This study looks at people who survived childhood cancer to see if they might have health problems later on. These problems, called complications, might happen years after cancer treatment. The study checks if a person's genes (which are like instructions in our bodies) can help predict these complications. Complications could include heart failure, bone problems, stroke, or new cancers.

Key Points:

• Participants will provide a blood or saliva sample for genetic study.
• No recent cancer treatment is required, but the patient should have had a cancer diagnosis before age 21.
• Participants must be actively followed by their medical institution and give consent to join the study.

To join, you must be under active follow-up within the last 24 months and be willing to provide a sample for analysis. This study is important because it might help doctors find out which survivors need more careful long-term follow-up. Participants will not need to undergo any new treatments as part of the study, but they must give permission for their data to be used.