Body mass index influences prostate cancer risk at biopsy in Japanese men

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

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

Dietary energy density and risk of prostate cancer: (A case-control study)

OBJECTIVE

Some observational studies investigated the association between dietary energy density (DED) and risk of cancers with inconstant results. In addition, there is no study on such association among patients with prostate cancer (PC). The present study was performed to evaluate the association between dietary energy density (DED) and PC risk.

METHODS

In this case-control study, one hundred and twenty-five participants were enrolled (62 cases and 63 controls). Dietary intakes were assessed using 160-item semi-quantitative food frequency questionnaire. In addition, demographic characteristics were collected using a general questionnaire and anthropometric indices were measured based on the available guidelines. The association between DED and PC risk was evaluated using multivariable logistic regression.

RESULTS

The results showed that higher DED score was associated with increased risk of PC (OR = 2.59; 95% CI= (1.24-5.40)). Interestingly, after adjusting for potential confounders ((smoking, physical activity, energy intake, education, ethnicity, job, anti-hyperlipidemic drugs, antihypertensive drugs, and aspirin) the results remained significant (OR = 2.87; 95% CI= (1.17-7.05)).

CONCLUSION

Our findings suggest that DED may increase the risk of PC. However, more prospective studies are warranted to confirm these results.

Incidental prostate cancer after transurethral resection of the prostate: analysis of incidence and risk factors in 458 patients

BACKGROUND

The aim of this study is to evaluate the incidence and risk factors of incidental prostate cancer (IPCA) in a contemporary cohort of lower urinary tract symptoms (LUTS) patients who underwent trans-urethral resection of the prostate (TURP).

METHODS

A series of 458 consecutive patients who underwent TURP were evaluated between January 2016 to June 2018. Evaluated factors included age (years), Body Mass Index (BMI; kg/square meters), treatment with inhibitors of 5-alpha reductase, previous prostate biopsies, basal prostate specific antigen (PSA) levels (ng/mL), serum leukocyte count (×10⁹/L), weight of resected prostate tissue (grams), grade and stage of IPCA. The multivariate logistic regression model evaluated associations of significant clinical factors with the risk of IPCA.

RESULTS

Overall, IPCA was detected in 30 of 454 patients (6.6%). A mean of 21.8 g of tissue was resected. The mean number of positive chips was 5.6 (mean percentage 3.9%) with tumor grade group 1 in 22 cases (73.4%) and tumor stage cT1a in 23 patients (76.7%). On multivariate analysis, independent factors that were positively associated with the risk of IPCA were BMI (odds ratio, OR=1.121; P=0.017) and leukocyte count (OR=1.144; P=0.027).

CONCLUSIONS

In a contemporary cohort of patients undergoing TURP for the treatment of LUTS, the risk of IPCA was not negligible with a rate of being 6.6%. BMI and serum leukocyte count were found to be independent factors that were positively associated with the risk of IPCA.

The incidence, mortality, and risk factors of prostate cancer in Asian men

The objective of this review was to describe the epidemiology and risk factors of prostate cancer (PCa) in Asian populations. English language publications published over the last 10 years covering studies on the incidence, mortality, and risk factors of PCa in Asia were reviewed. The incidence of PCa in Asia is rising but is still significantly lower than that in Western countries. Studies in Asia indicated that the consumption of red meat, fat, dairy, and eggs was associated with a higher risk for PCa. Age and family history were also found to be risk factors. The emergence of genetic data indicates that different genetic backgrounds between Asian and Western populations play a role in the observed differences in PCa incidence. The lower incidence of PCa in Asian men than in Western men may in part be due to a lack of systematic prostate-specific antigen screening, but environmental and genetic factors also play a role.

Epidemiology of prostate cancer in Asian countries

The incidence of prostate cancer has been increasing worldwide in recent years. The GLOBOCAN project showed that prostate cancer was the second most frequently diagnosed cancer and the fifth leading cause of cancer mortality among men worldwide in 2012. This trend has been growing even in Asian countries, where the incidence had previously been low. However, the accuracy of data about incidence and mortality as a result of prostate cancer in some Asian countries is limited. The cause of this increasing trend is multifactorial. One possible explanation is changes in lifestyles due to more Westernized diets. The incidence is also statistically biased by the wide implementation of early detection systems and the accuracy of national cancer registration systems, which are still immature in most Asian countries. Mortality rate decreases in Australia, New Zealand and Japan since the 1990s are possibly due to the improvements in treatment and/or early detection efforts employed. However, this rate is increasing in the majority of other Asian countries. Studies of latent and incidental prostate cancer provide less biased information. The prevalence of latent and incidental prostate cancer in contemporary Japan and Korea is similar to those in Western countries, suggesting the influence of lifestyle changes on carcinogenesis. Many studies reported evidence of both congenital and acquired risk factors for carcinogenesis of prostate cancer. Recent changes in the acquired risk factors might be associated with the increasing occurrence of prostate cancer in Asian countries. This trend could continue, especially in developing Asian countries.

