Obesity is not associated with aggressive pathologic features or biochemical recurrence after radical prostatectomy

Are associations between obesity and prostate cancer outcomes following radical prostatectomy the same in smokers and non-smokers? Results from the SEARCH Cohort

PURPOSE

Obesity and smoking have been associated with poor prostate cancer (PC) outcomes. We investigated associations between obesity and biochemical recurrence (BCR), metastasis, castrate resistant-PC (CRPC), PC-specific mortality (PCSM), and all-cause mortality (ACM) and examined if smoking modified these associations.

METHODS

We analyzed SEARCH Cohort data from men undergoing RP between 1990 and 2020. Cox regression models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for associations between body mass index (BMI) as a continuous variable and weight status classifications (normal: 18.5 ≤ 25 kg/m2; overweight: 25-29.9 kg/m2; obese: ≥ 30 kg/m2) and PC outcomes.

RESULTS

Among 6,241 men, 1,326 (21%) were normal weight, 2,756 (44%) overweight and 2159 (35%) obese; 1,841 (30%) were never-smokers, 2,768 (44%) former and 1,632 (26%) current-smokers. Among all men, obesity was associated with non-significant increased risk of PCSM, adj-HR = 1.71; 0.98-2.98, P = 0.057, while overweight and obesity were inversely associated with ACM, adj-HR = 0.75; 0.66-0.84, P < 0.001 and adj-HR = 0.86; 0.75-0.99, P = 0.033, respectively. Other associations were null. BCR and ACM were stratified for smoking status given evidence for interactions (P = 0.048 and P = 0.054, respectively). Among current-smokers, overweight was associated with an increase in BCR (adj-HR = 1.30; 1.07-1.60, P = 0.011) and a decrease in ACM (adj-HR = 0.70; 0.58-0.84, P < 0.001). Among never-smokers, BMI (continuous) was associated with an increase in ACM (adj-HR = 1.03; 1.00-1.06, P = 0.033).

CONCLUSIONS

While our results are consistent with obesity as a risk factor for PCSM, we present evidence of effect modification by smoking for BCR and ACM highlighting the importance of stratifying by smoking status to better understand associations with body weight.

Metabolic syndrome and its components predict the biochemical recurrence and adverse pathological features of patients following radical prostatectomy: a propensity score matching study

BACKGROUND

To investigate the predictive value of metabolic syndrome (MetS) and its components in biochemical recurrence (BCR) and adverse pathological features of patients with prostate cancer (PCa) after radical prostatectomy (RP).

METHODS

A total of 525 PCa patients who underwent RP between 2010 and 2019 at Peking University Third Hospital were analyzed retrospectively. The Kaplan-Meier method was performed to assess BCR-free survival (BCRFS). Univariate and multivariate Cox regression models and multivariate logistic regression models were conducted to identify the predictive factors of BCRFS and adverse pathological features respectively before and after propensity score matching (PSM).

RESULTS

Enrolled patients were allocated into MetS group (n = 136) and non-MetS group (n = 389) according to the presence or absence of MetS, and 127 new matched pairs were identified to balance the baseline characteristics after 1:1 PSM. In propensity matched patients, the Kaplan-Meier analysis revealed that MetS (P = 0.020), hyperglycemia (P = 0.015) and hypertriglyceridemia (P = 0.001) were significantly associated with worse BCRFS; the results of multivariate Cox analyses showed that hyperglycemia (P = 0.040), hypertriglyceridemia (P = 0.017), percentage of positive biopsy cores (P = 0.041) and prostate specific antigen (P = 0.019) were identified as independent prognostic factors for BCRFS. In addition, hypertriglyceridemia was independently associated with non-organ confined disease (NOCD) (P = 0.010), extra-capsular extension (ECE) (P = 0.010) and upgrading (P = 0.017) in the multivariate logistic analyses.

CONCLUSIONS

Hyperglycemia and hypertriglyceridemia are the two effective MetS components both identified as independent risk factors for worse BCRFS after RP, while hypertriglyceridemia was independently associated with NOCD, ECE and upgrading as well.

Obesity and biochemical recurrence in clinically localised prostate cancer: a systematic review and meta-analysis of 86,490 patients

BACKGROUND

The association of obesity with biochemical recurrence (BCR) after treatment of clinically localised prostate cancer (PC) shows inconsistent results. Our aim was to systematically review all evidence evaluating obesity as a prognostic factor for BCR.

