Abstract
BACKGROUND
Multiple Myeloma (MM) is still considered an incurable relapsing disease, despite major advances in multidrug combinations, incorporation of autologous transplant and achieving higher rates of CR. This suggests persistent presence of residual disease, not detected by current techniques. Minimal residual disease (MRD) monitoring by multiparameter flow cytometry (MFC) is a powerful tool to quantitatively measure residual disease and allow tailoring of the management plan on individual basis.
AIM
To assess the value of MRD by MFC in determining the efficacy of treatment, monitoring depth of remission and predicting impending relapse.
PATIENTS AND METHODS
We included 33MM patients, who were candidates for ASCT in this prospective study. MFC (with a 0.01% limit of detection) on a BM aspirate obtained before transplant and at day 100 post-transplant, was used to measure MRD for all patients. Patients were then later assessed for progression 1-year post-transplant.
RESULTS
MRD status at 100 days post-transplant was strongly related to the risk of 1-year post-transplant progression (p-value 0.001), and by using a ROC curve, we found that MRD (%) at 100 days post-transplant can predict progression after 1 year with a best cutoff value ≥ 0.04 achieving a 75% sensitivity and 81.2% specificity. On dividing the patients according to their MRD status before and after transplant, group 3 who were MRD positive pre- and post-transplant, had a high risk of progression 1year post-transplant (p-value 0.003). The use of bortezomib-based regimens resulted in a deeper response and a more negative MRD pre-transplant (p-value 0.01), that was maintained post-transplant. Also, ASCT resulted in the development of deeper remission (p-value 0.004) and more MRD negativity (p-value 0.02).
CONCLUSION
we recommend the use of MRD by MFC as a powerful prognostic tool that should be incorporated in routine myeloma workup.
False Negative Rate of Minimal Residual Disease Measurement by Multiparameter Flow Cytometry in Multiple Myeloma when Compared to Trephine Immunohistochemistry
