Increased incidence of myelodysplastic syndrome and acute myeloid leukemia following breast cancer treatment with radiation alone or combined with chemotherapy: a registry cohort analysis 1990-2005

• Main Authors: Malmgren Judith A, Kaplan Henry G, Atwood Mary K
• Format: Article
• Language: English
• Published: BMC 2011-06-01
• Series: BMC Cancer
• Online Access: http://www.biomedcentral.com/1471-2407/11/260

<p>Abstract</p> <p>Background</p> <p>Our objective was to measure myelodysplastic syndrome (MDS) and acute myelogenous leukemia (AML) risk associated with radiation and/or chemotherapy breast cancer (BC) treatment.</p> <p>Methods</p> <p>Our study cohort was composed of BC patients diagnosed from 1990 to 2005 and followed up for blood disorders, mean length of follow up = 7.17 years, range 2-18 years. 5790 TNM stage 0-III patients treated with surgery alone, radiation and/or chemotherapy were included. Patients without surgery (n = 111), with stem cell transplantation (n = 98), unknown or non-standard chemotherapy regimens (n = 94), lost to follow up (n = 66) or 'cancer status unknown' (n = 67) were excluded. Rates observed at our community based cancer care institution were compared to SEER incidence data for rate ratio (RR) calculations.</p> <p>Results</p> <p>17 cases of MDS/AML (10 MDS/7 AML) occurred during the follow up period, crude rate .29% (95% CI = .17, .47), SEER comparison RR = 3.94 (95% CI = 2.34, 6.15). The RR of MDS in patients age < 65 comparing our cohort incidence to SEER incidence data was 10.88 (95% CI = 3.84, 24.03) and the RR of AML in patients age < 65 was 5.32 (95% CI = 1.31, 14.04). No significant increased risk of MDS or AML was observed in women ≥ 65 or the surgery/chemotherapy-only group. A RR of 3.32 (95% CI = 1.42, 6.45) was observed in the surgery/radiation-only group and a RR of 6.32 (95% CI = 3.03, 11.45) in the surgery/radiation/chemotherapy group. 3 out of 10 MDS cases died of disease at an average 3.8 months post diagnosis and five of seven AML cases died at an average 9 months post diagnosis.</p> <p>Conclusions</p> <p>An elevated rate of MDS and AML was observed among breast cancer patients < 65, those treated with radiation and those treated with radiation and chemotherapy compared to available population incidence data. Although a small number of patients are affected, leukemia risk associated with treatment and younger age is significant.</p>