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

Charnita Zeigler-Johnson,Elaine Spangler,Karen Glanz,Aaron Hudson,Knashawn H Morales

doi:10.1186/s12885-018-4942-0

Charnita Zeigler-Johnson, Elaine Spangler + Show 3 more

Open Access

https://doi.org/10.1186/s12885-018-4942-0

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Abstract

BackgroundObesity 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.MethodsWe 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.ResultsAs 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.ConclusionsWe 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.

Highlights

Obesity has been associated with aggressive prostate cancer and poor outcomes
An increase risk of prostate cancer (PCa) recurrence was associated with increasing age and Arican American compared to Caucasian race
We have a limited number of patients in our analyses, these results provide evidence that warrants building larger studies that examine the interplay between prognostic risk group, obesity, and PCa outcomes

Summary

Introduction

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. Prostate cancer (PCa) is a major public health burden with few confirmed risk factors [1]. Nomograms are models that can predict PCa recurrence up to 10 years after the time of treatment with relatively high accuracy (71–79%) compared to other risk grouping methods [13, 14]. The Kattan nomogram, one of the most commonly used tools for predicting risk for PCa recurrence [15], includes information about year of radical prostatectomy, positive surgical margins, extracapsular extension, seminal vesicle invasion, lymph node invasion, primary and Zeigler-Johnson et al BMC Cancer (2018) 18:1061 secondary Gleason grades, and preoperative PSA [16]. The CaPSURE/CPDR recurrence equation includes information about patient race, sigmoid transformed PSA, pathology stage (including organ confined vs. extracapsular disease), and post-operative Gleason sum [17]

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