The relationship between adiposity and gleason score in men with localized prostate cancer

We investigated the relationship between body mass index (BMI) at the time of cancer diagnosis and malignant phenotype as measured by Gleason score.

This was a population-based cross-sectional study conducted on 1,096 prostate cancer patients treated for cure in Ontario, Canada between 1990 and 1998. An electronic-linked data set was enhanced by retrospective chart review. BMI was categorized as: normal (BMI <25.0), overweight (BMI 25.0-29.9), and obese (BMI ≥30). We also investigated the role of diabetic status. Gleason scores were categorized as: 2-4, 5-6, 7, and 8-10. We assessed the effect modification by patient age.

BMI was not associated with Gleason score; 9.7% of those with normal BMI had a Gleason score ≥8, and 9.4% fell into this Gleason category in both the overweight and obese groups (P = 0.73). 11.7% of diabetics had a Gleason score ≥8 compared to 9.3% in the non-diabetic group (P = 0.79). Both of these results persisted in a multivariate analysis controlling for age and diagnosis year. When stratified by age, only the Gleason score distribution in the youngest cohort (50- to 59-year olds) indicated higher Gleason scores in the obese group, with marginally significant results (P = 0.16).

With a possible exception in younger men, elevated BMI at the time of diagnosis does not appear to be associated with aspects of aggressive behavior associated with Gleason grade. The effect of adiposity on prostate cancer outcome is complex, requiring further study that includes attention to factors such as length of exposure, concomitant co-morbidities, and ethnicity.