soft tissue sarcomas ( stss ) are a heterogeneous group of solid tumors that arise from embryonic mesenchymal cells and that have distinct clinical and pathological features .
microscopically , arcinosarcomas are biphasic tumors comprising an intimate admixture of carcinomatous and sarcomatous components with an abrupt or gradual transition from one to the other .
stss of the genitourinary ( gu ) tract are relatively rare , accounting for only 2.1% of all stss and 1% to 2% of all malignant gu tumors [ 1 - 3 ] .
because of the rarity of urological stss , clinical data are limited and prognosis is often considered unpredictable .
recently , several groups have reported their long - term experiences with gu stss and have investigated prognosis and prognostic factors [ 4 - 6 ] .
although the consensus is that total surgical resection provides the patient the best chance for cure , there is no universal agreement concerning prognostic factors for gu stss .
several analyses of prognostic factors influencing the overall survival ( os ) of patients with gu stss have revealed that tumor stage , grade , size , and anatomic site are important for patient survival . to the best of our knowledge , no prior study has investigated clinical outcomes and prognostic factors of gu stss in a korean patient population . in this study , we investigated prognostic factors of gu stss on the basis of 28 years of experience with these tumors at a single center in korea .
between january 1982 and july 2009 , 48 patients who were histologically diagnosed with a gu sts at our institute were included in this study .
sarcomas of the gu tract that originated from the kidney , ureter , bladder , prostate , paratesticular region , and retroperitoneum were included .
sarcomas that originated from female genital organs such as the uterus , ovary , vulva , or vagina were excluded from this study .
demographic and clinical data were retrieved by reviewing patients ' charts , clinical data , operative notes , radiological reports , and pathological reports .
the variables analyzed were patient age , sex , tumor histology , tumor size , primary organ , metastasis at diagnosis , and status of surgical resection .
tumors were divided into two groups on the basis of size : one group comprised tumors smaller than 5 cm , and the other comprised tumors larger than 5 cm . local recurrence or metastasis
was defined as the first recurrence of disease at the primary tumor site or distant site detected by a radiographic modality , such as computed tomography .
univariate analysis of variables to determine prognostic factors was performed by using the log rank test .
the results of the cox model analysis are reported as hazard ratios and 95% confidence intervals .
the kaplan - meier estimate of the survival curve was used to summarize the data , whereas differences between patient groups were assessed by the log rank test .
between january 1982 and july 2009 , 48 patients who were histologically diagnosed with a gu sts at our institute were included in this study .
sarcomas of the gu tract that originated from the kidney , ureter , bladder , prostate , paratesticular region , and retroperitoneum were included .
sarcomas that originated from female genital organs such as the uterus , ovary , vulva , or vagina were excluded from this study .
demographic and clinical data were retrieved by reviewing patients ' charts , clinical data , operative notes , radiological reports , and pathological reports .
the variables analyzed were patient age , sex , tumor histology , tumor size , primary organ , metastasis at diagnosis , and status of surgical resection .
tumors were divided into two groups on the basis of size : one group comprised tumors smaller than 5 cm , and the other comprised tumors larger than 5 cm . local recurrence or metastasis
was defined as the first recurrence of disease at the primary tumor site or distant site detected by a radiographic modality , such as computed tomography .
univariate analysis of variables to determine prognostic factors was performed by using the log rank test .
the results of the cox model analysis are reported as hazard ratios and 95% confidence intervals .
the kaplan - meier estimate of the survival curve was used to summarize the data , whereas differences between patient groups were assessed by the log rank test .
during the study period , 48 patients with gu stss were treated at our institution .
the mean age at diagnosis was 47.1 years ( range , 3 to 80 years ) .
the mean follow - up duration was 43.6 months ( range , 6 to 167 months ) .
the most common site was the retroperitoneum ( n=16 , 33.3% ) followed by the kidney ( n=12 , 25% ) , prostate ( n=10 , 20.8% ) , bladder ( n=7 , 14.5% ) , ureter ( n=1 , 2% ) , and paratesticular region ( n=1 , 2% ) .
the mean tumor size was 9.5 cm ( range , 2.2 to 24 cm ) and 43 patients ( 89.5% ) had tumors larger than 5 cm .
