Incidence of secondary myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) in patients with ovarian or breast cancer in a real-world setting in the United States

Real-world data on patients with cancer developing secondary malignancies such as myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) are lacking. This study assessed the incidence and impact of select DNA-damaging therapy exposure on risk of secondary MDS and AML in patients with ovarian cancer (OC) or breast cancer (BC). Adults with a first observed OC or BC diagnosis (index date) between 1/1/2000 and 6/30/2014 were identified from MarketScan® Commercial and Medicare databases. Patients had ≥12 months of pre-index and ≥1 month of post-index continuous health plan enrollment. Incidence of MDS/AML was evaluated over a variable-length period following the index date for each cancer cohort. Risk factors for secondary MDS/AML, including duration of DNA-damaging therapy exposure, were assessed using Poisson regression. Study selection criteria identified 23,862 patients with OC and 281,473 patients with BC (mean [SD] follow-up: 35.8 [31.4] and 46.0 [37.2] months, respectively). Incidence of MDS/AML was 2.77 and 1.44 per 1000 person-years among patients with OC and BC, respectively. Within both cohorts, incidence of MDS and AML was higher among patients exposed than those not exposed to select DNA-damaging therapy (alkylating agents, antimetabolites, platinum-based antineoplastic agents, and topoisomerase inhibitors). Duration of exposure to DNA-damaging therapy was a significant risk factor for developing MDS/AML during follow-up. Data suggest that there is likely a background risk of secondary MDS/AML associated with use of DNA-damaging therapies in earlier lines of chemotherapy and it is elevated in subcohorts exposed to select DNA-damaging therapies. •Data on secondary MDS or AML and its association to DNA-damaging therapy is lacking.•Secondary MDS or AML was seen in ovarian and breast cancer in chemotherapy users.•DNA-damaging therapy use was associated with increased risk of secondary MDS or AML.