Study flowchart. The SEER Program database of the National Cancer Institute was searched to identify cases of primary, malignant neoplasms diagnosed during childhood or adolescence. A total of 88,418 patients with a single, primary malignant tumor and recorded follow‐up were identified. Over a median follow‐up of 6.3 (0–40.9) years, 21,422 deaths were recorded, 378 of which were due to cardiovascular causes. Follow‐up at least 5 years after diagnosis was available in 49,731 long‐term survivors across 18 SEER registries. Nine registries with prospective data collection since at least 1975 were selected, reporting on a total of 28,811 long‐term survivors. These were split in a derivation (n = 22,374 in seven registries) and an external validation set (n = 6,437 in two independent registries) in order to develop and test a clinical prediction model of cardiovascular mortality risk among long‐term childhood cancer survivors.
Abbreviations: LA, Los Angeles; SEER, Surveillance, Epidemiology, and End Results; SF, San Francisco; SJM, San Jose Monterrey; SMSA, Standard Metropolitan Statistical Area.