A second course of treatment for childhood acute lymphoblastic leukaemia: long-term follow-up is needed to assess results

We report the results of long-term follow-up of 94 children who completed treatment for acute lymphoblastic leukaemia (ALL) between 1974 and 1986 and subsequently experienced a bone marrow relapse before 1992. 91 children received further induction, intensification and CNS directed therapy; 19 proceeded to BMT or ABMT and the remainder were treated on one of three protocols which increased in intensity. The duration of second remission improved significantly with increasing intensity of treatment and bone marrow transplantion was followed by fewer relapses than chemotherapy. Analysis of factors influencing the duration of second remission showed that only length of first remission was of additional significance; the median duration of second remission being only 19 months in children with a first remission of less than 4 years and 62 months in those with longer first remissions. 29 children electively stopped chemotherapy a second time but only 11 of these remain still in second remission with recurrences occurring for up to 7 years from the the time first relapse. Only three of the 24 longterm survivors had no significant late effects of treatment; these were most marked in children who had received a second course of radiotherapy. We conclude that very long follow-up is necessary to determine whether patients may be successfully re-treated following late bone marrow relapse and that all such treatment is associated with a high incidence of late effects.