Total marrow and lymphoid irradiation [TMLI] can deliver higher doses of irradiation without increased toxicity. This study evaluated TMLI and Cyclophosphamide in patients undergoing stem cell transplantation for acute lymphoblastic leukemia [ALL] . Fifty-eight patients underwent matched related, unrelated or haplo-identical donor transplant using TMLI. The graft source was PBSC in all while GVHD prophylaxis consisted of cyclosporine with methotrexate or post-transplant cyclophosphamide. The median age was 20 years [range: 5 - 49] and included 20 children. Engraftment occurred in 56 [96.5%] at median of 15 days [range: 12 - 23] with 2 early deaths. Sinusoidal obstruction syndrome [SOS] was seen in 10 patients while hemorrhagic cystitis and cardiac dysfunction occurred in 2 patients each. Cumulative incidence of grade II - IV acute GVHD was 23.6% while grade III - IV was 10.9%. Chronic GVHD was seen in 46.9% while relapse was seen in 10 patients [17.2%]. The 2-year overall survival [OS] was 65.9 ± 6.8% and 2-year disease free survival [DFS] was 59 ± 6.7%. Outcomes were compared with 52 patients who received either Cy/TBI or Flu/Bu4 for conditioning during the same period. Engraftment rates and time to engraftment were similar. Acute GVHD [p = 0.002], regimen related toxicity [p = 0.043] and Day 100 non-relapse mortality [p = 0.020] were significantly lower with TMLI. TMLI was associated with better OS [p = 0.004] and DFS [p = 0.005] for haplo-identical transplants. Better DFS was seen with TMLI in patients with high-risk disease [p = 0.007] and disease status > CR1 [p = 0.041]. The use of TMLI and cyclophosphamide is associated with good outcomes in patients undergoing HSCT for ALL especially with haploidentical stem cell transplants.
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