Are IPCa Really Insignificant in Korean Men? and that they underestimated the disease stage and/or grade in 16% of USA patients.4 Another study reported that 24% of male European patients who fulfilled the Epstein criteria for presence of clinically insignificant prostate cancer were incorrectly classified as having clinically IPCa.12 Gleason 7-10 prostate cancer at radical prostatectomy was found in 24% patients with clinically IPCa. The pathological charac- teristics of these 24% might actually represent an absolute contraindication to active surveillance or similar treatment modalities that are usually applicable for men with clinical- ly IPCa. Lee, et al.6 reported an inaccuracy of the Epstein criteria of up to 30.5% in Korea. In our study, the inaccura- cy of the Epstein criteria of our study was 42.1% and this is, to our knowledge, the highest reported value. This high inaccuracy rate of the Epstein criteria might be due to more aggressive and poorly differentiated prostate cancer in Ko- rean men, despite a low clinical stage or low serum PSA level.13 Also, Man, et al.14 reported that a greater proportion of Asian patients present high risk prostate cancer than non Asian men. There were twice the percentage of Asian pa- tients with Gleason scores 8 or greater than nonAsians at presentation. Prostate cancer of predominantly high grade in Korean men may be attributed to reduced testosterone metabolism. Hoffman, et al.15 illustrated that patients with a low serum-free testosterone level have an increased mean percentage of biopsies revealing cancer with a Gleason score of 8 or higher, suggesting that a low serum-free tes- tosterone level may be a marker of more aggressive disease. In our current study, however, we are not certain whether there exists a relationship between aggressiveness of PCa and serum testosterone level. This hypothesis should be in- vestigated in a future study. In our study, PSA density was found to be a prognostic factor for clinically IPCa. The incidence of prostate cancer in the low PSA (2.5-4.0) group was reported to be more than 20% in Korea.16 Furthermore, PCa detected by biopsies with low PSA levels have been shown to be clinically significant, and there are no differences in pathologic stage and Gleason pattern between the preoperative low PSA and high PSA groups after radical prostatectomy.16-18 This implies that there are no definite preoperative variables for a diagnosis of clinically IPCa, thus confusing the diagnosis and treatment. Additional novel markers might be needed in order to ele- vate the predictive accuracy of the Epstein criteria. Besides the high inaccuracy rate of the Epstein criteria in our study, the criteria showed no change of incidence of an upgrade from IPCa to significant one after radical prosta- 50 45 40 35 30 25 20 15 10 5 0 Upgrading IPCa 2004-2005 2006-2007 2008-2009 Fig. 1. Incidence of insignificant prostate cancer after prostate biopsy and upgraded pathology after radical prostatectomy. IPCa, insignificant pros- tate cancer. tectomy. However, Chun, et al.19 found that the rate of up- grading decreased over time, from 52% to 27%, between 1992 and 2004. These contradictory results might result not only from different races, more aggressive tumor character- istics as compared to Western men,12 and environmental conditions, but also from the study design. Our study was carried out by a single surgeon and a single pathologist at a single institute, therefore, the quality of the data may be more homogenous than previous studies. Because the incidence and mortality of PCa differ accord- ing to race and dietary habits, the accuracy of the Epstein criteria of studies in Asian countries is unlikely to be as ac- curate as other countries. This is very meaningful in deter- mining the early stage treatment of PCa after a prostatic bi- opsy. Recently, there have been various treatment options developed for early prostate cancer, such as active surveil- lance, surgical treatment or radiation therapy.20 The optimal treatment of early PCa has been controversial; however, our present results indicate that caution should be advised when treatment decisions are based solely on the Epstein criteria, especially in Korea. This study has several limitations. First, this is a retro- spective study with a relatively small number of patients en- rolled, as it was conducted at a single institution. However, it should be noted that our cohort from a single surgeon may elevate the reliability of the results. Furthermore, con- sidering the large difference in prostate cancer incidence between Korean and Western men, the number of men in the present series should not be considered too small for a single institution.6 Furthermore, as follow up was limited, we could not assess the biochemical recurrence or progno- sis, which may be a more important issue than the presence of unfavorable pathological features.6 Further investigation Yonsei Med J http://www.eymj.org Volume 53 Number 2 March 2012 361