic fat relates to tumour response following androgen deprivation therapy (ADT) is unknown.

OBJECTIVE

To test if peri-prostatic fat volume (PPFV) predicts tumour response to ADT.

DESIGN, SETTING, AND PARTICIPANTS

We performed a retrospective study on consecutive patients receiving primary ADT. From staging pelvic magnetic resonance imaging scans, the PPFV was quantified with OsirixX 6.5 imaging software. Statistical (univariate and multivariate) analysis were performed using R Version 3.2.1.

RESULTS AND LIMITATIONS

Of 224 consecutive patients, 61 with advanced (≥T3 or N1 or M1) disease had (3-mm high resolution axial sections) pelvic magnetic resonance imaging scan before ADT. Median age=75 yr; median PPFV=24.8cm3 (range, 7.4-139.4cm3). PPFV was significantly higher in patients who developed castration resistant prostate cancer (CRPC; n=31), with a median of 37.9cm3 compared with 16.1cm3 (p <0.0001, Wilcoxon rank sum test) in patients who showed sustained response to ADT (n=30). Multivariate analysis using Cox proportional hazards models were performed controlling for known predictors of CRPC. PPFV was shown to be independent of all included factors, and the most significant predictor of time to CRPC. Using our multivariate model consisting of all known factors prior to ADT, PPFV significantly improved the area under the curve of the multivariate models receiver operating characteristic analysis. The main study limitation is a relatively small cohort to account for multiple variables, necessitating a future large-scale prospective analysis of PPFV in advanced PC.

CONCLUSIONS

PPFV quantification in patients with advanced PC predicts tumour response to ADT.

PATIENT SUMMARY

The amount of fat around the prostate predicts prostate cancer response to hormone treatment.

Obesity, risk of biochemical recurrence, and prostate-specific antigen doubling time after radical prostatectomy: results from the SEARCH database

OBJECTIVES

To examine the association between body mass index (BMI) and aggressive biochemical recurrence (BCR) using the Shared Equal Access Regional Cancer Hospital (SEARCH) database.

MATERIAL AND METHODS

We identified 4123 men with complete data treated by radical prostatectomy between 1988 and 2015. We tested the association between BMI and BCR using Cox models, and among men with BCR, prostate-specific antigen doubling time (PSADT) was compared across BMI categories using linear regression. Models were adjusted for age, race, prostate-specific antigen, biopsy Gleason score, clinical stage, year and surgical centre.

RESULTS

Overall, 922 men (22%) were of normal weight (BMI <25 kg/m² ), 1863 (45%) were overweight (BMI 25-29.9 kg/m² ), 968 (24%) were obese (BMI 30-34.9 kg/m² ), and 370 (9%) were moderately or severely obese (BMI ≥35 kg/m² ). After adjustment for multiple clinical characteristics, higher BMI was significantly associated with higher risk of BCR (P = 0.008). Among men with BCR, men in the four BMI categories had similar multivariable-adjusted PSADT values (increasing BMI categories: 20.9 vs 21.3 vs 21.0 vs 14.9 months; P = 0.48).

CONCLUSION

While we confirmed that higher BMI was associated with BCR, we found no link between BMI and PSADT at the time of recurrence. Our data suggest obese men do not have more aggressive recurrences. Future studies are needed to test whether obesity predicts response to salvage therapies.

Nutrition, physical activity, and lifestyle factors in prostate cancer prevention

PURPOSE OF REVIEW

To review current evidence for prostate cancer prevention with nutrition, physical activity, and lifestyle interventions and identify future research directions.

RECENT FINDINGS

Multiple preclinical and observational studies have observed that diet, exercise, and lifestyle interventions may play a role in mitigating disease progression, mortality, and overall disease burden for high-grade and fatal prostate cancer. Increased vegetable and fruit intakes, decreased red meat and saturated fat intakes, and increased exercise are potentially associated with decreased risk of incident disease and increased progression-free, prostate cancer-specific, and overall survival. Randomized controlled trials (RCTs) have demonstrated that selenium and vitamin C supplements are ineffective in preventing incident prostate cancer and that vitamin E supplements potentially increase incident prostate cancer risk. A large RCT of a high vegetable diet intervention among prostate cancer patients on active surveillance, the Men's Eating and Living study, will soon complete analysis. An RCT for an exercise intervention among men with metastatic castrate-resistant prostate cancer is currently accruing.