METHODS

We searched PubMed, Web of Science and Scopus, from inception to June 1, 2021. Cohort studies reporting BCR among PC patients stratified by body mass index (BMI) were included. To assess the quality of the selected studies, we used the Newcastle-Ottawa scale (NOS). Risk of BCR among obese patients (BMI ≥ 30 kg/m²) was compared with normal weight (BMI < 25), pooling individual hazard ratios (HR) in random-effect meta-analysis. Associations for continuous BMI per 5 kg/m² were also calculated. Subgroup analyses were conducted to assess reasons for heterogeneity and causal criteria were formally evaluated.

RESULTS

We identified 46 cohort studies including 86,490 PC patients. A total of 14,719 (17.1%) patients developed BCR. There was no consistent definition of BCR. Obesity was associated with BCR (HR: 1.25, 95% CI: 1.11-1.39, I²: 70.3%), and there was a 10% increase (95% CI: 4-15%, I²: 66.3%) in BCR per 5 kg/m² increase in BMI. The heterogeneity was high but decreased in the subgroup of highest-quality NOS score and when the BMI was measured by the researchers (I²: 0.0%). The association was consistent in patients receiving radical prostatectomy but not in patients receiving other therapies.

CONCLUSIONS

Obesity showed a moderate, consistent relationship with biochemical recurrence after radical prostatectomy. Measurement of BMI and BCR was variable, highlighting the need for standardised clinical guidelines. Preventive weight control programs may have a role in reducing BCR for clinically localised PC patients.

Overweight and obesity as risk factors for biochemical recurrence of prostate cancer after radical prostatectomy

BACKGROUND

Previous studies have shown a relationship between the occurrence and recurrence of prostate cancer; however, this relationship remains controversial. We investigated the relationship between obesity and biochemical recurrence in patients with prostate cancer.

METHODS

Clinicopathological factors were analyzed after dividing the patient population according to the Asian population-specific body mass index (BMI) criteria for "normal" (< 23 kg/m²), "overweight" (23-27.5 kg/m²), and "obese" (≥ 27.5 kg/m²). Among the 389 patients included in this study, 108 were classified as normal, while 227 and 54 patients were classified as overweight and obese, respectively. The relationships between clinicopathological factors and biochemical recurrence were analyzed by univariate and multivariate Cox ≤ proportional hazard models. Biochemical recurrence was defined as two consecutive prostate-specific antigen (PSA) measurements ≥ 0.2 ng/mL.

RESULTS

In univariate analysis, the categorical variables of "overweight" and "obese" were significant prognostic factors for biochemical recurrence. In multivariate analysis models including PSA density [hazard ratio (HR) 1.8, p = 0.01], extraprostatic extension (HR 2.0, p < 0.001), Gleason score (HR 1.7, p = 0.01), surgical margin positivity (HR 2.46, p < 0.001), and lymphovascular invasion (HR 2.53, p < 0.001), the categorical variables of "overweight" (HR 1.6, p = 0.03) and "obese" (HR 1.76, p = 0.035) were prognostic factors for biochemical recurrence.

CONCLUSION

The obesity status of patients with prostate cancer as "overweight" and "obese" was a risk factor for biochemical recurrence after adjusting for other clinicopathological factors.

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

Background

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

Methods

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

Results

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

Conclusions

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

Obesity leads to a higher rate of positive surgical margins in the context of robot-assisted radical prostatectomy. Results of a prospective multicenter study

Introduction

Current results concerning the effect of body mass index (BMI) on positive surgical margins (PSMs) after robot-assisted radical prostatectomy (RARP) in patients with localized prostate cancer are inconsistent. Therefore, the aim of this study was to further analyse the association between BMI and PSMs after RARP.

Material and methods

Between March 2017 and December 2017 a multicentre, prospective, randomised, single-blind series with a blinded outcome assessment of 232 RARP patients was performed. Multivariate logistical regression models were used to analyse the independent effect of obesity, with body-mass-index (BMI) dichotomised at 30 kg/m² (model-1) and at 90^th percentile (model-2), on PSMs.

