[Impact of obesity on PSA in prostate cancer screening]

Obesity is associated with changes of serum levels of androgens and oestrogens which could modulate prostate metabolism. The objective of this study was to investigate a possible correlation between the PSA level and the degree of obesity in a candidate population for prostate cancer screening in order to determine whether the PSA level needs to be adapted before performing biopsy.

During a screening campaign in a French district, serum PSA results and body mass index (BMI) were available for 541 men. These men were divided into 4 groups of corpulence: Normal (BMI < 25), Overweight (25 < or = BMI < 30), Stage I obesity (30 < or = BMI < 35), Stage II + III obesity (BMI > or = 35). The PSA levels of these various groups were compared, and a correlation between BMI and PSA was investigated.

The mean PSA in each group was inversely proportional to BMI, with mean PSA levels of 3.7, 2.9, 2.6 and 1.5 for Normal, Overweight, Obesity I and Obesity II + III groups, respectively. A significant difference was observed between these groups (p = 0.03) and an inverse correlation was also observed between BMI and PSA (r = 0.1, p = 0.01).

In a population submitted to prostate cancer screening, PSA is lower as BMI increases. An adaptation of the PSA screening cutoff value according to BMI should be investigated.