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it is important to accurately determine the epidemiology of pscats for decision - making regarding treatment as well as research and health care planning [ 4,5,7 - 10 ] .
only a small number of populationbased data concerning pscats are available , and there are no population - based data from asian countries . the korea central cancer registry ( kccr )
constructed the korea national cancer incidence database ( kncidb ) , which publishes an annual report of the national cancer incidence rate . in 2005 , the first national cancer incidence statistics for the years between 1999 and 2001 were reported by the kccr .
this exclusion of non - malignant cases restricted the ability to accurately estimate the incidence of pscats in korea . in 2004 , the kccr revised its criteria for cancer registration to include non - malignant primary brain and cns tumors ( benign , uncertain , and unknown behaviors ) . in january 2005 , the kccr began collecting data on non - malignant primary brain and cns tumors , including pscats .
the objective of this study was to provide more detailed estimates of population - based incidences of all primary malignant and non - malignant pscats diagnosed between 2006 and 2010 in korea .
the korean ministry of health and welfare initiated the nationwide cancer registry ( kccr ) in 1980 .
kccr data from 1999 to 2002 were published as the  cancer incidence in five continents , ' which reflects the completeness and validity of incidence data in korea .
the completeness of the kccr data has been estimated to be over 96% for malignant tumors .
data on pscats from 2006 to 2010 , including malignant and non - malignant cases , were identified in the kncidb .
the basic information available included the demographic characteristics of each patient , date of diagnosis , primary site , and histological type of the tumor according to the international classification of diseases for oncology , 3rd edition ( icdo- 3 ) .
the icd - o-3 , which contains topography codes and morphology codes , was developed by the world health organization ( who ) and international agency for research on cancer ( iarc ) for use in cancer registries , pathology , and other departments specializing in cancer .
primary tumors with the following icd - o-3 site codes were included in the analysis : c70.1 ( spinal meninges ) , c72.0 ( spinal cord ) , and c72.1 ( cauda equina ) . for histological type , we used histology categories used in duong et al.s report ( appendix 1 ) .
age - standardized incidence rates with 95% confidence intervals for all pscats were calculated overall as well as by tumor behavior , gender , histology , and year of diagnosis .
rates were expressed per 100,000 persons and were age - standardized according to the world standard population .
male - to - female rate ratios were calculated by dividing the age - standardized incidence rates for males by those for females .
frequencies according to demographic and tumor characteristics for all pscats were calculated . age - standardized incidence rates with 95% confidence intervals for all pscats were calculated overall as well as by tumor behavior , gender , histology , and year of diagnosis .
rates were expressed per 100,000 persons and were age - standardized according to the world standard population .
male - to - female rate ratios were calculated by dividing the age - standardized incidence rates for males by those for females .
table 1 shows the characteristics of pscats diagnosed from 2006 to 2010 . of 3,312 pscats cases , 443 ( 13.4% ) were malignant and 2,869 ( 86.6% ) were non - malignant .
the age - standardized incidence rate for non - malignant primary spinal tumors was 0.92 per 100,000 and 0.16 per 100,000 for malignant tumors .
age - specific incidence rate for all pscats was lowest in the age range from 0 to 9 years ( 0.20 per 100,000 ) and was highest in adults aged 60 to 69 years ( 3.03 per 100,000 ) .
age - specific rates gradually increased with advancing age , peaked from 60 to 69 years , and declined thereafter among non - malignant pscats . however , for malignant pscats , rates peaked in patients over 80 years of age .
malignant tumors were more frequent in men ( 59.8% ) , whereas non - malignant tumors were more frequently found in women ( 57.8% ) .
the spinal cord was the most frequent site ( 83.4% ) , followed by the spinal meninges ( 16.1% ) and cauda equina ( 0.5% ) .
the most common histological type was neurilemomas ( 41.3% ) , followed by meningiomas ( 20.1% ) , and ependymomas ( 7.6% ) .
meningioma had the highest incidence among the spinal meninges ( 91.2% ) . among tumors in the spinal cord , neurilemomas were the most common ( 49.3% , 0.43 per 100,000 ) , followed by ependymomas and meningiomas .
table 3 shows age - adjusted rate by sex and histological type , along with male - to - female age - adjusted rate ratios .
men showed at least 3-fold higher incidence rate of lymphomas compared to women ( male : female rate ratio , 3.20 ) .