SUMMARY

Although preclinical and observational studies have identified potential benefits for high vegetable, low fat, low meat diets, and increased exercise, Level I evidence is limited. To inform clinical care, future research should focus on RCTs evaluating clinical effectiveness.

Fatty Acids and Calcium Regulation in Prostate Cancer

Prostate cancer is a widespread malignancy characterized by a comparative ease of primary diagnosis and difficulty in choosing the individualized course of treatment. Management of prostate cancer would benefit from a clearer understanding of the molecular mechanisms behind the transition to the lethal, late-stage forms of the disease, which could potentially yield new biomarkers for differential prognosis and treatment prioritization in addition to possible new therapeutic targets. Epidemiological research has uncovered a significant correlation of prostate cancer incidence and progression with the intake (and often co-intake) of fatty acids and calcium. Additionally, there is evidence of the impact of these nutrients on intracellular signaling, including the mechanisms mediated by the calcium ion as a second messenger. The present review surveys the recent literature on the molecular mechanisms associated with the critical steps in the prostate cancer progression, with special attention paid to the regulation of these processes by fatty acids and calcium homeostasis. Testable hypotheses are put forward that integrate some of the recent results in a more unified picture of these phenomena at the interface of cell signaling and metabolism.

Obesity and prostate cancer

PURPOSE OF REVIEW

To investigate the association between obesity and prostate cancer (PCa).

RECENT FINDINGS

Obesity has been proposed to be involved in the pathogenesis of PCa through different biological mechanisms that include deregulation of the insulin axis, sex hormone secretion, adipokines signaling, and oxidative stress. Hypertrophic peritumoral adipocytes may also facilitate the local spread of PCa through the chemo-attraction of tumor cells. Clinical studies demonstrate that obesity might have clinical implications also in disease detection and management. Obese men have been shown to be less likely to be diagnosed with early-stage disease. Moreover, they are at increased risk of experiencing upgrading and upstaging when managed with active surveillance. However, the association between obesity and the risk of PCa recurrence and mortality after radical treatment is still debated.

SUMMARY

Obesity may facilitate the development and progression of PCa trough different biologic mechanisms that may pose obese men at higher risk of advanced and high-grade disease. However, the association between obesity and long-term oncologic outcome after radical treatments appears unclear.

Adipocyte p62/SQSTM1 Suppresses Tumorigenesis through Opposite Regulations of Metabolism in Adipose Tissue and Tumor

Obesity is a leading risk factor for cancer. However, understanding the crosstalk between adipocytes and tumor cells in vivo, independently of dietary contributions, is a major gap in the field. Here we used a prostate cancer (PCa) mouse model in which the signaling adaptor p62/Sqstm1 is selectively inactivated in adipocytes. p62 loss in adipocytes results in increased osteopontin secretion, which mediates tumor fatty acid oxidation and invasion, leading to aggressive metastatic PCa in vivo. Furthermore, p62 deficiency triggers in adipocytes a general shutdown of energy-utilizing pathways through mTORC1 inhibition, which supports nutrient availability for cancer cells. This reveals a central role of adipocyte's p62 in the symbiotic adipose tissue-tumor collaboration that enables cancer metabolic fitness.

Bone marrow adipocytes promote the Warburg phenotype in metastatic prostate tumors via HIF-1α activation

Metabolic adaptation is increasingly recognized as a key factor in tumor progression, yet its involvement in metastatic bone disease is not understood. Bone is as an adipocyte-rich organ, and a major site of metastasis from prostate cancer. Bone marrow adipocytes are metabolically active cells capable of shaping tumor metabolism via lipolysis and lipid transfer. In this study, using in vitro and in vivo models of marrow adiposity, we demonstrate that marrow fat cells promote Warburg phenotype in metastatic prostate cancer cells. We show increased expression of glycolytic enzymes, increased lactate production, and decreased mitochondrial oxidative phosphorylation in tumor cells exposed to adipocytes that require paracrine signaling between the two cell types. We also reveal that prostate cancer cells are capable of inducing adipocyte lipolysis as a postulated mechanism of sustenance. We provide evidence that adipocytes drive metabolic reprogramming of tumor cells via oxygen-independent mechanism of HIF-1α activation that can be reversed by HIF-1α downregulation. Importantly, we also demonstrate that the observed metabolic signature in tumor cells exposed to adipocytes mimics the expression patterns seen in patients with metastatic disease. Together, our data provide evidence for a functional relationship between marrow adipocytes and tumor cells in bone that has likely implications for tumor growth and survival within the metastatic niche.