Results

Median BMI was 27.2 kg/m², PSMs were found in 15.5% (n = 36). In multivariate model-1, obesity did not have a significant effect on PSMs (OR 2.34, p = 0.061). However, if BMI was dichotomized at the 90^th percentile (BMI ≥33.7 kg/m²), patients with a higher BMI showed PSMs four-times more frequently (OR 3.99, p = 0.013). In both models, preoperative prostate-specific antigen (PSA) levels and pathological tumour stage had a significant effect on PSMs. There was no significant correlation between BMI and the extent of PSMs, nor a significant difference between the BMI groups and the localisation of PSMs. There was a higher percentage of posteriolateral PSM localisation in obese patients compared to patients with a BMI of less than 30 kg/m² (58.3% and 25.3% of the localisations were posterolateral in obese and non-obese patients, respectively), however this effect was not statistically significant (p = 0.175).

Conclusions

In addition to a longer operation time and about twice as many complications, patients with a BMI of ≥33.7 kg/m² had a higher PSM rate after RARP. Differences in localization of PSMs in relation to obesity should be evaluated in future research.

Overweight and obesity in men with prostate cancer do not constitute risk factors for biochemical recurrence

AIM

To investigate if overweight and obesity were associated with a higher degree of biochemical recurrence (BCR) after radical prostatectomy, in Mexican men with prostate cancer (PCa).

METHODS

We included 180 men with PCa, who underwent radical prostatectomy (RP). Body mass index (BMI) was determined and the degree of PCa aggressiveness was established according to the D'Amico classification. Postoperative follow-up of all patients was performed with PSA quantification every/6 weeks after surgery and then at 3-month intervals for 1 year, followed every/6 months for 5 years. Postoperative BCR was defined as two consecutive increases in PSA levels ≥0.4 ng/mL, after RP.

RESULTS

Sixty eight percent of the patients presented overweight or obesity. We found that only intermediate/high risk patients presented an increased risk factor for BCR-free survival (HR = 4.39; 95% CI = 1.74-11.24; p = 0.002). The median follow-up of all men has been 7.9 years and no significant differences in BCR-free survival time has been observed between the BMI groups.

CONCLUSIONS

The overweight and obesity do not represent a risk factor to present BCR after RP for PCa. However, an intermediate/high risk, according to the D'Amico's classification, constitutes a risk factor to present BCR after radical prostatectomy, which is not related to the BMI.

Differences in risk factors for biochemical recurrence after radical prostatectomy stratified by the degree of obesity: Focused on surgical methods

This study aims to evaluate differences in the risk factors for biochemical recurrence (BCR) for radical prostatectomy stratified by degree of obesity, focusing on the surgical method used. All 3099 patients who underwent radical prostatectomy in two medical centres from January 2008 to March 2018 were retrospectively reviewed. Patients were divided into three groups based on body mass index: ‘normal’, ‘overweight’, and ‘obese’. Risk factors associated with biochemical recurrence were compared between different degrees of obesity. We analysed the contributing risk factors of BCR-free survival using univariate and multivariable Cox hazard models. There were 378 (12.2%) and 1815 (58.6%) patients in the ‘obese’ and ‘overweight’ groups, respectively. Accordingly, 1324 patients underwent retropubic radical prostatectomy (RRP), and 1775 underwent robotic-assisted laparoscopic prostatectomy (RALP). Multivariable analysis showed that patients who underwent RALP had significantly lower BCR free survival in the ‘overweight’ and ‘obese’ groups than those who underwent RRP, with adjusted hazard ratios of 0.75 (95% CI 0.59–0.95, p-value = 0.01) and 0.55 (95% CI 0.33–0.90, p-value = 0.02), respectively. The degree of obesity was not directly associated with BCR-free survival. Robotic prostatectomy showed greater benefits in BCR-free survival than open prostatectomy in the ‘overweight’ and ‘obese’ groups.

