Distribution of serum prostate-specific antigen in healthy Korean men: influence of ethnicity.

Objectives: To evaluate the normal distribution of serum prostate-specific antigen (PSA) levels in healthy Korean men. The subjects included men younger than 40 years of age, because information on serum PSA levels in younger men is scarce.

Methods: Between January 1997 and December 1998, the serum PSA levels of the subjects who visited our hospital for a routine health checkup were determined. All men who were older than 50 years with abnormal digital rectal examination findings and/or an abnormal serum PSA level (greater than 4.0 ng/mL) underwent transrectal ultrasound-guided sextant biopsy. Two men who were found to have cancer were excluded from the analysis. The detection rate of prostate cancer for men with abnormal digital rectal examination findings and/or an abnormal serum PSA level was 2.0% for men 50 to 59 years old; 0.0% for men 60 to 69 years old; and 11.1% for men 70 to 79 years old. A total of 8297 men (aged 20 to 79 years) were included in the study.

Results: The median serum PSA level (5th to 95th percentile range) was 0.90 ng/mL (0.33 to 2.25) for men 20 to 29 years old; 0.89 ng/mL (0.30 to 2.35) for men 30 to 39 years old; 0.89 ng/mL (0.30 to 2.36) for men 40 to 49 years old; 0.96 ng/mL (0.32 to 2.96) for men 50 to 59 years old; 1.22 ng/mL (0.33 to 3.78) for men 60 to 69 years old; and 1.25 ng/mL (0.30 to 7.49) for men 70 to 79 years old. The median and 95th percentile serum PSA levels of Korean men younger than 50 years were higher, but those for men 50 years old or older were lower than in other races. In our study cohort, the serum PSA level weakly correlated with age (r = 0.088, P <0.001). The serum PSA level weakly correlated with age in men 50 years old or older (r = 0.116, P <0.001) but in men younger than 50 years, it did not correlate (r = 0.000, P = 0.987).

Conclusions: These results suggest that the distribution and cutoff value of the serum PSA level in Korean men differ from those in other races. In addition, our findings raise the question of whether lowering the PSA cutoff may enhance the detection of cancer in this population with low prostate cancer rates.