PROGNOSTIC FACTORS IN CHILDHOOD ACUTE LYMPHOBLASTIC LEUKEMIA: CORRELATION WITH TREATMENT RESPONSE

In 1949 Dr. Zuelzer, in his note on progress in pediatric hematology, made a then passing observation that in childhood ALL, the level of WBC at diagnosis has a bearing on survival (1). He noted, in a group of children with leukemia treated before the days of chemotherapy, that those presenting with WBC 10,000 at diagnosis, survived longer than those presenting with higher WBC counts. Some nineteen years later in 1968, Hardisty and Till (2) observed that children with ALL presenting with mediastinal mass (ALL + MM) have a poor outcome and show distinctly different clinical characteristics and thus, may have a biologically different form of ALL compared to others. In a later study (3) we confirmed this and showed that children with ALL + MM tend to have higher WBC, higher hemoglobin and platelet counts at presentation; that this presentation is seen more often in boys of older age and that they relapse early and thei survival is shorter. From these modest beginnings we have come a long way in recognizing that childhood ALL is a heterogeneous disease both in terms of clinical presentation and biologic characteristics. It is now well accepted that treatment has to be “tailored”, keeping in mind the clinical prognostic factors and immunologic subtypes of ALL.