Study design and cohort characteristics of the Childhood Cancer Survivor Study: A multi-institutional collaborative project

Background. Increased attention has been directed toward the long-term health outcomes of survivors of childhood cancer. To facilitate such research, a multi-institutional consortium established the Childhood Cancer Survivor Study (CCSS), a large, diverse, and well-characterized cohort of 5-year survivors of childhood and adolescent cancer. Procedure. Eligibility for the CCSS cohort included a selected group of cancer diagnoses prior to age 21 years between 1970-1986 and survival for at least 5 years. Results. A total of 20,276 eligible subjects were identified from the 25 contributing institutions, of whom 15% are considered lost to follow-up. Currently, 14,054 subjects (69.3% of the eligible cohort) have participated by completing a 24-page baseline questionnaire. The distribution of first diagnoses includes leukemia (33%), lymphoma (21%), neuroblastoma (7%), CNS tumor (13%), bone tumor (8%), kidney tumor (9%), and soft-tissue sarcoma (9%). Abstraction of medical records for chemotherapy, radiation therapy, and surgical procedures has been successfully completed for 98% of study participants. Overall, 78% received radiotherapy and 73% chemotherapy. Conclusion. The CCSS represents the largest and most extensively characterized cohort of childhood and adolescent cancer survivors in North America. It serves as a resource for addressing important issues such as risk of second malignancies, endocrine and reproductive outcome, cardiopulmonary complications, and psychosocial implications, among this unique and ever-growing population.