United Kingdom Medical Research Council Acute Lymphoblastic Leukaemia (UKALL) Trials I-VIII: clinical features and results of treatment in four groups of children with adverse prognostic features.

Four groups of children with poor-prognosis disease were selected for study from the Medical Research Council childhood ALL trials. Each group was reviewed for distinguishing clinical features and response to therapy. The four comprised those with a diagnostic white cell count over 50 X 10(9)/l, those with a mediastinal mass, those less than a year old at diagnosis, and those presenting with meningeal involvement. They accounted for 17, 5.3, 2.6, and 3%, respectively, of unselected children with ALL. As expected, all four categories showed significantly inferior relapse-free survival to the rest, but only in patients with a mediastinal mass and in the under-1-year-olds did a recognisable syndrome emerge clearly associated with other clinical features. These two syndromes, high-count T-ALL and high-count infant null-ALL, are logical candidates for alternative therapy. Established meningeal disease also continues to present a major therapeutic challenge.