Positive surgical margins and biochemical recurrence in obese patients with intermediate- and high-grade prostate cancer with radical prostatectomy.

Abstract

50 Background: The relationship between obesity and prostate cancer outcomes is unclear. We performed a retrospective cohort study to determine the effect of body mass index (BMI) on a cohort of patients with intermediate to high grade prostate cancer treated with radical prostatectomy (RP). Methods: Our retrospective study cohort included 582 men diagnosed with Gleason 7-10 prostate cancer between 1998 and 2008 and treated with RP at a single institution. Patients were stratified into four groups on the basis of their BMI at the time of prostate cancer diagnosis (<25, 25-30, 30-35 or >35). The primary endpoints for comparison were biochemical failure free survival (BFFS) and the incidence of positive margins. PSA >0.2 ng/dl was used to define biochemical failure. Results: After adjusting for age, Gleason score, pre-treatment PSA and the presence of diabetes, we found patients with increasing BMI had an increased frequency of biochemical failure after RP. Compared to patients with a normal BMI (<25), patients with BMI 25-30, 30-35, and >35 had 1.82 (1.12, 2.97; p = 0.02), 2.14 (1.33, 3.45; p = 0.002) and 2.29 (1.1, 4.78; p = 0.03) times higher rates of biochemical failure, respectively. We additionally found increased positive margins after RP in patients with a BMI 30-35 and >35 (41.4% and 45.5%, respectively) when compared to patients with a BMI of <25 and 25-30 (33.3% and 28.9%, respectively); p = 0.02. Conclusions: Patients with increasing BMI seem to be at significantly increased risk for biochemical failure following RP potentially due to the increased technical difficulty of the surgery and increased incidence of positive margins. [Table: see text]