Risk Factors of Differentiated Thyroid Cancers in Child- and Young Adulthood in France: A Case-Control Study

Abstract

P-160 Abstract: In order to study the potential consequences of the Chernobyl nuclear power plant accident in April 1986 and to specify the risk factors of differentiated thyroid cancer for children and young adults, we are carrying out, in close collaboration with cancer registries, a population-based case-control study in the East regions of France, that were most contaminated by fallout from the Chernobyl accident. The study will include a total of more than 700 cases and 700 controls. The thyroid case patients must have been born from January 1, 1971 and been diagnosed with histologically verified differentiated thyroid carcinoma between 2002 and 2006 in one of the 8 areas concerned with the study (Alsace, Burgundy, Champagne-Ardennes, Franche Comté, Lorraine, Rhône-Alpes, Provence-Alpes-Côte d'Azur and Corsica). General population control subjects will be randomly drawn from telephone lists, and will be matched to case patients by age, sex, and regions of residence at the time of the cancer diagnosis. Information will be collected on study subjects by use of a detailed questionnaire that will be administered by a trained interviewer during an in-person interview. The interview includes questions about known or suspected risk factors for thyroid cancer together with selected lifestyle factors and accurate places of residence in the days and first 2 months after the accident. For each study subject, total individual radiation doses to the thyroid will be reconstructed by taking into account external radiation doses received during radiodiagnostic examinations, radiotherapeutic treatment or from occupational exposure, the whereabouts and dietary habits of the subjects and information on environmental contamination. This project will also include a study of gene-environment interactions. Buccal cell DNA will be collected during interviews of cases and controls. Interviews started in June 2005. The complete data and DNA collection should be completed at the beginning of 2008. First results are awaited for 2009. Once finished, this project will be pooled with 3 other case-control studies, including a similar project carried out on the adult population in France, one in New Caledonia, and one in French Polynesia. These 4 studies, whose questionnaires were initially designed to be compatible, will offer the possibility to study a population of approximately 2000 cases and 2000 controls, of various ethnic origins and with variable lifestyles, and thus, to investigate the main suspected risk factors of thyroid cancer. The presentation will point out the objectives, design and methods of the study, as well as an assessment after 12 months of implementation.