Obesity and capsular incision at the time of open retropubic radical prostatectomy

The goal of radical prostatectomy (RP) is complete removal of the intact prostate. Obese men can represent a technical challenge. However, to our knowledge objective data linking obesity with technically inferior surgery are lacking. Therefore, we examined the association between body mass index (BMI) and capsular incision at RP as a surrogate of a poor technical operation in men treated for prostate cancer by several high volume surgeons at a center of excellence.

The study population consisted of 7,027 men treated with anatomical retropubic RP between 1996 and 2004 by 7 high volume surgeons. We evaluated the association between BMI and capsular incision using logistic regression, adjusting for clinical and pathological variables, and for the surgeon.

Overall capsular incision was noted in 4.6% of all RP specimens. After adjustment for preoperative prostate specific antigen, patient race, height, year of surgery, clinical stage, pathological Gleason sum, prostate weight, extraprostatic extension and seminal vesicle invasion increased BMI was associated with increased odds of capsular incision (p trend = 0.005). After further adjustment for surgeon mild obesity was associated with 30% increased odds of capsular incision (OR 1.30, 95% CI 0.92 to 1.83), while moderate and severe obesity was associated with 57% increased odds of capsular incision (OR 1.57, 95% CI 0.82 to 3.00) relative to normal weight men (p trend = 0.06).

In a study of more than 7,000 men treated by 7 experienced surgeons BMI was positively related to capsular incision. This suggests that open retropubic RP is technically more difficult in obese men, which results in a greater likelihood of a less than technically ideal operation. Although this may be predicted to have a negative impact on disease-free survival outcomes in obese men, it is unlikely to alone explain the worse outcomes in obese men noted in previous RP series.