Is obesity a risk factor for prostate cancer, and does it even matter? A hypothesis and different perspective

Insulin Resistance: The Increased Risk of Cancers

Insulin resistance, also known as impaired insulin sensitivity, is the result of a decreased reaction of insulin signaling to blood glucose levels. This state is observed when muscle cells, adipose tissue, and liver cells, improperly respond to a particular concentration of insulin. Insulin resistance and related increased plasma insulin levels (hyperinsulinemia) may cause metabolic impairments, which are pathological states observed in obesity and type 2 diabetes mellitus. Observations of cancer patients confirm that hyperinsulinemia is a major factor influencing obesity, type 2 diabetes, and cancer. Obesity and diabetes have been reported as risks of the initiation, progression, and metastasis of several cancers. However, both of the aforementioned pathologies may independently and additionally increase the cancer risk. The state of metabolic disorders observed in cancer patients is associated with poor outcomes of cancer treatment. For example, patients suffering from metabolic disorders have higher cancer recurrence rates and their overall survival is reduced. In these associations between insulin resistance and cancer risk, an overview of the various pathogenic mechanisms that play a role in the development of cancer is discussed.

A novel prognostic risk factor for patients undergoing radical prostatectomy: Triglyseride-glucose index

BACKGROUND

Obesity and metabolic syndrome are growing health problems in western countries. Recently reported triglyseride-glucose (TyG) index is a reliable and accessible indicator of metabolic syndrome. TyG index could be used as a indicator of a prognostic risk factor for metabolic syndrome-related cancers.

OBJECTIVES

To investigate the prognostic role of TyG index on oncological outcomes in patients undergoing radical prostatectomy.

DESIGN, SETTING AND PARTICIPANTS

Data from 200 men who underwent radical prostatectomy were used.

OUTCOME MEASUREMENTS AND STATSITICAL ANALYSE

TyG was calculated based on TyG index = Ln [TG (mg/dL) FPG (mg/dL)/2] formula. Patients were divided into two groups according to the 8.55 level as cut-off value for TyG index. Laboratory results, oncological outcomes and survivals were comparised statistically between groups.

RESULTS

Mean ages of patients were 64.32 ± 6.1 years and median follow-up time was 61.6 ± 35 (range 4-140) month. Biochemical recurrens was observed in 42 (21%) patients. Positive correlation between TyG index, body mass index, waist circumference, prostate biopsy gleason score, clinical T stage, positive surgical margin, pathological T stage and biochemical recurrence were observed. There was no statistical significance in terms of survival between groups.

CONCLUSION

Association between TyG index and prostate cancer may facilitate to predict unfavorable prognostic factors of radical prostatectomy. Increased TyG index may use as a predictive marker of positive surgical margin status before radical prostatectomy, BCR, advanced cT and pT stages after radical prostatectomy or worse biopsy gleason score in clinical practice.

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

Background

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

Objectives

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

Methods

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

Results

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

Conclusion

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

Metabesity and urological cancers

Metabolic syndrome is one of today's most important health problems. Due to increased prevalence of metabolic syndrome in society, studies done on this topic have increased in number. Although metabolic syndrome was previously considered to be important only for cardiovascular health, it has been learned that with new data, human health is compromised more thoroughly by metabolic syndrome and is also a danger to malignancy. As a result, a new definition in the form of metabesity has been introduced. In this review, available information on metabesity and urological cancers is presented.

BMI and serum lipid parameters predict increasing risk and aggressive prostate cancer in Chinese people

OBJECTIVES

To determine if obesity and serum lipid parameters are associated with increased risk and more aggressive prostate cancer in Chinese population.

MATERIALS AND METHODS

We conducted a retrospective cohort analysis including 3102 patients. Kruskal-Wallis test for continuous variables and the chi-squared tests for categorical variables were used for univariate comparison of the differences in patient characteristics across BMI categories between different groups. Odds ratios (OR) and 95% confidence intervals (CI) were estimated for the association between prostate cancer and the various patient characteristics. Multivariable Cox proportional hazards regression was performed to assess the risk of prostate cancer recurrence.

RESULTS

974 consecutive men were diagnosed as prostate cancer and 700 patients subsequently received radical prostatectomy immediately, and 1031 patients were pathologically diagnosed as biopsy negative. The level of low-density-lipoprotein cholesterol (LDL-c) and total cholesterol was significantly higher and the high-density-lipoprotein cholesterol (HDL-c) level is much lower in prostate cancer patients. Patients with low level of HDL-c, who subsequently received radical prostatectomy, had increased risk of high risk disease. In addition, patients with normal weight were less likely to develop a biochemical recurrence. Combined analysis revealed that obese patients had significantly higher rates of PSA recurrence over time than nonobese patients.

CONCLUSIONS

In our study, lipid parameters are supposed to be associated with prostate cancer risk and aggressiveness. Obese men are at increased risk of PSA recurrence after radical prostatectomy.

The impact of body mass index on rectal dose in locally advanced cervical cancer treated with high-dose-rate brachytherapy

PURPOSE

The impact of body mass index (BMI) on rectal dose in brachytherapy for cervical cancer is unknown. We assessed the association of BMI on rectal dose and lower gastrointestinal (GI) toxicity.

METHODS AND MATERIALS

Between 2007 and 2010, 51 patients with 97 brachytherapy planning images were reviewed. Volumetric measurements of the maximum percentage, mean percentage, dose to 2cc (D2cc), and dose to 1cc (D1cc) of the rectum, and the Internal Commission on Radiation Units and Measurement (ICRU) rectal point were recorded. Linear mixed effect models, analysis of variance, and regression analyses were used to determine the correlation between multiple observations or to detect a difference in the mean. The GI acute and late toxicity were prospectively recorded and retrospectively analyzed.

RESULTS

The average BMI (kg/m(2)) was 27.7 with a range of 17.4-46.6. Among the patients, 8% were morbidly obese, 25% obese, 25% overweight, 40% normal weight, and 2% underweight. The mean D1cc, D2cc, mean rectal dose (%), maximum rectal dose (%), and ICRU rectum was 3.03 Gy, 2.78 Gy, 20%, 60%, and 2.99 Gy, respectively. On multivariate analysis, there was a significant decrease in the D1cc and D2cc rectal dose (p=0.016), ICRU rectal point dose (p=0.022), and mean rectal dose percentage (p=0.021) with an increase in BMI. There was, however, no statistically significant relationship between BMI and GI toxicity.