Subcutaneous Fat Distribution is a Prognostic Biomarker for Men with Castration Resistant Prostate Cancer

PURPOSE

The relationship between body fat distribution and survival remains unclear in patients with castration resistant prostate cancer treated with docetaxel and androgen receptor axis targeted agents. We investigated whether body composition parameters could predict radiographic progression-free and cancer specific survival in patients with castration resistant prostate cancer.

MATERIALS AND METHODS

In this multicenter retrospective study we evaluated data on 282 consecutive patients diagnosed with castration resistant prostate cancer between September 2009 and March 2017. The subcutaneous fat index, the visceral fat index and the skeletal muscle index at the diagnosis of castration resistant prostate cancer were determined by computerized tomography data. Survival analyses were performed using the subcutaneous fat, visceral fat and skeletal muscle indexes dichotomized at 39.9, 58 and 52.4 cm²/m², respectively.

RESULTS

At the diagnosis of castration resistant prostate cancer, cancer specific survival was independently predicted using prostate specific antigen levels, Gleason score 8 or greater, performance status, a shorter interval from androgen deprivation therapy to castration resistant prostate cancer and a subcutaneous fat index of less than 39.9 cm²/m². During the median followup of 16.0 months patients with a subcutaneous fat index of 39.9 cm²/m² or greater received more docetaxel cycles than patients with a subcutaneous fat index of less than 39.9 cm²/m². Compared to patients with a subcutaneous fat index of less than 39.9 cm²/m² those with an index of 39.9 cm²/m² or greater had better 1-year progression-free and 2-year cancer specific survival (p = 0.009 and 0.021, respectively).

CONCLUSIONS

Patients with a subcutaneous fat index of 39.9 cm²/m² or greater at the diagnosis of castration resistant prostate cancer showed higher progression-free and cancer specific survival rates than those with a subcutaneous fat index of less 39.9 cm²/m² at diagnosis. The subcutaneous fat index determined by computerized tomography data could serve as a useful objective prognostic factor to discuss patient therapeutic options. Further studies are needed to define the roles of each body composition parameter in relation to pharmacokinetics and oncologic outcome.

Abiraterone acetate and prednisone in the pre- and post-docetaxel setting for metastatic castration-resistant prostate cancer: a mono-institutional experience focused on cardiovascular events and their impact on clinical outcomes

Background:

The aim of this work was to to evaluate the incidence and risk factors of adverse events (AEs), focusing on cardiovascular events (CVEs) and hypokalemia, in patients treated with abiraterone acetate (AA) and prednisone (PDN) outside clinical trials, and their association with survival outcomes.

Methods:

This was a retrospective cohort study of 105 patients treated from 2011 to 2016. Incidence of AEs was descriptively summarized in the whole cohort and by subgroup (pre- versus post-docetaxel). Multivariable Cox proportional hazards models assessed factors associated with progression-free survival (PFS) and overall survival (OS).

Results:

Overall, median PFS and OS were 14.9 and 24.6 months, respectively. Prostate-specific antigen (PSA) ⩾ 10 ng/ml (p = 0.007), Gleason Score >7 (p = 0.008), Eastern Cooperative Oncology Group (ECOG) performance status (PS)1–2 (p = 0.002), duration of androgen deprivation therapy (ADT) ⩽ 43.2 months (p = 0.01), and body mass index (BMI) > 25 (p = 0.03) were associated with worse PFS; presence of pain (p = 0.01), ECOG PS1–2 (p = 0.004), duration of ADT ⩽ 43.2 (p = 0.05), and BMI > 25 (p = 0.042) were associated with worse OS. Incidence of CVEs was as follows: hypertension 17.1%, fluid retention 4.8%, cardiac disorders 8.6%. 16.2% of patients developed hypokalemia. Age ⩾ 75 years was associated with higher probability of cardiac disorders (p = 0.001) and fluid retention (p = 0.03). CVEs did not impact on PFS or OS. Hypokalemia was associated with better median OS (p = 0.036). Similar associations were observed after stratification by subgroup.