Impact of Body Mass Index on Oncological Outcomes of Prostate Cancer Patients after Radical Prostatectomy

Obesity, often represented by higher body mass index (BMI), is not yet fully understood as a potential risk factor for poor clinical outcomes of prostate cancer (PCa) after radical prostatectomy (RP). This study aimed to evaluate the relationship between BMI and biochemical recurrence (BCR)-free survival in RP patients. This study retrospectively reviewed a total of 2.997 PCa patients who underwent RP between 2006 and 2017. The patients were stratified into three BMI groups according to the WHO recommendations for Asian men: normal weight (<23 kg/m²), overweight (≥23 to <27.5 kg/m²) and obese (≥27.5 kg/m²). Multivariable logistic regression analyses were undertaken to evaluate the factors influencing the BCR rates including BMI. Multivariable Cox regression analyses and Kaplan-Meier analyses were performed to test the association of obesity with BCR-free survival. The final pathologic results showed obese patients had greater positive surgical margin rates (13.9%, p < 0.001), extraprostatic invasion (19.9%, p < 0.001), advanced pathological Gleason score (GS) ≥ 8 (50.8%, p = 0.017), and lymph node invasion (LNI) (14.5%, p = 0.021) than overweight and normal weight patients. According to Kaplan-Meier analyses, obese patients, especially with BMI ≥ 27.5, were more likely to have lower BCR-free-survival. Multivariate Cox analysis revealed that diabetes mellitus, LNI status, pT, pathologic GS, extraprostatic invasion, margin positivity and obesity with BMI ≥ 27.5 kg/m² were significantly associated with BCR-free survival after RP. Obesity (higher BMI) was significantly associated with BCR after RP. BMI ≥ 27.5 kg/m² was an independent predictor of BCR-free survival.

Examining the association between adiposity and biochemical recurrence after radical prostatectomy

INTRODUCTION

Herein, we examined the association between adiposity, as measured by computed tomography (CT), and biochemical recurrence (BCR) after radical prostatectomy (RP).

METHODS

Using axial CT images, preoperative fat mass index (FMI) was calculated for 698 men who underwent RP from 2007-2010 by using measurements of total surface area of adipose tissue at the L3 level. Obesity was classified according to National Health and Nutrition Examination Survey (NHANES) standards for obesity (FMI >9 kg/m²). The associations between obesity and the distribution of adiposity (visceral vs. subcutaneous) with BCR were examined using the Kaplan-Meier method and Cox proportional hazards regression analyses.

RESULTS

Obese men were older than non-obese men (63.0 vs. 60.7 years; p<0.001), but were similar with regards to all other clinical and pathological characteristics. With a median followup of six years, 152 patients were diagnosed with BCR. Five-year BCR-free survival was similar between obese and non-obese patients (80.6% vs. 82.1%; p=0.27). Furthermore, in multivariable analyses, obesity was not independently associated with the risk of BCR (hazard ratio [HR] 1.02; 95% confidence interval [CI] 0.73-1.43). Similar results were obtained when analyzing FMI as a continuous variable (HR 1.02; 95% CI 0.94-1.09 for each 1 kg/m² increase in FMI). Additionally, neither visceral adiposity, subcutaneous adiposity, or visceral-to-subcutaneous adiposity ratio were associated with BCR (all p>0.05) in multivariable analyses.

CONCLUSIONS

Neither total abdominal adiposity nor the distribution of adiposity were independently associated with BCR after RP in this study. As such, the presence of obesity may not be a marker of increased oncological risk after RP.

Clinical and biochemical markers of visceral adipose tissue activity: Body mass index, visceral adiposity index, leptin, adiponectin, and matrix metalloproteinase-3. Correlation with Gleason patterns 4 and 5 at prostate biopsy

Context:

The correlation between aggressive prostate cancer and obesity mainly based on body mass index (BMI) and pathology after surgery remains controversial.

Aims:

The aim of the study was to correlate BMI, visceral adiposity index (VAI), and the plasmatic levels of leptin, adiponectin, and matrix metalloproteinase-3 (MMP-3), and biomarkers of adipose tissue function, with the detection of Gleason patterns 4 and 5 at biopsy.

Subjects and Methods:

Consecutive patients with prostate cancer at 12-core transrectal biopsy were enrolled. BMI, waist circumference (WC), blood samples to evaluate the plasmatic levels of triglycerides (TG) and high-density lipoproteins (HDL), adiponectin, leptin, and MMP-3 were obtained immediately before biopsy. The VAI was calculated according to the formula: WC/(39.68 + [1.88 × BMI]) × TG/1.03 × 1.31/HDL.

