Bone marrow plasma cell ratio, is it must to evaluate before autologous stem cell transplantation in multiple myeloma?

Abstract

Objective: Complete remission in multiple myeloma (MM) is a defined as having a <5% bone marrow plasma cell (BMPC) ratio plus negative serum and urine immunofixation tests. However, it is necessary to reassess whether or not the bone marrow plasma cell ratio should be determined before transplantation in secretory multiple myeloma patients. A significant decrease in monoclonal protein levels or having negative serum and urine immunofixation tests after induction therapy might be enough to indicate chemo-sensitivity.
 Material and Methods: In this study, the data of 177 multiple myeloma patients that underwent autologous stem cell transplantation (ASCT) in our center were retrospectively evaluated.
 Results: We found a statistically significant difference in the post-ASCT response rates between the patients with a pre-ASCT BMPC ratio <5% vs BMPC ratio ≥5% (p:<0.001*). The 2-year progression-free survival (PFS) of the patients with BMPC ratio <5% and ≥5% post-ASCT was found 24% and 25% (median PFS 11 months (95% CI; 6,68-15,31) vs 12 months (95% CI; 9,47-14,53)) respectively (p: 0.900). The 2-year overall survival (OS), was 67% and 63% (median OS 35 months (95% CI; 25,59-44,41) vs 40 months (95% CI; 27,52-52,47)) respectively (p: 0.341).
 Conclusion: Patients with decreasing monoclonal protein in serological tests, the pre-ASCT BMPC ratio was not found to have an impact on neutrophil and platelet engraftment durations, transplantation related mortality (TRM), PFS and OS. Our study suggests that in MM patients with measurable disease, it is not required to evaluate the BMPC ratio if serologic response exists.