CONCLUSIONS

Obesity decreases the rectal dose given in high-dose-rate brachytherapy for locally advanced cervical cancer because of an increase in fatty tissue in the recto-uterine space. There is no significant correlation between BMI and acute or late GI toxicity.

Age-related changes in the innervation of the prostate gland: implications for prostate cancer initiation and progression

The adult prostate gland grows and develops under hormonal control while its physiological functions are controlled by the autonomic nervous system. The prostate gland receives sympathetic input via the hypogastric nerve and parasympathetic input via the pelvic nerve. In addition, the hypogastric and pelvic nerves also provide sensory inputs to the gland. This review provides a summary of the innervation of the adult prostate gland and describes the changes which occur with age and disease. Growth and development of the prostate gland is age dependent as is the occurrence of both benign prostate disease and prostate cancer. In parallel, the activity and influence of both the sympathetic and parasympathetic nervous system changes with age. The influence of the sympathetic nervous system on benign prostatic hyperplasia is well documented and this review considers the possibility of a link between changes in autonomic innervation and prostate cancer progression.

Effect of metabolic syndrome and its components on prostate cancer risk: meta-analysis

BACKGROUND

Literature data examining the role of metabolic syndrome and its components in prostate cancer risk are limited and contradictory.

AIM

We did a meta-analysis of studies that evaluated the association between metabolic syndrome, its components, and risk of prostate cancer.

SUBJECTS AND METHODS

We conducted an electronic search for articles published through September 2012 without restrictions. Every included study was to report risk estimates with 95% confidence intervals for the association between metabolic syndrome and prostate cancer.

RESULTS

The final number of papers included in the meta-analysis was 14, all published in English, with 4728 prostate cancer cases. Metabolic syndrome was associated with a 12% increase in prostate cancer risk (p=0.231), that was lower in cohort studies (7 studies, RR=1.04, p=0.791) than other studies (RR=1.23, p=0.125). The association was significant in the 8 European studies (RR=1.30, p=0.034), but not in the 4 U.S. or 2 Asiatic studies. The risk estimates of prostate cancer for higher values of body mass index, dysglycemia or dyslipidemia (high triglycerides, low HDL-cholesterol) were not significant; on the contrary, hypertension and waist circumference >102 cm were associated with a significant 15% (p=0.035) and 56% (p=0.007) greater risk of prostate cancer, respectively.

CONCLUSIONS

Metabolic syndrome is weakly and non significantly associated with prostate cancer risk, but associations vary with geography. Among single components of the syndrome, hypertension and higher waist circumference are significantly associated with increased risk of prostate cancer.

Serum lipid profiles and cancer risk in the context of obesity: four meta-analyses

The objective here was to summarize the evidence for, and quantify the link between, serum markers of lipid metabolism and risk of obesity-related cancers. PubMed and Embase were searched using predefined inclusion criteria to conduct meta-analyses on the association between serum levels of TG, TC, HDL, ApoA-I, and risk of 11 obesity-related cancers. Pooled relative risks (RRs) and 95% confidence intervals were estimated using random-effects analyses. 28 studies were included. Associations between abnormal lipid components and risk of obesity-related cancers when using clinical cutpoints (TC ≥ 6.50; TG ≥ 1.71; HDL ≤ 1.03; ApoA-I ≤ 1.05 mmol/L) were apparent in all models. RRs were 1.18 (95% CI: 1.08–1.29) for TC, 1.20 (1.07–1.35) for TG, 1.15 (1.01–1.32) for HDL, and 1.42 (1.17–1.74) for ApoA-I. High levels of TC and TG, as well as low levels of HDL and ApoA-I, were consistently associated with increased risk of obesity-related cancers. The modest RRs suggest serum lipids to be associated with the risk of cancer, but indicate it is likely that other markers of the metabolism and/or lifestyle factors may also be involved. Future intervention studies involving lifestyle modification would provide insight into the potential biological role of lipid metabolism in tumorigenesis.

Diet-induced hyperinsulinemia accelerates growth of androgen-independent PC-3 cells in vitro

We investigated the effect of insulin and diet-induced hyperinsulinemia on the growth of the PC-3 cells in vitro and discerned the growth promoting effect of insulin in the androgen-independent cells. Sprague-Dawley rats were kept on a high-fat diet for 4 wk for the induction of insulin resistance and hyperinsulinemia. Insulin alone or serum of the rats kept on either normal-pellet diet or high-fat diet was used to stimulate the serum-starved PC-3 cells growth in culture. S961, a high-affinity insulin-receptor antagonist, was used to confirm the insulin-mediated effects. Significant impairment in the glucose disposal rate and increase in the serum glucose and insulin levels was observed in the high-fat-diet-fed rats. The media supplemented with the serum of the high-fat-diet-fed rats accelerated the growth of the PC-3 cells in comparison to that of normal-pellet-diet-fed rats. Insulin treatment led to accelerated growth of the serum-starved PC-3 cells in a dose-dependent manner and inhibited by the S961 pretreatment. Insulin and serum of the diet-induced hyperinsulinemic rats promote the growth of androgen-independent prostate cancer PC-3 cells. Further, our results provide support for the concept that diet-associated elevation in insulin level may augment the growth of prostate cancer cells.

Body mass index and death rate of colorectal cancer among a national cohort of U.S. adults

Substantial evidence suggests that increasing adiposity is associated with an increased death rate of colorectal cancer, but no studies were conducted among national representative populations in the United States. The current study examined the death rate across BMI levels in 7,016 adults who participated in the National Health and Nutrition Examination Survey in 1971-1975. BMI categories were defined as normal (18.5-24.9 kg/m(2)), overweight (25-29.9), and obese (≥30). A total of 519 cancer deaths were identified during a 17-yr follow-up with 118,998 person-years. No significantly increased death rates of total cancers, lung, breast, and prostate cancer were observed among participants with an increased BMI. However, colorectal cancer death rates were 0.39, 0.68, and 0.96/1,000 person-years, respectively, for normal weight, overweight, and obese (P value for log-rank trend test < 0.001), and the corresponding adjusted hazard ratios [95% confidence intervals (CI)] were 1.00 (reference), 1.25 (95% CI = 0.72-2.19), and 2.04 (1.08-3.83), respectively. No gender difference of the association was identified. The authors conclude that a significantly increased death rate of colorectal cancer was associated with excess body weight. The current study is an addition to the expanding body of literature indicating an increased risk of colorectal cancer development among the obese.