Results:

One hundred and forty-nine patients were entered. The median PSA, BMI, and VAI were 10.0 ng/ml, 27.6 kg/m², and 4.6, respectively. Gleason patterns 4 or 5 were detected in 68 (45.6%) patients; in 15 (41.7%), 31 (44.9%), and 22 (50.0%) among normal weight, overweight, and obese patients, respectively (P = 0.55). The statistical analysis did not show any significant correlation between BMI, VAI, the plasmatic levels of leptin, adiponectin, MMP-3, and the detection of Gleason patterns 4 and 5 at biopsy. A statistically significant association emerged with older age (P = 0.017) and higher PSA values (P = 0.02).

Conclusion:

We did not find any association between BMI, VAI, the plasmatic levels of adiponectin, leptin, and MMP-3 and the detection of Gleason patterns 4 and 5 at prostate biopsy.

The Association Between Sarcopenia and Oncologic Outcomes After Radical Prostatectomy

PURPOSE

Sarcopenia is associated with inferior perioperative and oncologic outcomes in patients undergoing surgery for multiple malignancies. The purpose of this study was to evaluate the association between sarcopenia and outcomes after radical prostatectomy (RP) for men with prostate cancer.

PATIENTS AND METHODS

Using a representative computed tomographic image from the L3 level, preoperative skeletal muscle indices (SMI) calculated for 698 patients who underwent RP between 2007 and 2010. Patients were classified as sarcopenic if they had a SMI < 55 cm²/kg² according to international consensus. The associations between sarcopenia and biochemical recurrence (BCR), systemic progression (SP), and all-cause mortality (ACM) were investigated by Cox proportional hazards regression.

RESULTS

Sarcopenic patients were older than nonsarcopenic patients (mean age, 63.0 vs. 60.4 years, P < .001) but were otherwise similar with regard to clinical and pathologic characteristics. There was no significant difference in the perioperative complication rate after RP between sarcopenic and nonsarcopenic patients (16.5% vs. 17.4%, P = .82). At a median follow-up after surgery of 6.0 years, 152 patients were diagnosed with BCR, patients were diagnosed with SP, and 50 patients died. In multivariable analysis, the presence of sarcopenia was not significantly associated with the risks of BCR, SP, or ACM. Similar results were obtained when analyzing SMI as a continuous variable.

CONCLUSION

Sarcopenia was not found to be independently associated with perioperative complications or oncologic outcomes after RP. As such, the presence of sarcopenia may not be prognostic marker for inferior outcomes among men with localized prostate cancer undergoing RP.

The impact of a family history of prostate cancer on the prognosis and features of the disease in Korea: results from a cross-sectional longitudinal pilot study

PURPOSE

Reports on the impact of a family history of prostate cancer among Asians are scarce. We evaluated whether a positive prostate cancer family history is associated with the prognosis and features of the disease.

METHODS

From January 2006 to December 2015, patients who received treatment for pathologically diagnosed prostate cancer were enrolled. Information on family history was obtained via self-administered questionnaires between January 2015 and December 2016. The overall survival rate for all patients and the rate of biochemical failure after radical prostatectomy were assessed according to the presence of family history.

RESULTS

Of 1266 patients (median age, 68.1 years; median prostate-specific antigen, 8.73 ng/mL; median follow-up, 40.0 months), 47 (3.8%) were identified as having a family history. Men with a family history had a younger age, higher proportion of cases diagnosed before 55 years of age, and lower stage than those without a family history. Family history was not a potential risk factor for overall survival. In an analysis of patients who underwent radical prostatectomy (median prostate-specific antigen, 7.40 ng/mL; median follow-up, 40.5 months), no differences in pathologic characteristics were found between patients with (n = 39, 93.5%) and without (n = 567, 6.4%) a family history. Family history was not predictive of biochemical failure.

CONCLUSIONS

A family history of prostate cancer seemed to have no effect on prognosis and disease aggressiveness. However, this study proposed a rationale for performing earlier prostate-specific antigen testing in men with a family history of prostate cancer.

Body mass index as a classifier to predict biochemical recurrence after radical prostatectomy in patients with lower prostate-specific antigen levels

Prostate cancer, one of the most common malignant tumors among men, is closely associated with obesity and, thus far, several studies have suggested the association between obesity and aggressive pathological characteristics in the United States. However, the effect of obesity on prostate cancer mortality is controversial, and it remains unclear whether obesity contributes to the aggressiveness of prostate cancer in Asian patients. The aim of the present study was to investigate the association between body mass index (BMI) and the clinicopathological characteristics of prostate cancer in 2,003 Japanese patients who underwent radical prostatectomy. There was a significant association between higher BMI and higher Gleason score (GS). The multivariate analysis also revealed that BMI was an independent indicator for GS ≥8 at surgery. Moreover, among patients with lower prostate-specific antigen levels, biochemical recurrence-free survival was significantly worse in those with higher BMI. These results suggest that BMI may be a classifier for predicting adverse pathological findings and biochemical recurrence after radical prostatectomy in Japanese patients.

