Total body irradiation and risk of breast cancer after transplantation in patients with leukemia-lymphoma

This study aimed to investigate the association between total body irradiation and further breast cancer diagnosis in patients treated with blood or marrow transplantation for leukemia-lymphoma. 

This study concluded that there is an association between the total body irradiation and an increased risk of breast cancer in certain patients.  

Patients with leukemia-lymphoma often benefit from blood or marrow transplantation (BMT). BMT involves transplanting healthy blood or bone marrow cells in order to help the immune system fight cancer and replace cells damaged by radiation or chemotherapy. This can be done with the patient's own healthy cells (autologous BMT) or with cells from a donor (allogeneic BMT). Total body irradiation (TBI) is a form of radiotherapy used as part of the regimen to prepare for BMT.  

Therapy used to remove cancer cells is known to increase the risk of further cancers. However, if there was an association between TBI and subsequent breast cancer (BC) in patients who receive BMT as a treatment for leukemia-lymphoma remains under investigation.  

This study involved 1464 female BMT survivors. Patients had either autologous (46.2%) or allogeneic (53.8%) BMT for acute leukemia, chronic myeloid leukemia (CML), Hodgkin lymphoma (HL), or non-Hodgkin lymphoma (NHL). 45.5% of the patients had TBI before BMT. Patients were followed up with an average of 9.3 years after BMT.  

Overall, 37 women developed BC after an average of 9.1 years after BMT. Exposure to TBI was associated with an increased risk of further BC among allogenic BMT survivors and autologous BMT survivors. 2.6% of patients younger than 50 who had TBI developed BC compared to 0.3% in the non-TBI group. 4.5% of patients younger than 60 with TBI developed BC compared to 1.6% non-TBI. 8.8% TBI patients before 70 years of age developed BC compared to 3.6% non-TBI patients.

TBI was associated with a 3.73 times higher risk for BC in patients receiving allogeneic BMT and a 2.6 times higher risk for those receiving autologous BMT. Additionally, receiving chemotherapy with alkylating agents or anthracycline before BMT was associated with a 2.5-3 times higher risk of BC among patients receiving autologous BMT. This effect of chemotherapy was not seen in those who had an allogeneic BMT.

When compared to the general population, TBI was associated with a 1.5 times higher risk of developing BC. Exposure to TBI before the age of 30 was associated with a 4.4 times higher risk of BC after allogeneic BMT and a 4.6 times higher risk after autologous BMT. 

This study concluded that there is an association between TBI and subsequent breast cancer in women with leukemia-lymphoma undergoing BMT, especially among those exposed at a young age.