Periprostatic fat measured on computed tomography as a marker for prostate cancer aggressiveness

The effect of different adipose tissue measurements on clinical prognosis in bladder cancer patients undergoing radical cystectomy: preliminary results

PURPOSE

Obesity has been linked to an increased incidence of various cancers, including bladder cancer. Among the different types of adipose tissue, visceral fat is recognized as the most metabolically active. However, there is a notable scarcity of studies investigating the impact of fat distribution, as measured by computed tomography (CT), on the prognosis of bladder cancer patients undergoing radical cystectomy (RC).

MATERIALS AND METHODS

Between January 2013 and January 2024, preoperative CT images of 34 patients who underwent RC were analyzed to measure total perivesical fat area (TPFA, mm²), fat density (FD, %), and subcutaneous fat thickness (SFT, mm). Multivariate Cox regression analysis was used to assess the effects of these variables on prognosis.

RESULTS

The median age (IQR) of the patients was 65.5 years (12.5), and the median BMI (IQR) was 26.05 (5.98) kg/m². The median follow-up period (IQR) was 11 (31.2) months. A positive correlation was observed between BMI, TPFA, and SFT (r = 0.39, p = 0.02; r = 0.69, p < 0.001, respectively). According to Cox regression analysis, SFT, T stage, and N stage were found to be predictive factors for progression (HR = 1.11, p = 0.007; HR = 4.01, p = 0.04; HR = 6.47, p = 0.02, respectively), and T stage was also identified as an independent predictor for overall survival (HR = 5.32, p = 0.04).

CONCLUSION

SFT measurement alongside clinical staging would be beneficial in determining progression following RC. Future randomized controlled trials supporting our findings will highlight the significance of these measurements.

Periprostatic adipose tissue inhibits tumor progression by secreting apoptotic factors: A natural barrier induced by the immune response during the early stages of prostate cancer

Prostate cancer (PCa) is the second most prevalent malignancy in men worldwide. The risk factors for PCa include obesity, age and family history. Increased visceral fat has been associated with high PCa risk, which has prompted previous researchers to investigate the influence of body composition and fat distribution on PCa prognosis. However, there is a lack of studies focusing on the mechanisms and interactions between periprostatic adipose tissue (PPAT) and PCa cells. The present study investigated the association between the composition of pelvic adipose tissue and PCa aggressiveness to understand the role played by this tissue in PCa progression. Moreover, PPAT-conditioned medium (CM) was prepared to assess the influence of the PPAT secretome on the pathophysiology of PCa. The present study included 50 patients with localized PCa who received robot-assisted radical prostatectomy. Medical records were collected, magnetic resonance imaging scans were analyzed and body compositions were calculated to identify the associations between adipose tissue volume and clinical PCa aggressiveness. In addition, CM was prepared from PPAT and perivesical adipose tissue (PVAT) collected from 25 patients during surgery, and its effects on the PCa cell lines C4-2 and LNCaP, and the prostate epithelial cell line PZ-HPV-7, were investigated using a cell proliferation assay and RNA sequencing (RNA-seq). The results revealed that the initial prostate-specific antigen level was significantly correlated with pelvic and periprostatic adipose tissue volumes. In addition, PPAT volume was significantly higher in patients with extracapsular tumor extension. PCa cell proliferation was significantly reduced when the cells were cultured in PPAT-CM compared with when they were cultured in control- and PVAT-CM. RNA-seq revealed that immune responses, and the cell death and apoptosis pathways were enriched in PPAT-CM-cultured cells indicating that the cytokines or other factors secreted from PPAT-CM induced PCa cell apoptosis. These findings revealed that the PPAT secretome may inhibit PCa cell proliferation by activating immune responses and promoting cancer cell apoptosis. This mechanism may act as a first-line defense during the early stages of PCa.

MRI-measured periprostatic to subcutaneous adipose tissue thickness ratio as an independent risk factor in prostate cancer patients undergoing radical prostatectomy

The purpose of this study is to evaluate whether the periprostatic adipose tissue thickness (PPATT) is an independent prognostic factor for prostate cancer patients after laparoscopic radical prostatectomy (LRP). This retrospective cohort study included consecutive prostate cancer patients who underwent LRP treatment at Wuhan Union Hospital from June 2, 2016, to September 7, 2023. PPATT was defined as the thickness of periprostatic fat and was obtained by measuring the shortest vertical distance from the pubic symphysis to the prostate on the midsagittal T2-weighted MR images. Subcutaneous adipose tissue thickness (SATT) was obtained by measuring the shortest vertical distance from the pubic symphysis to the skin at the same slice with PPATT. The primary outcome of the study was biochemical recurrence (BCR), and the secondary outcome was overall survival (OS). Multivariable Cox regression analysis was used to identify independent prognostic factors for prostate cancer survival and prognosis. Based on the optimal cutoff value, 162 patients were divided into a low PPATT/SATT group (n = 82) and a high PPATT/SATT group (n = 80). During the entire follow-up period (median 23.5 months), 26 patients in the high PPATT/SATT group experienced BCR (32.5%), compared to 18 in the low PPATT/SATT group (22.0%). Kaplan-Meier curve analysis indicated that the interval to BCR was significantly shorter in the high PPATT/SATT group (P = 0.037). Multivariable Cox regression analysis revealed that an increase in the PPATT/SATT ratio was associated with BCR (hazard ratio: 1.90, 95% CI, 1.03-3.51; P = 0.040). The PPATT/SATT ratio is a significant independent risk factor for BCR after LRP for prostate cancer patients.

