No advantage for patients who receive splenic irradiation before bone marrow transplantation for chronic myeloid leukaemia: Results of a prospective randomized study

A total of 239 patients with chronic myeloid leukaemia (CML) in chronic phase awaiting bone marrow transplantation (BMT) from an HLA-identical sibling donor were randomized to receive, as part of their conditioning, splenic irradiation (SI+) or no splenic irradiation (SI-). There was no difference between the SI+ and SI- groups regarding the distribution of age, sex, donor/recipient sex combination and blood counts at diagnosis and at BMT. Survival, leukaemia-free survival (LFS), incidence of transplant-related mortality, incidence of rejection and probability of relapse do not differ between the 117 SI+ and the 118 SI- patients at a median follow-up time of 2.5 years (minimum 0.5 years). LFS at 30 months is 56% (SE 5%) for the SI+ and 51% (SE 6%) for the SI- group (p = 0.65). LFS is better for younger patients (9/l) (p <0.05). It is worst for male recipients of a female marrow (p <0.05). The incidence of graft-versus-host disease grade ≥II was higher in the SI+ group, though not significantly. We conclude that routine splenic irradiation prior to BMT for patients with CML is of no benefit and should not be used as a routine procedure.