Obesity and survival after radical prostatectomy: A 10-year prospective cohort study

BACKGROUND. Obesity and prostate cancer are among the most common health problems affecting American men today. The authors' goal was to assess the impact of obesity on clinical and pathologic features of prostate cancer and long-term outcomes. METHODS. The authors performed a prospective cohort study on 5313 men who underwent radical prostatectomy between 1990 and 1999. Patient height and weight were measured at the time of surgery to calculate the body mass index (BMI). The patients were separated into 3 BMI groups: BMI <25, 25-29.9, and ≥30 kg/m². The associations between BMI and age, prostate-specific antigen (PSA) level, and Gleason score were assessed with the Spearman rank correlation test. The associations between BMI and pathologic features were assessed with the Mantel-Haenszel χ² test. Fifteen-year biochemical progression-free survival, systemic progression-free survival, cancer-specific survival, and overall survival were estimated using the Kaplan-Meier method and evaluated using Cox models. RESULTS. The median length of follow-up for the entire cohort was 10.1 years. Clinical and pathologic features appear worse in patients with a higher BMI. On univariate and multivariate analyses, it was found that BMI had no impact on biochemical progression, systemic progression, prostate cancer survival, or overall survival. CONCLUSIONS. Obese patients appear to have worse pathologic features at the time of prostatectomy. Despite these features, long-term oncologic outcomes, including cancer-specific survival, remain the same regardless of BMI. BMI appears to influence prostate cancer outcomes at the time of prostatectomy, as evidenced by more aggressive pathologic features. However, after prostatectomy, BMI does not appear to be an independent predictor of recurrence or survival.