Effect of body mass index on histopathologic parameters: results of large European contemporary consecutive open radical prostatectomy series.

Objectives: To determine whether an increased body mass index (BMI) is a predictor of advanced pathologic findings in European men undergoing radical prostatectomy (RP). The relationship between obesity and prostate cancer is controversial. Studies, predominantly derived from the United States, have suggested that an increased BMI is a significant predictor of adverse pathologic findings in patients treated with open RP.
Methods: From April 2005 to June 2008, 1538 consecutive patients were treated with open RP at a single tertiary referral center. We tested the effect of BMI on the rate of extracapsular extension, seminal vesicle invasion, lymph node invasion, and positive surgical margins in univariate and multivariate logistic regression models. The covariates consisted of clinical stage, prostate-specific antigen, biopsy Gleason score, age, prostate volume, and rate of nerve-sparing surgery.
Results: On multivariate analysis, both continuously coded and categorically coded BMI was unrelated to the rate of extracapsular extension (odds ratio [OR] 1.02, P = .5), seminal vesicle invasion (OR 1.03, P = .3), lymph node invasion (OR 0.98, P = .7), or positive surgical margins (OR 1.03, P = .3).
Conclusions: Obese patients who are candidates for open RP should not expect to have worse pathologic findings after surgery than their nonobese counterparts. Differences in patients' weight and height between North America and Europe might explain the lack of adverse effects of an elevated BMI in this European cohort.