Effects of Amyloid Light-Chain Amyloidosis on Clinical Characteristics and Prognosis in Multiple Myeloma: A Single-Center Retrospective Study

Abstract

Background

Amyloid light-chain amyloidosis (AL amyloidosis) is commonly associated with multiple myeloma. However, the clinical characteristics and prognosis of symptomatic and smoldering multiple myeloma with AL amyloidosis are not particularly clear.

Methods

Patients with symptomatic and smoldering multiple myeloma in the Peking University First Hospital registry from 2010 to 2018 were studied. The clinical and laboratory information was collected from first presentation to death or until the last available clinical follow-up. The patients’ survival and outcomes were analyzed, and the relationship between the clinical parameters and survival was also assessed.

Results

Compared with symptomatic multiple myeloma patients without AL amyloidosis, patients with AL amyloidosis had higher incidence of BNP≧700pg/mL (P<0.001), ALP>187.5IU/L (P=0.032) and ALB<25g/L (P<0.001). Similarly, compared with smoldering multiple myeloma patients without AL amyloidosis, patients with AL amyloidosis had higher incidence of BNP≧700pg/mL (P=0.030) and Alb<25g/L (P=0.024). The existence of AL amyloidosis, especially those with the heart involvement, was related to shorter long-term survival of symptomatic and smoldering multiple myeloma according to univariate analyses. Renal involvement and gastrointestinal tract involvement had an impact on the prognosis of smoldering multiple myeloma but not on the symptomatic multiple myeloma. Cox regression model for overall survival detected BNP≧700pg/mL in symptomatic multiple myeloma having independent poorer prognostic significance (HR=2.455, P=0.004). Interestingly, BNP at diagnosis was significantly correlated with cardiac amyloidosis (r=0.496, P<0.001). Cox regression model for overall survival detected the presence of AL amyloidosis in smoldering multiple myeloma having independent poorer prognostic significance (HR=8.741, P=0.002).

Conclusion

AL amyloidosis is an independent poor prognostic factor for not only symptomatic multiple myeloma but also smoldering multiple myeloma. It is mainly because of involvement of important organs, especially the heart. AL amyloidosis probably has a greater impact on the prognosis of smoldering multiple myeloma than on the symptomatic multiple myeloma.

Keywords:

• symptomatic multiple myeloma
• smoldering multiple myeloma
• AL amyloidosis
• poor prognostic factor

Abbreviations

AL amyloidosis, amyloid light-chain amyloidosis; BNP, brain natriuretic peptide; ALP, alkaline phosphatase; ALB, albumin; Hb, hemoglobin; LDH, lactate dehydrogenase; Ca, calcium; Scr, serum creatinine; BMPC, bone marrow plasma cells; dFLC, difference between involved and uninvolved serum free light chains; NT-proBNP, N terminal pro B type natriuretic peptide; CTNI, cardiac troponin I; OS, overall survival; HR, hazard ratio; D-S stage, Durie Salmon stage; ITE, Initial therapeutic effect; PD, progressive disease; SD, stable disease; MR, minimal response; PR, partial response; VGPR, very good partial remission; CR, complete remission; sCR, stringent complete remission; Cybor-D, cyclophosphamide–bortezomib and dexamethasone.

Data Sharing Statement

Not applicable.

Ethics Approval and Consent to Participate

The Ethics Committee of Peking University First Hospital provided ethical approval (NO. 2017[1304]). Written informed consent for collecting details was obtained from each patient. This study was conducted in accordance with the Declaration of Helsinki.

Consent for Publication

Not applicable.

Author Contributions

All authors made substantial contributions to conception and design, acquisition of data, or analysis and interpretation of data; took part in drafting the article or revising it critically for important intellectual content; agreed to submit to the current journal; gave final approval of the version to be published; and agree to be accountable for all aspects of the work.

Disclosure

The authors declare that they have no conflicts of interest for this work.