Influence of abdominal adiposity, waist circumference, and body mass index on clinical and pathologic findings in patients treated with radiotherapy for localized prostate cancer.

Background: Increased body mass index (BMI) has been associated with more aggressive prostate cancer (PC). The relation among abdominal visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), waist circumference (WC), and BMI was compared with clinical and pathologic findings in patients treated with radiotherapy for localized PC.

Methods: VAT, SAT, WC (all measured by planning abdominopelvic computed tomography scan) and BMI were compared with clinical and pathologic factors using univariate analyses. Cox regression analyses were performed to evaluate whether obesity measures significantly predicted risk for secondary malignancies.

Results: Of 276 analyzed patients, 80 (29%) were obese (BMI ≥ 30 kg/m(2) ). Median BMI at baseline was 27.6 kg/m(2) (interquartile range [IQR], 25.1-30.5 kg/m(2) ). Increased SAT and VAT were associated with a higher National Comprehensive Cancer Network (NCCN) PC risk group (P = .0001 and .008, respectively). Greater SAT was associated with a higher Gleason score (GS) (P = .030). Younger age at diagnosis was significantly correlated with higher SAT and BMI, whereas increased prostate size was found in patients with higher BMI, WC, SAT, and VAT. At a median follow-up of 42.3 months (IQR, 32.3-59.9 months), 15 secondary malignancies were observed. On multivariate analysis, VAT was a significant predictor for secondary cancers (adjusted hazards ratio, 1.014; P = .0001).

Conclusions: Measurements of greater abdominal adiposity were strongly associated with adverse pathologic features in patients with localized PC, including higher GS and NCCN PC risk groups. Moreover, VAT was found to be a strong risk factor for secondary malignancies.