Conclusions:

Median PFS and OS estimates and incidence of CVEs and hypokalemia in our series are consistent with those of pivotal trials of AA plus PDN, confirming the efficacy and safety of this regimen also in the real-world setting. Elderly patients have higher odds of developing/worsening CVEs. However, regardless of age, CVEs were not associated with worse outcomes. Treatment-related hypokalemia seemed to be associated with longer OS, albeit this finding needs confirmation within larger, prospective series.

Contribution of Adipose Tissue to Development of Cancer

Solid tumor growth and metastasis require the interaction of tumor cells with the surrounding tissue, leading to a view of tumors as tissue-level phenomena rather than exclusively cell-intrinsic anomalies. Due to the ubiquitous nature of adipose tissue, many types of solid tumors grow in proximate or direct contact with adipocytes and adipose-associated stromal and vascular components, such as fibroblasts and other connective tissue cells, stem and progenitor cells, endothelial cells, innate and adaptive immune cells, and extracellular signaling and matrix components. Excess adiposity in obesity both increases risk of cancer development and negatively influences prognosis in several cancer types, in part due to interaction with adipose tissue cell populations. Herein, we review the cellular and noncellular constituents of the adipose "organ," and discuss the mechanisms by which these varied microenvironmental components contribute to tumor development, with special emphasis on obesity. Due to the prevalence of breast and prostate cancers in the United States, their close anatomical proximity to adipose tissue depots, and their complex epidemiologic associations with obesity, we particularly highlight research addressing the contribution of adipose tissue to the initiation and progression of these cancer types. Obesity dramatically modifies the adipose tissue microenvironment in numerous ways, including induction of fibrosis and angiogenesis, increased stem cell abundance, and expansion of proinflammatory immune cells. As many of these changes also resemble shifts observed within the tumor microenvironment, proximity to adipose tissue may present a hospitable environment to developing tumors, providing a critical link between adiposity and tumorigenesis. © 2018 American Physiological Society. Compr Physiol 8:237-282, 2018.

Investigating the role of the IGF axis as a predictor of biochemical recurrence in prostate cancer patients post-surgery

BACKGROUND

Between 20% and 35% of prostate cancer (PCa) patients who undergo treatment with curative intent (ie, surgery or radiation therapy) for localized disease will experience biochemical recurrence (BCR). Alterations in the insulin-like growth factor (IGF) axis and PTEN expression have been implicated in the development and progression of several human tumors including PCa. We examined the expression of the insulin receptor (INSR), IGF-1 receptor (IGF-1R), PTEN, and AKT in radical prostatectomy tissue of patients who developed BCR post-surgery.

METHODS

Tissue microarrays (TMA) of 130 patients post-radical prostatectomy (65 = BCR, 65 = non-BCR) were stained by immunohistochemistry for INSR, IGF-1R, PTEN, and AKT using optimized antibody protocols. INSR, IGF1-R, PTEN, and AKT expression between benign and cancerous tissue, and different Gleason grades was assessed. Kaplan-Meier survival curves were used to examine the relationship between proteins expression and BCR.

RESULTS

INSR (P < 0.001), IGF-1R (P < 0.001), and AKT (P < 0.05) expression was significantly increased and PTEN (P < 0.001) was significantly decreased in cancerous versus benign tissue. There was no significant difference in INSR, IGF-1R, or AKT expression in the cancerous tissue of non-BCR versus BCR patients (P = 0.149, P = 0.990, P = 0.399, respectively). There was a significant decrease in PTEN expression in the malignant tissue of BCR versus non-BCR patients (P = 0.011). Combinational analysis of the tissue proteins identified a combination of decreased PTEN and increased AKT or increased INSR was associated with worst outcome. We found that in each case, our hypothesized worst group was most likely to experience BCR and this was significant for combinations of PTEN+INSR and PTEN+AKT but not PTEN+IGF-1R (P = 0.023, P = 0.028, P = 0.078, respectively).

CONCLUSIONS

Low PTEN is associated with BCR and this association is strongly modified by high INSR and high AKT expression. Measurement of these proteins could help inform appropriate patient selection for postoperative adjuvant therapy and prevent BCR.