the histological subtypes of sarcoma were as follows : leiomyosarcoma ( 24 , 50% ) , rhabdomyosarcoma ( 9 , 18.7% ) , and liposarcoma ( 4 , 8% ) .
of the 48 patients , 33 ( 68.7% ) underwent surgical resection and 15 ( 31.2% ) were treated by chemotherapy , radiotherapy , or both . at the time of analysis ,
20 patients ( 41.6% ) had died of their sts , 2 patients ( 4.1% ) had died of unrelated causes , and 26 patients ( 54.1% ) were alive .
the 5-year estimated survival rate of patients with a retroperitoneal sarcoma was 82% , while that of patients with a bladder sarcoma was 73% .
the 5-year estimated survival rate for patients who presented with prostate sarcoma was 44% , while that for patients who presented with renal sarcoma was 39% . there were no significant differences in survival according to age ( p=0.79 ) , gender ( p=0.84 ) , tumor size ( p=0.59 ) , or histological subtype ( p=0.69 ) according to the univariate analysis ( table 2 ) .
however , a significant difference in survival according to metastasis at diagnosis was observed ( fig .
2 ) . patients who underwent surgical resection also showed significantly better overall survival ( fig .
patients with retroperitoneal sarcomas had more favorable survival outcomes than did patients with bladder , kidney , or prostate sarcomas ( fig .
these three factors ( metastasis , surgical resection , and primary organ ) were also significantly associated with improved overall survival in the multivariate analysis ( table 2 ) .
during the study period , 48 patients with gu stss were treated at our institution .
the mean age at diagnosis was 47.1 years ( range , 3 to 80 years ) .
the mean follow - up duration was 43.6 months ( range , 6 to 167 months ) .
the most common site was the retroperitoneum ( n=16 , 33.3% ) followed by the kidney ( n=12 , 25% ) , prostate ( n=10 , 20.8% ) , bladder ( n=7 , 14.5% ) , ureter ( n=1 , 2% ) , and paratesticular region ( n=1 , 2% ) .
the mean tumor size was 9.5 cm ( range , 2.2 to 24 cm ) and 43 patients ( 89.5% ) had tumors larger than 5 cm .
the histological subtypes of sarcoma were as follows : leiomyosarcoma ( 24 , 50% ) , rhabdomyosarcoma ( 9 , 18.7% ) , and liposarcoma ( 4 , 8% ) .
of the 48 patients , 33 ( 68.7% ) underwent surgical resection and 15 ( 31.2% ) were treated by chemotherapy , radiotherapy , or both .
at the time of analysis , 20 patients ( 41.6% ) had died of their sts , 2 patients ( 4.1% ) had died of unrelated causes , and 26 patients ( 54.1% ) were alive .
the 5-year estimated survival rate of patients with a retroperitoneal sarcoma was 82% , while that of patients with a bladder sarcoma was 73% .
the 5-year estimated survival rate for patients who presented with prostate sarcoma was 44% , while that for patients who presented with renal sarcoma was 39% .
there were no significant differences in survival according to age ( p=0.79 ) , gender ( p=0.84 ) , tumor size ( p=0.59 ) , or histological subtype ( p=0.69 ) according to the univariate analysis ( table 2 ) .
however , a significant difference in survival according to metastasis at diagnosis was observed ( fig .
2 ) . patients who underwent surgical resection also showed significantly better overall survival ( fig .
patients with retroperitoneal sarcomas had more favorable survival outcomes than did patients with bladder , kidney , or prostate sarcomas ( fig .
these three factors ( metastasis , surgical resection , and primary organ ) were also significantly associated with improved overall survival in the multivariate analysis ( table 2 ) .
less than 5% of stss arise in the gu tract and only 15% of stss arise within the retroperitoneum .
the rarity of gu sts is a major obstacle to clinical   research ; contemporary data in the medical literature are limited .
mondaini et al reviewed sarcomas of different histological types in a multicenter study involving eight different hospitals in tuscany , italy .
the mskcc group reported two consecutive series , one including 43 patients treated between 1982 and 1989 and another including 131 patients treated between 1977 and 2003 .
the latter study was an extension of the former study with a prolonged follow - up .
owing to the rareness of stss , and therefore the absence of randomized controlled trials , no standard treatment options for this disease exist .
