Myelodysplastic syndrome/ Myeloproliferative disorder, Nos.

Background: Population-based research is limited for myelodysplastic syndrome/ myeloproliferative neoplasm, not otherwise specified (MDS/MPN-NOS) which comprises a heterogenous group of patients that do not fit into the other established MDS/MPN subgroups. Methods: We identified patients from the Surveillance, Epidemiology, and End Results (SEER) database with a diagnosis of MDS/MPN-U logged from 2010-2020. Age-standardized incidence rates (ASIR) and incidence rate ratios (IRR) were calculated using eight age subgroups. Subgroup analyses were performed for race and gender. Join point regression analyses were performed to model trends in ASIRs, and annual percent change (APC) was calculated. Results: A total of 2447 patients over age 50 were included in analysis. Incidence of MDS/MPN-U increased gradually between 2010-2016 (APC 12.90) then decreased between 2016-2020 (APC -19.56). ASIR was significantly higher in males compared to females in several age groups (age 65-69, 80-84, 85+). Conclusion: The underlying molecular complexity of these diseases remains a significant challenge. It is critical to identify MDS/MPN- specific therapeutic response criteria and suitable end points correlated with survival and AML risk for transformation to acute myeloid leukemia (AML) uniform assessment of treatment benefit.