Cigarette smoking and risk of prostate cancer among Singapore Chinese

Prospective epidemiologic studies conducted in Western populations support an association between current smoking and aggressive subtypes of prostate cancer. In Singapore, where prostate-specific antigen is not used for population-wide screening, prostate cancer incidence has tripled within the past two decades. Using Cox regression methods, we examined the relationship between smoking and prostate cancer established between 1993 and 1998 in a cohort of 27,293 Singapore Chinese men. As of December 2006, 250 incident prostate cancer cases were diagnosed. In our cohort, 42.2% reported never smoking cigarettes, 15.7% quit over 5 years ago (long-term former), 5.7% quit within the past 5 years (recent former), and 36.4% were current smokers. From multivariable models, we observed no association with smoking status, age at starting to smoke, years smoked, or number of cigarettes per day. Among recent former and current smokers combined, we observed a small positive association for earlier age at starting to smoke that was somewhat stronger for nonadvanced disease (hazard ratio = 1.63, 95% confidence interval: 0.85, 3.12, for <15 years versus nonsmokers). Smoking was not a major risk factor for prostate cancer in our Singapore Chinese cohort, a traditionally low risk population with parallel increases in incidence and mortality.

Clinicopathologic features and determinants of Gleason score of prostate cancer in Ghanaian men

OBJECTIVE

Prostate cancer is reported to be more aggressive in Blacks. We studied the clinicopathologic features of prostate cancer in Ghana, in order to determine the factors responsible for them and to find out if there is any relationship between them.

METHOD

Patients referred with a biopsy proven diagnosis of carcinoma of the prostate to the Cancer Center of Korle Bu Teaching Hospital, Accra, Ghana, from 2003 to 2007 were studied. Information with respect to age at diagnosis, presenting symptoms, initial PSA (iPSA), Gleason score, and disease extent were studied. Age was partitioned into 50-65 and >65 years, Gleason score into 2-6, 7, and 8-10, iPSA into 4-20 ng/ml and >20, and disease extent into T1, T2, vs. T3, T4, M1, and the relationship between them was determined. Various presenting symptoms were described. Known risk factors and screening in a context of high grade disease is discussed.

RESULTS

A total of 170 patients were studied. Mean age was 65.4 years. Majority of patients (73.7%) presented with an iPSA > 20 ng/ml, whilst 22 (14.1%) had PSA < 10 ng/ml. Gleason score ≥ 7 was found in 95 (56%) of patients. Asymptomatic patients constituted 24.0%, the rest had bone pain (22.6%), urinary (50.4%), and neurologic symptoms (3.0%).There was a statistically significant relationship between age and Gleason score (P = 0.049), PSA and Gleason score (P = 0.0001), and between extent of disease and Gleason score (P = 0.0002). High fat diet and low intake of fruits and vegetables are probable risk factors in Ghana.

CONCLUSION

Majority of patients present with symptomatic disease at a relatively older age. These patients tend to have high Gleason score partly attributable to advanced disease, age, PSA at the time of diagnosis, and race. Screening with PSA should be recommended and individualized in this group of patients in order to allow diagnosis of less aggressive disease until better screening tools are identified.

Body size and risk of prostate cancer in Jamaican men

We investigated the associations between body size and risk of prostate cancer in a hospital-based case-control study in Jamaica. Height, weight, waist, and hip circumference were measured at enrollment, and data collected on medical and lifestyle factors for newly diagnosed cases (n = 243) and controls (n = 275). Compared with men in the normal range of waist-hip ratio (WHR), men with WHR > or =0.95 were at greater risk of total prostate cancer (OR,1.72; CI, 1.01-3.00) and high-grade cancer (OR, 2.02; CI, 1.03-3.96). With additional control for BMI, the association with WHR remained significant for total prostate cancer (OR, 1.90; CI, 1.01-3.53) and high-grade disease (OR, 2.94; CI, 1.34-6.38). There was no association between waist circumference and cancer without control for BMI but after controlling for BMI, waist circumference >90 cm (OR, 2.45; CI, 1.01-5.94) and >102 cm (OR, 5.57; CI, 1.43-18.63) showed a dose-response relationship with high-grade disease. Height and BMI were not associated with risk of prostate cancer. Abdominal obesity may be associated with risk of high-grade prostate cancer. Risk may be greater in those with higher abdominal obesity relative to overall size. The results further highlight the importance of investigating relationships by characteristics of the tumor.

Hypothetic association between greater sympathetic activity and prostate cancer

Among men, prostate cancer is the most common cancer diagnosed, and the second leading cause of death from cancer in the industrialized countries. In spite of substantial progress in research, diagnosis and treatment, the causes of prostate cancer remain largely unknown. In this paper, we propose the hypothesis that prostate cancer represents another entity in the constellation of disease incited by the greater sympathetic activity that develops with age. However, the specific mechanisms of changes of increased prostatic cell proliferation and carcinogenesis caused by the autonomic nervous system have not yet been clarified. In regard to this matter, future studies should outline a more complete mechanism.

Body mass index influences prostate-specific antigen in men younger than 60 years of age

OBJECTIVES

Prostate-specific antigen (PSA) levels can be affected by many factors. Body mass index (BMI) is suspected to influence PSA levels, but the associations are controversial. The aim of this study was to examine whether PSA levels were affected by BMI and age in Koreans.

METHODS

We evaluated the association between BMI and PSA in a group of 8640 Korean men (aged 40-79 years) without prostate cancer who received a general health checkup. Eligible men were classified into age groups spanning 10 years. BMI was categorized as normal (BMI <22.9), overweight (BMI 23.0-24.9), obese (BMI 25.0-29.9), and very obese (BMI > or =30) according to the re-defined World Health Organization (WHO) criterion for the Asia Pacific Region. PSA levels were stratified by age and BMI category.

