San Francisco, CA—According to a study from the US Oncology Network, patients with breast cancer who are treated with adjuvant chemotherapy have no increased risk for acute myeloid leukemia (AML) or myelodysplastic syndromes (MDS), at least within the first 3 years of treatment.
“The rates of AML/MDS were found to be low after adjuvant chemotherapy, and similar to those noted in nonchemotherapy-treated patients,” reported Neelima Denduluri, MD, a medical oncologist at Virginia Cancer Specialists, Arlington, during the 2012 Breast Cancer Symposium.
Previous estimates have placed the risk for AML or MDS after breast cancer therapy at approximately 1%, with the greatest risk seen among older patients and patients who receive anthracyclines, higher cumulative doses of cyclophosphamide, or radiotherapy. It has not been established whether granulocyte colony-stimulating factors are correlated with increased risk, and incidence rates with taxane combinations are not well-characterized.
Dr Denduluri and colleagues explored the oncology-specific electronic health record iKnowMed, which contains nearly 1.3 million patient records. The base population included 20,900 patients with breast cancer, of whom 11,295 received chemotherapy.
At a median follow-up time of approximately 3 years, 12 cases of AML or of MDS were identified among chemotherapy recipients (0.106%); of these 12 patients, 8 were receiving anthracyclines and 11 were receiving pegfilgrastim. The median time to onset of AML or MDS in chemotherapy recipients was 22 months. Among patients with breast cancer who were not receiving chemotherapy, 16 cases of AML or MDS (0.167%) were reported.
The risk was significantly increased, by 7-fold, among patients aged ≥70 years and nearly 4-fold among those who received anthracyclines. By contrast, the almost 3-fold increase with pegfilgrastim was numerically higher but not statistically significant, Dr Denduluri said.
“With the recent news that Robin Roberts with Good Morning America developed MDS after beating breast cancer, many of my patients were concerned about the risk,” Dr Denduluri said. “This study can reassure patients who receive adjuvant chemotherapy that their risk of a secondary AML/MDS is very low within the first 3 years.”
