On entry into the cohort, participants, including both survivors and siblings, completed a baseline questionnaire that collected basic demographic and health-related information. For participants under age 18 at baseline, the questionnaire was completed by a parent or guardian. Follow-up questionnaires are mailed to participants approximately every two years to update baseline data and to gather additional information on questions of interest.
In addition to completing the baseline questionnaire, survivors agreed to release medical records of their cancer treatment; participating centers provided detailed abstracts of treatment records for all consenting survivors enrolled in the cohort from their site. Treatment information includes cumulative dose-specific exposure to chemotherapy, surgical procedures, and radiation therapy. The latter is evaluated by the radiation physics center at M.D. Anderson Cancer Center.