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

Abstract

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.