for ependymomas , men showed statistically higher rates than women ( male : female rate ratio , 1.35 ) .
conversely , women showed at least 4-fold higher rates for meningiomas ( male : female rate ratio , 0.27 ) .
women showed 3-fold higher incidence rates of tumors of the spinal meninges . for tumors of the spinal cord ,
to our knowledge , this is the first asian epidemiologic report on pscats based on a nationwide population - based registry in korea .
the incidence of pscats in our study ( 1.08 per 100,000 persons ) was slightly higher than that observed in the united states ( 0.97 per 100,000 persons )   or estonia ( 0.80 per 100,000 persons ) , whereas it was slightly lower than that found in france ( 1.20 per 100,000 persons )   or croatia ( 1.60 per 100,000 persons ) . in our study ,
the most common site of pscats was the spinal cord ( 83.4% ) , followed by spinal meninges ( 16.1% ) and cauda equina ( 0.5% ) .
the spinal cord was more frequently cited as a tumor location in our study compared with studies in western countries .
studies in the united states reported the same order , whereas frequency of tumors of the spinal cord was less than that in korea ( 60%-70% ) .
however , a study in norway reported similar tumor rates in the spinal cord and spinal meninges , and a study in croatia reported that the spinal meninges is the most common site with a rate of over 50% .
we also found that the most common histological type of pscats was neurilemomas ( 41.3% ) , followed by meningiomas ( 20.1% ) and ependymomas ( 7.6% ) .
reported that the most common histological types in the united states are meningiomas ( 29% ) , nerve sheath tumors ( 24% ) , and ependymomas ( 23% ) , which supports the results of duong et al . .
with regard to sex differences , we found that the overall incidence rate among men was 0.99 per 100,000 persons while women had an incidence rate of 1.15 per 100,000 persons , which is similar to incidence rates in the united states , although the difference in incidence rates between men and women was greater in our study .
age - specific incidence patterns differ between malignant and non - malignant pscats . for non - malignant pscats
we found that 32% of tumors childhood ( age , 0 to 19 years ) pscats were malignant , whereas only 13.4% were malignant in adults . in the united states ,
firstly , there may be variability in completeness of the data on non - malignant tumors with time , as the accuracy of the data may have improved during study period .
especially , in january 2005 , the kccr began collecting data on non - malignant primary brain and cns tumors , including pscats .
when we analyzed trends in non - malignant primary brain and cns tumors , we found that incidence rates in 2006 were relatively low compared to following years .
secondly , it should be noted that the frequency of unclassified tumors was found to be relatively high ( 17.5% ) compared with that of the united states ( 4.6% ) .
therefore , the real incidence of each histological subtype would be higher than that reported in this study , particularly for malignant tumors ( 23.7% )
. this may be due to the fact that many pscat patients are diagnosed using imaging modalities without surgery or biopsy in non - operated or inoperable cases .
this is the first population - based study in korea to present a descriptive epidemiology of pscats .
our study found that 86.6% of pscats were non - malignant , and the most common site was the spinal cord ( 83.4% ) .
purposeprimary spinal cord and appendage tumors ( pscat ) originating from the spinal cord , spinal meninges , and cauda equina are uncommon . worldwide , 
 population - based cancer registry data are mostly based on malignant tumors only , which means few data are available on pscats , including non - malignant tumors . therefore , the objective of this study was to provide information regarding the incidence of both non - malignant and malignant pscats in korea on a national level.materials and methodsincidence of pscats was estimated from cases diagnosed between 2006 and 2010 using the national cancer incidence database in korea . 
 age - adjusted rates were calculated using the world standard population , and male - to - female rate ratios were calculated by histology type.resultsof all pscats registered ( n=3,312 ) , 86.6% were non - malignant . 
 the overall age - adjusted incidence of pscats was 1.08 per 100,000 person - years , with an incidence of 0.99 per 100,000 in females and 1.15 in males . 
 the most common site of pscats was the spinal cord ( 83.4% ) , followed by spinal meninges ( 16.1% ) and cauda equina ( 0.5% ) . 
 the most common histological type was neurilemmoma ( 41.3% ) , followed by meningiomas ( 20.1% ) and ependymomas ( 7.6% ) . 
 men had significantly higher rates than women for ependymomas and lymphomas but had lower rates for meningiomas.conclusionthis study provides the first population - based analysis of pscats in korea .