this multimodal approach has replaced amputation as the primary surgical treatment of choice . in the present study
the mean tumor size of 9.5 cm found in the present study is slightly smaller than that reported previously [ 9 - 11 ] .
the 5-year os was 51.4% , similar to the results of previous studies that reported 5-year os rates of 50% .
dotan et al reported that the presence of metastasis and rhabdomyosarcoma were unfavorable prognostic variables . in our study , the presence of metastasis at diagnosis was associated with survival in both univariate and multivariate analyses .
lewis et al reported that the presence of unresectable disease and incomplete surgical resection were the most significant factors predictive of disease - specific death . in a study by van dalen et al of 143 patients treated in the netherlands ,
complete tumor resection was correlated with better overall survival in the multivariate analysis . however ,
dotan et al reported that complete resection was not a significant factor predictive of disease - specific survival in univariate and multivariate analysis in 102 patients with primary tumors only .
these results suggest that any type of surgical resection can provide the best chance of survival in patients presenting with primary disease or with primary and metastatic disease .
consistent with this , we found that the absence of surgical resection was an unfavorable prognostic variable for overall survival .
therefore , we suggest that surgical resection may contribute to a favorable prognosis in patients with urological stss . the prognosis of retroperitoneal stss has been reported to be more favorable than that of the other gu stss .
disease prognosis was the worst for stss of the kidney , whereas the prognosis was better for retroperitoneum , bladder , and prostate sarcomas , as reported previously . according to a previous study
, the size of stss is an important prognostic variable , in contrast with our findings .
this discrepancy may be because stss arising from the retroperitoneum can attain a large size owing to the flexibility of the retroperitoneum . however , retroperitoneal stss showed a better prognosis than bladder , prostate , and renal stss in our study .
the histological subtype of the gu stss was not a prognostic factor for disease - specific survival in either the univariate or the multivariate analysis ; in other words , we did not observe an association between histological subtype and disease - specific survival .
surgical resection , metastasis at diagnosis , and the primary organ were significant predictors of prognosis .
the data presented in this study contribute to our understanding of urological stss and may help in the development of an optimal therapeutic strategy to treat stss .
 purposethe purpose of this study was to elucidate prognostic factors for survival and clinical outcomes of rological soft tissue sarcomas ( stss).materials and methodsthis was a retrospective review of the medical records of 48 patients with urological sts treated from january 1982 to july 2009 . 
 demographic and pathological characteristics were compared . 
 patients ' demographics , clinico - pathological parameters , overall survival , and the factors expected to predict survival , such as sex , age at diagnosis , primary organ , surgical resection , metastasis , and mass size , were analyzed . 
 we evaluated differences in survival on the basis of histological subtype by kaplan - meier analysis and multivariate cox proportional hazards regression.resultsthe study included 34 males ( 70.8% ) and 14 females ( 29.1% ) . 
 the mean age at diagnosis was 47.1 years ( range , 3 to 80 ) . 
 the most common site was the retroperitoneum ( n=16 ) , followed by the kidney ( n=12 ) , prostate ( n=10 ) , bladder ( n=7 ) , ureter ( n=1 ) , and paratesticular region ( n=1 ) . 
 nineteen patients ( 39.5% ) had other organ metastases at diagnosis . 
 the most common subtypes of sarcoma were leiomyosarcoma ( 50% ) , rhabdomyosarcoma ( 18.7% ) , and liposarcoma ( 8% ) . 
 the remaining 11 cases had other histological subtypes ( 22.9% ) . 
 mean tumor size was 9.5 cm ( range , 2.2 to 24 ) . 
 thirty - three patients ( 68.7% ) underwent surgical resection . 
 the overall survival rate at 5 years was 51.4% . in the univariate and multivariate analysis , surgical resection , primary tumor site , and 
 metastasis at diagnosis remained significant predictors of prognosis . 
 patients with retroperitoneal sarcoma had a higher overall survival rate by 5 years compared with patients with other organ sarcoma.conclusionsthe overall survival rate at 5 years was 51.4% . 
 surgical resection , primary tumor site , and metastasis at diagnosis remained significant predictors of prognosis . 
INTRODUCTION
MATERIALS AND METHODS
1. Patients
2. Variables
3. Statistical analysis
RESULTS
1. Patient characteristics
2. Survival
3. Prognostic factors
DISCUSSION
CONCLUSIONS