Survivals of 5 to 15 years in acute leukemiaa study of 21 children

Among 269 children with acute leukemia diagnosed between 1957 and 1967, 21 or 7.8% have lived for more than 5 years, although treated conservatively by present standards. Nine patients in whom therapy was stopped after 5 years remain in continuous complete remission, 6 for 10 to 15 1/2 years. Six others survive from 61 1/4 to 8 3/4 years, but have had leukemic meningitis or bone marrow relapse or both. Six patients, 5 of whom had relapse before 5 years, died at 5 1/4 to 8 1/4 years. Discontinuation of therapy in 12 children who had no evidence of disease for 5 years was followed by bone marrow relapse in 3 of them in 6, 12, and 13 months. Analysis of features at time of diagnosis suggests that a normal platelet count and a low or normal white blood cell count may predispose to 5-year survival. A Spanish-American ethnic background is associated with an unfavorable prognosis. Interruption of remission by extramedullary disease, notably meningeal involvement, is a major impediment to continued long survival. In this study patients living 8 years without relapse are presumed to have been cured; long-term survivors who have had prior relapse have a constant rate of mortality. The nature and interaction of intrinsic factors contributing to longevity, and particularly the role of host immunity, remain to be determined.