Plasmocytosis and Immunoparesis but Not Neutrophil to Lymphocyte Ratio Can Predict Time to Treatment in Smoldering Myeloma

Objectives: We recently identified the ratio between absolute neutrophils count and absolute lymphocyte count, NLR ≥2, as a predictor of progression free survival (PFS) and overall survival (OS) in patients younger than 65 years with symptomatic Multiple Myeloma (MM). We retrospectively examined the NLR in a cohort of 140 smoldering Myeloma (sMM) defined accordingly to the updated IMWG 2014 guidelines accessed our Center between June 2006 and June 2014.

Methods: NLR was calculated using data obtained from the complete blood count (CBC) at diagnosis and subsequently correlated with time to treatment (TTT) for symptomatic MM. All patients underwent bone marrow evaluation to estimate plasma cells infiltration (BMPC), Magnetic Resonance Imaging (MRI) to detect bone lesions, serum free-lite chain evaluation (sFLC) starting from January 2012 when they became evaluable in our center.

Results: The mean NLR was 2.0 ± 0.1, lower than the value previously found for MM (2.7 ± 0.2, p= 0.005). Higher NLR was independent of BMPC amount, cytogenetics and sFLC. Using NLR ≥2 as predictive biomarker we could not predict TTT.

In univariate analysis only BMPC ≥ 30% (p<0.0001), immunoparesis (suppression of one or more uninvolved immunoglobulins, p=0.017) and presence of at least one bone lesion at MRI (p<0.0001) could predict TTT. In multivariate analysis, these three parameters were independent (p<0.0001). Since new guidelines consider BMPC≥ 60% and positive MRI as myeloma-defining events, we proposed a simplified score model based on BMPC ≥ 30% (1 point) and immunoparesis (1 point).

We identified patients with score 0 (20%) as low-risk (TTT at 60 months 0%), with score 1 (61%) as intermediate risk (TTT at 60 months 61%) and with score 2 as high-risk (TTT at 60 months 22%, p<0.0001).

Conclusion: We confirmed BMPC and immunoparesis as strong predictors of outcome in sMM.