RESUMO
PURPOSE: To assess the importance of early clearance of blast cells in peripheral blood and the predictability of outcome in childhood acute lymphoblastic leukemia (ALL) through this method. METHODS: We reviewed medical records of all childhood patients with ALL enrolled on Severance Hospital (January 1992 to December 1997) to determine the presence of blast cells in peripheral blood at diagnosis and after 1 week of intensive induction therapy. RESULTS: Persistent circulating leukemic blasts were present at day 7 in 14 patients (11.4%) among 123 ALL patients. Compared with blast negative group, these patients had two adverse clinical and laboratory features (Hemoglobin level and L2 morphology), and a poorer 4-year event-free survival (69.8% vs. 82.7%, P<0.01). CONCLUSION: We found that this simple and noninvasive method, which can replace bone marrow examination, may be very beneficial to predict the prognosis of ALL.