PURPOSE: Higher BMI is linked to lower PSA.
This has given rise to concerns PSA may be less reliable for predicting prostate cancer among obese men. We test the accuracy of pre-biopsy PSA for predicting prostate cancer across BMI categories.
MATERIAL AND METHODS: We used the REDUCE study, which tested dutasteride for prostate cancer risk reduction in men with a PSA of 2.5-10.0 ng/mL and a negative pre-study biopsy. All men were required to have a biopsy at 2- and 4-years independent of PSA. We assessed the performance of pre-biopsy PSA to predict overall and high-grade prostate cancer (Gleason sum ≥7) within each BMI group using the area under the ROC curve (AUC).
RESULTS: Of 6,103 men who had a 2-year biopsy, 1,646 (27%) were normal weight, 3,209 (53%) overweight, and 1,248 (20%) were obese. Mean-adjusted PSA values for normal weight, overweight, and obese subjects on placebo were 7.73, 7.17, and 6.79 ng/mL (p-trend=0.192), and on dutasteride were 3.16, 2.93, and 2.62 ng/mL (p=0.008). AUC analysis using raw PSA data for predicting prostate cancer ranged from 0.60-0.64 in the placebo arm and from 0.58-0.66 in the dutasteride arm with no difference across BMI categories (p-interactions≥0.212). Similar results were found for high-grade prostate cancer with AUCs ranging from 0.69-0.70 in the placebo arm and 0.65-0.75 in the dutasteride arm but no differences across BMI categories (p-interactions≥0.157).
CONCLUSIONS: Among men with a previous negative biopsy, the accuracy of pre-biopsy PSA to predict overall and high-grade prostate cancer was independent of BMI.
Vidal AC, Howard LE, Moreira DM, Castro-Santamaria R, Andriole GL, Freedland SJ. Are you the author?
Duke Prostate Center, Division of Urological Surgery, Department of Surgery, Duke University School of Medicine, Durham, NC, USA; Surgery Section, Durham VA Medical Center, Durham, NC, USA; Mayo Clinic, Department of Urology, Rochester, MN, USA; GlaxoSmithKline Inc., Metabolic Pathways and Cardiovascular R&D Unit, King of Prussia, PA, USA; Washington University School of Medicine in St. Louis, St. Louis, Missouri; Department of Pathology, Duke University School of Medicine, Durham, NC, USA.
Reference: J Urol. 2015 Feb 5. pii: S0022-5347(15)00236-0.