His research is focused on health care utilization by adult survivors of childhood cancer, as well as specific “late effects” of cancer therapy, including cardiac disease and second malignant neoplasms. He is a member of several North American research and clinical committees focused on research, clinical care, and policy creation for long-term survivors of childhood cancer.

Dr. Nathan’s clinical practice and research program is focused on survivors of childhood cancer. His research addresses specific "late effects" of cancer therapy (such as cardiac disease) as well as healthcare utilization and screening for complications in survivors. He is a member of the steering committees of the Children’s Oncology Group (COG) Survivorship and Outcomes Committee, and the Childhood Cancer Survivor Study (CCSS).