Prostate cancer detection: The impact of obesity on Asian men

To evaluate the impact of body mass index (BMI) on prostate cancer detection in biopsy-naive men presenting to a single tertiary hospital in Singapore.

We retrospectively examined 458 men who underwent initial prostate biopsies between January 2012 and April 2014. Indications for biopsy were serum prostate-specific antigen level≥4.0ng/ml, or digital rectal examination findings suspicious for malignancy, or both. Only men with serum prostate-specific antigen level <20ng/ml were included. BMI categories were based on the World Health Organization recommendations (normal:<25.0, overweight: 25.0-29.9, and obese: ≥30).

Of the 458 men included in our cohort, 125 (27.3%) men were positive for prostate cancer on biopsy, with 69 (15.1%) being clinically significant (Gleason≥7). Men with BMI≥25kg/m(2) (41.7%) were younger (67.2 vs. 68.8y, P = 0.030), had larger prostates (45.5 vs. 40.1g, P = 0.014), and were more likely to have a positive biopsy finding (34.6% vs. 22.1%, P = 0.003). On multivariate analysis, being overweight or obese was associated with increased risk of having prostate cancer on biopsy (odds ratio [OR] = 2.61, 95% CI: 1.58-4.30, P<0.001 and OR = 3.26, 95% CI: 1.37-7.73 P = 0.007, respectively). The same trend was observed for clinically significant cancers but not for clinically insignificant cancers (OR = 3.57, 95% CI: 1.87-6.82, P<0.001 and OR = 3.86, 95% CI: 1.33-11.21, P = 0.013 for being overweight and obese, respectively).

Asian men with BMI≥25kg/m(2) are at greater risk of having a positive initial biopsy result. The BMI threshold (BMI≥25kg/m(2)) for Asian men to be at increased risk of prostate cancer detection on initial biopsy is lower than that of Western populations (BMI≥30kg/m(2)).