Periprostatic Adipose Tissue: A New Perspective for Diagnosing and Treating Prostate Cancer

Prostate cancer (PCa) is the most common tumor of the male genitourinary system. It will eventually progress to fatal metastatic castration-resistant prostate cancer, for which treatment options are limited. Adipose tissues are distributed in various parts of the body. They have different morphological structures and functional characteristics and are associated with the development of various tumors. Periprostatic adipose tissue (PPAT) is the closest white visceral adipose tissue to the prostate and is part of the PCa tumor microenvironment. Studies have shown that PPAT is involved in PCa development, progression, invasion, and metastasis through the secretion of multiple active molecules. Factors such as obesity, diet, exercise, and organochlorine pesticides can affect the development of PCa indirectly or directly through PPAT. Based on the mechanism of PPAT's involvement in regulating PCa, this review summarized various diagnostic and therapeutic approaches for PCa with potential applications to assess the progression of patients' disease and improve clinical outcomes.

Obesity-Related Cross-Talk between Prostate Cancer and Peripheral Fat: Potential Role of Exosomes

The molecular mechanisms of obesity-induced cancer progression have been extensively explored because of the significant increase in obesity and obesity-related diseases worldwide. Studies have shown that obesity is associated with certain features of prostate cancer. In particular, bioactive factors released from periprostatic adipose tissues mediate the bidirectional communication between periprostatic adipose tissue and prostate cancer. Moreover, recent studies have shown that extracellular vesicles have a role in the relationship between tumor peripheral adipose tissue and cancer progression. Therefore, it is necessary to investigate the feedback mechanisms between prostate cancer and periglandular adipose and the role of exosomes as mediators of signal exchange to understand obesity as a risk factor for prostate cancer. This review summarizes the two-way communication between prostate cancer and periglandular adipose and discusses the potential role of exosomes as a cross-talk and the prospect of using adipose tissue as a means to obtain exosomes in vitro. Therefore, this review may provide new directions for the treatment of obesity to suppress prostate cancer.

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.

Thromboinflammatory Processes at the Nexus of Metabolic Dysfunction and Prostate Cancer: The Emerging Role of Periprostatic Adipose Tissue

Simple Summary

As overweight and obesity increase among the population worldwide, a parallel increase in the number of individuals diagnosed with prostate cancer was observed. There appears to be a relationship between both diseases where the increase in the mass of fat tissue can lead to inflammation. Such a state of inflammation could produce many factors that increase the aggressiveness of prostate cancer, especially if this inflammation occurred in the fat stores adjacent to the prostate. Another important observation that links obesity, fat tissue inflammation, and prostate cancer is the increased production of blood clotting factors. In this article, we attempt to explain the role of these latter factors in the effect of increased body weight on the progression of prostate cancer and propose new ways of treatment that act by affecting how these clotting factors work.

Abstract

The increased global prevalence of metabolic disorders including obesity, insulin resistance, metabolic syndrome and diabetes is mirrored by an increased incidence of prostate cancer (PCa). Ample evidence suggests that these metabolic disorders, being characterized by adipose tissue (AT) expansion and inflammation, not only present as risk factors for the development of PCa, but also drive its increased aggressiveness, enhanced progression, and metastasis. Despite the emerging molecular mechanisms linking AT dysfunction to the various hallmarks of PCa, thromboinflammatory processes implicated in the crosstalk between these diseases have not been thoroughly investigated. This is of particular importance as both diseases present states of hypercoagulability. Accumulating evidence implicates tissue factor, thrombin, and active factor X as well as other players of the coagulation cascade in the pathophysiological processes driving cancer development and progression. In this regard, it becomes pivotal to elucidate the thromboinflammatory processes occurring in the periprostatic adipose tissue (PPAT), a fundamental microenvironmental niche of the prostate. Here, we highlight key findings linking thromboinflammation and the pleiotropic effects of coagulation factors and their inhibitors in metabolic diseases, PCa, and their crosstalk. We also propose several novel therapeutic targets and therapeutic interventions possibly modulating the interaction between these pathological states.

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.

