Role of Serum Free Light Chain Assay in Relapsed/Refractory Multiple Myeloma. A Real-Life Unicentric Retrospective Study

Abstract

Background: In the era of novel drugs a growing number of multiple myeloma (MM) patients are treated until disease progression. Serum free light chain (sFLC) assay is recommended for disease monitoring in oligo-secretory and micromolecular MM. Methods: In this real-life survey, a total of 130 relapsed/refractory MM patients treated at our center with at least three lines were investigated as a retrospective cohort. Results: The median age at diagnosis was 64 years and more than half of patients were male. A total of 24 patients (18%) had oligo-secretory/micromolecular disease at diagnosis. More than 20% of 106 normo-secretory patients had oligo-secretory/micromolecular escape. In order to evaluate potential role of sFLC assay before (“pre”) and after (“post”) every treatment line, involved serum free light chain values (iFLC) less than 138 mg/mL and serum free light chain ratios (FLCr) <25 were identified by using ROC curve analysis. The analysis of the entire cohort throughout four treatment lines demonstrated a statistically significant negative impact on progression-free survival (PFS) for both involved pre-sFLC and its ratio (respectively p = 0.0086 and p = 0.0065). Furthermore, both post-iFLC and post-FLCr greater than the pre-established values had a negative impact on PFS of the study cohort; respectively, p = 0.014 and p = 0.0079. Odds ratio analysis evidenced that patients with both involved post-sFLC greater than 138 mg/mL and post-FLCr above 25 at disease relapse had a higher probability of having clinical relapse (respectively p = 0.026 and p = 0.006). Conclusions: Alterations of sFLC values, namely iFLC and FLCr, both prior to treatment initiation and in the course of therapy at every treatment line, could be of aid in relapse evaluation and treatment outcome. We therefore suggest close periodical monitoring of sFLC assay, independently from secretory status.

Serum free light chains benefit diagnosis of multiple myeloma in orthopaedic patients with normal serum total proteins, creatinine, calcium and hemoglobin

“…SFLC has long become a valuable marker for diagnosing and monitoring light-chain MM, amyloid light-chain amyloidosis, and monoclonal gammopathies of undetermined signi cance (MGUS) (8-12). According to the IMWG diagnostic criteria, sFLC assay is recommended for disease surveillance in oligo-secretory and micromolecular MM (13).…”

Prognosis of concurrent renal impairment at diagnosis of multiple myeloma: a systematic review

“…The most common form of monoclonal free light chain nephropathy is light chain tubular nephropathy, caused by precipitation of the free light chain in the distal convoluted tubules with urinary regulatory factors [ 4 ]. Excessive production of free light chains can induce renal damage and fibrosis, leading to decreased quality of life and a poor patient prognosis [ 5 ]. In recent years, highly truncated haemodialysis has been used to remove the free light chain to avoid direct damage to the kidney and improve the adverse effects of multiple myeloma [ 6 ].…”