Morphologic Classification Is an Important Prognostic Factor in Patients with Newly Diagnosed Multiple Myeloma Treated with Bortezomib or Lenalidomide

The morphological classification of multiple myeloma (MM) has long been known to have an impact on its clinical course. We retrospectively analyzed 30 cases of newly diagnosed MM initially treated with bortezomib or lenalidomide between November 2014 and November 2018. The morphological bone marrow types were assessed on the basis of the Greipp classification. The patients' median age was 74.5 years (range, 49-88), and the male-to-female ratio was 0.67. The International Staging System stages were as follows: stages I, II, and III accounted for 3.3%, 46.7%, and 50.0% of patients, respectively. The Mproteins were IgG (n=21) and non-IgG (n=9). The median progression free survival (PFS) was not reached. The proportion of plasma, immature, and plasmablastic cells in the bone marrow was significantly affected by PFS. When scored with 1 point each, PFS could be stratified into three groups. All patients who had >= 5% of immature cells had a complex karyotype. This study shows that the visual morphological classification of plasma cells is an important prognostic factor even when bortezomib or lenalidomide is used as induction therapy. Further research is expected to reveal the optimal treatment strategy for immature and plasmablastic MM.