Prognostic Value of CT-Attenuation and 18F-Fluorodeoxyglucose Uptake of Periprostatic Adipose Tissue in Patients with Prostate Cancer

This study aimed to assess the prognostic value of computed tomography (CT)-attenuation and ¹⁸F-fluorodeoxyglucose (FDG) uptake of periprostatic adipose tissue (PPAT) for predicting disease progression-free survival (DPFS) in patients with prostate cancer. Seventy-seven patients with prostate cancer who underwent staging FDG positron emission tomography (PET)/CT were retrospectively reviewed. CT-attenuation (HU) and FDG uptake (SUV) of PPAT were measured from the PET/CT images. The relationships between these PPAT parameters and clinical factors were assessed, and a Cox proportional hazard regression test was performed to evaluate the prognostic significance of PPAT HU and SUV. PPAT HU and SUV showed significant positive correlations with tumor stage and serum prostate-specific antigen level (PSA) (p < 0.05). Patients with high PPAT HU and SUV had significantly worse DPFS than those with low PPAT HU and SUV (p < 0.05). In multivariate analysis, PPAT SUV was a significant predictor of DPFS after adjusting for tumor stage, serum PSA, and tumor SUV (p = 0.003; hazard ratio, 1.50; 95% confidence interval, 1.15–1.96). CT-attenuation and FDG uptake of PPAT showed significant association with disease progression in patients with prostate cancer. These imaging findings may be evidence of the role of PPAT in prostate cancer progression.

Abdominal and pelvic adipose tissue distribution and risk of prostate cancer recurrence after radiation therapy

BACKGROUND

Fat distribution varies between individuals of similar body mass index (BMI). We hypothesized that visceral obesity is more strongly associated with poor prostate cancer outcomes than overall obesity defined by BMI.

MATERIALS AND METHODS

We quantified abdominal visceral and subcutaneous fat area (VFA and SFA), and pelvic periprostatic adipose tissue area (PPAT), using computed tomography scans from radiation-treated prostate cancer patients at the Durham North Carolina Veterans Administration Hospital. Multivariable-adjusted Cox regression examined associations between each adiposity measure and risk of recurrence, overall and stratified by race and receipt of androgen deprivation therapy (ADT).

RESULTS

Of 401 patients (59% black) treated from 2005 to 2011, 84 (21%) experienced recurrence during 9.3 years median follow-up. Overall, obesity defined by BMI was not associated with recurrence risk overall or stratified by race or ADT, nor was any measure of fat distribution related to the risk of recurrence overall or by race. However, higher VFA was associated with increased risk of recurrence in men who received radiation only (hazard ratio [HR], 1.79; 95% confidence interval [CI], 0.87-3.66), but inversely associated with recurrence risk in men treated with radiation and ADT (HR, 0.49; 95% CI, 0.24-1.03; P-interaction = .002), though neither association reached statistical significance. Similar patterns of ADT-stratified associations were observed for PPAT and SFA.

CONCLUSIONS

Associations between abdominal and pelvic adiposity measures and recurrence risk differed significantly by ADT receipt, with positive directions of association observed only in men not receiving ADT. If confirmed, our findings suggest that obesity may have varying effects on prostate cancer progression risk dependent on the hormonal state of the individual.

Assessment of Periprostatic and Subcutaneous Adipose Tissue Lipolysis and Adipocyte Size from Men with Localized Prostate Cancer

The prostate is surrounded by periprostatic adipose tissue (PPAT), the thickness of which has been associated with more aggressive prostate cancer (PCa). There are limited data regarding the functional characteristics of PPAT, how it compares to subcutaneous adipose tissue (SAT), and whether in a setting of localized PCa, these traits are altered by obesity or disease aggressiveness. PPAT and SAT were collected from 60 men (age: 42–78 years, BMI: 21.3–35.6 kg/m²) undergoing total prostatectomy for PCa. Compared to SAT, adipocytes in PPAT were smaller, had the same basal rates of fatty acid release (lipolysis) yet released less polyunsaturated fatty acid species, and were more sensitive to isoproterenol-stimulated lipolysis. Basal lipolysis of PPAT was increased in men diagnosed with less aggressive PCa (Gleason score (GS) ≤ 3 + 4) compared to men with more aggressive PCa (GS ≥ 4 + 3) but no other measured adipocyte parameters related to PCa aggressiveness. Likewise, there was no difference in PPAT lipid biology between lean and obese men. In conclusion, lipid biological features of PPAT do differ from SAT; however, we did not observe any meaningful difference in ex vivo PPAT biology that is associated with PCa aggressiveness or obesity. As such, our findings do not support a relationship between altered PCa behavior in obese men and the metabolic reprogramming of PPAT.

