This study looks at how a medicine called dexrazoxane hydrochloride affects people who had cancer treatment. The research focuses on checking blood samples for biomarkers, which are signals in the body that can indicate cardiomyopathy (heart muscle disease) and heart failure. The study involves patients who have had leukemia, lymphoma, or osteosarcoma, and compares those who took dexrazoxane to those who did not.

For the study, patients will have tests like a physical exam, echocardiogram (a heart ultrasound), and a 6-minute walk test. They will also fill out questionnaires about their quality of life and family health history.

• The study is open to participants who have cancer treatment records.
• Participants must have had cancer treatment before age 21 and be alive a year after.
• No known congenital heart disease is allowed for participation.