Long-term survival in childhood acute lymphocytic leukemia in Italy.
Among 727 children with acute lymphocytic leukemia (ALL) observed at eight pediatric clinics in Italy in the years 1967-1974, 200 (27.5%) survived for more than five years after diagnosis. The proportion of long-term survivors rose significantly during the years 1970-1974 when aggressive therapeutic programs with curative intent were uniformly adopted in Italy (19.8% vs. 29.4%; P less than 0.05). Clinical and laboratory data at diagnosis of the 200 long-term survivors were analyzed and compared with that of the 527 nonsurvivors. We found that, besides a leukocyte count greater than 50,000 cells/mm3, other factors such as early central nervous system CNS leukemia and the presence of mediastinal mass were predictive of a poorer prognosis for long-term survival. Life-table analysis revealed that the chance of long-term survival was significantly higher in those children who have survived for five years without relapse (82.9% vs. 24.1%; P less than 0.01). Although late initial relapse is always possible, if a child with ALL remains in continuous complete remission for at least nine years, it is likely that the patient is cured.