Thrombocytopenia With High C-reactive Protein in Myeloma Patients Treated With Proteasome Inhibitor and/or Immunomodulatory Drugs.

Background/aim: Background/Aim: Thrombocytopenia is a poor prognostic factor in patients with myeloma; however, the factors associated with thrombocytopenia have not been extensively discussed. This study aimed to investigate the clinical significance of thrombocytopenia, defined as 130×10³/μl or less, in patients with newly diagnosed multiple myeloma (NDMM) treated with proteasome inhibitors and/or immunomodulatory drugs.

Patients and methods: This is a retrospective review of medical records of myeloma patients treated between 2000 and 2021. A total of 241 patients were included in this study, with a median age of 72 years. Overall survival (OS) and time to next treatment (TTNT) were assessed using Kaplan-Meier analysis and Cox regression analysis. Prognostic factors were evaluated by univariate and multivariate analyses.

Results: The incidence of thrombocytopenia was 17.8%. In the median follow-up period of 46.6 months, OS and TTNT in the thrombocytopenia group were significantly shorter than those in the non-thrombocytopenia group using multivariate analysis (p<0.001 and p<0.001). C-reactive protein (CRP) level was not associated with thrombocytopenia, and high CRP predicted short OS and TTNT independently from thrombocytopenia. When the low (neither thrombocytopenia nor high CRP), intermediate (either thrombocytopenia or high CRP), and high (thrombocytopenia and high CRP) risk groups were defined, the OS and TTNT among these groups showed significant differences; the hazard ratios for survival in the high and intermediate risk groups were 7.022 and 2.598, and for TTNT, they were 4.216 and 1.887, respectively, compared to the low-risk group.

Conclusion: Thrombocytopenia was associated with the activity of NDMM and predicted prognosis in NDMM. When combined with high CRP levels, thrombocytopenia serves as a new indicator of poor prognosis in these patients.