Pathologic variables and recurrence rates as related to obesity and race in men with prostate cancer undergoing radical prostatectomy

Purpose: To determine if obesity is associated with higher prostate specific antigen recurrence rates after radical prostatectomy (RP), and to explore racial differences in body mass index (BMI) as a potential explanation for the disparity in outcome between black and white men. Patients and Methods: A retrospective, multi-institutional pooled analysis of 3,162 men undergoing RP was conducted at nine US military medical centers between 1987 and 2002. Patients were initially categorized as obese (BMI ≥ 30 kg/m²), overweight (BMI 25 to 30 kg/m²), or normal (BMI ≤ 25 kg/m ²). For analysis, normal and overweight groups were combined (BMI < 30 kg/m²) and compared with the obese group (BMI ≥ 30 kg/m²) with regard to biochemical recurrence (prostate-specific antigen ≥ 0.2 ng/mL) after RP. Results: Of 3,162 patients, 600 (19.0%) were obese and 2,562 (81%) were not obese. BMI was an independent predictor of higher Gleason grade cancer (P < .001) and was associated with a higher risk of biochemical recurrence (P = .027). Blacks had higher BMI (P < .001) and higher recurrence rates (P = .003) than whites. Both BMI (P = .028) and black race (P = .002) predicted higher prostate specific antigen recurrence rates. In multivariate analysis of race, BMI, and pathologic factors, black race (P = .021) remained a significant independent predictor of recurrence. Conclusion: Obesity is associated with higher grade cancer and higher recurrence rates after RP. Black men have higher recurrence rates and greater BMI than white men. These findings support the hypothesis that obesity is associated with progression of latent to clinically significant prostate cancer (PC) and suggest that BMI may account, in part, for the racial variability in PC risk.