ABSTRACT
PURPOSE: Many physicians now use serum prostate specific antigen(PSA) to screen the prostate cancer in asymptomatic men. Normal distribution of PSA values was determined and age-related serum PSA ranges were well established in the white. Until recently, studies conducted to establish the normal serum PSA values have involved few Asian populations. We aimed to establish normal distribution of serum PSA levels in Korean men and to elucidate PSA variation among different races by comparing this result with those of Caucasian and Japanese. MATERIALS AND METHODS: Between May 1995 and June 1997, 5,805 healthy Korean men aged 30 to 79 years who visited our hospital for regular health checkup were entered a prospective study for early screening of prostate cancer. All men underwent detailed clinical examinations including digital rectal examination(DRE) and serum PSA determination. Any man who was over 50 years old with an abnormal DRE and/or elevated serum PSA(>4.0ng/ml) underwent transrectal ultrasonography(TRUS). Twenty seven men underwent a TRUS-guided sextant prostatic biopsy and 4 were found to have cancer who were excluded from this analysis. RESULTS: Median serum PSA concentration is 0.77ng/ml for 4th decade(n=1,382); 0.78ng/ml for 5th decade(n=1,776); 0.85ng/ml for 6th decade(n=1,775); 1.03ng/ml for 7th decade(n=746); 1.32ng/ml for 8th decade(n=122). Serum PSA concentration is correlated with age(p<0.01) with increase by approximately 0.019ng/ml per year, but its statistical correlation was weak(r=0.14). There were almost no change in median PSA concentration and 95th percentile values until 50 years of age, while gradual increase over ages in fifties. The age-specific ranges of median serum PSA of Korean males were lower than those of Caucasian and a little higher than those of Japanese whose ages were fifties and sixties. Ninety fifth percentile value of serum PSA for Korean men were lower than those of Caucasian or Japanese up to age in sixties but were higher in age in seventies than that for Japanese. CONCLUSIONS: Contrary to earlier observations that serum PSA is strongly correlated with age, the influences of age on serum PSA are thought to be weaker in Korean. These findings imply that serum PSA levels in Korean males associated with prostate disease may be lower than that of Western male. These characteristics might not have the potential to make the age-specific serum PSA range more discriminating for detecting clinically significant cancers in Korean.