[The contribution of the Italian association of cancer registries (AIRTUM)]

The study of cluster requires the ability to identify, with accuracy and completeness, the health events of interest and their geographical location and time of occurrence. For rare and complex diseases, such as childhood cancers, it is possible to observe a significant health migration from the place of residence, which makes the detection even more complex. The best tool to identify these rare diseases is represented by cancer registries (CRs). In fact, CRs collect, through many sources, information related to tumours that arise in the population resident in their areas of activity. The number of the sources of information has increased thanks to the computerization of health services. The availability of multiple sources of information increases the completeness of data collection overcoming the limits of a single source, and makes it possible to describe the diagnostic-therapeutic course and the outcome of the cases. Among all data sources, for childhood cancers the model 1.01, which summarize the clinical information of the cases treated in one of the Italian Association of paediatric haematology and oncology (AIEOP) centres, is relevant. Moreover, CRs produce reliable and comparable data due to the use of international rules and classifications for the definition of the topography and morphology of cancer, for the date of diagnosis, and for quality checks. In Italy, the Italian association of cancer registries (AIRTUM) coordinates the activities of 45 population CRs, both general and specialized (by age or tumour type). AIRTUM involves a population of over 6.7 million citizens under the age of 20 years, approximately 60% of the total resident population. AIRTUM plays a role of coordination, support, and harmonization for Italian CRs through training, accreditation, and a shared database, it promotes and participates in national and international collaboration involving scientific societies (AIEOP, Italian Association of medical oncology - AIOM, Italian Federation of volunteer-based cancer organisations - FAVO) and institutions (Italian national Institute of health, Italian national cancer institute of Milan) and performs analysis on key epidemiological indicators (incidence, mortality, survival, and prevalence). The AIRTUM database contains 19,650 cancer cases in child/ adolescent patients diagnosed from 1967 to 2011. The epidemiology of childhood cancers has been the subject of two AIRTUM monographs published in 2008 and in 2013 in collaboration with AIEOP; the latter includes specific contributions on polluted sites, on the psychological side, and on the experience of the parents of young cancer patients. The collaboration between different professionals, needs, and knowledge is the policy followed by AIRTUM to build up a complete picture of cancer epidemiology, even of childhood cancer, in Italy.