The effect of BMI on clinicopathologic and functional outcomes after open radical prostatectomy

To analyze the effect of body mass index (BMI) on pathologic and functional outcomes after open radical retropubic prostatectomy.

We retrospectively analyzed 2,471 patients who underwent RP. Clinicopathologic and patient characteristics were compared with respect to patients' BMI (normal weight: BMI < 25 kg/m(2) [n = 795], overweight: BMI ≥ 25 kg/m(2) and < 30 kg/m(2) [n = 1305], and obese: BMI ≥ 30 kg/m(2) [n = 371]). Multivariable logistic and linear regression models were used to quantify the effect of BMI on pathologic and functional outcomes.

Compared with normal weight patients, overweight and obese patients demonstrated higher pathologic Gleason grade and higher pathologic T stage, without any difference in preoperative prostate-specific antigen levels. Overweight and obese men were less likely to have a negative surgical margin (odds ratio (OR) 0.74 [confidence interval (CI) 0.65-0.84, P<0.001] for overweight men and OR 0.66 [CI 0.49-0.89, P<0.01] for obese men) and had a lower rate of postoperative erectile function (OR 0.60 [CI 0.48-0.76, P<0.001] for overweight patients and OR 0.34 [CI 0.27-0.44, P<0.001] for obese patients). Moreover, duration of surgery and intraoperative blood loss increased significantly with an increase in BMI. When using BMI as a continuous variable, the same trends were demonstrated. However, a lower rate of continence was not evident for overweight or obese men.

In contrast to many other studies, in this cohort of patients with prostate cancer, BMI was an independent risk factor for most analyzed pathologic and functional outcomes after radical prostatectomy, including negative surgical margin, potency, duration of surgery, and intraoperative blood loss.