Myelodysplastic Syndrome and Acute Myeloid Leukemia Incidence Following Primary Breast Cancer Treatment.

Abstract

Abstract Background: Breast cancer (BC) patients receiving surgery plus radiation and/or adjuvant chemotherapy treatment are routinely monitored for incidence of myelodysplasia (MDS) and leukemia.Methods: A cohort of all breast cancer patients TNM stage 0-III treated with surgery and/or radiation or chemotherapy from 1989 to 2005 at our institution were followed for incidence of blood disorders of any type by our registry system and by linkage to the Surveillance, Epidemiology and End Results registry (SEER) for our area. Cases without surgery (n=111), with stem cell transplantation (n=98), unknown or non-standard chemotherapy regimens (n=23 + 71= 94), lost to follow up (n=66) or cancer status unknown at follow up (n=67) were excluded. The remaining 5790 cases were reviewed for incidence of leukemia including MDS and acute myelogenous leukemia (AML) post breast cancer treatment by chart review including pathology reports, SEER coding for MDS/AML, and death certificates if appropriate. Mean length of follow up was 7.17 years, range 2-18 years.Results: The mean age of MDS/AML patients was 57 years, range 33-76 years. The crude rate of MDS/AML occurrence was .29% (17/5790). 17 cases of MDS/AML (10 MDS/7 AML) occurred during the follow up period as compared with 6.22 (4.03 MDS/2.19 AML) expected on the basis of rates in the general population by age <65, ≥ 65 years calculated from SEER registry data (risk ratio (observed/expected)). The risk of MDS in women <65 was 11.68 times that expected and the risk of AML in women <65 was 9.2 times the expected rate. Risk among women over 65 was not as large (1.38 MDS, ≥ 65, 1.21 AML, ≥ 65). Average time from treatment with radiation or chemotherapy to MDS diagnosis was 5.50 years (range 1.03-12.95) and 3.42 years (range .41-6.84) for AML. The majority of MDS/AML cases occurred in the first five years post treatment (n=10) with 7 more cases observed from 5 to 12.95 years (see figure). Initial treatment of MDS/AML patients was surgery only (n=2), surgery/chemotherapy (n=1), surgery/ radiation (n=7), and surgery/chemotherapy/radiation (n=7). The two MDS patients who had initial treatment of surgery only were subsequently treated with chemotherapy and radiation for recurrence. Fifty percent of MDS patients (5/10) received surgery and radiation treatment without adjuvant chemotherapy treatment.Discussion: The incidence of MDS/AML is very small in this cohort but significantly greater than that expected in the population at large especially among women less than 65 years of age. A significant number of women who received radiation treatment without chemotherapy developed MDS post breast cancer treatment. Average time from treatment to MDS diagnosis exceeded the 2-5 year time period previously reported as an expected interval. Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2082.