Background: Acute myeloblastic leukemia (AML) usually presents with cytopenias, although its degree is variable and in some cases it is non-existent. We herein highlight the existence of “de novo” AML patients that debut with a normal or elevated platelet count.
Aims: Our aim was to evaluate the prognostic impact of a platelet count over >300 x109/L at diagnosis.
Methods: One hundred and twenty-eight adult patients from nine tertiary centers of Spain, with a diagnostic of non-promyelocytic AML between 2000 and 2021, were included.
Two groups were defined based on platelet count at diagnosis: those who debuted with a platelet count over >300 x109/L and those who debuted with a lower platelet count. Patients were also distributed in two different groups according to whether they received intensive chemotherapy treatment.
We used the Kaplan-Meier and the Cox method to analyze overall survival (OS), with a two-sided P value ≤ 0.15 for a factor in the univariate analysis to be included in the multivariate regression, where a P value ≤ 0.05 was considered statistically significant.
Statistical analysis was performed using SPSS software (IBM SPSS Statistics 21, IBM Corporation, Chicago, IL).
Results: A total of 128 patients were included. The median age at diagnosis was 65 y.o (25-89). Eighty patients (62.5%) had received an intensive regimen.
Patients were considered upon platelet count: higher or less than 300 x109/L. We found significant differences in the white blood cells (WBC) count (19.9x109/L vs 5.3x109/L, p= 0.047), the percentage of patients who responded to treatment and in those who achieved complete remission, (56.0% vs 87.0%, p=0.004 and 44 .0% vs 80.4%, p=0.002, respectively).
Figure 1 shows how presenting a platelet count over 300 x109/L was an adverse prognostic factor only in the group that received an intensive regimen. Within this group, only the age (p=0.079), the blast count (%) in bone marrow (p=0.05) and belong to intermediate-adverse European LeukemiaNet-2017 (ELN2017) risk group (p=0.008), were significantly associated with a shorter OS in the univariate analysis
When confronting these variables with the presence of a platelet count at diagnosis over 300x109/L, only intermediate-adverse ELN2017 risk group and the platelet count remained significant for a shorted OS (p=0,023, HR 2.17, 95%CI 1.11-4.24 and p=0.025, HR 3.50, 95% CI 1.16-10.54, for platelet count and ELN risk group, respectively).
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Summary/Conclusion: In “de novo” AML patients treated with an intensive regimen, an unusually high platelet count is related to a worse prognosis. In those patients, a specific molecular study focused on megakaryopoiesis could be of interest.