RESULTS

Prostate-specific antigen levels decreased with increasing BMI (P trend <0.001). However, the inverse correlations between PSA and BMI were significant only among men 40-59 years old (P trend <0.05, respectively). BMI showed no significant associations with PSA in 60-79 years old (P trend >0.05, respectively).

CONCLUSIONS

Our study demonstrates that increased BMI is associated with decreased PSA levels only in men younger than 60 years of age. When determining whether to carry out prostate biopsy as part of early prostate cancer detection, obesity should be considered as a factor associated with reduced PSA in healthy young men (<60 years old) with marginal PSA levels.

Obesity is not predictive of overall survival following permanent prostate brachytherapy

PURPOSE

To evaluate the impact of obesity on cause-specific (CSS), biochemical progression-free (bPFS), and overall survival (OS) following prostate brachytherapy.

MATERIALS AND METHODS

From April 1995 through March 2003, 1093 consecutive patients underwent brachytherapy for clinical T1b-T3a (2002 AJCC) prostate cancer. The median follow-up was 5.6 years. Evaluated body mass index (BMI) subgroups were < 25 (n = 258), 25.0 to 29.9 (n = 547), 30.0 to 34.9 (n = 214), and > or = 35 (n = 74) kg/m2, respectively. A total of 430 (39.9%) and 589 (53.9%) of the patients received androgen deprivation therapy or supplemental external beam radiation therapy, respectively. Multiple clinical, treatment, and dosimetric parameters were evaluated as predictors of CSS, bPFS, and OS.

RESULTS

The 11-year CSS, bPFS, and OS for the entire cohort were 97.5%, 95.6%, and 77.6%, respectively. BMI did not impact CSS or bPFS for any of the BMI cohorts. However, OS was statistically lower in patients with a BMI < 25 kg/m2 (P = 0.014). A Cox linear regression analysis demonstrated that Gleason score was the best predictor of CSS while percent-positive biopsies, risk group, V100 and hypertension predicted for bPFS. Patient age and tobacco use were the strongest predictors of OS. A total of 128 patients have died with 108 (84.4%) of the deaths the result of cardiovascular/pulmonary disease (73) and second malignancies (35). To date, 12 patients have died of metastatic prostate cancer.

CONCLUSION

Obesity did not impact CSS, bPFS, or OS in patients treated with permanent prostate brachytherapy. Cardiovascular or pulmonary disease and second malignancies substantially outweighed prostate cancer as competing causes of death.

Relationship between body mass index and prostate cancer screening in the United States

PURPOSE

Obesity is associated with more advanced disease and worse outcomes in men with prostate cancer. To our knowledge the relationship between obesity and prostate cancer screening behavior in men 40 or older is unknown. Thus, we examined associations between body mass index and prostate cancer screening behavior.

MATERIALS AND METHODS

We used the 2002 Behavioral Risk Factor Surveillance System to study prostate cancer screening in a representative sample of 57,827 men 40 years or older. Primary outcomes were the proportion of men ever screened and the proportion screened in the last year for prostate cancer.

RESULTS

Obese men were more likely than normal weight men to have had a prostate specific antigen test (62.1% vs 56.1%, p <0.001) and to have had a prostate specific antigen test in the last year (44.2% vs 38.2%, p <0.001). After controlling for sociodemographic characteristics obese men remained more likely than normal weight men to have had a prostate specific antigen test (OR 1.46, 95% CI 1.33-1.61) and to have had a prostate specific antigen test in the last year (OR 1.42, 95% CI 1.30-1.55). Respondents reporting an ongoing relationship with a physician (OR 2.88, 95% CI 2.57-3.22) and black nonHispanic men vs white men (OR 1.58, 95% CI 1.38-1.81) were also more likely to have had a prostate specific antigen test in the last year.

CONCLUSIONS

Obese men are more likely than normal weight men to be screened for prostate cancer. Associations between advanced stage, worse outcomes and obesity may not be explained by disparities in the screening of obese men for prostate cancer.

Obesity is negatively associated with prostate-specific antigen in U.S. men, 2001-2004

BACKGROUND

Recent studies have shown a negative association between body mass index (BMI) and prostate-specific antigen (PSA), a commonly used serum marker for the detection and diagnosis of prostate cancer. We have examined the association between several anthropometric measures and PSA in a nationally representative sample of men.

METHODS

We analyzed data from the 2001-2004 National Health and Nutrition Examination Survey. Participants in this study were men ages >or=40 years without previously diagnosed prostate cancer who had PSA measured. Height, weight, waist circumference, BMI, triceps skinfold, subscapular skinfold, and calculated total body water were examined categorically by quintiles using multiple linear regression models. All tests of significance were two sided.

RESULTS

Among white men, we report a trend for decreasing PSA with increasing weight, BMI, waist circumference, triceps skinfold thickness, and calculated total body water. Among Mexican American men, we found a trend for decreasing PSA with increasing BMI, and among black men we found a trend for decreasing PSA with increasing triceps thickness. None of the interaction terms between race/ethnicity and any of the anthropometric measures were statistically significant. Controlling for age and race/ethnicity in the multiple linear regression model, we found moderate declines in PSA with a 1 SD increase in BMI [5.9% decrease (95% confidence interval, -9.0% to -2.8%) in geometric mean PSA per 5.2-unit increase], weight [5.9% decline (-8.8% to -2.8%) per 17.7-kg increase], waist circumference [6.6% decline (-9.4% to -3.6%) per 13.4-cm increase], triceps skinfold [5.4% decline (-8.9% to -1.8%) per 6.4-mm increase], and calculated total body water [5.7% decline (-8.9% to -2.4%) per 6.5-liter increase].

CONCLUSION

Our population-based, nationally representative results expand the validity of previous studies on obesity and PSA. Higher weight, BMI, waist circumference, triceps skinfold, and total body water are associated with moderately lower PSA values. A prospective study is needed to verify whether this association affects the accuracy of the PSA test in obese men.

