Characteristics of the study population, comparing participants, non-participants and siblings of the current analysis.

NOTE: Percentages are based upon available data for each variable.Abbreviations: CNS, Central Nervous System; ICCC-3, International Classification of Childhood Cancer – Third Edition; n, number; n.a., not applicable.aAge- and sex-standardized numbers and percentages are given for siblings.bNon participants include: 107 without current address, 239 who did not respond, 85 who refused to participate, and 83 who answered an abridged questionnaire (Supplementary Figure S1).cColumn percentages are given.dP-value calculated from chi-square statistics comparing survivor participants and survivor non-participants.eInformation derived from questionnaire survey is not available for non-responders.fInformation on former cancer disease is not applicable for siblings.gOther malignant epithelial neoplasms, malignant melanomas and other or unspecified malignant neoplasms.hEach person can have had several treatments.