Independent surgical validation of the new prostate cancer grade-grouping system

OBJECTIVE

To report the independent prognostic impact of the new prostate cancer grade-grouping system in a large external validation cohort of patients treated with radical prostatectomy (RP).

PATIENTS AND METHODS

Between 1994 and 2013, 3 694 consecutive men were treated with RP at a single institution. To investigate the performance of and validate the grade-grouping system, biochemical recurrence-free survival (bRFS) rates were assessed using Kaplan-Meier tests, Cox-regression modelling, and discriminatory comparison analyses. Separate analyses were performed based on biopsy and RP grade.

RESULTS

The median follow-up was 52.7 months. The 5-year actuarial bRFS for biopsy grade groups 1-5 were 94.2%, 89.2%, 73.1%, 63.1%, and 54.7%, respectively (P < 0.001). Similarly, the 5-year actuarial bRFS based on RP grade groups was 96.1%, 93.0%, 74.0%, 64.4%, and 49.9% for grade groups 1-5, respectively (P < 0.001). The adjusted hazard ratios for bRFS relative to biopsy grade group 1 were 1.98, 4.20, 5.57, and 9.32 for groups 2, 3, 4, and 5, respectively (P < 0.001), and for RP grade groups were 2.09, 5.27, 5.86, and 10.42 (P < 0.001). The five-grade-group system had a higher prognostic discrimination compared with the commonly used three-tier system (Gleason score 6 vs 7 vs 8-10).

CONCLUSIONS

In an independent surgical cohort, we have validated the prognostic benefit of the new prostate cancer grade-grouping system for bRFS, and shown that the benefit is maintained after adjusting for important clinicopathological variables. The greater predictive accuracy of the new system will improve risk stratification in the clinical setting and aid in patient counselling.

Open Versus Robotic Radical Prostatectomy in Obese Men

OBJECTIVES

Robotic-assisted radical prostatectomy (RARP) has been shown to reduce blood loss, peri-operative complications and length of stay when compared to open radical prostatectomy (ORP). We sought to determine whether the reported benefits of RARP over ORP translate to obese patients.

PATIENTS AND METHODS

We utilized the 2009-2010 Nationwide Inpatient Sample to identify all obese men with prostate cancer who underwent ORP and RARP. Our primary outcome was the presence of a peri-operative adverse event (i.e. blood transfusion, complication, prolonged length of stay). We fit multivariable logistic regression models to examine whether RARP in obese patients was independently associated with decreased odds of all three outcomes.

RESULTS

We identified 9,108 obese patients who underwent radical prostatectomy. On multivariable analysis, the use of RARP in the obese population was not independently associated with decreased odds of developing a peri-operative complication (OR = 0.81, CI: 0.58-1.13, p = 0.209). RARP was, however, associated with decreased odds of blood transfusion (OR = 0.17, CI: 0.10-0.30, p < 0.001) and prolonged length of stay (OR = 0.28, CI: 0.20-0.40, p < 0.001).

CONCLUSION

Our findings suggest that in obese patients, the use of RARP may reduce length of stay and blood transfusions compared to ORP. Both approaches, however, are associated with similar odds of developing a complication.

Low body mass index is associated with adverse oncological outcomes following radical prostatectomy in Korean prostate cancer patients

PURPOSE

The purpose of this study was to determine the impact of obesity on clinicopathological features and biochemical recurrence (BCR) following radical prostatectomy (RP) in Korean prostate cancer (PCa) patients.

METHODS

A single-institutional retrospective analysis was performed on 880 PCa patients treated by RP without neoadjuvant therapy between July 2005 and December 2011. Patients were stratified according to body mass index (BMI) standards for Asian populations: obese (BMI ≥25 kg/m(2)), overweight (BMI 23-24.9 kg/m(2)), or normal weight (BMI <23 kg/m(2)). For analysis, overweight and obese patients were combined (n = 592, BMI ≥23 kg/m(2)) and compared with normal weight patients (n = 288, BMI <23 kg/m(2)). BCR was defined as prostate-specific antigen (PSA) ≥0.2 ng/ml following RP.

