Obesity does not predict risk for biochemical failure after RP
Posted Sep 28 2008 1:49pm
According to Motamedinia et al., in an analysis of over 700 patients treated with radical prostatectomy (RP) for localized disease between 1988 and 2006, obesity does not contribute to prediction of risk for biochemical failure for a given tumor stage, grade, or prostate specific antigen level.
One in three American men is now defined as obese (defined as a body mass index ≥ 30 kg/m 2 ). Because the relationship between obesity and prostate cancer has been much debated, the authors decide to examine body mass trends in patients undergoing RP over time and evaluate whether obesity had any role in predicting biochemical failure after RP.
Between 1988 and 2006, there were 964 patients who underwent RP at the authors’ institution and for whom body mass data were available. Patients who had received neoadjuvant therapy or who were followed up for < 1 year were excluded, yielding 702 patients who were grouped by body mass and stratified by year of surgery. The postoperative Kattan nomogram was then used to assess their risk for biochemical failure after RP.
The following results were obtained:
The mean body mass and the proportion of patients undergoing RP who are obese have both increased, in parallel with, but less than, national trends.
Our obese patients had higher grade cancer and showed a trend toward having a more advanced pathologic stage.
Obese patients had a lower predicted rate of biochemical progression-free survival at 7 years (74.3 vs 80.1 percent).
There was no difference between the actual, observed rates of biochemical failure for the obese and non-obese patients (P = 0.48).
Obesity was not an independent predictor of biochemical failure.