Treatment of acute lymphoblastic leukemia with chemotherapy alone or hematopoeietic stem cell transplantation-long term follow up

From 1988 to 1998 one hundred forty eight patients with acute lymphoblastic leukemia (ALL) were enrolled into prospective study. The aim of the study was to evaluate efficacy of common treatment for acute lymphoblastic leukemia and to determine risk factor for outcome. Out of 148 patients, 31 (21%) had acute nondifferentiated leukemia (according to the FAB criteria) with expression of lymphoid markers. Those patients were treated in the same way as patients with ALL. According to the type of consolidation therapy patients were divided into three groups. Chemotherapy alone received 38 (38%) patients, and 30 (31%) patients received autologous stem cell transplantation (SCT) or allogeneic STC. There were no statistical difference in sex, age, FAB subtype, number of WBC and platelets in the time of diagnosis and incidence of cytogenetic abnormalities between these three groups. Median follow-up for chemotherapy group was 68 (range 12-98) months, for allogeneic SCT 102 (range 12-120) and for autologous SCT 99 (range 12-105) months. As a condition regimen the majority of patients treated with SCT received total body irradiation followed by cyclophosphamide. There was statistically significant difference in the source of stem cell for transplantation: in 20% of autologous SCT peripheral blood was used as source of stem cells. Relapse rate was significantly higher in patients receiving chemotherapy alone than in patients receiving either autologous or allogeneic SCT (83 vs. 45 vs. 27%, p<0.03). Treatment related mortality was low for chemotherapy and autologous SCT group and higher for allogeneic SCT (10 vs. 18%, p<0.05). There was statistically significant difference in the probability of disease free survival between chemotherapy and other two groups (p=0.01). Five year probability of disease free survival for chemotherapy group was 12+-12%, for autologous SCT 54+-13% and allogeneic SCT 55+-17%. In univariate analysis risk factors for treatment failure in all three groups were older age and high number of WBC at the time of diagnosis. The third risk factor in allogeneic SCT for treatment failure was development of acute or chronic graft vs. host disease. In multivariate analysis risk factor for treatment failure were older age and treatment with chemotherapy alone. The main cause of death for patients enrolled into chemotherapy group and autologous SCT was disease relapse while the main cause of death for allogeneic SCT were disease recurrence and graft vs. host disease with or without infections.