Leptin and cancer

The prevalence of obesity has markedly increased over the past two decades, especially in the industrialized countries. While the impact of excess body weight on the development of cardiac disease and diabetes has been well documented, the link between obesity and carcinogenesis is just being recognized. This review will focus on the link between leptin, a cytokine that is elevated in obese individuals, and cancer development. First, we briefly discuss the biological functions of leptin and its signaling pathways. Then, we summarize the effects of leptin on different cancer types in experimental cellular and animal models. Next, we analyze epidemiological data on the relationship between obesity and the presence of cancer or cancer risk in patients. Finally, leptin as a target for cancer treatment and prevention will be discussed.

Insulin-Like Growth Factor (IGF) family and prostate cancer

There is abundant in vitro, animal and epidemiologic evidence to suggest that the Insulin-Like Growth Factor (IGF) family is a multi-component network of molecules which is involved in the regulation of both physiological and pathological growth processes in prostate. The IGF family plays a key role in cellular metabolism, differentiation, proliferation, transformation and apoptosis, during normal development and malignant growth. This family also seem essential in prostate cancer bone metastases, angiogenesis and androgen-independent progression. Therapeutic alternatives in men with progressive prostate cancer after androgen ablation are very limited. More effective therapies are needed for these patients. Pharmacologic interventions targeting the IGF family are being devised. Such strategies include reduction of IGF-I levels (growth hormone-releasing hormone antagonists, somatostatin analogs), reduction of functional IGF-I receptor levels (antisense oligonucleotides, small interfering RNA), inhibition of IGF-IR and its signalling (monoclonal antibodies, small-molecule tyrosine kinase inhibitors) and Insulin-Like Growth Factor Binding Proteins.

Effects of obesity and height on prostate-specific antigen (PSA) and percentage of free PSA levels among African-American and Caucasian men

BACKGROUND

Prior studies suggest that obese men have lower prostate-specific antigen (PSA) levels than leaner men. Caucasian (CA) men also may have lower PSA levels than African-American (AA) men, but the relevance of body size to racial disparities in PSA levels is unclear. The association between body mass index (BMI) and height on PSA and percentage of free PSA (%fPSA) was investigated within AA and CA men without a prior prostate cancer diagnosis.

METHODS

AA (n = 150) and CA (n = 149) men of similar socioeconomic status completed an extensive in-person interview and donated blood. PSA and %fPSA levels were compared across race, BMI, and height categories after adjusting for age and other factors.

RESULTS

PSA levels decreased with increasing BMI (PSA = .72, .69, .67, .59 ng/mL for BMI 18.5 to <25, 25 to <30, 30 to <35, and > or =35, respectively; P(trend) = .18), and trends were significant among men less than age 60 years (PSA = .81, .76, .66, .59, respectively; P(trend) = .02). fPSA also significantly decreased with BMI among men <60 years (P(trend) = .04). In contrast, %fPSA was not associated with BMI. However, %fPSA increased 27% across height categories (P(trend) = .02). PSA levels were significantly lower among CA men (PSA(AA) = 0.87, PSA(CA) = 0.63 ng/mL; P < .01), whereas %fPSA levels did not differ by race. Also, associations between body size and PSA or %fPSA did not significantly differ by race, and adjustment for BMI and height had no effect on the racial disparity in PSA (PSA(AA) = 0.87, PSA(CA) = 0.63 ng/mL; P < .01).

CONCLUSIONS

The data suggest that race, BMI, and height are independently associated with PSA and %fPSA levels.

Complementary and alternative medicine in urology

Complementary and alternative medicine (CAM) includes various practices, measures and products which are not presently considered to be a part of conventional (mainstream) medicine. Herbal products, vitamins, minerals and amino acids are increasingly popular as dietary supplements for the treatment, improvement and prophylaxis of urological diseases, and to improve general health and well-being. As these products are freely available without prescription, conventional healthcare providers are often unaware that their patients are using CAM. It is essential to know that some herbal supplements may act in the same way as chemical drugs, and that they originate 'from nature' does not mean that they are safe and/or with no potential harmful effects and/or toxicity. Eventual interactions with conventional medications and contamination with prescription drugs and metals have been reported. The active components of many phytotherapeutic preparations and their mechanism(s) of action are still being determined and evaluated. There is scientific evidence for the effectiveness of some CAM treatments, but for most there are important key questions yet to be answered through basic research and well-designed studies according to established guidelines. Because of the increasing popularity and use of CAM, conventional healthcare providers, including urologists, should not ignore it, and be well informed about the benefits and potential risks of dietary supplements, so that they can advise their patients about this developing field. Whenever necessary and possible, lifestyle and behavioural changes should be recommended before using CAM, and eventually be supplemented by CAM as a second step.

Influence of body mass index on biochemical outcome after permanent prostate brachytherapy

OBJECTIVES

To evaluate the impact of body mass index (BMI) on the 8-year biochemical outcome after permanent prostate brachytherapy with or without the addition of supplemental external beam radiotherapy and/or androgen deprivation therapy (ADT).

METHODS

From April 1995 through February 2001, 686 consecutive patients underwent brachytherapy using either palladium-103 or iodine-125 for clinical Stage T1b-T3aNxM0 (2002 American Joint Committee on Cancer) prostate cancer. No patient underwent seminal vesicle biopsy or pathologic lymph node staging. The median follow-up was 59.5 months. The evaluated BMI subgroups were less than 25, 25.0 to 29.9, 30.0 to 34.9, and 35 or more kg/m2. Biochemical progression-free survival was defined by a prostate-specific antigen (PSA) level of 0.4 ng/mL or less after a nadir. The clinical, treatment, and dosimetric parameters evaluated for biochemical progression-free survival included BMI, patient age, clinical T stage, Gleason score, preimplant PSA level, risk group, percentage of positive biopsies, isotope, use of supplemental external beam radiotherapy, use of ADT, prostate volume, planning volume, percentage of target volume receiving 100%, 150%, and 200% of the prescribed dose, minimal percentage of dose covering 90% of the target volume, tobacco use, and the presence of hypertension and diabetes.

