Characteristics of children with acute nonlymphocytic leukemia in long-term continuous remission: A report for childrens cancer study group

Abstract
Children and young adults less than 18 years of age with acute nonlymphocytic leukemia who remained in long term bone marrow and extramedullary remission for two years or longer since starting maintenance were compared to the remaining responders for the following characteristics: cell type, sex, age at diagnosis, race, pretreatment, white blood count, length of time from start of induction therapy to achievement of an M1 marrow, marrow rating at day 56 of therapy, marrow rating at the start of maintenance therapy, and specific study. Forty‐eight patients of a group of 333 qualified as having long term remission (14.4%). Multivariant analysis indicated that patients between the ages of 3 and 10 years (p = 0.003) as well as the length of time to achieve an M1 marrow from the start of treatment (p = 0.03) were the only characteristics associated with achievement of a long term remission. Maintenance therapy was discontinued in 15 patients from 2.5 to 4.8 years after start of maintenance and all patients remained in bone marrow remission for periods from 0+ to 3.0+ years after stopping treatment. Of the 33 who have remained on a continuous maintenance therapy 12 have had bone marrow relapses. These data confirm the prognostic value of age and length of time to achieve remission during induction in acute nonlymphocytic leukemia and suggest that there may be no significant benefit from maintenance therapy continued beyond 2 years for patients in their initial remission.