Analysis of prognostic factors in newly diagnosed acute promyelocytic leukemia treated with all-trans retinoic acid and chemotherapy

Purpose: We conducted a multicenter study of differentiation therapy with all-trans retinoic acid (ATRA) followed by intensive chemotherapy in patients with newly diagnosed acute promyelocytic leukemia (APL) and analyzed the prognostic factors for predicting complete remission (CR), event-free survival (EFS), and disease-free survival (DFS). Patients and Methods: All patients received ATRA until CR. If patients had an initial leukocyte count greater than 3.0 x 10(9)/L, they received daunorubicin (DNR) and behenoyl cytarabine (BHAC). During therapy if patients showed blast and promyelocyte counts greater than 1.0 x 10(9)/L, they received additional DNR and BHAC. After achieving CR, patients received three courses of consolidation and six courses of maintenance/intensification chemotherapy. Results: Of 198 registered, 196 were assessable (age range, 15 to 86 years; median, 46) and 173 (88%) achieved CR. Multivariate analysis showed that no or minor purpura at diagnosis (P = .0046) and age less than 30 years (P = .0076) were favorable factors for achievement of CR. Predicted 4-year overall survival and EFS rates were 74% and 54%, respectively, and the 4-year predicted DFS rate for 173 CR patients was 62%. Multivariate analysis showed that age less than 30 years (P = .0003) and initial leukocyte count less than 10 x 10(9)/L (P = .0296) were prognostic factors for longer EFS, and initial leukocyte count less than 10.0 x 10(9)/L was a sole significant prognostic factor for longer DFS (P = .0001). Conclusion: Our results show that age, hemorrhagic diathesis, and initial leukocyte count are prognostic factors for APL treated with ATRA followed by intensive chemotherapy. (C) 1998 by American Society of Clinical Oncology.