Marrow relapse on maintenance chemotherapy in childhood acute lymphoblastic leukaemia.

A retrospective study on 190 children with acute lymphoblastic leukaemia and marrow relapse on therapy demonstrated a universally poor prognosis with a high risk of extramedullary leukaemia. 49.1% of children achieved a second remission, the median duration of haematological remission being 97 days. The median duration of survival was 157 days, with no survivors beyond 2 years 3 months from relapse. Children with high white blood counts at diagnosis, those relapsing early and older children had a particularly poor prognosis. Children who achieved a first remission with difficulty and those receiving regular vincristine and prednisolone in their remission were less likely to achieve a second remission. Those who failed to go back into remission with the more commonly used drugs were not usually responsive to other drugs.