Body mass index and prognostic markers at radical prostatectomy

Obesity is increasing rapidly in Western countries. Approximately 40% of adult Danes are overweight and approximately 15% of these are obese. Epidemiological studies of obesity in relation to prostate cancer have provided conflicting results. Therefore, we examined correlations between body mass index (BMI) and clinicopathological prognostic markers, biochemical recurrence and operative morbidity in patients who had undergone radical prostatectomy.

The sample consisted of 293 Danish men treated with radical prostatectomy between 2000 and 2005 at Aarhus University Hospital. BMI was calculated as an indicator of obesity. Prospectively collected clinical and pathologic data from this population were used.

The median BMI value was 26.2 kg/m(2) (range 19.6-41.7 kg/m(2)), which is slightly above the upper limit of normal. Currently accepted prognostic markers, such as prostate-specific antigen level, Gleason score and pT class, showed no statistically significant correlations with BMI. Patients with biochemical recurrence were evenly distributed among four different BMI quartiles and there was no difference in the length of hospitalization, indicating no differences in pre- or postoperative morbidity. Computations were repeated using only patients with the lowest (19.6-21.3 kg/m(2)) and highest (34.2-41.7 kg/m(2)) BMI values but statistically significant correlations were still not found.

Several American studies have shown that obesity can lead to prostate cancer becoming more aggressive. The results of the present study involving a Danish prostate cancer population do not substantiate this or suggest any connection between BMI and operative morbidity. A possible explanation is that Danish obesity problems are not yet as severe as those in the USA.