Incidence of secondary myelodysplastic syndrome and acute myeloid leukemia in patients with ovarian and breast cancer in real-world setting in the U.S.

Abstract

5574 Background: Limited real-world data are available on cancer patients withsecondary malignancies such as myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) caused by use of certain chemotherapeutic agents that interfere with DNA. This study assessedthe incidence of secondary MDS and AML in patients (pts) with ovarian cancer (OC) or breast cancer (BC), including subcohorts tested for BRCA mutations and those exposed to DNA damaging therapy. Methods: Adult females with OC or BC between 1/1/2000 and 6/30/2014 (first observed diagnosis of OC or BC = index date) were identified from the MarketScan Commercial and Medicare claims databases. Patients had ≥12 months of pre- and ≥1 month of post-index continuous health plan enrollment. The incidence of MDS and AML (per 1000 person-years [PY]) was assessed using ICD-9 codes over a variable-length post-index period for each cancer cohort and separately for pts with BRCA testing and those exposed to DNA damaging therapy. Results: The study identified 23,862 OC pts (mean [SD] follow-up: 35.8 [31.4] months), and 281,473 BC pts (mean [SD] follow-up: 46.0 [37.2] months). Among OC pts, 10.9% had BRCA testing (OC- BRCA) and 56.6% had exposure to DNA damaging therapy (OC-DNA); 12.9% of BC pts were BRCA tested (BC- BRCA) and 28.1% had exposure to DNA damaging therapy (BC-DNA). The incidence of MDS and AML expressed as cases per 1,000 PY in the OC cohort was 0.51 (0.2%) and 0.39 (0.1%); in OC- BRCA pts, 0.62 and 0.25; and in OC-DNA pts, 0.68 and 0.41. In the BC cohort, the incidence of MDS and AML was 0.33 (0.1%) and 0.19 (0.1%); in BC- BRCA pts, 0.07 and 0.15; and in BC-DNA pts, 0.60 and 0.50. Conclusions: In addition to providing background rates in OC and BC pts, these data suggest that the incidence of MDS and AML in OC and BC pts was higher in patient subcohorts exposed to DNA damaging agents than in the overall cohort.