Toxicity associated with high-dose cytosine arabinoside and total body irradiation as conditioning for allogeneic bone marrow transplantation.

Seventy-three patients with hematological cancers undergoing allogeneic bone marrow transplantation (BMT) were evaluated for event-free survival (EFS) and toxicity. All received 36 g/m2 cytosine arabinoside (HDA) and 1200 cGy fractionated total body irradiation (TBI). We assessed the association of EFS and toxicities with the following risk factors; age, gender, diagnosis, initial relapse risk and patient-donor histocompatibility. The EFS probability is 33% at 800 days post-BMT. Twenty-six patients (36%) died of toxicity within 100 days and 14 (19%) have relapsed. EFS was inversely associated with age (P < 0.0001) and initial relapse risk (P = 0.007). The risk of pulmonary (P = 0.023) and hepatic toxicity (P = 0.011) increased with age. Diagnosis other than acute lymphoblastic leukemia (ALL) was a risk factor (P = 0.015) for graft-versus-host disease (GVHD); and fewer ALL patients died from toxicity (P = 0.014). The probability of sepsis within 100 days post-BMT correlated (P = 0.007) with initial relapse risk. We conclude: (1) the lower EFS and greater pulmonary and hepatic toxicity associated with increasing age indicate a need for less toxic regimens that maintain high antileukemic efficacy for older patients; (2) the high GVHD and sepsis rates seen in certain categories of patients indicate a need for careful definition of eligibility criteria for this still highly toxic treatment.