Autologous or allogeneic bone marrow transplantation for acute myeloblastic leukemia in second complete remission. Importance of duration of first complete remission in final outcome

Between May 1983 and March 1994, 31 patients with AML in second CR underwent BMT. Fifteen underwent allogeneic BMT from an HLA-identical sibling donor and 16 without a donor, unpurged ABMT. Two different preparative regimens were used : CY (120 mg/kg) and 12 Gy of fractioned TBI (19 patients), and Bu (16 mg/kg) and Cy (120 mg/kg) (BuCy2) in 12 patients. Main clinical characteristics including age, sex, length of first remission, FAB type, and number of leukocytes at diagnosis were similar in both groups. A combination of MTX and CsA was used in 13 cases whereas either CsA or MTX alone was employed in the other two patients. With a median follow-up of 5 years the actuarial 5 year probability of disease-free survival (DFS) for the whole group was 39.8% (95% CI : 29.5-50.1%). The 5 year DFS was equivalent for those who received either ABMT (41.6 ± 14.2%) or allogeneic BMT (40 ± 15%). Probabilities of relapse and non-relapse mortality for ABMT and allo BMT patients were 48.7 ± 16.1 and 18.7 ± 14.3, and 30.1 ± 19.2 and 40.7 ± 16.9, respectively. DFS was better in those patients with a longer duration of first CR (>18 months) 62.5 ± 14.4 vs 30.4 ± 17.9%, attributable to a significantly lower relapse rate in this group of patients 16.6 ± 12.8 vs 57.8 ± 22.7 (P 0.05). In conclusion, similar results were observed when ABMT and allo BMT were compared for AML in CR2. A higher antileukemic effect associated with the allo BMT is balanced by an increase in transplant-related mortality. Duration of first remission was the most important factor affecting DFS and better outcome was observed for patients with longer CR1.