Evaluating the effectiveness and safety of busulfan plus cyclophosphamide versus total body irradiation plus cyclophosphamide for patients with adult B-cell acute lymphoblastic leukemia.

This study evaluated the effectiveness and safety of busulfan (Bu; Busulfex) plus cyclophosphamide (Cy; Cytoxan) (BuCy) regimen versus total body irradiation (TBI) plus cyclophosphamide (TBI-Cy) regimen for patients with adult B-cell acute lymphoblastic leukemia (B-ALL) in first complete remission undergoing allogeneic hematopoietic stem-cell transplantation (allo-HSCT). The data showed that the BuCy regimen was as effective and as safe as the TBI-Cy regimen for these patients.

B-cell acute lymphoblastic leukemia (B-ALL) is a type of cancer in which the body makes too many lymphocytes (a type of white blood cell). This is the most common type of blood cancer in children. A conditioning regimen is a treatment used to prepare a patient for stem cell transplantation.

Total body irradiation (TBI) in combination with chemotherapy is widely used as a conditioning regimen for pediatric and adult hematopoietic stem cell transplantation (HSCT). TBI kills any cancer cells left after chemotherapy and helps make room for new blood stem cells to grow. It can also help prevent the immune system from rejecting transplanted cells. TBI is very effective but has important later-life side effects.

Cyclophosphamide combined with intravenous busulfan is the main conditioning regimen for allo-HSCT in young patients with B-ALL. However, the effectiveness and safety of BuCy regimen versus TBI-Cy regimen for patients with adult B-cell-ALL in first complete remission undergoing allo-HSCT are still under investigation.

This study involved 545 patients with B-ALL. Patients were randomly assigned into two groups. Group 1 included 273 patients who received the BuCy regimen. Group 2 included 272 patients who received TBI-Cy. The average follow-up time was 42 months.

After 2 years, 76.6% of the patients in group 1 were alive versus 79.4% of the patients in group 2. This difference was not considered statistically significant.

After 2 years, 20.2% of the patients in group 1 experienced relapse (cancer coming back) versus 18.4% of the patients in group 2. This difference was not considered statistically significant. The number of patients who died without cancer relapse was 11% in both groups.

There were no differences in treatment-related side effects between the two groups.

This study concluded that the BuCy regimen was as effective and as safe as the TBI-Cy regimen for patients with adult B cell-ALL in first complete remission undergoing allo-HSCT.

The patients knew which treatment they were getting, which might affect the conclusions. This study only included patients treated at institutions in China. Further studies are needed.