Predictive Value of Post-Transplant Bone Marrow Plasma Cell Percent in Multiple Myeloma Patients Undergone Autologous Transplantation

Background/Aims: Autologous stem cell transplantation (ASCT) has become the treatment of choice for patients with multiple myeloma (MM). Studies have shown that maintenance treatment with interferon-alpha is associated with improved survival rates following ASCT. However, despite these recent advances in regimes, relapses are inevitable; thus, the prediction of relapse following ASCT requires assessment. Methods: We retrospectively analyzed 39 patients who received ASCT between 2003 and 2008. All patients received chemotherapy with vincristine, adriamycin, and dexamethasone (VAD), and ASCT was performed following high-dose melphalan conditioning therapy. We evaluated the influence of the post-transplant day +14 (D+14) bone marrow plasma cell percent (BMPCp) (${\geq}$ 2 vs. < 2%), international scoring system (ISS) stage (II vs. III), response after 3 cycles of VAD therapy (complete response [CR] vs. non-CR), deletion of chromosome 13q (del[13q]) (presence of the abnormality vs. absence), and BMPCp at diagnosis (${\geq}$ 50 vs. < 50%) on progression-free survival (PFS) and overall survival (OS). Results: During the median follow-up of 28.0 months, the median PFS and OS were 29.1 and 42.1 months, respectively. By univariate analysis, ISS stage III at diagnosis, BMPCp ${\geq}$ 50% at diagnosis, CR after 3 cycles of VAD therapy, del (13q) by fluorescence in situ hybridization, and BMPCp ${\geq}$ 2% at post-transplant D+14 were correlated with PFS and OS. A multivariate analysis revealed that a post-transplant D+14 BMPCp ${\geq}$ 2% (PFS, hazard ratio [HR] = 4.426, p = 0.008; OS, HR = 3.545, p = 0.038) and CR after 3 cycles of VAD therapy (PFS, HR = 0.072, p = 0.014; OS, HR = 0.055, p = 0.015) were independent prognostic parameters. Conclusions: Post-transplant D+14 BMPCp is a useful parameter for predicting the outcome for patients with MM receiving ASCT.