[Clinical Significance of sFLC/MP Level and Light Chain Escape in Patients with Multiple Myeloma Relapse]

To explore the effects of serum free light chain (sFLC) and monoclonal protein (MP) on the efficacy and prognosis of patients with multiple myeloma relapse, and investigate the clinical value of light chain escape (LCE).

The relationship between sFLC/MP levels and clinical features and outcomes in 71 patients with multiple myeloma after relapse were retrospective analyzed. The patients were divided into MO group, MLC group and LCE group according to different levels of sFLC/MP after relapse. Then the clinical indicators, efficacy, survival after relapse (SAR) and overall survival (OS) of the patients in each group were compared. Meanwhile a paired sample t test was used to analyze the relevant indicators of the patients before and after relapse in LCE group.

There were significant differences in ISS stage, the levels of Hb, PLT, ALB, SFLC/MP and the proportion of myeloplasma cells afte relapse (P<0.05). The initial treatment effect of the patients in MO group was better than those in the other groups, and the LCE group was the worst (P<0.05). Comparison of relevant indicators between the patients before and after relapse in LCE group showed that the levels of MP, Hb and PLT decreased significantly, while sFLC, LDH and Cr increased significantly (P<0.05). Multivariate analysis showed that MO was the independent risk factor affecting SAR, while MO and LCE were the independent risk factors affecting OS (P<0.05) of the patients.The average SAR of the patients in MO, MLC and LCE group was 41, 28.6 and 23.5 months (P=0.002), and the average OS was 79.6, 57.9 and 41 months (P<0.001), respectively. The patients in MO group showed longer SAR and OS, while the LCE group was the shortest.

After relapse, patients only with elevated MP levels have a better curative effect and prognosis, while only with elevated sFLC levels have poor curative effects and prognosis, which suggesting that sFLC/MP levels can be used as a good indicator for predicting the prognosis of multiple myeloma patients.The appearance of LCE indicates disease progression, poor prognosis and early relapse.