Older breast cancer survivors treated with anthracycline/cyclophosphamide chemotherapy that was enhanced by granulocyte colony-stimulating factors (G-CSF) have increased risk of myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML), according to a study of 56,251 women aged ≥ 66 years with stage I to III breast cancer. Researchers found:

• 1.2% of patients developed MDS/AML during median follow-up of 3.2 years.

• 47.1% of women received radiation and 14.3% received chemotherapy.

• Compared to patients treated with surgery alone, patients treated with chemotherapy (HR, 1.38) and chemotherapy/radiation (HR, 1.77) had increased risk of MDS/AML, but not radiation alone.

• MDS/AML was differentially associated with anthracycline/cyclophosphamide-containing regimens (HR, 1.86) and filgrastim (HR, 1.47), but not pegfilgrastim (HR, 1.10).

Citation: Calip GS, Malmgren JA, Lee WJ, Schwartz SM, Kaplan HG. Myelodysplastic syndrome and acute myeloid leukemia following adjuvant chemotherapy with and without granulocyte colony-stimulating factors for breast cancer. [Published online ahead of print October 8, 2015]. Breast Cancer Res Treat. doi: 10.1007/s10549-015-3590-1.