268 the overall bone scan stage is that the result should not impact our decision to recommend patients for prostatec- tomy. By applying the EAU or AUA guideline [3, 4], 3.6% (21/579) patients in our study would have not been detected with bone metastasis at proper time. Recently, Briganti et al. [14] suggested that staging bone scans might be con- sidered only for patients with a biopsy GS > 7 or with PSA > 10 ng/mL and palpable disease (cT2/T3) prior to treatment (AUC range: 88.0%; P < 0.002). Similarly, AUC increased from 0.640 with PSA > 20 ng/mL to 0.828 with PSA > 10 ng/mL. These results suggest that skeletal screening may be required even for patients with a serum PSA level between 10 and 20 ng/mL. In contrast to other studies conducted in Western coun- tries, a multi-center retrospective study conducted in Japan revealed that bone metastasis was common in Japanese patients with newly diagnosed untreated prostate carcinoma with an overall positive rate of 22.2% on bone scans [8]. Moreover, Ito et al. [15] found 303 patients with CaP and 36 with bone metastasis among 9,671 patients. Among those with bone metastasis, 13 patients (36%) had PSA lev- els of 10 ng/mL or less. The incidence of positive bone scan in a patient group with low PSA levels is much higher than the other studies in the Western countries. In a Hong Kong study, Lai et al. [11] recommend omitting bone scan if serum PSA is 10 ng/mL or less. If imaging had been denied only to patients with a PSA level of 20 ng/mL or less, imag- ing sensitivity would have decreased to 94%. Our data are inconsistent when applied to AUA or EAU guideline. Our results might be due to more aggres- sive and poorly diVerentiated PCa in Korean men, despite a low clinical stage or low serum PSA level [16]. In another report, twice as many Asian men had a GS of 8 or greater, the worst stage at presentation, and were, accordingly, classiWed as being at high risk, as compared with non-Asian men [17]. PSA expression is strongly inXuenced by androgens [18]. Thus, hypogonadal men with low testosterone levels may show low serum PSA levels because of decreased expression, and their serum PSA may not reXect the presence of prostate disease such as cancer [19]. Asian males tend to have lower total serum testosterone and hormone-binding levels, a reduc- tion in 5-alpha-reductase levels, and lower testosterone production rates compared with white men [20]. A pre- vious investigation involving a large number of healthy Japanese [6], Chinese [21], and Korean [9] men showed a lower median value of serum PSA for Asian men than that for Caucasians. 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