Allogeneic bone marrow transplantation for adult acute lymphoblastic leukemia in first complete remission: factors predictive of transplant-related mortality and influence of total body irradiation modalities.

In a retrospective multicentre study, we analyzed 184 consecutive patients who underwent bone marrow transplantation (BMT) from identical siblings for adult acute lymphoblastic leukemia in first complete remission between March 1980 and May 1989. The main causes of transplant-related mortality were GVHD and interstitial pneumonitis. Univariate and multivariate analyses identified the mode of total body irradiation (TBI) as the only independent predictive factor of transplant-related mortality. Ninety-one patients received single-dose TBI and 93 received fractionated-dose TBI as part of the conditioning regimen prior to BMT. Transplant-related mortality was more frequent in the single dose group (p = 0.017). The incidence of interstitial pneumonitis, acute and chronic GVHD and veno-occlusive disease of the liver was not statistically different between the two irradiation groups. However, fatal interstitial pneumonitis was significantly more frequent in the single dose irradiation group (p = 0.031). These results show that transplant-related mortality is closely associated with the mode of TBI administration. The increased relapse rate in the fractionated group explains why there was no difference between the two groups in terms of overall leukemia-free survival.