Interrelationship among Age, Prostate Specific Antigen and Prostate Volume in Korean Men Living at the Metropolitan Area

Lee, Sang Eun; Kim, Dae Young; Kwak, Cheol

Abstract

PURPOSE: We aimed to investigate normal distributions of serum PSA and prostatic volume according to age and interrelationship among age, PSA, and prostatic volume in Korean men living at the metropolitan area.
MATERIALS AND METHODS
Eight hundred and forty-seven Korean men living at the metropolitan area participated in the BPH awareness program completed digital rectal examination, IPSS questionnaire, uroflowmetry and transrectal ultrasonography and 351 men had measurement of serum total PSA and free PSA concentration. The men who had conditions(except BPH) known to interfere with normal voiding were excluded from analysis. As a result, 618 men formed the study population on which all analyses were performed. Descriptive statistics were calculated for the entire study cohort and different age groups for the prostate volume, serum PSA levels, percent free PSA and PSAD. Normogram portraying the distribution of prostate volume and total PSA levels as a function of age were generated based on the least-squares regression models.
RESULTS
Age was correlated directly with prostate volume(r=0.32, p<0.0001), serum PSA level(r=0.21, p<0.0001) and percent free PSA(free/total PSA, r=-0.15, p<0.05). Median prostate volume(5-95th percentile) was 21.4(15.5-32.9)ml for less than 50 years(n=47); 24.7(14.0-41.3)ml for 50-59 years(n=162); 27.7(13.9-49.8)ml for 60-69 year(n=264); 33.0(14.6-64.7)ml for more than 70 years(n=145). Percentage of the men with prostate volume of greater than 40ml was 15.2%(94/618) for the all population; 0%(0/47) for less than 50years; 6.0%(10/162) for 50-59 years; 14.0%(37/264) for 60-69 years; 32%(47/145) for more than 70 years. Serum PSA was directly propotional to the total prostate volume(r=0.46, p<0.0001).
CONCLUSIONS
Our study confirmed the earlier observations that prostate volume, serum PSA and percent free PSA are age-dependent and serum PSA is propotional to the prostate volume. When we compared age-adjusted prostate volume with different races, prostate volume for Korean was smaller than that for Caucasian and larger than that for Japanese. The proportion of large prostate more than 35ml and 40ml that is suitable candidate for 5-alpha reductase inhibitor therapy was 24.4% and 15.2% of all men respectively. We hope that this study would be a basic guideline for the management of BPH and early detection of prostate cancer in Korean men.