Clinical Significance of F/T PSA Ratio in Advanced Prostate Cacner 151 FIG. 1. The pattern of change in the free-to-total prostate-spe- cific antigen ratio between the two groups during hormone treatment. a: p＜0.001. to progression to CRPC was 15 months (IQR, 12 to 24 months). There were 24 patients in group 1 and 28 patients in group 2. There were no significant differences in the me- dian age, lymph node invasion, bone metastasis, initial PSA, initial f/t PSA ratio, or time to PSA nadir between the two groups. The median Gleason score was 8 (IQR, 7 to 9) in group 1 and 6 (IQR, 6 to 8) in group 2, which was statisti- cally significant. The median nadir f/t PSA ratio was 90.00% (IQR, 80.00 to 90.00%) in group 1 and 60% (IQR, 30 to 60%) in group 2. Fig. 1 shows the change in the f/t PSA ratio between the two groups. After PSA nadir, the median f/t PSA ratio of group 1 and group 2 increased from 37% (IQR, 30 to 76%) and 34% (IQR, 19 to 60%) at 3 months from the initiation of therapy to 75% (IQR, 40 to 87%) and 60% (IQR, 60 to 61%) at 6 months, respectively. There was no significant differ- ence in the median f/t PSA ratio between the two groups. However, at 9 months, an increase in the ratio to 80% (IQR, 55 to 100%) was observed in group 1, whereas a decrease to 31% (IQR, 30 to 42%) was noted in group 2 (p＜0.001). After 12 months, the ratio showed a tendency to decrease in both groups from 75% (IQR, 50 to 97%) to 37% (IQR, 27 to 90%) in group 1 and from 27% (IQR, 20 to 40%) to 20% (IQR, 10 to 28%) in group 2 (p＜0.001 and 0.001, re- spectively). The difference in the median f/t PSA ratio be- tween the two groups was significant from 9 to 15 months after the time of PSA nadir. The probability of progression to CRPC during the fol- low-up period is illustrated in Fig. 2. The number of cases involving progression to CRPC was 10 in group 1 and 24 in group 2 (p=0.002). The median time to CRPC in both groups was 15 months (IQR, 12 to 24 months and 12 to 24 months, respectively), and it was not significantly different as shown in Table 1 (p=0.792). FIG. 2. The probability of progression to castration-resistant prostate cancer (CRPC) during hormone treatment in the two groups. DISCUSSION In the United States, prostate cancer has the highest in- cidence of all noncutaneous malignancies and has the sec- ond-highest mortality rate in men [1]. Advances in screen- ing and diagnostic techniques have resulted in a downward migration of stage [13]. In Korea, however, more than half of newly diagnosed prostate cancer is already of a locally advanced or metastatic stage [5]. Hormone therapy is the standard treatment for ad- vanced prostate cancer [6,14]. Nonetheless, the timing of hormonal treatment in advanced prostate cancer remains controversial [6]. Although radical prostatectomy and ra- diation therapy have been recommended in localized ad- vanced prostate cancer [15-18], Heidenreich [19] reported that hormone treatment has benefits in high-risk patients, such as those with poorly differentiated prostate cancer (Gleason score of 8 to 10) and those with a very short PSA doubling time (＜12 months). Also, Park et al. [5] reported that many of those with advanced prostate cancer have been treated with hormone treatment for various reasons, such as failure of surgical or radiation treatment, age at the time of diagnosis, or socioeconomic status. However, most patients with advanced prostate cancer who have received hormone treatment eventually progress to CRPC, despite the maintenance of castration serum testosterone levels [8]. In the present study, patients treated with hormone treatment showed biochemical improvements, with PSA decreasing to 0.01 ng/ml or lower in an average of 6 months, as well as progression to CRPC in an average of 15 months. Therefore, it is important to detect patients who may show early progression to CRPC and to perform other salvage therapies, including secondary hormone therapy, chemo- therapy, and radiation therapy, early. Although the pathophysiology of prostate cancer has not been elucidated completely, well-known prognostic factors include age, Gleason score, bone pain, serum hemoglobin level, PSA nadir, time to PSA nadir, and PSA level 3 months Korean J Urol 2012;53:149-153