Linear extent of positive surgical margin impacts biochemical recurrence after robot-assisted radical prostatectomy in a high-volume center

The objective of this study is to evaluate if surgeon volume and stratifying positive surgical margins (PSM) into focal and non-focal may differentially impact the risk of biochemical recurrence (BCR) after robot-assisted radical prostatectomy (RARP). Between January 2013 and December 2017, 732 consecutive patients were evaluated. The population included negative cases (control group) and PSM subjects (study group). PSMs were stratified as focal (≤ 1 mm) or non-focal (> 1 mm). A logistic regression model assessed the independent association of factors with the risk of PSM. The risk of BCR of PSM and other factors was assessed by Cox's multivariate proportional hazards. Overall, 192 (26.3%) patients had PSM focal in 133 patients; non-focal in 59 cases. Focal PSM was associated with the percentage of biopsy positive cores (BPC; OR 1.011; p = 0.015), extra-capsular extension (pT3a stage; OR 2.064; p = 0.016), seminal vesicle invasion (pT3b; OR 2.150; p = 0.010), body mass index (odds ratio, OR 0.914; p = 0.006), and high surgeon volume (OR 0.574; p = 0.006). BPC (OR 1.013; p = 0.044), pT3a (OR 4.832; p < 0.0001) and pT3b stage (OR 5.153; p = 0.001) were independent predictors of the risk of non-focal PSM. Surgeon volume was not a predictor of non-focal PSM (p = 0.224). Independent factors associated with the risk of BCR were baseline PSA (hazard ratio, HR 1.064; p = 0.004), BPC (HR 1.015; p = 0.027), ISUP biopsy grade group (BGG) 2/3 (HR 2.966; p 0.003) and BGG 4/5 (HR 3.122; p = 0.022) pathologic grade group 4/5 (HR 3.257; p = 0.001), pT3b (HR 2.900; p = 0.003), and non-focal PSM (HR 2.287; p = 0.012). Surgeon volume was not a predictor of BCR (p = 0.253). High surgeon volume is an independent factor that lowers the risk of focal PSM. Surgeon volume does not affect non-focal PSM and BCR. Negative as well as focal PSM are not associated with BCR.

High surgeon volume and positive surgical margins can predict the risk of biochemical recurrence after robot-assisted radical prostatectomy

Background:

The aim of this study was to determine whether any clinical factors are independent predictors of positive surgical margins (PSM), and to assess the association of PSM and biochemical recurrence (BR) after robot-assisted radical prostatectomy (RARP).

Methods:

The population included cases with negative surgical margins (control group) and patients with PSM (study group). Tumor grade was evaluated according to the International Society of Urologic Pathology (ISUP) system. A logistic regression model assessed the independent association of factors with the risk of PSM. The risk of BR was assessed by Cox’s multivariate proportional hazards.

Results:

A total of 732 consecutive patients were evaluated. Extend pelvic lymph node dissection (ePLND) was performed in 342 cases (46.7%). Overall, 192 cases (26.3%) had PSM. The risk of PSM was positively associated with the percentage of biopsy positive cores (BPC; odds ratio, OR = 1.012; p = 0.004), extracapsular extension (pT3a; OR=2.702; p < 0.0001), invasion of seminal vesicle (pT3b; OR = 2.889; p < 0.0001), but inversely with body mass index (OR = 0.936; p = 0.021), and high surgeon volume (OR = 0.607; p = 0.006). Independent clinical factors associated with the risk of BR were baseline prostate-specific antigen (PSA; hazard ratio, HR = 1.064; p = 0.004), BPC (HR = 1.015; p = 0.027), ISUP biopsy grade group (BGG) 2/3 (HR = 2.966; p = 0.003), and BGG 4/5 (HR = 3.122; p = 0.022). Pathologic factors associated with the risk of BR were ISUP group 4/5 (HR = 3.257; p = 0.001), pT3b (HR = 2.900; p = 0.003), and PSM (HR = 2.096; p = 0.045).

Conclusions:

In our cohort, features related to host, tumor, and surgeon volume are associated with the risk of PSM, which is also an independent parameter predicting BR after RARP. The surgical volume of the operating surgeon is an independent factor that decreases the risk of PSM, and, as such, the risk of BR.

Periprostatic fat adipokine expression is correlated with prostate cancer aggressiveness in men undergoing radical prostatectomy for clinically localized disease

OBJECTIVES

To investigate the relationship between periprostatic adipose tissue (PPAT) adipokine expression and prostate cancer (PCa) aggressiveness using both pathological features of radical prostatectomy (RP) and multiparametric magnetic resonance imaging ( MRI) variables.

PATIENTS AND METHODS

Sixty-nine men were recruited to assess immunohistochemical expression of tumour necrosis factor (TNF)α and vascular endothelial growth factor (VEGF) of periprostatic fat of RP specimens. Per cent immunopositivity was quantified on scanned slides using the Aperio Positive Pixel Count algorithm for PPAT TNFα, VEGF and androgen receptors. Periprostatic fat volume (PFV) was segmented on contiguous T₁ -weighted axial MRI slices from the level of the prostate base to apex. PFV was normalized to prostate volume (PV) to account for variations in PV (normalized PFV = PFV/PV). MRI quantitative values (K_ep , K_trans and apparent diffusion coefficient) were measured from the PCa primary lesion using Olea Sphere software. Patients were stratified into three groups according to RP Gleason score (GS): ≤6, 7(3 + 4) and ≥7(4 + 3).

