approximately 217,730 persons were diagnosed with prostate cancer in the united states in 2010 , which makes up 28% of all cancers in men . of the 217,730 persons
, 32,250 died , which is the second highest mortality rate of male cancers despite the small number when considering the number of people diagnosed .
therefore , risk assessment is essential in prostate cancer in both high - risk and low - risk patients to avoid the potential effects of additional treatment on quality of life .
proposed the cancer of the prostate risk assessment ( capra ) score , which is a prognosis - predicting method that uses age , clinical stage , prostate - specific antigen ( psa ) before surgery , biopsy gleason score , and malignancy ratio of the biopsy cores .
the accuracy of the capra score has been verified in the united states and europe [ 3 - 6 ] . however , the clinical stage , biopsy gleason score , and malignancy ratio of the biopsy cores , 3 of the variables that define the capra score , can overestimate or underestimate the actual stage or the range of cancer .
information on pathologic specimen gleason score ( pgs ) , surgical margin ( sm ) , extracapsular extension ( ece ) , seminal vesicle invasion ( svi ) , and lymph node invasion ( lni ) that can be obtained after prostate resection may help to assess the risk of cancer . accordingly , cooperberg et al .   proposed the capra - s score , which uses additional information that can be obtained after surgery and that can predict relapse of cancer accurately and easily .
the aim of the present study was therefore to assess the validity of applying the capra - s score , which is an assessment measure of biochemical recurrence ( bcr ) that uses histopathologic data after prostate cancer surgery , to koreans .
in 2011 , cooperberg et al .   analyzed the data of 3,837 patients who underwent prostatectomy in ucsf cancer of the prostate strategic urologic research endeavor ( capsure , university of california , san francisco , ca , usa ) to investigate the capra - s score and reported that it can be applied to the prediction of bcr after surgery and for determining suitable treatment .
on the basis of these findings , 203 prostate cancer patients who underwent radical prostatectomy between february 1997 and november 2010 were observed for longer than 6 months and the capra - s score of 134 patients for whom records for preoperative psa , pgs , sm , svi , ece , and lni were available were calculated .
bcr was defined as repetitive measurement of psa 0.2 ng / ml at least 6 months after surgery with at least a 4-week interval .
the purpose of the capra - s score is to predict bcr more accurately than with existing pathologic data .
the capra - s score was calculated by using psa , sm , svi , pgs , ece , and lni ( table 1 ) .
these variables were each verified for bcr by use of the cox proportional hazards regression model ( table 2 ) . for statistical analysis
, we used a cox proportional hazards regression model and kaplan - meier survival analysis by use of ibm spss ver . 18.0 ( ibm co. , armonk , ny , usa ) .
the 134 patients were divided into groups with a capra - s score of 0 , 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 and 9 , respectively , ( table 1 ) , and survival analysis was performed for each group ( fig .
16 patients had a capra - s score of 0 , 15 patients had a score of 1 , 13 patients had a score of 2 , 17 patients had a score of 3 , 12 patients had a score of 4 , 13 patients had a score of 5 , 11 patients had a score of 6 , 6 patients had a score of 7 , 11 patients had a score of 8 , and 20 patients had a score of 9 or higher . when the patients were divided according to capra - s score into 10 groups , the 5-year disease - free survival rate was predicted in each group differently . although the groups with scores of 4 and 8 showed different tendencies for 5-year disease - free survival from the other neighboring groups , overall , the 5-year disease - free survival rate decreased with increasing capra - s score ( p=0.03 ) ( fig .
sm positivity showed statistical significance with a hazard ratio ( hr ) of 1.663 ( p=0.048 ) , and pgs also showed statistical significance ( hr , 1.603 ; p=0.01 ) .
the survival rate was analyzed according to the capra - s score , with a score of 0 - 2 as the low - risk group , a score of 3 - 5 as the intermediate - risk group , and a score of 6 and higher as the high - risk group .
the 5-year disease - free survival rate differed significantly between the groups ( p=0.002 ) ( fig .
radical prostatectomy is done in more than one third of all patients diagnosed with prostate cancer . some of the patients scheduled for surgery experience bcr , and some of these patients experience clinical recurrence and metastasis , eventually leading to death .
variation in the postoperative psa level helps to identify high - risk patients , but there are demerits such as the need for repetitive tests and delayed initiation of some treatments such as radiation therapy and hormonal therapy . also , a number of high - risk patients , in whom only restricted pathological factors were considered , can avoid the morbidity caused by additional treatment because they do not progress after surgery [ 10 - 12 ]
recently , several models for predicting biochemical outcomes after prostatectomy have been reported , and the validity of the prediction formula suggested by bauer et al .
