Primary and Secondary Central Nervous System Involvement in Acute Myeloid Leukemia

Abstract

Introduction: Central Nervous System involvement (CNSi) in patients with Acute Myeloid Leukemia (AML) rarely occurs. It is not well characterized clinically and lacks standardized treatments. Patients and methods: A retrospective analysis of 77 consecutive AML patients with primary and secondary CNSi during 2004-2016 was performed in eight Polish haematological centres. Results: 77 patients (38 with primary CNSi-AML) were included. Median age was 44 years in both groups. Elevated lactate dehydrogenase activity was found in the majority of subjects. Patients in primary CNSi-AML group more often had myelomonocytic and monoblastic AML subtypes (68.4%) compared to secondary CNSi AML (43.5%) (p=0.039). There were no differences between both groups in the number of leukocytes or the proportion of blast cells rates in peripheral blood or bone marrow at AML diagnosis. There were also no statistically significant differences between both groups in the incidence of cytogenetic or molecular abnormalities. In both groups, CNSi was most frequently found in the cerebrospinal fluid and the most common neurological symptom was headache. The following manifestations were more frequent in secondary than in primary CNSi-AML: lower extremity weakness (38.46% vs. 13.16%; p=0.023), paraesthesia (38.46% vs. 13.16%; p=0.023), motor deficits (31.58% vs. 10.53%; p=0.047), and asymmetry of reflexes (26.32% vs. 2.7%; p=0.007). Median pleocytosis was also significantly higher in secondary than in primary CNSi-AML: 27 (IQR 2-146) vs. 2 (IQR: 1-12; p=0.004). Both groups had rather short Overall Survival (OS), with a median of 16.6 months (9.9-NA) for patients with primary CNSi-AML and 15.4  months (10.1-21.1) for patients with secondary CNSi. Conclusion: Patients with CNSi AML were relatively young, having high lactate dehydrogenase activity and high rates of the myelomonocytic and monoblastic/monocytic AML subtypes. The advisability of undertaking CNS examination and prophylaxis in patients with such characteristics thus merits further reassessment.