Risk Factors Associated With Secondary Extramedullary Multiple Myeloma Development

Younger age, extensive bone disease, higher lactate dehydrogenase (LDH) levels, and immunoglobulin A (IgA) or a nonsecretory type of multiple myeloma (MM) at the time of MM diagnosis were significantly associated with the development of secondary extramedullary multiple myeloma (EMD) in a cohort of nearly 5000 patients. Researchers published study results online ahead of print in the British Journal of Haematology.

“Multiple myeloma is characterized by malignant plasma cell infiltration of the bone marrow,” researchers explained. “In EMD, a subclone of these cells migrates out of the bone marrow.”

Because secondary EMD is associated with a poor prognosis, early identification of patients at high risk of secondary EMD development is important, researchers wrote. To clarify risk factors, they identified 234 patients with secondary EMD among almost 4985 patients with MM diagnosed in the Czech Republic between 2005 to 2017.

At the time of MM diagnosis, the main risk factors for secondary EMD development were age younger than 65 years, LDH levels higher than 5 μkat/l, more than two osteolytic lesions diagnosed by skeletal survey, hypercalcemia, and IgA M-protein type or the non-secretory type of MM, the study indicated.

Compared with newly diagnosed MM patients without EMD development, those with future EMD had shorter median progression-free survival (13.8 months vs 18.8 months) and overall survival (26.7 months vs 58.7 months), researchers reported. 

“While EMD pathogenesis has not been clarified yet, there may be a hidden molecular mechanism affecting disease course before EMD is revealed,” researchers wrote. “Thus, these patients subsequently manifest with extramedullary involvement, leading to further disease escalation and early death.”

Reference:
Stork M, Sevcikova S, Minarik J, et al. Identification of patients at high risk of secondary extramedullary multiple myeloma development [published online ahead of print November 2, 2021]. Br J Haematol. doi:10.1111/bjh.17925