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the danish sarcoma group is one of the danish multidisciplinary cancer groups ( dmcg ) fulfilling different criteria to be part of the parachute organization dmcg.dk .
one criterion is to have a database approved by the danish national board of health .
danish sarcoma database ( dsd ) was established as a national , population - based database on january 1 , 2009 .
the aim of the database is to gather information about incidence , treatment , and prognosis of sarcomas ( including borderline malignant connective tissue tumors ) in denmark in order to monitor and improve the quality of sarcoma treatment in both a national and an international perspective .
sarcoma is a rather seldom malignant tumor entity ( incidence approximately six to eight per 100,000 inhabitants corresponding to ~350 new cases / year),1 and according to the danish national board of health , all sarcoma treatment in denmark must be confined to two nationally approved sarcoma centers at aarhus university hospital , aarhus , and rigshospitalet / herlev hospital , copenhagen .
the database has since its establishment included all bone and soft tissue sarcomas of the musculoskeletal system in denmark , including the trunk wall .
also , the treatment of intra - abdominal and retroperitoneal sarcomas and sarcomas of the neck and face has been centralized at copenhagen and aarhus so that almost all sarcomas in denmark are now registered in dsd ( figure 1 ) . according to figure 1 , there seems to be an increase in the number of patients at least from 2013 to 2014 .
this is not due to increased inclusion of patients from previously unregistered anatomical region , and also , the distribution between superficial and deep - seated tumors is unchanged
. we do not know for sure whether the increase reflects an increased amount of sarcomas , but the figures for 2015 ( not yet validated ) indicate that the increase is only transitory .
sarcomas of the female genitalia have traditionally been registered in the danish gynaecological cancer database only , and not consequently in dsd .
therefore , a new corporation between the two databases has been established , and from 2015 , the gynecological sarcomas ( ~40/year ) will be registered in dsd too .
the database is approved by the danish national board of health as a clinical quality database and economically supported by the danish health authorities . as a consequence ,
registration to dsd can take place without consent due to a law regulation from 2006 on the reporting of information to clinical databases adopted by the ministry of health . so far , this is our best guarantee for a high completeness of the database . as all citizens in denmark
are provided with a unique ten - digit civil registration code describing age , sex , and date of birth , it is possible to link dsd to different administrative databases , eg , the danish national pathology registry . in this registry ,
all histological specimens from all sarcomas are registered according to the world health organization classification.2 we have cross - checked the registry for 2013 and 2014 and have established an ongoing validation project to clarify whether it can be used for a precise assessment of the completeness of the database . by december 31 , 2014 ,
2,000 patients were registered in the database : 49% women and 51% men , with a mean age ranging from 53.9 to 56.2 years ( table 1 ) and an age distribution from 2 months to 95 years ( figure 2 ) .
the database contains information of sarcomas and borderline tumors , including giant cell tumor of the bone and aggressive fibromatosis ( figure 3 ) , and contains information about the patients before and after their first visit in a sarcoma center .
thus , 23% of the patients have had a resection and 16% a biopsy before referral to the sarcoma center involving both superficial and deep - seated tumors .
most of the variables ( the main variables are described in table 2 ) in the database can be applied to any patient , but sarcomas occur in any part of the body and therefore some variables may not be meaningful in every case .
for example , the margin of resection of a tumor in an extremity can be described as intralesional , marginal , wide , or radical , but the distinctions between marginal and wide can not be made for a retroperitoneal tumor .
when all diagnostic procedures have been performed , it is decided whether the treatment is intended to be curative or palliative , a decision made at the weekly multidisciplinary tumor conferences based on the results of the investigations of the patient s tumor . in all , 14% of the patients have disseminated disease at referral to a degree that curative treatment is not considered possible .
comorbidity is registered according to the charlson comorbidity score.3 information about comorbidity is gathered at the patient s first visit at the sarcoma center .
the information can ( with patient s consent ) be supplied by electronic access to the patient s previous medical records .
