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

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

BACKGROUND

Multiple myeloma is a malignant tumour of the blood in which abnormal proliferation of plasma cells leads to bone destruction, renal impairment, anaemia, and hypercalcaemia. Renal impairment caused by multiple myeloma is a common and serious condition; however, the prognosis of multiple myeloma at the time of diagnosis remains unclear.

METHOD

We conducted searches for literature in PubMed, Web of Science, Cochrane, Embase, CNKI, Wanfang, and VIP databases up to 30 April 2023. Progression-free survival and overall survival with and without renal impairment at the time of multiple myeloma diagnosis were compared, and prognostic indicators were analysed.

RESULTS

Six studies were finally included. Among patients with multiple myeloma, 319 had renal impairment, and 1166 had no renal impairment. Compared to the control group, no significant difference was observed in overall or progression-free survival in patients with multiple myeloma complicated with renal impairment.

CONCLUSION

The limited low-quality evidence available does not support an association between prognosis and multiple myeloma complicated by kidney injury.

Urine immunofixation electrophoresis and serum free light chain analyses benefit diagnosis of multiple myeloma in orthopedic patients with normal serum total proteins, creatinine, calcium, and hemoglobin

BACKGROUND

A substantial number of patients with multiple myeloma (MM) who have bone destruction are initially admitted into the orthopedic service at the hospital. However, routine laboratory testing usually fails to identify these patients, thus delaying optimal therapy. Therefore, there is a clear medical need for early diagnosis of MM in these patients.

METHODS

Between 2019 and 2021, 42 patients receiving treatment for orthopedic conditions had normal hemoglobin (Hb), total protein (TP), albumin (ALB), creatinine (CREA), and blood calcium (Ca) levels before their surgical procedure(s) but were subsequently pathologically confirmed to have MM, based on their presenting orthopedic symptoms. During the same period, 52 patients with orthopedic conditions were pathologically excluded from the diagnosis of MM and were recruited into our control group. Serum free light chain (sFLC) testing was performed in 94 consecutive patients in the orthopedic service using Siemens N Latex FLC kits. The levels of Hb, TP, ALB, CREA, and Ca were also measured. All 42 patients with MM were divided into group A (n = 25: κ proliferation) and group B (n = 17: λ proliferation) by the pathology department.

RESULTS

There were no significant differences in levels of Hb, TP, ALB, CREA, and Ca between group A and group B and the control group. However, the sFLC κ/λ ratio of group A and B was also significantly different from that of the control group (P < .001). The results of serum immunofixation electrophoresis (IFE) testing demonstrated negative results in 14 cases (58.3%) in group A and 4 cases (25.0%) in group B.

CONCLUSIONS

Some patients with orthopedic conditions who do not have typical MM laboratory results, such as those with abnormal Hb, TP, ALB, CREA, and Ca levels before their operation(s), actually have MM. MM should be highly suspected in patients with unexplained bone lesions and with an abnormal sFLC κ/λ ratio. Further tissue or bone marrow biopsy is needed in these patients even if serum and urine IFE results are negative and light chain ratio is normal.