ASCOPost.com | OCTOBER 15, 2012
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2012 Breast Cancer Symposium Adjuvant Chemotherapy for Breast Cancer Not Linked to Acute Myeloid Leukemia and Myelodysplastic Syndromes By Caroline Helwick
Neelima Denduluri, MD
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ontradicting 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– See Page 110 chemotherapy-treated patients,” Dr. Denduluri reported. She acknowledged that the followup 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 colonystimulating 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-contain-
Adjuvant Chemotherapy and AML/MDS Risk ■■ A large population-based study found that the risk of secondary acute myeloid leukemia and myelodysplastic syndromes following adjuvant chemotherapy is not increased, compared to patients not receiving chemotherapy.
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“We can identify patients with high residual risk in spite of receiving chemotherapy. We can try to find a better treatment for them or enroll them in clinical trials evaluating novel adjuvant therapies. On the other hand, patients with low residual risk may do well with shorter duration of chemo-
therapy and will not be the best candidates for such clinical trials.” He suggested that for low-risk patients it might be sufficient to treat with four cycles of AC, rather than a full course of eight cycles, including a taxane, though this will require further confirmation. Existing data already suggest, he added, that low-risk patients may not benefit from che-
ing therapy. The median time to onset of AML/ MDS was 1.8 years in the chemotherapy group and 2.2 years in the nochemotherapy group. Among patients for whom cytogenetic information was available, abnormal cytogenetics were identified in 8 of 11 chemotherapytreated patients with AML/MDS and in 3 of 15 cases with no prior chemotherapy.
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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.
EXPERT POINT OF VIEW
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lifford A. Hudis, MD, of Memorial SloanKettering Cancer Center, New York, said that the findings of the US Oncology study should be “very reassuring” to physicians and patients. “Several recent publications and SEER (Surveillance, Epidemiology, and End Results) database analyses have reported what strike some of us as remarkably high rates of AML/MDS,” he Clifford A. Hudis, MD told The ASCO Post. The current study results are much more in line with clinical trial data (such as the pivotal Cancer and Leukemia Group B [CALGB] 9741 trial of dose-dense chemotherapy1) that show the risk to be “a fraction of a percentage,” he said. Dr. Hudis added, “I think studies based on SEER data are overestimating the real risk. Dr. Denduluri showed data that are more in line with what the prospective randomized trials have reported. My argument has always been that prospective randomized clinical trials are the right way to identify this toxicity, and not Medicare claims.”
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Disclosure: Dr. Hudis reported no potential conflicts of interest.
Reference 1. Citron ML, Berry DA, Cirrincione C, et al: Randomized trial of dose-dense versus conventionally scheduled and sequential versus concurrent combination chemotherapy as postoperative adjuvant treatment of node-positive primary breast cancer: First report of Intergroup Trial C9741/Cancer and Leukemia Group B Tiral 9741. J Clin Oncol 21:1431-1439, 2003.
motherapy at all, and this is being further tested in a prospective Southwest Oncology Group (SWOG) trial (RxPONDER). The NSABP B-28 analysis indicates that the extent of chemotherapy might be tailored according to the estimation of residual risk, he said.
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Disclosure: Dr. Mamounas serves as consultant (advisory board) and speaker for Genomic Health, Inc.
Reference 1. Mamounas EP, Tang G, Paik S, et al: Prognostic impact of the 21-gene recurrence score on disease-free and overall survival of node-positive, ER-positive patients with breast cancer treated with adjuvant chemotherapy: Results from NSABP B-28. 2012 Breast Cancer Symposium. Abstract 1. Presented September 13, 2011.