The role of total body irradiation in acute lymphoblastic leukemia

This study compared the long-term effects of total body irradiation (TBI – powerful radiotherapy) plus cyclophosphamide (Cytoxan) with busulfan (Myleran) plus cyclophosphamide as part of the treatment for acute lymphoblastic leukemia (ALL). Researchers found that TBI is effective in younger patients and had higher overall survival rates in these patients.

Acute lymphoblastic leukemia is a cancer of the bone marrow that affects the cells of the immune system. It is often treated by deleting the abnormal cells from the immune system (myeloablative conditioning) and replacing them with healthy cells from a donor (a stem cell transplant). This conditioning can be carried out using radiation or with chemotherapy drugs. It is important to research the safety and effectiveness of these different treatment types.

One-hundred and fifty-one patients with ALL who were previously treated with conditioning and transplantation were included in the study. 93 (61.5%) were in complete remission (no signs of disease) and 58 (38.5%) were refractory/relapse (unresponsive to treatment). TBI was administered to 84 (55%) patients. TBI patients were followed up after 19 months. Non-TBI patients were followed for 14.5 months. 

No differences were found when comparing the groups in graft versus host disease (when transplanted cells attack healthy cells), blood clots or bacterial and fungal infections. Viral infections were significantly increased in the non-TBI group. TBI patients under 40 years of age had a 5-year overall survival (time from treatment until death from any cause) rate of 55.1%. 5-year disease-free survival was 48.6%.

The study concluded that total body irradiation may be a useful part of treatment for ALL when compared to busulfan-based therapy, in younger patients.

The study had a small sample size which may affect results. More research into the effect of different doses on treatment may be useful.