The Comparison of Multiple Myeloma Staging Systems and Their Value for Disease Stage Determination.

Aim of the study: To evaluate the significance of different Multiple Myeloma staging systems – Durie-Salmon (DS), International Stage System (ISS) and the Revised International Stage System (R-ISS) – for determining the stage of Multiple Myeloma (MM). Goals of the study: To evaluate the usage of MM staging systems and possible changes of MM stages distribution using different staging systems; To evaluate and compare the changes of laboratory parameters (erythrocytes, platelets, leukocyte populations, markers of inflammation, kidney function and protein metabolism, β2-microglobulin, LDH) in relation to MM stages using different staging systems; To compare the value of MM staging systems for the determination of the disease stage. Patienths and methods: Patients with MM were selected for the study. They were divided into three MM stages using three different staging systems: DS, ISS, R-ISS. The hematology tests were performed by a SYSMEX XE-5000 hematology analyzer (Sysmex Corporation, Japan). Biochemical analysis (CRP, LDH, creatinine, urea, calcium, ionized calcium, total protein, albumin, IgG, IgA, IgM) were performed by clinical system SYNCHRON UniCel® DxC 800 (Beckman Coulter, USA), β2 microglobulin were measured by immunoassay analyzer AIA-2000 LA (Tosoh Bioscience, USA). Results: It was found significant differences of lymphocytes between I and II stages in MM patients staged according to the DS system. When staged by the ISS system, the stage III patients had significantly higher β2-microglogulin and CRP levels compared to stage II and I. Restaging by R-ISS revealed significant higher values of β2M and CRP in stage II patients compared to stage I patients, but any significance wasn‘t detected between stage III and the other stages. LDH results were statistically significantly higher in patients with stage III than in patients with stage II or I. Conclusions: In most cases, the MM stages were determined by Durie-Salmon (DS) staging system. The stage of MM may vary depending on the type of staging system, but the relationship between MM stage and used staging system was not significant. There were found significant differences of β2-microglogulin and CRP between stage III vs. stages I and II using ISS system. Meanwhile, using R-ISS staging the statistically significant differences of β2M and CRP were detected even between the first and second MM stages. Assessing the results of the study, it can be assumed that R-ISS is more advanced for staging of MM compared to the others staging systems