, the nomogram developed by kattan et al . , and the updated version of stephenson et al .   have been verified externally on the basis of standard clinical and pathological variables .
the c - index of these models is reported to be in the range of 0.77 to 0.86 , and the possibility of non - progression tends to be exaggerated in high - risk patients .
the original capra - s study reported by cooperberg et al .   showed relatively accurate distinction with a c - index of 0.77 [ 13 - 15 ] .
the c - index in the present study was 0.776 , which indicates that this score can predict the prognosis of prostate cancer in koreans very accurately .
the results , however , represent only relative risks , and continuous correction may be required with the use of additional clinical data .
two studies have directly compared the pretreatment capra score and the established popular nomogram ; one is a united states study that compared the capra score with the original kattan preoperative nomogram , and the other is a european study that compared the capra score with the updated preoperative nomogram of stephenson et al . [ 2,13 - 15 ] .
the accuracy of the capra score was shown to be similar to these nomograms in these two studies , but the capra score showed superiority in calibration and decision curve analysis in the european study [ 2,13 - 15 ] .
reported that the postoperative nomogram , which is different from the capra - s score , shows similar distinction when looking at the calculation by c - index , and the capra - s score showed superiority in calibration and decision curve analysis [ 13 - 15 ] .
reported that although the capra - s score shows a tendency of relatively many patients converging in the lower score , there was wider patient distribution than the original pretreatment capra score .
therefore , the capra - s score is expected to be more useful for understanding the risk of recurrence and the availability of adjuvant therapy .
the capra - s score shows more diverse score distribution compared with the capra score , which is the preoperative recurrence prediction score , and the capra - s score can be said to be more useful than the capra score at predicting the recurrence risk or determining whether to perform adjuvant therapy because the clinical staging , biopsy gleason score , and malignancy ratio of the biopsy cores used in the capra score can overestimate or estimate the actual stage or range of cancer [ 2,9,16 - 18 ] .
however , it has to be acknowledged that lni , which is expected to have more influence on recurrence , only contributes 0 to 1 points in the capra - s score despite the fact that the original capra - s score is a pathologic record recorded with various subjective criteria by several pathologists .
it seems that although the actual lni rate is high , lymph node dissection is done restrictively even in high - risk patients in the united states , where the capra - s score was devised .
thus , the score contributed by lni has been limited to minimize the effects of unknown lni [ 19 - 21 ] .
therefore , active lymph node dissection as well as giving more contributable points to lni in the capra - s score must be considered for a more accurate capra - s score in koreans .
the groups with a capra - s score of 4 and 8 showed different tendencies for the 5-year disease - free survival rate from other neighboring groups .
however , it is estimated that this arose as a statistical error owing to the small population number and also owing to the nonequality of score distribution of lni mentioned before .
however , a significant difference was shown when the capra - s score divided into low - risk ( 1 - 2 ) , intermediate - risk ( 3 - 5 ) , and high - risk ( 6 ) groups , which is easier for clinical application ( p=0.002 ) ( fig .
although bcr does not necessarily correlate with the ultimate mortality of prostate cancer , the capra - s score is expected to be able to predict cancer - specific mortality , and it is also expected to be used to predict cancer - specific and overall mortality through accumulation of more patient data and partial correction and supplementation in the future .
application of the capra - s score in koreans is significant in that it becomes easier to apply in practice by objectively charting the prediction of prognosis , which is partially dependent on empirical data .
the capra - s score can be easily calculated with data on several variables and can be applied to predicting postoperative recurrence and classifying high - risk patients who need adjuvant therapy . however , the relatively few data compared with the united states .
 purposeto evaluate the validity of the university of california san francisco cancer of the prostate risk assessment - s score ( capra - s score ) , a biochemical indicator of recurrent prostate cancer that uses histopathologic data , in korean prostate cancer patients.materials and methodsa total of 203 prostate cancer patients who underwent radical prostatectomy between february 1997 and november 2010 were observed for longer than 6 months . the capra - s score of 134 patients for whom records were available for preoperative prostate - specific antigen ( psa ) , pathologic specimen gleason score , surgical margin , seminal vesicle invasion , extracapsular extension , and lymph node invasion were calculated . 
 biochemical recurrence was defined as repetitive measurement of psa 0.2 ng / ml at least 6 months after surgery with at least a 4-week interval . the cox proportional hazard model and kaplan - meier analysis were used for the statistical testing.resultsthe capra - s scores were divided into nine groups . 
 the 5-year disease - free survival rate was reduced as the capra - s score increased compared with the group with a capra - s score of 0 - 1 . 
 the capra - s score in this study was more sensitive to biochemical recurrence than was the capra score conducted at this institution ( capra - s concordance index , 0.776 ; capra concordance index , 0.728).conclusionsthe capra - s score is judged to be a useful tool for predicting the disease - free survival rate of korean prostate cancer patients and is thought to assist in establishing postoperative management . 
INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
CONCLUSIONS