A follow-up study was made of two independent series of 1,807 and 425 children who were alive five years after diagnosis of a malignant neoplasm. Over the subsequent 20 years (5 to 24 years after initial diagnosis), actuarial survival rates for the cohorts were 83% and 79%, respectively, compared to 97% for matched control subjects in the general population (P less than 0.01). Cure was achieved in a large majority of the 5-year relapse-free survivors of cancer in this study.