Effect of hemodilution on prostatic specific antigen in obese men.

LÓPEZ LAUR JD; PEREZ ELIZALDE R; DI MILTA N; MASELLI ME; VANRELL C; RECALDE GM; UVILLA A; MESSINA D; CORICA AP; LÓPEZ FONTANA C

Chicago (Illinois), Estados Unidos

Congreso; AUA annual meeting.; 2009

American Urological Association

Se adjunta poster y publicación.Introduction and objetive: Recent studies point out that obese men have a lower serum prostatic specific antigen (PSA) concentration than men with a normal weight, probably due to a lower androgenic activity and /or a greater plasma volume (hemodilution)that hinder the early diagnosis and detection of prostatic cancer (CaP) in these patients. The objective was to determine the relation between the body mass index (BMI), hemodilution and screening PSA in CaP. Methods: 243 men aged 40-80 years old were chosen.The study consited in the assessment of body composition by means of anthropometry (weight, height and BMI) and a laboratory test including a complete blood count and measure of PSA concentration (ng/ml). The total circulation PSA protein (PSA mass ) was calculated as PSA concentration multiplied by plasma volume. The statistical analysis was made with Anova and Pearson´s correlation coefficient and the statistical significance was established with a p<0.05. Results: The average age was 57.25 + 0.59 years old and the mena BMI was 28.57 + 0.26 kg/m2. Normal weight subjects (BMI 20-25kg7m2; n=43) showed a mean PSA of 1.19 + 0.14 ng/ml; overweight pacients (BMI 25-30 kg/m2; n=133) had a PSA of 1.19 + 0.07 ng/ml; while obese I subjects (BMI 30-35kg/m2; n=54) showed a PSA of 0.96 + 0.9ng/ml; and obese II volunteers (BMI > 35kg/m2; n=13) had a PSA of 0.8 + 0.1 ng/ml. A higer BMI was significantly associated with a lower PSA concentration (r=-0.17;p=0.0009) and with a greater plasma volume (r=0.64;p=0.001). Finally, the PSA mass did not change significantly with the BMI (p=0.12).  Conclusion: Obese subjects show a greater plasma volume but the same PSA mass; this points out that hemodilution could be responsible for the lower serum PSA concentration. We can infer, then, that obese patients should undergo a biopsy in the presence of a lower serum PSA concentration allowing an earlier diagnosis of CaP in this group of people.