Leukemia is a rare but severe side effect that can occur as a result of breast cancer treatment. The National Comprehensive Cancer Network conducted a study to assess the incidence of leukemia in 20,533 patients diagnosed with early-stage breast cancer who were treated at NCCN cancer centers. The ten year cumulative incidence of leukemia in the population as a whole was 0.46%. When treatment subgroups were compared, women treated with surgery alone had a lower risk (0.2%) compared to women treated with radiation (0.44%), chemotherapy (0.52%), or chemotherapy and radiation (0.51%). Of note, the frequency of myelodysplatic syndrome (MDS) is likely under-represented in this study due to the under-reporting of this condition until recently. Furthermore, very few patients in this population were prescribed docetaxel/cycolphosphamide (TC) chemotherapy, so the risk of leukemia for this regimen cannot be inferred from this study.
Source: “Myelodysplatic syndrome and/or acute myelogenus leukemia (MDS and/or AML) after a breast cancer diagnosis: the National Comprehensive Cancer Network (NCCN) experience.” Presented at the 2012 San Antonio Breast Cancer Symposium by Karp et al., abstract S3-5.