Long-term supplementation of decaffeinated green tea extract does not modify body weight or abdominal obesity in a randomized trial of men at high risk for prostate cancer

Background

Evidence continues to demonstrate the role of obesity in prostate carcinogenesis and prognosis, underscoring the need to identify and continue to evaluate the effective interventions to reduce obesity in populations at high risk. The aim of the study was to determine the effect of daily consumption of decaffeinated green tea catechins (GTC) formulation (Polyphenon E^® (PolyE)) for 1 year on biomarkers of obesity in men who are at high risk for prostate cancer.

Materials and Methods

A randomized, double-blinded trial was conducted targeting 97 men diagnosed with HGPIN or ASAP. Subjects were randomized to receive GTC (PolyE) (n = 49) or placebo (n = 48) for 1 year. Anthropometric data were collected at baseline, 6 and 12 months and data analyzed to observe change in weight, body mass index (indicator of obesity) and waist: hip ratio (indicator of abdominal obesity).

Results

Decaffeinated GTC containing 400 mgs of the bioactive catechin, EGCG administered for 1 year to men diagnosed with ASAP and HGPIN appears to be bioavailable, well tolerated but not effective in reducing biomarkers of obesity including body weight, body mass index and waist: hip ratio.

Conclusions

The results of our trial demonstrates that men who are obese and at high risk for prostate cancer should resort to effective weight management strategies to reduce obesity and not resort to ineffective measures such as taking supplements of green tea to reduce biomarkers of obesity. Changes in body mass index and abdominal obesity seen in other studies were potentially due to caffeine and not GTC.

Obesity, age, ethnicity, and clinical features of prostate cancer patients

Approximately 36.5% of the U.S. adults (≥ 20 years old) are obese. Obesity has been associated with type 2 diabetes mellitus, cardiovascular disease, stroke, and several types of cancer. The present study included 1788 prostate cancer patients who were treated with radical prostatectomy at the Ochsner Health System, New Orleans, Louisiana, from January, 2001 to March, 2016. The patient's medical records were retrospectively reviewed. Body mass index (BMI), age, ethnicity (Caucasians versus African Americans), clinical stage, Gleason score, and prostate-specific antigen (PSA) levels were retrieved. The relative risk of the patients was stratified into low risk and high risk groups. Associative analyses found that BMI was associated with age, clinical stage, Gleason score, but not ethnicity, PSA levels, or the relative risk in this cohort. Age was associated with ethnicity, clinical stage, Gleason score, and PSA levels, as well as the relative risk. Ethnicity was associated with Gleason score and PSA levels as well as the relative risk, but not clinical stage. These findings suggest that obesity is associated with advanced prostate cancer with stage T3 or Gleason score ≥ 7 diseases, and age and ethnicity are important factors that are associated with the clinical features of prostate cancer patients.

Peculiarities of the obese patient with cancer: a national consensus statement by the Spanish Society for the Study of Obesity and the Spanish Society of Medical Oncology

The relationship between obesity and cancer is clear and is present at all times during course of the disease. The importance of obesity in increasing the risk of developing cancer is well known, and some of the most prevalent tumours (breast, colorectal, and prostate) are directly related to this risk increase. However, there is less information available on the role that obesity plays when the patient has already been diagnosed with cancer. Certain data demonstrate that in some types of cancer, obese patients tolerate the treatments more poorly. Obesity is also known to have an impact on the prognosis, favouring lower survival rates or the appearance of secondary tumours. In this consensus statement, we will analyse the scientific evidence on the role that obesity plays in patients already diagnosed with cancer, and the available data on how obesity control can improve the quality of daily life for the cancer patient.

Obesity and Other Cancers

Purpose

Evidence on overweight, obesity, and an increased risk of cancer continues to accumulate and was updated in the 2016 handbook on weight control from the International Agency for Research on Cancer (IARC). The underlying primary data, together with dose-response meta-analysis and, finally, pooled analysis of individual participant data, add insight into the relation between obesity and cancer risk and prognosis. We summarize the evidence for mortality from prostate cancer, hematologic malignancies, and kidney cancer.

