Data Collection

The Handbook of functions provides details how NARECHEM-ST is organized and the processes followed for collecting quality data for both cancer registration and analytic epidemiology research purposes. In brief:

Inclusion criteria

NARECHEM–ST aims to include all incident cases of specific cancer types including leukemias, lymphomas, CNS tumors, neuroblastomas, renal and liver tumors and sarcomas diagnosed in children aged 0-14 years who are born or reside and are treated in Greece; even those who may have sought some time treatment abroad and are followed up by our NARECHEM-ST network. History of second primary tumors is also tracked. Only those with a free history of previous cancer, however, participate in the concurrent case-control NARECHEM studies.

Collected data

NARECHEM-ST collects demographic data, personal and family history of the index child as well as detailed information regarding the disease (confirmed diagnosis coded under ICD-O-3 since 2007, localization and morphology of the tumor, stage, metastases and survival). Biological samples are available for most of our cases and controls. The analytical list of other variables available through interviews for cases and controls or provided by the treating physicians is electronically stored. Bone marrow aspiration slides and biopsy reports are provided as appropriate, whereas biopsy specimens are stored in the respective Pathology Departments.

Data sources

All seven collaborating pediatric hematology/oncology departments across the country as well as alternative sources of information, such as the two private neurosurgery Departments of MITERAs Hospital, Athens and St. Luke's Hospital, Salonica, the pathology and neurosurgery departments of “P. & Al. Kyriakou and “Aghia Sophia” Children's Hospitals in Athens, the Radiology and Radiotherapy Departments of the General “Attiko” Hospital and Private “Hygeia” Hospital, the 1st Department of Pathology, Medical School, University of Athens and the two Bone Marrow Transplantation Units have contributed to the registration of variables available at NARECHEM-ST.

Data Coding

Data are coded in ICD-10, ICD-O-3 for all registered malignancies. Toronto staging is being gradually implemented.

Completeness of coverage

NARECHEM-ST reaches >95% completeness for registered childhood tumors. Public and private institutions treating childhood malignancies in Greece are contributing their incident cases and multiple sources of information are used including collaboration with institutions outside Greece to which cases may be referred to. Albeit data linkage with the Hellenic Statistical Services is not feasible, it is believed that data certificate only (DCO) cases are minimal in Greece following discussions with forensic medicine officials.

Clinical and follow up data

Treating physicians provide detailed clinical and long-term follow-up/survival data of the registered patients as well as information on second primary tumors. Comparisons of NARECHEM-ST mortality figures with the tabulated ones provided by the Hellenic Statistics Department (ELSTAT) have been used to ensure completeness of NARECHEM-ST death data. Causes of death reported by NARECHEM hospital collaborators are being also reviewed by independent panels.

Dissemination of data

Each collaborating childhood hematology-oncology Unit collaborator can enquire a copy their own electronic file, whereas NARECHEM-ST is responsible to check the quality and manage the full dataset; hence, individual Unit data can be used for research purposes by the respective Unit or in the combined format by NARECHEM-ST collaborators. Collaborating personnel can submit research proposals to NARECHEM-ST officials on specific projects which can be conducted in common once approved for feasibility and scientific integrity.
Reports and Standard Summary Tables of demographic characteristics by disease subtype as well time trends become available online in the website usually by next year of registration. Special caution is paid to protect anonymity. Basic fully anonymized primary data have been contributed to European childhood cancer registries, handled by IARC or to international consortiums following specific Data Transfer Agreements and for certain time periods. Since 2016, we aim compliance with EU-GDPR 2016.

Further use of data and international collaborations

NARECHEM-ST has a rich record of publications on a great range of topics pertaining to descriptive and analytic epidemiology (>100 articles in scientific peer reviewed journals and >2000 citations). Expansion to registration of clinical, cytogenetic and follow up data opens a new research era for international collaborations provided issues of confidentiality are properly handled.