RESULTS

The mean rank of VEGF and TNFα was significantly different between the groups [H(2) = 11.038, P = 0.004] and [H(2) = 13.086, P = 0.001], respectively. Patients with stage pT₃ had higher TNFα (18.2 ± 8.95) positivity than patients with stage pT₂ (13.27 ± 10.66; t [67] = -2.03, P = 0.047). TNFα expression significantly correlated with K_trans (ρ = 0.327, P = 0.023). TNFα (P = 0.043), and VEGF (P = 0.02) correlated with high grade PCa (GS ≥ 7) in RP specimens and also correlated significantly with upgrading of GS from biopsy to RP histology.

CONCLUSIONS

The expression levels of TNFα and VEGF on immunostaining significantly correlated with aggressivity of PCa. As biomarkers, these indicate the risk of having high grade PCa in men undergoing RP.

The combination of prostate imaging reporting and data system version 2 (PI-RADS v2) and periprostatic fat thickness on multi-parametric MRI to predict the presence of prostate cancer

PURPOSE

To evaluate the auxiliary effectiveness of periprostatic fat thickness (PPFT) on multi-parametric magnetic resonance imaging (mp-MRI) to Prostate Imaging Reporting and Data System version 2 (PI-RADS v2) in predicting the presence of prostate cancer (PCa) and high-grade prostate cancer (HGPCa, Gleason Score ≥ 7).

RESULTS

Overall, there were 371 patients (54.3%) with PCa and 292 patients (42.8%) with HGPCa. The mean value of PPFT was 4.04 mm. Multivariate analysis revealed that age, prostatic specific antigen (PSA), volume, PI-RADS score, and PPFT were independent predictors of PCa. All factors plus abnormal digital rectal exam were independent predictors of HGPCa. In addition, the PPFT was the independent predictor of PCa (Odds ratio [OR] 2.56, p = 0.004) and HGPCa (OR 2.70, p = 0.014) for subjects with PI-RADS grade 3. The present two nomograms based on multivariate analysis outperformed the single PI-RADS in aspects of predicting accuracy for PCa (area under the curve: 0.922 vs. 0.883, p = 0.029) and HGPCa (0.919 vs. 0.873, p = 0.007). Decision-curve analysis also indicated the favorable clinical utility of the present two nomograms.

MATERIALS AND METHODS

The clinical data of 683 patients who received transrectal ultrasound guided biopsy and prior mp-MRI were reviewed. PPFT was measured as the shortest perpendicular distance from the pubic symphysis to the prostate on MRI. Univariate and multivariate analyses were performed to determine the independent predictors of PCa and HGPCa. We also constructed two nomograms for predicting PCa and HGPCa based on the logistic regression.

CONCLUSION

The PPFT on mp-MRI is an independent predictor of PCa and HGPCa, notably for patients with PI-RADS grade 3. The nomograms incorporated predictors of PPFT and PI-RADS demonstrated good predictive performance.

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.

Normalized periprostatic fat MRI measurements can predict prostate cancer aggressiveness in men undergoing radical prostatectomy for clinically localised disease

Periprostatic and pelvic fat have been shown to influence prostate cancer behaviour through the secretion of chemokines and growth factors, acting in a paracrine mode. We have measured periprostatic fat volume (PFV) with normalisation to prostate gland volume on pelvic magnetic resonance imaging (MRI) and have correlated this with grade (Gleason score; GS) and pathological staging (pT) of prostate cancer (PCa) following radical prostatectomy (RP). PFV was determined using a segmentation technique on contiguous T1-weighted axial MRI slices from the level of the prostate base to the apex. The abdominal fat area (AFA) and subcutaneous fat thickness (SFT) were measured using T1-weighted axial slices at the level of the umbilicus and the upper border of the symphysis pubis, respectively. PFV was normalised to prostate volume (PV) to account for variations in PV (NPFV = PFV/PV). Patients were stratified into three risk groups according to post-operative GS: ≤6, 7(3 + 4), and ≥7(4 + 3). NPFV was significantly different between the groups (p = 0.001) and positively correlated with post-operative GS (ρ = 0.294, p < 0.001). There was a difference in NPFV between those with upgrading of GS from 6 post prostatectomy (2.43 ± 0.98; n = 26) compared to those who continued to be low grade (1.99 ± 0.82; n = 17); however, this did not reach statistical significance (p = 0.11).

Influence of adipocytokines in periprostatic adipose tissue on prostate cancer aggressiveness

OBJECTIVE

To evaluate the correlation between the level of adipocytokines expression in periprostatic adipose tissue and the prostate cancer aggressiveness.

