Spinal Disease Predicts CNS Involvement in Patients with Plasma Cell Leukemia

Background: Plasma cell leukemia (PCL) is a rare and aggressive hematologic malignancy with an incidence of approximately 1,200 patients per year in the United States with a median disease-specific survival of 6 months. PCL can either originate de novo (primary PCL) or as a secondary leukemic transformation of multiple myeloma (secondary PCL). A feared complication is infiltration of plasma cells into the central nervous system (CNS), meninges, or cerebrospinal fluid (CSF) which is challenging to treat and most often results in early mortality. We have observed a higher incidence of CNS disease among patients with PCL compared to multiple myeloma and were motivated to conduct a retrospective analysis to identify risk factors for the occurrence of CNS involvement among patients with primary or secondary PCL. Aim: Identify risk factors that should prompt clinicians to obtain a lumbar puncture and neuroimaging to screen for CNS involvement in patients with PCL. Methods: We conducted a retrospective analysis utilizing clinical data from patients who were found to have greater than 5% abnormal plasma cells in their peripheral blood detected by flow cytometry at the Seattle Cancer Care Alliance from 1990 to the present. IRB approval was obtained before data abstraction. Features extracted included laboratory values, radiographic data, pathologic data, treatment regimens, and response outcomes to chemotherapy regimens. The Fisher test was used identify risk factors associated with CNS disease. A P value