RESULTS

For the entire group, the actuarial 8-year biochemical progression-free survival rate was 95.8%, 95.6%, 94.1%, and 100% for patients in BMI categories less than 25, 25.0 to 29.9, 30.0 to 34.9, and 35 or more kg/m2, respectively. In hormone-naive and hormone-manipulated patients free of biochemical progression, the median post-treatment PSA level was less than 0.1 ng/mL. When integrated across risk groups and ADT use, BMI had no statistically significant impact on biochemical progression-free survival. At last follow-up, 5 patients (0.7%) had died of metastatic prostate cancer. In multivariate Cox regression analysis, pretreatment PSA level, Gleason score, clinical stage, percentage of positive biopsies, ADT use, and tobacco status, but not BMI, were statistically significant predictors of 8-year biochemical progression-free survival.

CONCLUSIONS

Prostate brachytherapy results in a high probability of 8-year biochemical progression-free survival for low, intermediate, and high-risk patients. When integrated across risk groups and hormonal status, BMI had no statistically significant influence on biochemical progression-free survival.

Effects of excess weight on cancer incidences depending on cancer sites and histologic findings among men: Korea National Health Insurance Corporation Study

PURPOSE

The effects of excess weight on the development of cancers are controversial, and little is known for populations outside the United States and Europe. We conducted this study to assess the effects of excess weight with a large cohort of Koreans.

METHODS

We assessed the relationship between body mass index (BMI) and various cancers in a 10-year follow-up cohort of 781,283 Korean men who were free of prior cancer at baseline. Weight and height were measured, and questionnaires related to health behaviors and medical history were completed. Data on newly developed cancers were obtained from two organizations in Korea. A proportional hazards model was used to examine the relationship between BMI and cancer.

RESULTS

Adenocarcinoma in the colon and rectosigmoid, hepatocellular carcinoma, cholangiocarcinoma, adenocarcinoma in the prostate, renal cell carcinoma, papillary carcinoma in the thyroid, small-cell carcinoma in the lung, non-Hodgkin's lymphoma, and melanoma had positive dose-dependent relationships with BMI (all P < .05). Although no linear trend was found (P = .267), obese men who never smoked with a BMI of >or= 30 kg/m(2) had an increased risk of developing gastric adenocarcinoma (relative risk = 1.73). Other cancers, such as leukemia, multiple myeloma, and gallbladder and pancreatic cancer, did not show significant associations.

CONCLUSION

These findings show that, even in Koreans, obesity clearly increases the risk of many types of cancers and the strength of the associations varies with the organ and histologic type. Because these obesity-related cancers are reported to be rapidly increasing in Korea and many other Asian countries, controlling obesity epidemics could be an effective tool for preventing these cancers in these areas.

Comparison of proposed frameworks for grouping polychlorinated biphenyl congener data applied to a case-control pilot study of prostate cancer

Although the commercial synthesis of polychlorinated biphenyls (PCBs) has been banned in the United States for several decades, they are persistent in the environment with exposure mainly being through diet. The biologic and toxic effects of PCBs and their metabolites are due in part to their ability to interact with several cellular and nuclear receptors, thereby altering signaling pathways and gene transcription. These effects include endocrine modulation and disruption. Therefore, the natural history of cancer in tissues expressing these receptors may be modulated by PCB congeners, which are known to have estrogenic, antiestrogenic, and other hormonal effects. Several frameworks for grouping PCB congeners based on these interactions have been proposed. We conducted a hospital-based, case-control pilot study of 58 prostate cancer cases and 99 controls to evaluate the association between the proposed PCB groupings and the risk of prostate cancer. Serum samples were analyzed for a total of 30 PCBs. In multivariate analyses, the odds of prostate cancer among men with the highest concentrations of moderately chlorinated PCBs or PCBs with phenobarbital-like activities (constitutively active receptor (CAR) agonists) was over two times that among men with the lowest concentrations. Increasing trends in risk across the concentration levels were also observed. These results suggest that a higher burden of PCBs that are CAR agonists may be positively associated with an increased risk of prostate cancer and they encourage further research in this area.

Alcohol consumption and risk of colon cancer: evidence from the national health and nutrition examination survey I epidemiologic follow-up study

The epidemiologic findings on the relationship between alcohol consumption and colon cancer are inconsistent. The National Health and Nutrition Examination Survey (NHANES) I Epidemiologic Follow-Up Study (NHEFS) included a prospective cohort population representative of the general U.S. population, which had not been fully utilized for examining the risk between colon cancer and alcohol drinking. The NHEFS consisted of 10,220 participants prospectively followed over a decade. Alcohol consumption, amount and type of beverage, and drinking patterns at baseline were considered in examination of the effect of alcohol consumption on the risk of colon cancer. The consumption of one or more alcoholic beverages a day at baseline was associated with approximately a 70% greater risk of colon cancer [relative risk (RR)=1.69; 95% confidence interval (CI)=1.03, 2.79], with a strong positive dose-response relationship (P=0.04). This association appeared to be exclusively related to daily drinking of one or more drinks of liquor (RR=2.48; 95% CI=1.66, 4.53). Additionally, more than a 70% increased risk of colon cancer was observed for more than 34 yr of alcohol drinking history compared with nondrinkers (RR=1.73; 95% CI=1.08, 2.78). Overall, alcohol consumption was significantly associated with increased risk of colon cancer. The most important factor for colon cancer seems to be liquor consumption.

OBESITY AND PROSTATE CANCER CLINICAL RISK FACTORS AT PRESENTATION: DATA FROM CaPSURE

PURPOSE

We investigated the association of obesity with prostate cancer case demographics and clinical disease features at presentation.

MATERIALS AND METHODS

Data were abstracted from CaPSURE (Cancer of the Prostate Strategic Urologic Research Endeavor), a disease registry of 10,018 men with prostate cancer. A total of 2,952 men were included who were treated between 1989 and 2002, and had complete body mass index (BMI) information. BMI classes were defined as normal (less than 25 kg/m), overweight (25 to 29.9 kg/m), obese (30 to 34.9 kg/m) or very obese (35 kg/m or greater). Patients were categorized as having low, intermediate or high risk disease based on the D'Amico classification. Associations among BMI, risk and demographics were analyzed using univariate and multivariate models.