the sarcoma patients are registered using the international classification of diseases  tenth edition ( icd-10 ) codes and the tumor 
unfortunately , the icd-10 codes are not fully descriptive for sarcomas as in some organs ; for example , in the breast , a sarcoma can only be classified as a breast cancer and not as a breast sarcoma ( malignant connective tissue tumor ) .
therefore , the database can not be completely validated by cross - checking with the danish cancer registry .
all types of treatment given to the patients are registered ( surgery , radiation and chemotherapy for both primary tumor and possible recurrence ) , and both early and late complications are registered .
the sarcomas in the database are graded according to the fdration nationale des centres de lutte contre le cancer ( fnclcc ) system4 ( if gradable ) . for many years , it has been a debate which surgical margin is the optimal to reduce the risk of recurrence . to help answering this question ,
the pathologist , for the soft tissue tumors of the musculoskeletal system , measures the smallest distance from tumor to a well - defined margin , eg , a fascia , and to an undefined margin as the resection line of a muscle containing the tumor .
this registry has recorded all changes in vital status and migration for the entire danish population since 1968 ( thus including all sarcoma patients registered in dsd ) , with daily electronic updates .
the database is constructed to secure a good data quality through a current online registration by the clinician responsible for a given event , eg , surgery .
however , some data will be missing and some data have been typed erroneously . for this reason , in both of the two sarcoma centers ,
a dedicated person has been employed to cross - check all data with the patients medical records when the patient has finished treatment and changed to follow up .
data validity is further secured by some build - in logical locks that prevent the sequence of events from being not chronological , for example , if date of operation erroneously is registered as before onset of symptoms .
dsd is a combined quality and research database , and therefore , some quality indicators have been defined ( table 3 ) . for indicators 7 and 8 , we still only have the figures for the first year of the database ( 2009 ) , being 19% and 16% on the national level , respectively .
if the standards are not fulfilled , the relevant center is asked to perform medical record audit in order to find an explanation and suggest a plan for future improvement , if possible .
for example , in those cases where radiotherapy has not been initiated within 60 days after surgery , this has been due to patient - related causes , such as wound problems , other disease , or the like .
comorbidity is registered according to the charlson comorbidity score.3 information about comorbidity is gathered at the patient s first visit at the sarcoma center . the information can ( with patient s consent ) be supplied by electronic access to the patient s previous medical records .
the sarcoma patients are registered using the international classification of diseases  tenth edition ( icd-10 ) codes and the tumor 
unfortunately , the icd-10 codes are not fully descriptive for sarcomas as in some organs ; for example , in the breast , a sarcoma can only be classified as a breast cancer and not as a breast sarcoma ( malignant connective tissue tumor ) .
therefore , the database can not be completely validated by cross - checking with the danish cancer registry .
all types of treatment given to the patients are registered ( surgery , radiation and chemotherapy for both primary tumor and possible recurrence ) , and both early and late complications are registered .
the sarcomas in the database are graded according to the fdration nationale des centres de lutte contre le cancer ( fnclcc ) system4 ( if gradable ) . for many years , it has been a debate which surgical margin is the optimal to reduce the risk of recurrence . to help answering this question ,
the pathologist , for the soft tissue tumors of the musculoskeletal system , measures the smallest distance from tumor to a well - defined margin , eg , a fascia , and to an undefined margin as the resection line of a muscle containing the tumor .
this registry has recorded all changes in vital status and migration for the entire danish population since 1968 ( thus including all sarcoma patients registered in dsd ) , with daily electronic updates .
the database is constructed to secure a good data quality through a current online registration by the clinician responsible for a given event , eg , surgery .
however , some data will be missing and some data have been typed erroneously . for this reason , in both of the two sarcoma centers , a dedicated person has been employed to cross - check all data with the patients medical records when the patient has finished treatment and changed to follow up .
data validity is further secured by some build - in logical locks that prevent the sequence of events from being not chronological , for example , if date of operation erroneously is registered as before onset of symptoms .
dsd is a combined quality and research database , and therefore , some quality indicators have been defined ( table 3 ) . for indicators 7 and 8 , we still only have the figures for the first year of the database ( 2009 ) , being 19% and 16% on the national level , respectively .
