Association of body mass index with prostate cancer biochemical failure

The association between obesity and biochemical failure measured by prostate specific antigen after prostate cancer treatment is controversial. We determined whether there is an association between body mass index and biochemical failure in men treated for low and intermediate risk prostate cancer with various treatment modalities.

We performed a cohort study in 2,687 patients who underwent treatment for low and intermediate risk prostate adenocarcinoma as described by National Comprehensive Cancer Network guidelines at Cleveland Clinic between January 1996 and December 2005. Univariate and multivariate analyses were done to determine the effect of multiple patient characteristics on biochemical failure.

There were 319 biochemical failures (11.9%). Body mass index as a continuous variable was significantly associated with biochemical failure on univariate analysis (HR 1.030, p = 0.02). There was a significant association with biochemical failure when comparing normal vs overweight and normal vs obese men but not overweight vs obese men. On multivariate analysis body mass index as a continuous or a categorical variable was not significantly associated with biochemical failure. Multivariate analysis revealed certain variables significantly associated with biochemical failure, including black race, greater initial prostate specific antigen, Gleason score 7, treatment type and more frequent prostate specific antigen screening.

We found a significant association between body mass index and biochemical failure on univariate analysis that did not hold true on multivariate analysis. Black race was associated with biochemical failure on multivariate analysis. The reason for this is unclear. Future studies should further characterize the relationship between race and biochemical failure.