Higher body mass index increases the risk for biopsy-mediated detection of prostate cancer in Chinese men

Objective

To investigate the relationship between body mass index (BMI) and prostate cancer (PCa) risk at biopsy in Chinese men.

Patients and Methods

We retrospectively reviewed the records of 1,807 consecutive men who underwent initial multicore (≥10) prostate biopsy under transrectal ultrasound guidance between Dec 2004 and Feb 2014. BMI was categorised based on the Asian classification of obesity as follows: <18.5 (underweight), 18.5–22.9 (normal weight), 23–24.9 (overweight), 25–29.9 (moderately obese), and ≥30 kg/m2 (severely obese). The odds ratios (OR) of each BMI category for risk of PCa and high-grade prostate cancer (HGPCa, Gleason score ≥4+3) detection were estimated in crude, age-adjusted and multivariate-adjusted models. Prevalence ratios and accuracies of PSA predicted PCa were also estimated across BMI groups.

Results

In total, PCa was detected by biopsy in 750 (45.4%) men, and HGPCa was detected in 419 (25.4%) men. Compared with men of normal weight, underweight men and obese men were older and had higher prostate specific antigen levels. The risk of overall PCa detection via biopsy presented an obvious U-shaped relationship with BMI in crude analysis. Overall, 50.0%, 37.4%, 45.6% 54.4% and 74.1% of the men in the underweight, normal weight, overweight, moderately obese and severely obese groups, respectively, were diagnosed with PCa via biopsy. In multivariate analysis, obesity was significantly correlated with a higher risk of PCa detection (OR = 1.17, 95%CI 1.10–1.25, P<0.001). However, higher BMI was not correlated with HGPCa detection (OR = 1.03, 95%CI 0.97–1.09, P = 0.29). There were no significant differences in the accuracy of using PSA to predict PCa or HGPCa detection across different BMI categories.

Conclusion

Obesity was associated with higher risk of PCa detection in the present Chinese biopsy population. No significant association was detected between obesity and HGPCa.

Obesity affects the biopsy-mediated detection of prostate cancer, particularly high-grade prostate cancer: a dose-response meta-analysis of 29,464 patients

BACKGROUND AND OBJECTIVES

In previous studies, obesity (measured according to the body mass index) has correlated inconsistently with the risk of biopsy-measured prostate cancer, and specifically high-grade prostate cancer. This meta-analysis aimed to clarify these correlations.

METHODS

A comprehensive literature search of the MEDLINE and EMBASE databases was conducted for relevant studies published through January 2014. The pooled estimates of odds ratios (OR) and confidence intervals (CI) were computed, and the meta-analysis was performed with the STATA software according to a random effects approach.

RESULTS

A total of 11 studies that included 29,464 individuals were identified. A 5-kg/m2 increase in body mass index was associated with a 15% (OR, 1.15; 95% CI, 0.98-1.34) higher risk of prostate cancer detection and a 37% (OR, 1.37; 95% CI, 1.19-1.57) higher risk of high-grade prostate cancer detection at biopsy. There were no differences among the results of studies conducted in the USA, Europe or Asia. We also found that studies that had adjusted for prostate-specific antigen levels, digital rectal examination results, and prostate volumes obtained positive significant outcomes (OR, 1.27; 95% CI, 1.12-1.44), whereas studies that did not adjust for the above-mentioned confounding variables obtained negative results (OR, 0.92; 95% CI, 0.68-1.25). Moreover, the positive correlation between body mass index and the detection of both prostate cancer and high-grade diseases tended to be stronger as the number of biopsy cores increased.

CONCLUSION

The present meta-analysis demonstrated that a high body mass index correlated positively with prostate cancer detection, especially high-grade prostate cancer detection. The adoption of a modified and possibly more aggressive biopsy strategy was suggested for obese populations.