Long-term survival of children with leukemia achieved by the end of the second millennium

BACKGROUND. The prognosis for patients with childhood leukemia has improved steadily over the last decades due to major progress in therapy. Much of t his progress remains unaccounted for in traditional estimates of long-term survival rates, which essentially reflect the survival experience of patien ts who were diagnosed many years ago. METHODS. The authors applied a new method of survival analysis, called peri od analysis, to provide up-to-date estimates of long-term survival rates. T he analysis is based on data from the nationwide German Childhood Cancer Re gistry and includes 8059 children who were diagnosed with leukemia between 1981 and 1998. The most up-to-date 5-year, 10-year, and 15-year survival es timates were obtained by period analysis and were compared with to the most up-to-date survival estimates from traditional methods of survival analysi s. RESULTS. Period estimates (95% confidence intervals) of 5-year, 10-year, an d 15-year survival rates achieved by 1998 were 81% (79-83%), 77% (74-79%), and 73% (70-76%), respectively, for all patients with leukemia combined; 86 % (84-88%), 81% (79-84%), and 77% (74-81%), respectively, for patients with acute lymphocytic leukemia; and 59% (53-65%), 59% (53-65%), and 57% (49-64 %), respectively, for patients with acute nonlymphocytic leukemia. Substant ially lower estimates would have been obtained with traditional methods of survival analysis. CONCLUSIONS. These results from one of the world's largest childhood cancer registries reveal that cure rates of childhood leukemia achieved by the en d of the second millennium are higher than suggested by previous estimates based on traditional methods of survival analysis. (C) 2001 American Cancer Society.