Prognostic significance of leukopenia in childhood acute lymphoblastic leukemia

Chemotherapy-induced leukopenia has been shown to be associated with the outcomes of several types of cancer, but the association with childhood acute lymphoblastic leukemia (ALL) remains unknown. To elucidate the association of chemotherapy-induced leukopenia with the clinical outcome of childhood ALL, retrospective analysis was performed on 19 child patients with ALL treated according to the ALL-BFM 95 high-risk (HR) protocol. The mean minimum leukocyte count over the first three courses of the consolidation phase was used as the measure of hematological toxicity and ranged between 200 and 1,167/μl. The risk of relapse was significantly higher in patients with a mean minimum leukocyte count above the median of 433/μl (hazard ratio, 6.61; P=0.047). In conclusion, chemotherapy-induced leukopenia was found to correlate with relapse-free survival in childhood HR ALL. Dose escalation based on hematologic toxicity must be prospectively studied.