TRANSFUSIONS AND RISK OF FAILURE IN CHILDHOOD ACUTE LYMPHOBLASTIC-LEUKEMIA

To examine the relationship of blood product support to treatment outc ome in childhood ALL, we reviewed records of all 358 patients with new ly diagnosed ALL treated on St Jude Total Therapy Study XI (February 1 984 to September 1988). All but six patients received blood products ( median 7 units, range 0-246), with approximately 90% given during the 6-week induction period. Because all 16 patients who received greater than or equal to 50 units failed, the number of units transfused was p redictive of treatment failure in multivariate analysis (relative risk =1.8, p = 0.02), although the number of units transfused was also ass ociated with initial leukocyte count and age. Among the remaining 342 patients who received <50 units, the number of units transfused was as sociated with reduced event-free survival in univariate analysis only, with maximal significance at >7 units (p = 0.006). Because exclusion of the 16 patients who received the most blood eliminates the independ ent effect of transfusions on patient outcome, we believe that the num ber of transfusions is largely an epiphenomenon which reflects the eff ects of two risk factors not included in traditional outcome analysis in childhood ALL. These are acuity of illness during induction, and re duction of chemotherapy doses during induction therapy, due to the sev erity of illness. Immunomodulation caused by exposure to blood product s appears unlikely to contribute strongly to outcome in childhood ALL.