RESULTS

Of the patients 29% had a normal BMI, 51% were overweight, 16% were obese and 5% were very obese. Patients who were overweight or obese were more likely to be young, have hypertension and diabetes, and have a lower education level. The overweight group had a lower serum prostate specific antigen (p = 0.010) and lower stage disease (p = 0.030) at diagnosis, but there was no association between Gleason score and obesity (p = 0.57). However, among men with a BMI of 25 kg/m or greater there was a positive correlation between increasing BMI and risk of being in a worse prognostic group at diagnosis (p = 0.018).

CONCLUSIONS

Overweight and obese patients are more likely to be young at diagnosis and have multiple comorbidities. Men in the overweight and obese groups presented with lower risk prostate cancer at diagnosis. This may be due to earlier disease detection secondary to more frequent interaction with the medical community. Among overweight and obese patients increased obesity is associated with a slightly increased chance of having high risk prostate cancer at diagnosis.

Obesity and risk of cancer in Japan

We conducted a population-based prospective cohort study in Japan to examine the relationship between body mass index (BMI) and the risk of incidence of any cancer and of cancer at individual sites. Body mass index was calculated from self-administered body weight and height at baseline. Relative risks (RR) and 95% confidence intervals (CI) were calculated in multivariate proportional-hazards models. Among 27,539 persons (15,054 women and 12,485 men) aged 40 years or older who were free of cancer at enrollment in 1984, 1,672 (668 women and 1,004 men) developed cancer during 9 years of follow-up. In women, after adjustment for potential confounders, the RR of all cancers associated with different BMI, relative to a BMI of 18.5-24.9, were 1.04 (95% CI = 0.85-1.27) for BMI = 25.0-27.4, 1.29 (1.00-1.68) for BMI = 27.5-29.9 and 1.47 (1.06-2.05) for BMI >/=30.0 (p for trend = 0.007). Higher BMI was also significantly associated with higher risk of cancers of the colorectum, breast (postmenopausal), endometrium and gallbladder in women. In men, we observed significantly increased all-cancer risk among only never-smokers. Overweight and obesity could account for 4.5% (all subjects) or 6.2% (never-smokers) of the risk of any cancer in women and -0.2% (all subjects) or 3.7% (never-smokers) in men. The value for women was within the range among women reported from Western populations (3.2%-8.8%). Our data demonstrate that excess weight is a major cancer risk among Japanese women.

Childhood obesity and hormonal abnormalities associated with cancer risk

There is growing evidence that overweight and obesity increase the risk of certain cancers. Studies in adults support the role of insulin-like growth factors (IGFs) and oestrogens in the pathogeneses of several cancers. We propose that hormone alterations described as risk factors for cancer in obese adults are present in prepubertal obese children. A group of obese children aged 6-9 years (n=40), and control group paired for age and sex, were used for the study. The obese children presented a significantly high level of IGF-I (P=0.0173) and insulin (P=0.0250), with a drop in sex hormone-binding globulin (SHBG) (P=0.0282). The 17 beta-oestradiol (E2)/SHBG ratio increase in obese subjects was marginally significant (P=0.0635). Grouping together all the children in quartiles for insulin and body mass index, the upper quartiles showed a rise in IGF-I and E2/SHBG. In a multivariant correlation analysis, only height (partial r=0.2464) and insulin (partial r=0.3002) were independent prediction variables for IGF-I concentration. The only variables statistically correlated with the E2/SHBG ratio were insulin (r=0.2879) and IGF-I (r=0.4140). The obese children in our study showed hormone changes described as risk factors for cancer in obese adults. These changes were significantly associated with the hyperinsulinaemia. We hypothesize that this potential risk should be taken into account given the long period of exposure involved in the presence of hormone alterations at such early ages.

Prostate cancer and body size at different ages: an Italian multicentre case-control study

We investigated the influence of anthropometric measures at diagnosis and at different ages on prostate cancer risk using an Italian multicentre case–control study conducted between 1991 and 2002 of 1294 histologically confirmed cases and 1451 controls admitted to the same network of hospitals for acute non-neoplastic conditions. Height, weight, body mass index (BMI), waist-to-hip ratio, lean body mass 1 year before diagnosis/interview were not significantly associated with risk. However, a positive association with high BMI at age 30 years was found (odds ratio=1.2 for BMI⩾24.7 vs <22.7) and: for less differentiated prostate cancer, with BMI 1 year before diagnosis/interview. This study supports possible relationships between high body mass in young adulthood, and a tendency to high weight throughout adult life, and the risk of prostate cancer.

The metabolic syndrome or the insulin resistance syndrome? Different names, different concepts, and different goals

The goal of this article is to differentiate the insulin resistance syndrome from the metabolic syndrome. In the case of the insulin resistance syndrome, the abnormalities and clinical syndromes that are increased in prevalence in insulin-resistant individuals have been summarized, with a brief discussion of the causal relationship between insulin resistance, compensatory hyperinsulinemia, and associated consequences. Discussion of the metabolic syndrome has focused on the five criteria chosen by the adult treatment panel III to diagnose the syndrome, evaluating them in terms of their relationship to insulin resistance and their role as cardiovascular disease risk factors.

Lifestyle recommendations to prevent prostate cancer, part I: time to redirect our attention?

This article provides a foundation for clinicians willing to provide lifestyle change recommendations for the prevention of prostate cancer. In part II, more general and specific lifestyle recommendations will be provided. It is imperative to provide patients with realistic and practical recommendations that are not only consistent in the medical literature, but will improve overall compliance.

Impact of obesity on biochemical control after radical prostatectomy for clinically localized prostate cancer: a report by the Shared Equal Access Regional Cancer Hospital database study group

PURPOSE

Given the limited information regarding the impact of obesity on treatment outcomes for prostate cancer, we sought to examine the relationship between body mass index (BMI) and cancer control after radical prostatectomy (RP).

PATIENTS AND METHODS

We compared clinicopathologic and biochemical outcome information across BMI groups from 1,106 men treated with RP between 1988 and 2002. Multivariate analysis was used to determine if BMI significantly predicted adverse pathology or biochemical recurrence.