Methods

We reviewed pooled analysis of rare end points across cohorts, regardless of primary results reported from the individual studies, further reducing risk of publication bias. Of these cancer sites, only kidney cancer was included in the IARC 2002 report, although mortality from prostate cancer and hematologic malignancies was noted in the American Cancer Society prospective cohort study in 2003. The 2016 update from the IARC added details for prostate and hematologic malignancies, classifying the evidence as sufficient to conclude that avoiding excess body fatness lowers the risk of multiple myeloma but found that the evidence for it lowering the risk of prostate cancer mortality or diffuse large B-cell lymphoma was limited.

Results

A higher body mass index is associated with an increased risk of advanced prostate cancer and prostate cancer mortality and is associated with worse survival in most subtypes of hematologic malignancies, in a dose-response fashion. Evidence for kidney cancer is built mostly on retrospective data, which supports an obesity paradox in patients with the clear cell variant; however, population-based cohort data indicate that a higher cohort-entry body mass index is associated with worse kidney cancer–specific survival.

Conclusion

Together, these data add support to the evidence for a growing cancer burden caused by adiposity in both early adult and later adult life, yet leave open the question of the means of weight management after diagnosis as a strategy to improve survival.

Omentum and bone marrow: how adipocyte-rich organs create tumour microenvironments conducive for metastatic progression

A number of clinical studies have linked adiposity with increased cancer incidence, progression and metastasis, and adipose tissue is now being credited with both systemic and local effects on tumour development and survival. Adipocytes, a major component of benign adipose tissue, represent a significant source of lipids, cytokines and adipokines, and their presence in the tumour microenvironment substantially affects cellular trafficking, signalling and metabolism. Cancers that have a high predisposition to metastasize to the adipocyte-rich host organs are likely to be particularly affected by the presence of adipocytes. Although our understanding of how adipocytes influence tumour progression has grown significantly over the last several years, the mechanisms by which adipocytes regulate the metastatic niche are not well-understood. In this review, we focus on the omentum, a visceral white adipose tissue depot, and the bone, a depot for marrow adipose tissue, as two distinct adipocyte-rich organs that share common characteristic: they are both sites of significant metastatic growth. We highlight major differences in origin and function of each of these adipose depots and reveal potential common characteristics that make them environments that are attractive and conducive to secondary tumour growth. Special attention is given to how omental and marrow adipocytes modulate the tumour microenvironment by promoting angiogenesis, affecting immune cells and altering metabolism to support growth and survival of metastatic cancer cells.

Obesity and prostate cancer-specific mortality after radical prostatectomy: results from the Shared Equal Access Regional Cancer Hospital (SEARCH) database

Background:

At the population level, obesity is associated with prostate cancer (PC) mortality. However, few studies analyzed the associations between obesity and long-term PC-specific outcomes after initial treatment.

Methods:

We conducted a retrospective analysis of 4268 radical prostatectomy patients within the Shared Equal Access Regional Cancer Hospital (SEARCH) database. Cox models accounting for known risk factors were used to examine the associations between body mass index (BMI) and PC-specific mortality (PCSM; primary outcome). Secondary outcomes included biochemical recurrence (BCR) and castration-resistant PC (CRPC). BMI was used as a continuous and categorical variable (normal <25 kg/m², overweight 25–29.9 kg/m² and obese ⩾30 kg/m²). Median follow-up among all men who were alive at last follow-up was 6.8 years (interquartile range=3.5–11.0). During this time, 1384 men developed BCR, 117 developed CRPC and 84 died from PC. Hazard ratios were analyzed using competing-risks regression analysis accounting for non-PC death as a competing risk.

Results:

On crude analysis, higher BMI was not associated with risk of PCSM (P=0.112), BCR (0.259) and CRPC (P=0.277). However, when BMI was categorized, overweight (hazard ratio (HR) 1.99, P=0.034) and obesity (HR 1.97, P=0.048) were significantly associated with PCSM. Obesity and overweight were not associated with BCR or CRPC (all P⩾0.189). On multivariable analysis adjusting for both clinical and pathological features, results were little changed in that obesity (HR=2.05, P=0.039) and overweight (HR=1.88, P=0.061) were associated with higher risk of PCSM, but not with BCR or CRPC (all P⩾0.114) with the exception that the association for overweight was no longer statistical significant.

Conclusions:

Overweight and obesity were associated with increased risk of PCSM after radical prostatectomy. If validated in larger studies with longer follow-up, obesity may be established as a potentially modifiable risk factor for PCSM.