Radical prostatectomy neutralizes obesity-driven risk of prostate cancer progression

INTRODUCTION: Obesity negatively affects several prostate cancer (PCa) outcomes, including mortality to PCa. However, the validity of several such associations is still under debate, including its effect on pathological stage at radical prostatectomy (RP) and subsequent biochemical recurrence (BCR), which represents the focus of this study.

METHODS: We relied on patients with PCa treated with RP at the Martini-Klinik Prostate Cancer Center between 2004 and 2015. First, multivariable logistic regression analyses tested for association between obesity and non-organ-confined disease (≥pT3 or pN1). Second, multivariable Cox regression analyses examined obesity effect on BCR. Last, in a propensity score-matched cohort, Kaplan-Meier analyses assessed BCR-free survival according to body mass index (kg/m2) (BMI) strata (≥30 vs.<25).

RESULTS: Of 16,014 individuals, 2,403 (15%) men were obese (BMI≥30). Median follow-up was 36.4 months (interquartile range: 13.3-60.8). Obese patients were more likely to harbor non-organ-confined disease at final pathology (odds ratio = 1.27; 95% CI: 1.13-1.43; P<0.001) but did not have higher BCR rates (hazard ratio = 0.98; 95% CI: 0.86-1.11; P = 0.7). Similarly, BCR-free survival was not different between obese and nonobese men, after propensity score matching (log rank P = 0.9).

CONCLUSION: Obesity (BMI ≥30) might predispose to higher rates of non-organ-confined disease at RP. However, obesity was not an independent predictor of BCR after surgery. Consequently, the unfavorable effect of obesity on PCa might be limited to local spread of the disease and might be neutralized after RP.