The impact of body mass index on treatment outcomes for patients with low-intermediate risk prostate cancer

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 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.

Obese men undergoing radical prostatectomy: Is robotic or retropubic better to limit positive surgical margins? Results from SEARCH

OBJECTIVES

To evaluate the association between obesity and positive surgical margins in patients undergoing retropubic radical prostatectomy versus robotic-assisted laparoscopic prostatectomy.

METHODS

We retrospectively reviewed the data of 3141 men undergoing retropubic radical prostatectomy and 1625 undergoing robotic-assisted laparoscopic prostatectomy between 1988 and 2017 at eight Veterans Health Administration hospitals. The positive surgical margin location (peripheral, apical, bladder neck, overall) was determined from pathology reports. We adjusted for age, race, prostate-specific antigen, surgery year, prostate weight, pathological grade group, extracapsular extension, seminal vesicle invasion, hospital surgical volume and surgical method (in analyses not stratified by surgical method). Interactions between body mass index and surgical approach were tested.

RESULTS

Among all patients, higher body mass index was associated with increased odds of overall, peripheral and apical positive surgical margins (OR 1.02-1.03, P ≤ 0.02). Although not statistically significant, there was a trend between higher body mass index and increased odds of bladder neck positive surgical margins (OR 1.03, P = 0.09). Interactions between body mass index and surgical method were significant for peripheral positive surgical margins only (P = 0.024). Specifically, there was an association between body mass index and peripheral positive surgical margins among men undergoing retropubic radical prostatectomy (OR 1.04, P < 0.001), but not robotic-assisted laparoscopic prostatectomy (OR 1.00, P = 0.98). Limitations include lacking individual surgeon data and lacking central pathology review.

CONCLUSIONS

In this multicenter cohort, higher body mass index was associated with increased odds of positive surgical margins at all locations except the bladder neck. Furthermore, there was a significant association between obesity and peripheral positive surgical margins in men undergoing retropubic radical prostatectomy, but not robotic-assisted laparoscopic prostatectomy. Long-term clinical significance requires further study.

Iron Metabolism in Prostate Cancer; From Basic Science to New Therapeutic Strategies

An increasing amount of research has recently strengthened the case for the existence of iron dysmetabolism in prostate cancer. It is characterized with a wide array of differential expression of iron-related proteins compared to normal cells. These proteins control iron entry, cellular iron distribution but also iron exit from prostate cells. Iron dysmetabolism is not an exclusive feature of prostate cancer cells, but it is observed in other cells of the tumor microenvironment. Disrupting the machinery that secures iron for prostate cancer cells can retard tumor growth and its invasive potential. This review unveils the current understanding of the ways that prostate cancer cells secure iron in the tumor milieu and how can we exploit this knowledge for therapeutic purposes.

Performance of prostate cancer recurrence nomograms by obesity status: a retrospective analysis of a radical prostatectomy cohort

Background

Obesity has been associated with aggressive prostate cancer and poor outcomes. It is important to understand how prognostic tools for that guide prostate cancer treatment may be impacted by obesity. The goal of this study was to evaluate the predicting abilities of two prostate cancer (PCa) nomograms by obesity status.

Methods

We examined 1576 radical prostatectomy patients categorized into standard body mass index (BMI) groups. Patients were categorized into low, medium, and high risk groups for the Kattan and CaPSURE/CPDR scores, which are based on PSA value, Gleason score, tumor stage, and other patient data. Time to PCa recurrence was modeled as a function of obesity, risk group, and interactions.

Results

As expected for the Kattan score, estimated hazard ratios (95% CI) indicated higher risk of recurrence for medium (HR = 2.99, 95% CI = 2.29, 3.88) and high (HR = 8.84, 95% CI = 5.91, 13.2) risk groups compared to low risk group. The associations were not statistically different across BMI groups. Results were consistent for the CaPSURE/CPDR score. However, the difference in risk of recurrence in the high risk versus low risk groups was larger for normal weight patients than the same estimate in the obese patients.

Conclusions

We observed no statistically significant difference in the association between PCa recurrence and prediction scores across BMI groups. However, our study indicates that there may be a stronger association between high risk status and PCa recurrence among normal weight patients compared to obese patients. This suggests that high risk status based on PCa nomogram scores may be most predictive among normal weight patients. Additional research in this area is needed.

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.

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

Background

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

Materials and Methods

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

Results

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

Conclusions

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

The impact of body mass index on dosimetric quality in low-dose-rate prostate brachytherapy

Purpose

Low-dose-rate (LDR) brachytherapy has been established as an effective and safe treatment option for men with low and intermediate risk prostate cancer. In this retrospective analysis, we sought to study the effect of body mass index (BMI) on post-implant dosimetric quality.

Material and methods

After institutional approval, records of patients with non-metastatic prostate cancer treated in Puerto Rico with LDR brachytherapy during 2008-2013 were reviewed. All patients were implanted with ¹²⁵I seeds to a prescription dose of 145 Gy. Computed tomography (CT) based dosimetry was performed 1 month after implant. Patients with at least 1 year of prostate-specific antigen (PSA) follow-up were included. Factors predictive of adequate D₉₀ coverage (≥ 140 Gy) were compared via the Pearson χ² or Wilcoxon rank-sum test as appropriate.

Results

One-hundred and four patients were included in this study, with 53 (51%) patients having a D₉₀ ≥ 140 Gy. The only factor associated with a dosimetric coverage detriment (D₉₀ < 140 Gy) was BMI ≥ 25 kg/m² (p = 0.03). Prostate volume (p = 0.26), initial PSA (p = 0.236), age (p = 0.49), hormone use (p = 0.93), percent of cores positive (p = 0.95), risk group (p = 0.24), tumor stage (p = 0.66), and Gleason score (p = 0.61) did not predict D₉₀.

Conclusions

In this study we show that BMI is a significant pre-implant predictor of D₉₀ (< 140 Gy vs. ≥ 140 Gy). Although other studies have reported that prostate volume also affects D₉₀, our study did not find this correlation to be statistically significant, likely because all of our patients had a prostate volume < 50 cc. Our study suggests that in patients with higher BMI values, more rigorous peri-implant dosimetric parameters may need to be applied in order to achieve a target D₉₀ > 140 Gy.