Allogeneic bone marrow transplantation for chronic myeloid leukemia using sibling and volunteer unrelated donors. A comparison of complications in the first 2 years.

Objective: To compare the short- and medium-term complications (particularly infection) of bone marrow transplantation for chronic myeloid leukemia in patients with HLA-identical sibling donors or volunteer unrelated donors.
Design: Retrospective review of two cohorts of patients.
Setting: Tertiary referral center.
Patients: One hundred three patients with chronic myeloid leukemia in first chronic phase.
Intervention: Patients were treated with bone marrow transplantation using marrow from HLA-identical siblings (n = 57) and volunteer donors (n = 46).
Main Results: In total, 68 patients survived a median of 22 months from bone marrow transplant (range, 7 to 81 months). The actuarial probabilities of overall survival and leukemia-free survival at 2 years for the sibling donor group were 73% (95% CI, 60% to 86%) and 72% (CI, 60% to 84%), respectively, and for the volunteer donor group, 47% (CI, 31% to 63%) and 42% (CI, 26% to 58%) (P = 0.07 and 0.05, respectively). However, after adjustment for duration of disease, overall and disease-free survival in the two donor groups did not differ significantly. A major problem was an increased incidence of severe viral infection in the volunteer unrelated donor group (19 episodes in 16 of 46 patients compared with 7 episodes in 7 of 57 sibling donor patients, P = 0.01). The actuarial incidence of chronic graft-versus-host disease (GVHD) was higher in volunteer unrelated donor patients (77% [CI, 63% to 91%] compared with 49% [CI, 35% to 63%]; P = 0.02) but that of acute GVHD was not. The median performance status of the survivors in the volunteer donor group is similar to that in the sibling donor group. The incidence of hematologic relapse in both groups so far is low.
Conclusion: Results appear to justify the continued use of volunteer donors in chronic-phase chronic myeloid leukemia, but infection and chronic GVHD are still major problems.