PATIENTS AND METHOD

The periprostatic adipose tissues were collected from 30 patients who underwent radical retropubic prostatectomy. The subcutaneous adipose, periprostatic adipose tissues and prostate cancer tissue from the same patient were collected from 10 patients for match research. The expression level of IL-6, Leptin and Adiponectin was detected by immunohistochemistry and by Real-time quantitative PCR in periprostatic adipose tissues.

RESULT

There were differences in the positive rates of IL-6, Leptin and Adiponectin expression in the periprostate adipose between prostate cancer and control (P<0.001, P=0.032, 0.003). Nothing but the "IL-6 expression intensity" was seen in difference with the aggressiveness of prostate cancer (P=0.001), and was relevant with the prostate cancer aggressiveness (rs=0.668, P<0.001); The mRNA expression of IL-6 in periprostatic adipose tissues of prostate cancer was higher than that of control (P=0.049), and the mRNA expression of Adiponectin was lower (P<0.0001); IL-6 mRNA expression in periprostate adipose tissue and prostate cancer tissue were higher than that in subcutaneous adipose (P<0.001, P=0.001); IL-6 mRNA expression in periprostate adipose was correlated with that in prostate cancer tissue (r=0.663, p=0.036); Adiponectin mRNA expression in prostate cancer tissue was lower than that in periprostate adipose (P=0.006), and Adiponectin mRNA expression in periprostate adipose was correlated with that in prostate cancer tissue (r=0.707, p=0.022).

CONCLUSION

IL-6, Leptin and Adiponectin were expressed in the periprostatic adipose tissues, which constitute the microenvironment of prostate cancer aggressiveness. There might be intimate relationship between periprostate adipose and prostate cancer tissue.

Prostate cancer in East Asia: evolving trend over the last decade

Prostate cancer is now becoming an emerging health priority in East Asia. Most of our current knowledge on Prostate cancer has been generated from studies conducted in Western population; however, there is considerable heterogeneity of Prostate cancer between East and West. In this article, we reviewed epidemiologic trends, risk factors, disease characteristics and management of Prostate cancer in East Asian population over the last decade. Growing evidence from East Asia suggests an important role of genetic and environmental risk factors interactions in the carcinogenesis of Prostate cancer. Exposure to westernized diet and life style and improvement in health care in combination contribute substantially to the increasing epidemic in this region. Diagnostic and treatment guidelines in East Asia are largely based on Western knowledge. Although there is a remarkable improvement in the outcome over the last decade, ample evidence suggests an inneglectable difference in diagnostic accuracy, treatment efficacy and adverse events between different populations. The knowledge from western countries should be calibrated in the Asian setting to provide a better race-based treatment approach. In this review, we intend to reveal the evolving trend of Prostate cancer in the last decade, in order to gain evidence to improve Prostate cancer prevention and control in East Asia.

Periprostatic fat thickness on MRI: correlation with Gleason score in prostate cancer

OBJECTIVE

The purpose of this study was to retrospectively evaluate the relationship between periprostatic fat thickness on MRI and Gleason score of prostate cancer using radical prostatectomy as the reference standard.

MATERIALS AND METHODS

This study included 190 patients (mean age [± SD], 66.9 ± 7.0 years) who underwent MRI before radical prostatectomy. Two radiologists measured the subcutaneous and periprostatic fat thickness on midsagittal T2-weighted MR images as the shortest perpendicular distance from the pubic symphysis to the skin and prostate, respectively. Subcutaneous and periprostatic fat along with age, height, weight, body mass index, and prostate-specific antigen (PSA) were correlated with Gleason score by using Pearson (r) or Spearman (ρ) correlation coefficients and compared between low- (Gleason score = 6) and high- (≥ 7) grade prostate cancer by using univariate and multivariate logistic regression analyses.

RESULTS

The mean subcutaneous and periprostatic fat thicknesses were 24.0 ± 8.4 mm and 5.0 ± 2.0 mm, respectively. The Gleason score was significantly correlated with age (ρ = 0.181, p = 0.012), PSA (ρ = 0.345, p < 0.001), and periprostatic fat thickness (ρ = 0.228, p = 0.002). Multivariate analysis revealed that age, height, PSA level, and periprostatic fat thickness (odds ratio, 1.331; 95% CI, 1.063-1.666) were independently predictive of high-grade (p ≤ 0.013) disease.

CONCLUSION

Periprostatic fat thickness on MRI showed a mild to modest but significant correlation with Gleason score of prostate cancer with radical prostatectomy as the reference standard and was an independent predictive factor for high-grade prostate cancer.

Is periprostatic adipose tissue associated with aggressive tumor biology in prostate cancer?

