Effects of varying radiation schedule, cyclophosphamide treatment, and duration of treatment in acute lymphoblastic leukaemia. Report to the Medical Research Council by the Working Party on Leukaemia in Childhood.

In a multicentre trial of treatment for acute lymphoblastic leukaemia the effects of three types of central nervous system prophylaxis, the inclusion of cyclophosphamide, and the total duration of chemotherapy were assessed. A schedule with a high dose of spinal irradiation (2400 rads) without intrathecal methotrexate was inferior to schedules with some (1000 rads) or no spinal irradiation but with intrathecal methotrexate. The addition of cyclophosphamide 600 mg/m2 given intravenously every 12 weeks was of no benefit and was possibly deleterious. There was no advantage in adding four 12-week courses of chemotherapy after eight courses (total duration two years) had been given. Girls fared significantly better than boys, the difference being only partly due to the occurrence of testicular relapse.