[Evaluation and comparison of prognostic value of serum free light chain ratio/difference in patients with newly diagnosed multiple myeloma].

To evaluate the prognostic value of serum free light chain ratio (rFLC) and difference (dFLC) in patients with multiple myeloma (MM) . Clinical data of 479 cases of newly diagnosed MM patients with FLC test records referred to our hospital from January 2012 to March 2016 were collected. rFLC preferred cut-off values were selected as≤14.828,14.828-364.597, ≥364.597 according to the literatures. The dFLC was divided into ≤112.85,112.85-2891.83, ≥2891.83 mg/L three groups. The rFLC and dFLC values among the death, the non-death, the progress and the non-progress groups were compared by test. The correlation analysis showed that the rFLC and dFLC values were related to the death or progression of the disease. Logistic regression was used to analyze the correlation between each factor and death or progression. Univariate survival analysis (PFS) and total survival (OS) were performed using Kaplan-Meier. Single-variable and multivariate prognostic analysis were performed using Cox model. The cutoff values of rFLC less than 14.828 or dFLC less than or equal to 112.85 mg/L impacted most significant on OS and PFS of the patients (<0.05) . Different rFLC cut-off values between two groups showed that when rFLC=14.828, OS was significantly better than the other two groups (NR 61 & 47 months, =0.019) ; different dFLC cut-off values between two groups disclosed that PFS and OS were statistically significant when dFLC less than or equal to 112.85 mg/L compared with the other two groups (<0.05) . The 4-year PFS/OS rates in the initial dFLC≤112.85 mg/L and rFLC≤14.828 groups was significantly higher than of the other two groups. Different cutoff levels of rFLC and dFLC might have obviously effects on the prognoses of patients with newly diagnosed MM. The difference of survival prognosis would be more pronounced when rFLC≤14.828 or dFLC≤112.85 mg/L with lower risk of death and lower risk ratio, which might be ideal cutoff value for determining the prognosis of these patients.