Contradicting what some previous investigations have found, a study from The US Oncology Network found that adjuvant chemotherapy for breast cancer does not increase the risk of acute myeloid leukemia and myelodysplastic syndromes (AML/MDS), at least within the first 3 years of treatment.1 The study was presented at the 2012 Breast Cancer Symposium by Neelima Denduluri, MD, of Virginia Cancer Specialists, Arlington, Virginia.
“The rates of AML/MDS were found to be low after adjuvant chemotherapy, and similar to those noted in non–chemotherapy-treated patients,” Dr. Denduluri reported.
She acknowledged that the follow-up time is short. However, she pointed out, “the majority of topoisomerase-induced leukemias are detected within the first 3 years.”
The risk of developing AML/MDS after breast cancer treatment has been estimated at approximately 1% overall, though higher risks may be incurred by patients who are older and those who have received anthracyclines, high cumulative doses of cyclophosphamide, or radiotherapy. It has not been established whether granulocyte colony-stimulating factors or taxanes are correlated with increased risk.
The goal of this study was to evaluate risk among the population of 20,900 breast cancer patients in the oncology-specific electronic health record, iKnowMed.
No Increased Risk from Chemotherapy
At a median follow-up of about 3 years, 12 cases of AML/MDS were identified among 11,295 chemotherapy recipients (0.106%), including 11 cases among 8,829 patients receiving pegfilgrastim (Neulasta) and 1 case among 2,466 patients not receiving pegfilgrastim. Among 9,605 patients not receiving chemotherapy, there were 16 cases (0.167%, P = .26). Of the 12 cases of AML/MDS in chemotherapy-treated patients, 8 patients had received anthracycline-containing therapy.
The median time to onset of AML/MDS was 1.8 years in the chemotherapy group and 2.2 years in the no-chemotherapy group. Among patients for whom cytogenetic information was available, abnormal cytogenetics were identified in 8 of 11 chemotherapy-treated patients with AML/MDS and in 3 of 15 cases with no prior chemotherapy. ■
Disclosure: Dr. Denduluri reported no potential conflicts of interest.
Reference
1. Denduluri N: Risk of acute myeloid leukemia and myelodysplastic syndrome after adjuvant chemotherapy for early breast cancer in the community setting. 2012 Breast Cancer Symposium. Abstract 62. Presented September 14, 2012.
