Management of Ontario children with acute lymphoblastic leukemia by the Dana-Farber Cancer Institute protocols

There is ample evidence of the value of intensive therapeutic strategies in the management of acute lymphoblastic leukemia (ALL), the commonest form of malignant disease in children. Such a program, devised at the Dana-Farber Cancer Institute (DFCI), Boston, and incorporating high-dose L-asparaginase, was adopted in 1984 by the Children's Hospital at Chedoke-McMaster, Hamilton, Ont., and the Children's Hospital of Western Ontario, London. We describe the experience of these institutions in the treatment of 82 children with ALL, 19 of whom were switched to the DFCI protocols while in continuing first remission with other treatment programs to complete a minimum of 2 years of maintenance therapy; the remaining 63 children, who had recently diagnosed disease, were consecutively enrolled in the DFCI protocols. Each child was assigned at diagnosis to a category of risk for relapse and treated accordingly. There were no remission induction failures or deaths due to induction therapy among the patients with newly diagnosed disease. There were no differences in total or event-free survival rates between the patients in Hamilton and those in London or between those whose protocols were switched and those who were treated from the beginning with the DFCI protocols. With a median follow-up interval of 144 weeks the total survival rate was 95% and the event-free survival rate 88%. For patients at standard risk of relapse the event-free survival rate was 100%, for those at high risk the rate was 82%, and for those at very high risk the rate was 67%. If infants (all of whom suffered a relapse) are excluded from the last category the rate was 89%. These results were achieved with moderate toxic effects (except for two deaths, one of which was due to a therapeutic misadventure) and suggest that the prospect for cure in children with ALL. may now approximate 80%, a degree of success that demands that consideration be given to reducing total therapy, at least for children with standard-risk disease. Further follow-up will determine whether these high event-free survival rates will stabilize and meet the criteria for cure.