Probability of prostate cancer on biopy according to serum PSA level in Korean men : Is there any racial difference ?

초록

Introduction: The incidence of prostate cancer is increasing in Korea. However comparing with western people the incidence is relatively low. It may result from a different kind of food: Koreans like vegetables and soy beans. The size of prostate in Korean is also smaller than that of Caucasian or African American. The detection rate of prostate cancer according to serum PSA level is thought to be lower in Korean men, but is not yet known. We reviewed prostate biopsies retrospectively and evaluated the probability of prostate cancer on biopsy according to serum PSA level in Korean men. Material and methods: We reviewed 2,287 Korean men who had prostate biopsy retrospectively. In case that PSA level is lower than 4ng/ml, patients with abnormal DRE or abnormal image on TRUS were performed prostate biopsies. Result: Of the 2287 men, 39.6% had a positive biopsy. In PSA level less than 4 ng/ml, 12.4% of men had prostate cancer. In PSA level between 4 and 10 ng/ml, the detection rate of prostate cancer was 16% (137/2287). This rate is similar with that of Japanese (15.8 %) and quite different from that of Americans (25%). In PSA level above 10, 59.4% of men had a positive biopsy. For values of PSA under 20 ng/ml, 20.1% (308/1533) had a positive biopsy. Among 308 cancer patients whose PSA level under 20 ng/ml 9.7% of patients were found out stage D diseases. For PSA of > 4 ng/ml, positive and negative predictive values were 42.0% and 87.6%, respectively. For PSA of > 10 ng/ml, positive and negative predictive values were 59.1% and 84.6%, respectively. Conclusion: The probability of prostate cancer according to PSA level in oriental people is different from that of Caucasians especially in gray zone. And bone scan should be performed in patients with PSA level under 20 ng/ml because one of 10 prostate cancer patients under 20 ng/ml of serum PSA can have a distant metastasis.