The Childhood Cancer Survivor Study (CCSS) looks at the long-term effects of cancer treatments like radiation, chemotherapy, and surgery in children and young adults who survived cancer. This study includes about 50,000 cancer survivors diagnosed before age 21 from 1970 to 1999 and 10,000 siblings for comparison. Cancer survivors are children or young adults who have lived for five years after being treated for cancer. The study checks their health, behaviors, and needs for medical care. Siblings who were not diagnosed with cancer will help researchers compare. Researchers will also collect samples like saliva and blood for further studies.

• Participants will be part of a long-term study, so they should be ready for ongoing involvement.
• Only people who speak English or Spanish and live in the U.S. or Canada can join.
• Researchers will use the study to learn about how cancer affects survivors over time.