if the standards are not fulfilled , the relevant center is asked to perform medical record audit in order to find an explanation and suggest a plan for future improvement , if possible .
for example , in those cases where radiotherapy has not been initiated within 60 days after surgery , this has been due to patient - related causes , such as wound problems , other disease , or the like .
all patients are offered a follow - up program from 3 to 6 months to 5 years to 10 years after the end of treatment , depending on the type of tumor . at the first follow - up ( 36 months ) , after 1 year , and at the last follow - up , a musculoskeletal tumor society score5 for patients treated for an extremity tumor is calculated .
so far , publications based on the dsd included clinical results of inverse shoulder prosthesis after tumor resection,6 alarm symptoms of soft tissue and bone sarcomas,7 some effects of cancer patient pathways,8 a danish validation of the tess - score,9 and a characterization of tumor type in patients referred after unplanned excision of tumor outside a sarcoma center.10 at present , three phd studies based on the dsd are taking place , with the titles : 
 comorbidity , socioeconomic position , use of health care services and causes of death in sarcoma patients : four nationwide population based studies;the impact of cancer pathways on the improvement of diagnostics in soft tissue and bone sarcomas ; andimprovement in physical rehabilitation in sarcoma patients  a national multicenter study.other ongoing studies including patients from the database are : comparison of clinical results with bone allograft or pmma after curettage for giant cell tumor of the bone;radiation induced angiosarcoma of the breast ; andthoracic wall resection due to sarcoma .
comorbidity , socioeconomic position , use of health care services and causes of death in sarcoma patients : four nationwide population based studies ; the impact of cancer pathways on the improvement of diagnostics in soft tissue and bone sarcomas ; and improvement in physical rehabilitation in sarcoma patients  a national multicenter study .
other ongoing studies including patients from the database are : comparison of clinical results with bone allograft or pmma after curettage for giant cell tumor of the bone ; radiation induced angiosarcoma of the breast ; and thoracic wall resection due to sarcoma .
dsd is economically supported solely by the danish national health authorities as part of the dmcg.dk program . also , as part of this program , the department of clinical epidemiology , centre for clinical epidemiology and biostatistics , north , aarhus university hospital is a mandatory cooperative institution with the aim of delivering epidemiological and biostatistical assistance .
physicians employed at departments who are members of the danish sarcoma group have access to the database .
access to data for research must be given by both the steering group of the database and the danish clinical registry , which is a national parachute organization approving the databases for funding .
the dsd is a national population - based database now including all sarcomas in denmark , both the musculoskeletal and the extraskeletal tumors ( including borderline malignant tumors ) , which makes it a rather unique database in comparison with other countries .
dsd provides possibilities to data linkage and cooperation for quality and research studies with other sarcoma groups .
aimthe aim of the database is to gather information about sarcomas treated in denmark in order to continuously monitor and improve the quality of sarcoma treatment in a local , a national , and an international perspective.study populationpatients in denmark diagnosed with a sarcoma , both skeletal and ekstraskeletal , are to be registered since 2009.main variablesthe database contains information about appearance of symptoms ; date of receiving referral to a sarcoma center ; date of first visit ; whether surgery has been performed elsewhere before referral , diagnosis , and treatment ; tumor characteristics such as location , size , malignancy grade , and growth pattern ; details on treatment ( kind of surgery , amount of radiation therapy , type and duration of chemotherapy ) ; complications of treatment ; local recurrence and metastases ; and comorbidity . 
 in addition , several quality indicators are registered in order to measure the quality of care provided by the hospitals and make comparisons between hospitals and with international standards.descriptive datademographic patient - specific data such as age , sex , region of living , comorbidity , world health organization s international classification of diseases  tenth edition codes and tnm classification of malignant tumours , and date of death ( after yearly coupling to the danish civil registration system ) . 
 data quality and completeness are currently secured.conclusionthe danish sarcoma database is population based and includes sarcomas occurring in denmark since 2009 . it is a valuable tool for monitoring sarcoma incidence and quality of treatment and its improvement , postoperative complications , and recurrence within 5 years follow - up . the database is also a valuable research tool to study the impact of technical and medical interventions on prognosis of sarcoma patients .