RESULTS

Normal weight patients tended to be classified into the higher D'Amico risk category with smaller prostate volumes compared with obese and overweight patients. Normal weight patients had higher pathological Gleason scores and were at higher risk of BCR during the mean follow-up of 58.2 months. This translated to a higher 5-year BCR-free survival rate for obese and overweight patients compared with normal weight patients (77.8 vs. 70.3 %; p = 0.017). On multiple Cox-proportional hazards regression analysis incorporating variables of BMI category, PSA, positive surgical margins, pathological T stage, and Gleason score, higher BMI category remained a significant predictor of a lower risk of BCR (HR = 0.634, p = 0.028).

CONCLUSIONS

Obese and overweight Korean PCa patients have lower Gleason scores and a reduced risk of BCR compared with normal weight patients. These findings suggest that body fat influences pathological features and oncologic outcomes of PCa.

Nonalcoholic fatty liver disease is a negative risk factor for prostate cancer recurrence

Nonalcoholic fatty liver disease (NAFLD) is closely related to the metabolic syndrome, which is associated with an increased risk of various malignancies. In this study, we investigated the association between NAFLD and prostate cancer biochemical recurrence (BCR) after radical prostatectomy. Consecutive prostate cancer patients who underwent radical prostatectomy were enrolled from two hospitals in Korea and randomly assigned to the training (n=147) or validation set (n=146). The presence of NAFLD, BMI, preoperative prostate-specific antigen, and histological findings including Gleason score (GSc) were analyzed in regard to their association with BCR. NAFLD was diagnosed based on ultrasonography or unenhanced computed tomography images. BCR-free survival rates were calculated using the Kaplan-Meier method. In the training set, 32 (21.8%) patients developed BCR during a median follow-up period of 51 (inter-quartile range, 35-65) months. In the multivariate analysis, the presence of NAFLD (hazard ratio (HR), 0.36; 95% CI, 0.14-0.97; P=0.04) was an independent negative predictive factor of BCR after adjustment for pathological GSc. Applied to the validation set, the presence of NAFLD maintained its prognostic value for longer time-to-BCR (HR, 0.17; 95% CI, 0.06-0.49; P=0.001). In the subgroup analysis of patients with NAFLD, NAFLD fibrosis score was a single independent negative predictor for BCR (HR, 0.54; 95% CI, 0.30-0.98; P=0.04). Our study demonstrated that NAFLD may play a protective role against BCR after radical prostatectomy for prostate cancer. Further study is warranted to elucidate the mechanism of protective effect in patients with NAFLD.

Obesity has multifaceted impact on biochemical recurrence of prostate cancer: a dose-response meta-analysis of 36,927 patients

Obesity is inconsistently related to biochemical recurrence (BCR) of prostate cancer (PCa) in different epidemiological studies. We conducted a systematic review and dose-response meta-analysis of published studies from MEDLINE and EMBASE in order to determine the relationship between body mass index (BMI) and BCR of PCa. We identified a total of 26 studies including 36,927 individuals. Pooled estimates of relative risk (RR) and confidence interval (CI) were computed, and dose-response meta-analysis was subsequently performed. Based on the random-effects approach, a 5 kg/m(2) increase in BMI was associated with 16 % (RR 1.16, 95 % CI 1.08-1.24) higher risk of BCR for entire set of 26 studies. Significantly higher rates of BCR were also observed in radical prostatectomy series (RR 1.17, 95 % CI 1.07-1.28) and external beam radiation therapy series (RR 1.19, 95 % CI 1.10-1.28), while no significant correlation was observed in brachytherapy series (RR 0.91, 95 % CI 0.64-1.28). Different BCR outcomes came out for studies held in USA (RR 1.18, 95 % CI 1.10-1.28), Europe (RR 1.04 95 % CI 0.91-1.17) and Asia (RR 1.83 95 % CI 0.85-3.97), respectively. There was limited evidence of a nonlinear association between BMI and BCR, which showed a critical point of 33 in BMI. The findings from meta-analysis showed that excess BMI was positively correlated with BCR of PCa multifacetedly, indicating good weight control and detailed attention to treating obese patients might improve the prognosis of PCa.