The prevalence of overweight and obesity and their health-related problems have been increasing. Obesity is increasingly recognized as a risk factor in different types of cancer in humans. The mechanisms supporting the link between obesity and cancer development have not been fully understood. Leptin, a circulating cytokine produced by adipocytes, may influence prostate cancer (PCa) progression in different ways. Body mass index seems to be an unreliable predictor for the development of PCa, but its influence on progression and poor oncological outcomes seems to be clear. Given the fact that abdominal fat is the most metabolically active fat, with different metabolic and paracrine effects, related anthropometric measurements may lead to a better estimation of PCa risk. Metabolically active periprostatic abdominal fat may also play an important role in releasing cytokines and growth factors that may promote tumor cell proliferation or even create a favorable environment for aggressive tumor biology. Different imaging measurements, e.g., periprostatic adipose tissue (PPAT) thickness, may be significant predictors of PCa. Several genes in the PPAT of obese men have been identified to contribute to chronic immuno-inflammatory responses which eventually lead to cell cycle alteration with oncological potential. In vitro studies showed the importance of PCa and its interaction with its microenvironment particularly in patients with aggressive PCa. Different types of cytokines, such as interleukin-6, may promote a tumorigenic microenvironment. This article endeavors to review the current literature on the association of PPAT with aggressive tumor biology in PCa.

Influence of adipocytokines and periprostatic adiposity measurement parameters on prostate cancer aggressiveness

BACKGROUND

The relationship between obesity and prostate cancer aggressiveness is controversial in recent studies, partly because BMI is the only generally applied marker of obesity. Our study aimed at evaluating the correlation of periprostatic fat (PF) on magnatic resonance imaging (MRI) and adipocytokines with prostate cancer aggressiveness.

PATIENTS AND METHOD

A total of 184 patients who underwent radical retropubic prostatectomy (RRP) were analyzed retrospectively; different fat measurements on MRI slices and levels of adipocytokines were compared with the clinical and pathologic factors using SSPS ver.13.0.

RESULT

The PF rates showed a statistically significant variation (p=0.019, 0.025) among groups, that is to say, more adipose tissue was distributed in periprostatic areas of high risk patients. Logistic regression analysis adjusted for age revealed a statistically association between the PF, the ratio and the risk of having high-risk disease (p=0.031, 0.024). The levels of IL-6, leptin and c-reactive protein (CRP) significantly increased with the aggressiveness of prostate cancer, and also with PF and its ratio. The strongest correlation was seen between IL-6 and PF (Pearson r coefficient=0.67, P<0.001). No association was observed between adipocytokines and BMI.

CONCLUSION

Periprostatic adiposity not only affects prostate cancer aggressiveness, but also influences the secretion of adipocytokines. IL-6, PF and CRP have promoting effects on progression of prostate cancer.

Racial differences in adipose tissue distribution and risk of aggressive prostate cancer among men undergoing radiotherapy

BACKGROUND

Although elevated body mass index (BMI) has been associated with increased risk of aggressive prostate cancer, the importance of adipose tissue distribution is not well understood. We examined associations between overall and visceral obesity and aggressive prostate cancer risk. Moreover, given racial differences in adipose tissue distribution, we examined whether race modified these associations.

METHODS

We conducted a cross-sectional analysis of 308 radiotherapy-treated patients with prostate cancer within the Durham VA from 2005 to 2011. Multivariable logistic regression examined the association between BMI categories and tertiles of waist circumference (WC), visceral fat area (VFA), and periprostatic adipose tissue area (PPAT) with high-grade prostate cancer risk (Gleason score ≥7 vs. ≤6). Models stratified by race examined whether these associations differed between black and nonblack men.

RESULTS

Both elevated BMI (Ptrend = 0.054) and WC (Ptrend = 0.040) were associated with increased high-grade prostate cancer risk, with similar results between races, although the association with BMI was not statistically significant. In contrast, elevated VFA was associated with increased aggressive prostate cancer risk in black men (Ptrend = 0.002) but not nonblack men (Ptrend = 0.831), with a significant interaction between race and VFA (Pinteraction = 0.035). Though similar patterns were observed for PPAT, none was statistically significant.

CONCLUSIONS

Among men undergoing radiotherapy for prostate cancer, visceral obesity is associated with increased aggressive prostate cancer risk, particularly among black men. If confirmed in future studies, these results suggest that adipose tissue distribution differences may contribute to prostate cancer racial disparity.

IMPACT

These findings highlight the need to elucidate mechanisms contributing to racial differences in the association between visceral obesity and aggressive prostate cancer.

Influence of body mass index and periprostatic fat on rectal dosimetry in permanent seed prostate brachytherapy

PURPOSE

We examined the influence of body mass index (BMI) and body fat distribution on rectal dose in patients treated with permanent seed brachytherapy for localized prostate cancer.

METHODS AND MATERIALS

We analyzed 213 patients treated with I125 seed brachytherapy for localized prostate cancer. BMI and rectal dosimetry data for all patients were available. Data on visceral and subcutaneous fat distribution at the level of the iliac crest (n = 140) as well as the distribution of periprostatic and subcutaneous fat at the symphysis pubis level were obtained (n = 117). Fat distribution was manually contoured on CT on day 30 after brachytherapy. The correlation between BMI, fat distribution and rectal dose (R100 (in cc), R150 (cc), D2 (Gy)) was analyzed using the Spearman correlation coefficient. Differences in rectal dose between tertiles of body fat distribution were calculated using nonparametric tests.

