The incidence, risk factors, and survival of acute myeloid leukemia secondary to chronic myelomonocytic leukemia: a population-based study.

Background: Chronic myelomonocytic leukemia (CMML) is a heterogeneous myeloid malignancy, characterized by sustained peripheral blood monocytosis and an inherent risk of secondary acute myeloid leukemia (s-AML). This study aimed to determine the incidence, risk factors, and survival of AML secondary to CMML.

Methods: We conducted this retrospective analysis based on the Surveillance, Epidemiology, and End Results (SEER) database.

Results: We identified 3,218 patients with primary CMML. After a median follow-up time of 23 months, 291 patients developed s-AML and most of them occurred in the first year of CMML diagnosis, with cumulative incidence of 10.8%. In competing risk analysis, risk factors for s-AML were younger age and exposure to chemotherapy at CMML diagnosis. The post-progression survival (PPS) of s-AML was dismal with a median survival of 4 months (1-, 3-, and 5-year PPS of 26.6%, 9.6%, and 7.1%, respectively), while younger age and exposure to chemotherapy at s-AML development were protective factors for PPS. Considering CMML, s-AML development, older age, and exposure to chemotherapy at CMML diagnosis were risk factors for overall survival (OS). In addition, being married, higher income, and non-Hispanic White were important protective factors for OS of CMML.

Conclusions: The risk of s-AML among CMML was high and the PPS was poor. Age and exposure to chemotherapy at CMML diagnosis were associated with the high risk of s-AML and the poor survival of s-AML. In addition to clinical factors, demographic factors, including marital status, economic level, and race/ethnicity, should also be included when assessing the CMML survival.