Obesity and risk of biochemical progression following radical prostatectomy at a tertiary care referral center

Purpose: We have previously reported that obesity is an independent predictor of biochemical progression after radical prostatectomy (RP) in men treated by a single surgeon at our institution. We sought to validate or refute these findings using data on men treated by multiple other surgeons at our institution. Materials and Methods: The study population consisted of 2,796 men treated with anatomical radical RP between 1988 and 2004 by 1 of 17 surgeons at our institution, a tertiary care referral center. We evaluated the association between body mass index (BMI), and adverse pathological features and biochemical progression. Results: On multivariate analysis increased BMI was associated with high grade disease in the RP specimen (p = 0.03), positive surgical margins (p. <0.001), extraprostatic extension (p <0.001) and lymph node metastasis (p = 0.01) but not with seminal vesicle invasion (p = 0.59). After multivariate adjustment for preoperative clinical characteristics increased BMI was significantly associated with an increased risk of biochemical progression (p <0.001), which was somewhat but not completely attenuated by further adjusting for RP specimen pathological features (p = 0.03). Adjustment for surgeon did not affect these results. Conclusions: In men undergoing RP increased BMI was associated with adverse pathological features and a greater risk of biochemical progression. These findings together with the results of several recently published series collectively provide strong evidence that obese men undergoing RP are more likely to have aggressive prostate cancer.