RESULTS

Obesity was related to year of surgery (P <.001) and race (P <.001), with black men having the highest obesity rates. Obese patients had higher biopsy and pathologic grade tumors (P <.001). On multivariate analysis, BMI > or = 35 kg/m(2) was associated with a trend for higher rates of positive surgical margins (P =.008). Overweight patients (BMI, 25 to 30 kg/m(2)) had a significantly decreased risk of seminal vesicle invasion (P =.039). After controlling for all preoperative clinical variables including year of surgery, BMI > or = 35 kg/m(2) significantly predicted biochemical failure after RP (P =.002). After controlling for surgical margin status, BMI > or = 35 kg/m(2) remained a significant predictor of biochemical failure (P =.012). There was a trend for BMI > or = 35 kg/m(2) to be associated with higher failure rates than BMI between 30 and 35 kg/m(2) (P =.053).

CONCLUSION

The percentage of obese men undergoing RP in our data set doubled in the last 10 years. Obesity was associated with higher-grade tumors, a trend toward increased risk of positive surgical margins, and higher biochemical failure rates among men treated with RP. A BMI > or = 35 kg/m(2) was associated with a higher risk of failure than a BMI between 30 and 35 kg/m(2).

Insulin and cancer

Obesity has recently been linked to mortality from the majority of cancers. The insulin/insulin-like growth factor (IGF) system may partly explain this effect. The metabolic syndrome, associated with hyperinsulinemia, may modulate this effect. Recent evidence supports the role of insulin and IGF-1 as important growth factors, acting through the tyrosine kinase growth factor cascade in enhancing tumor cell proliferation. In addition, the metabolic syndrome associated with a chronic inflammatory state and accompanying cytokine abnormalities may also contribute to tumor progression. Growing links between insulin and the etiology as well as prognosis in colon, prostate, pancreatic, and, particularly, breast cancer are reviewed. Of particular concern is the evidence that elevated IGF-1 may interfere with cancer therapy, adversely affecting prognosis. The role of insulin is of concern because of the increasing levels of obesity and the associated metabolic syndrome. Weight gain, through typical Western diet; limited levels of activity; and, more recently, stress-related changes in neuroendocrine function may lead to insulin resistance and hyperinsulinemia. The opportunity for a multidisciplinary approach involving nutrition, exercise, and stress reduction in an integrative setting may be crucial to limiting the insulin-resistant state and improving cancer outcomes.

Case-control study of anthropometric measures and prostate cancer risk

A population-based case-control study of 988 stage T2 or greater prostate cancer cases and 1063 controls was conducted in Alberta from November 1997 to December 2000 to examine the influence of anthropometric risk factors on the risk of prostate cancer using several different measures. An in-person interview was conducted, and all anthropometric measurements were taken using standardized methods. Respondents also recalled their body weight at each decade from age 20 to the referent year. Several anthropometric variables were derived, and unconditional logistic regression analyses were performed. The multivariable odds ratios, when comparing the highest to the lowest quartile were: for body mass index, OR = 1.12 (95% CI 0.85-1.47); for waist-hip ratio, OR = 1.07 (0.83-1.38); for height, OR = 0.78 (0.60-1.02); for weight, OR = 0.91 (0.70-1.18); for weight gain since age 20, OR = 0.91 (0.70-1.19); and for difference between minimum and maximum adult weight, OR = 0.89 (0.69-1.16). Our study provides evidence for no association between any measures of anthropometry including several derived measures of changes in weight over lifetime and prostate cancer risk.

Family history of prostate cancer and obesity in relation to high-grade disease and extraprostatic extension in young men with prostate cancer

BACKGROUND

Little is known about predictors of prostate cancer severity in young men. Therefore, we examined whether family history and obesity influence risk of high-grade disease and extraprostatic extension in men < 55-years old.

METHODS

Four hundred ninety-eight men aged < 55 years who had had a radical prostatectomy (1992-1999) by one surgeon were mailed a survey in 2000 to assess family history of PCa and anthropometrics. Body mass index (BMI = kg/m(2)) was calculated as an indicator of obesity. Logistic regression was used to compute odds ratios (OR) for high-grade disease (Gleason score > or = 7) and extraprostatic extension.

RESULTS

Of the 363 respondents, 35.8% had at least one first-degree relative with PCa. Men with a family history were younger at surgery than those without a family history (48.8 vs. 50.1 years, P < 0.001). After controlling for age, cigarette smoking, and race/ethnicity, men with an affected father had a lower risk of high-grade disease compared to those without an affected father (OR = 0.42, 95% CI 0.23-0.76). Risk of high-grade disease increased with increasing BMI, especially in men < 50-years old (P-trend = 0.02). Family history and BMI were not clearly associated with extraprostatic extension.

CONCLUSIONS

After taking into account a younger age at presentation among men with a family history, young men with a family history of PCa were less likely to have high-grade disease. Obesity may be associated with a poorer histology in young men with PCa, especially in men younger than 50 years of age.

The use of complementary/preventive medicine to prevent prostate cancer recurrence/progression following definitive therapy: part I--lifestyle changes

PURPOSE OF REVIEW

The number one cause of death in the United States and in most countries around the world is cardiovascular disease. The number one or number two cause of death in prostate cancer patients is also cardiovascular disease. These observations do not serve to belittle the impact of prostate cancer, but are a reminder that the ultimate goal of healthy lifestyle recommendations is to reduce the burden of both of these major causes of death, especially after definitive prostate therapy. Patients need to be encouraged to know their cholesterol levels and other cardiovascular markers including blood pressure, as well as being aware of their prostate-specific antigen values.

RECENT FINDINGS

Patients should not smoke, they should reduce their intake of saturated and trans fats, increase their consumption of a diversity of fruit and vegetables, consume moderate quantities of dietary soy or flaxseed, increase their consumption of fish or fish oils and other omega-3 fatty acids, as well as maintaining a healthy weight, getting at least 30 min/day of physical activity, and lifting weights several times a week. When in doubt it is important for the clinician and patient to realize that what is healthy for the heart is generally found to be healthy for the prostate. Many of these lifestyle changes, when accomplished on a regular basis, may dramatically reduce the risk of overall early mortality. Despite the simplistic and moderate recommendations in this manuscript, research suggests that few individuals are currently following these suggestions.

SUMMARY

Clinicians need to constantly emphasize these basic changes in order to truly impact the overall health of any patient following definitive prostate therapy.