Optimizing bone marrow transplantation in Bulgaria

From the IAEA Division of Human Health, Applied Radiation Biology and Radiotherapy Section

Each year, hundreds of cancer patients in Bulgaria receive a bone marrow transplant (BMT) as treatment for haematological cancers such as leukaemia, lymphoma and multiple myeloma, or for solid tumours such as neuroblastoma - one of the most common cancers in infants.

To undergo a bone marrow transplant, patients must first go through a preparatory process that conditions the body for the transplant. This involves a special radiotherapy technique called total body irradiation (TBI). TBI helps to make space for the transplanted marrow, kills any malignant cells that may be left after chemotherapy and suppresses the immune system to help prevent rejection of the transplant. To avoid complications, patients must also receive irradiated cellular blood components during the preparatory process.

Radiation therapy technologists (RTTs) in the control console room, administering total body radiation. (Photo: L. Gocheva-Petkova, Queen Giovanna University Hospital, Bulgaria)

The IAEA helps medical professionals in Bulgaria to optimize bone marrow transplantation by providing the equipment and building the capabilities necessary to carry out TBI. The IAEA also offers very specialized radiotherapy training to the medical staff, including blood irradiation.

Under the IAEA technical cooperation (TC) project 'Routine Application of Highly Specialized Total Body Irradiation Prior to Bone Marrow Transplantation', the IAEA provided technical support to hospitals in Bulgaria in some essential areas of the pre-transplant conditioning regime that are key to improving cancer treatment in the country. These include optimizing total body irradiation treatment and dose, and reducing the incidence and severity of a significant and usually fatal complication called a transfusion-associated graft-versus-host disease (TA-GVHD). TA-GVHD may occur in several clinical conditions, such as autologous bone marrow transplant or peripheral blood stem cell transplant. To avoid this kind of complication, patients should receive irradiated cellular blood components throughout the period of their conditioning regime.

With the support of the TC project, a blood irradiator was purchased for the Queen Giovanna University Hospital in Sofia for irradiation of blood components to prevent the occurrence of TA-GVHD. A new linear accelerator (LINAC), which is the best tool to carry out total body irradiation, was also provided through the project. The LINAC was installed at the Queen Giovanna University Hospital in 2010, making its Radiotherapy Clinic the first and only one in the country capable of performing total body irradiation.

In addition, the project supported the delivery of a treatment table dedicated for carrying out TBI. This special bed places patients in a certain position, allowing for a more homogenous delivery of radiation to the whole body, while placing adequate shields for the lungs.

The routine application of a highly specialized and expensive therapeutic procedure such as bone marrow transplant with total body irradiation conditioning is now a reality in Bulgaria, and blood irradiation is being used to support several areas of practice such as transfusion haematology, transplantation of organs, tissues and cells, and neonatology. These services are of especially high value for the children of Bulgaria.

Radiation therapy technologist (RTT) preparing the treatment room for total body irradiation. (Photo:L. Gocheva-Petkova, Queen Giovanna University Hospital, Bulgaria)