Body mass index and prostate cancer severity: do obese men harbor more aggressive disease on prostate biopsy?

OBJECTIVE: To examine the association of obesity with the prebiopsy prostate-specific antigen (PSA), Gleason score, clinical stage, and D'Amico tumor risk in 2 independent cohorts of men with prostate cancer.
MATERIALS AND METHODS: We retrospectively reviewed the medical records of men with biopsy-proven prostate cancer from California's Improving Access, Counseling and Treatment for Californians with Prostate Cancer program and from a random sample of men treated at the University of Michigan. We performed multivariate analyses to examine the relationship of body mass index (BMI) with the prebiopsy PSA level, Gleason score, clinical stage, and D'Amico tumor risk, while controlling for demographics.
RESULTS: The mean age was 61.5 years, and the median prebiopsy PSA level was 6.7 ng/mL. Greater than 70% of men were at least overweight. On univariate analysis, the BMI was not associated with prebiopsy PSA levels, Gleason score, or D'Amico tumor risk. On multivariate analysis, we found no association between BMI and log-transformed PSA, Gleason score, clinical T stage, or D'Amico risk. Advancing age was associated with a greater risk of a higher prebiopsy PSA level, Gleason score, and D'Amico tumor risk.
CONCLUSION: Obese men with prostate cancer were no more likely to have a higher prebiopsy PSA level, Gleason score, clinical T stage, or D'Amico risk than those of normal weight. Although we do not know whether the BMI affected the prebiopsy PSA values in those without a diagnosis of prostate cancer, our findings suggest that the BMI does not affect the interpretation of the prebiopsy PSA levels in those with cancer.