A population-based study of acute panmyelosis with myelofibrosis in the United States: 2004 to 2015.

e19003 Background: Acute panmyelosis with myelofibrosis (APMF) is a rare subtype of acute myeloid leukemia characterized by acute panmyeloid proliferation with increased blasts, cytopenias with bone marrow fibrosis, and absence of splenomegaly. There is a paucity of population-based studies of APMF. Methods: We queried the United States Surveillance, Epidemiology, and End Results (SEER) database and National Cancer Database (NCDB) using the ICD-O-3 code 9931/3. The SEER 17 registries (2004-2015) were used to find data on incidence. For NCDB data, comorbid disease burden was calculated using the Charlson-Deyo Score (CDS). Hazard ratios (HR) with confidence intervals (CI) were calculated using a Cox proportional hazards model. Overall survival (OS) was estimated with the Kaplan-Meier method. Variables significant in univariable analysis were included in a multivariable analysis. Results: We identified 260 APMF patients using the SEER database. Incidence was 0.3 cases/million individuals and did not change significantly from 2004-2015. With a median follow up of 6.9 years (95% CI 6.1-7.8), the median OS was 2.3 years (95% CI 1.7-2.8). We identified 530 APMF patients using the NCDB. The median age at diagnosis was 67 years (range 22-90) and 311 (59%) were male. With a median follow up of 5.0 years (95% CI 3.0-7.6), the median OS was 2.3 years (95% CI: 0.8-6.5). OS was 69%, 31%, and 18% at 1-, 5-, and 10- years, respectively. Patients diagnosed in 2012-2015 had a significantly improved OS compared to those diagnosed in 2004-2007 (HR 0.65, 95% CI 0.49-0.85; p=0.002). 271 patients (53%) patients received chemotherapy. The OS for those that received chemotherapy was 70% at 1 year and 30% at 5 years versus 70% and 32% at 1- and 5- years for those who did not ( p=0.99). The median time to chemotherapy from time of diagnosis was 25 days (range 0-532 days). 52 patients (10%) underwent transplantation and the OS of those patients was 90% at 1 year and 45% at 5 years versus 67% and 29% at 1- and 5- years for those who did not (HR: 1.7 (95% CI: 1.2-2.6), p=0.006). In univariable analysis, factors predicting inferior OS were age ≥ 65 years old at diagnosis (HR 1.8, 95% CI 1.5-2.3; p<0.001), male sex (HR 1.5, 95% CI 1.2-1.8; p<0.001), CDS ≥ 1 (HR: 1.5 (95% CI: 1.2-2.0), p<0.001), government insurance (HR 1.8, 95% CI 1.4-2.3; p<0.001), diagnosis at a non-academic facility (HR 1.6, 95% CI 1.2-2.0, p<0.001), and not receiving a hematologic transplant (HR 1.7, 95% CI 1.2-2.6; p=0.006). Multivariable-adjusted analysis is shown in the Table. Conclusions: The overall incidence of APMF has not changed between 2004 and 2015, but OS for 2012-2015 was improved compared to 2004-2007. Age ≥ 65 years old, male sex, CDS ≥ 1, and diagnosis at a nonacademic facility predicted inferior OS. Multivariable-adjusted analysis.[Table: see text]