Data Collection

The Handbook of functions provides details on 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 leukemias, lymphomas, CNS tumors, neuroblastomas and nephroblastomas diagnosed in children aged 0 to 14 years who are born or resident and treated in Greece; even those who may have sought treatment at some time abroad are followed up by our network of collaborators and their experience contributed to NARECHEM-ST. History of one or more other primary tumors is also tracked, although only those with a free history of previous cancer participate in the concurrent case-control NARECHEM study.

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 for the majority of cases are available, 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 contribute to the registration of variables available at NARECHEM-ST.

Data Coding

Data are coded in ICD-10, ICD-O-3 for all registered malignancies.

Completeness of coverage

NARECHEM-ST reaches ~100% completeness for all 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 (e.g. Stergios Zacharoulis, Consultant Paediatric Oncologist, Harley Street Clinic, London, UK). Albeit data linkage with the Hellenic Statistical Services is not currently feasible, it is firmly believed that data certificate only (DCO) cases are minimal in Greece.

Clinical and follow up data

Treating physicians provide electronically detailed clinical data and long-term follow-up/survival of the registered patients as well as information on previous and subsequent development of second primary tumors. After a certain period of time, it is feasible to compare NARECHEM-ST mortality figures with the tabulated ones provided by the Hellenic Statistics Department (ELSTAT) to ensure completeness of death data.

Dissemination of data

Each of the 7collaborating childhood hematology-oncology Units has access to their own electronic files, which are eventually checked and managed by NARECHEM-ST; hence, these data can be used for research purposes by the individual unit or combined by NARECHEM-ST collaborators.
Reports and Standard tables of demographic characteristics by disease subtype as well time trends become available online in the narechem.gr website usually by next year of registration. Basic primary data are also being contributed to European childhood cancer registries, handled by IARC.

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 (>75 articles and ~1500 citations); extension to registration of clinical, cytogenetic and follow up data opens a new research era.