RESULTS

Periprostatic adipose was only weakly correlated with BMI (r = 0.0.245, p = 0.008) and only weakly correlated with the other fat measurements (r = 0.31-0.37, p < 0.001). On the other hand, BMI was correlated with all other fat measurements (≥0.58, p < 0.001). All the other fat measurements were strongly correlated with each other (r = 0.5-0.87, p < 0.001). Patients with an R100 of >1.3 cc (23% of patients) had less visceral fat (p = 0.004), less subcutaneous fat at the level of the iliac crest (p = 0.046) and a lower BMI (26.8 kg/m2 vs. 28.5 kg/m2, p = 0.02) than patients with an R100 of <1.3 cc. Results were very similar when comparing an R100 of >1.0 cc (34% of patients) across the tertiles. None of the tested linear regression models were predictive (max 12%) of dose to the rectum.

CONCLUSION

Dose to the rectum is dependent on BMI and body fat distribution. Periprostatic fat does not influence rectal dose. Dose to the rectum remains difficult to predict and depends on many factors, one of which is body fat distribution.

Measurement of peri-prostatic fat thickness using transrectal ultrasonography (TRUS): a new risk factor for prostate cancer

Study Type - Prognosis (cohort) Level of Evidence 2b. What's known on the subject? and What does the study add? ADIPOSE tissue secretes various endocrine and paracrine mediators. Some authors have begun to consider whether peri-prostatic fat (PPF) may interact with the prostate and play a role in carcinogenesis. It has recently been shown that the PPF quantity measured by CT is associated with more aggressive disease in patients undergoing radiation therapy. Our group studied a population not yet diagnosed with prostate cancer. By doing so we were able to identify PPF thickness on transrectal ultrasonography as a risk factor for prostate cancer detection upon biopsy, and as a risk factor for high-grade disease. Our study also raises interesting questions about the underlying mechanisms of the association between PPF quantity and prostate cancer.

OBJECTIVE

To determine if the amount of peri-prostatic fat (PPF) on transrectal ultrasonography (TRUS) is a risk factor for incident prostate cancer overall and high-grade prostate cancer (Gleason ≥4).

PATIENTS AND METHODS

A prospectively maintained database of patients undergoing prostate biopsy at Princess Margaret Hospital for cancer suspicion was used. • All TRUS examinations were retrospectively reviewed upon 'blinding' to outcome. • PPF thickness, measured as the distance between the prostate and the pubic bone, was used as an index of the quantity of PPF. • PPF measurements, together with other prostate cancer risk factors, were evaluated against prostate cancer and high-grade prostate cancer detection upon biopsy with univariable and multivariable logistic regression and area under the receiver operating characteristic curve (AUC) analysis.

RESULTS

Of the 931 patients, 434 (47%) were diagnosed with prostate cancer and 218 (23%) were diagnosed with high-grade prostate cancer. • The mean (range) PPF thickness was 5.3 (0-15) mm. • Increasing PPF thickness was associated with prostate cancer and high-grade prostate cancer diagnosis, with graded effect. When adjusting for other variables, the odds of detecting any prostate cancer and high-grade prostate cancer increased 12% (odds ratio [OR] 1.12, 95% confidence interval [CI] 1.02-1.23) and 20% (OR 1.20, 95% CI 1.07-1.34), respectively, for each millimetre increase in PPF thickness. • The AUCs for the association of PPF with prostate cancer and high-grade prostate cancer were 0.58 (95% CI 0.54-0.62) and 0.59 (95% CI 0.55-0.64), respectively.

CONCLUSION

The amount of PPF can be estimated with TRUS and is a predictor of prostate cancer and high-grade prostate cancer at biopsy. To our knowledge, this study is the first to investigate PPF quantity in patients without prior prostate cancer diagnosis.

Predictors in the outcome of 125I brachytherapy as monotherapy for prostate cancer

A number of different prostate cancer treatment modalities exist. Nomograms are used to assist clinicians and patients in choosing the most appropriate treatment. However, the predicted outcome for (125)I brachytherapy is much worse than what would be expected considering the actual survival rates. This underestimation may result in suboptimal treatment decisions. Therefore, better predictors for outcome after (125)I brachytherapy are necessary. The following factors, which may either influence outcome or predict outcome after brachytherapy, are discussed: tumor characteristics and risk stratification, patient age at treatment, obesity, adjuvant androgen-deprivation therapy, prostate-specific antigen bounce, implantation technique and dosimetry. For the prediction of outcome after (125)I brachytherapy, as long as the quality of the implant is optimal, only high-risk prostate cancer was found to have a negative impact on outcome.