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 this progress remains unaccounted for in traditional estimates of long-term survival rates, which essentially reflect the survival experience of patients who were diagnosed many years ago.

Methods: The authors applied a new method of survival analysis, called period analysis, to provide up-to-date estimates of long-term survival rates. The analysis is based on data from the nationwide German Childhood Cancer Registry 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 estimates were obtained by period analysis and were compared with to the most up-to-date survival estimates from traditional methods of survival analysis.

Results: Period estimates (95% confidence intervals) of 5-year, 10-year, and 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. Substantially 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 end of the second millennium are higher than suggested by previous estimates based on traditional methods of survival analysis.