Prognostic Factors of AL-PCMM and AL-MM: A Single-Center Retrospective Study

Background: Patients with amyloid light-chain (AL) amyloidosis with a bone marrow plasma cell ratio > 10% (AL-PCMM) have a poorer prognosis than patients with AL amyloidosis with a bone marrow plasma cell ratio of <10% (AL-only), similar to that of patients with AL amyloidosis and multiple myeloma (AL-MM). However, the prognostic factors for AL-PCMM and AL-MM have not been studied. Methods: A total of 49 patients with AL-PCMM or AL-MM in the Peking University First Hospital registry in 2010-2018 were enrolled. Clinical and follow-up data were collected. The relationship between clinical parameters and survival time was also assessed. Results: Compared with patients with AL-PCMM, patients with AL-MM only had a higher incidence of bone marrow plasma cell ratio ≥ 20%. In AL-PCMM and AL-MM, the survival time was significantly shorter in patients with alkaline phosphatase (ALP) ≥ 187.5 IU/L, γ-glutamyl transpeptidase (GGT) ≥ 85 IU/L, total bilirubin (TBIL) ≥ 20 µmol/L, cardiac troponin I (CTNI) ≥ 0.1 ng/mL, ejection fraction (EF) < 50%, initial therapeutic effect (ITE) < very good partial response (VGPR), and Boston University (BU) staging system stage ≥ III. ALP at diagnosis was correlated with brain natriuretic peptide (BNP) level, CTNI level, and EF rather than TBIL level. Cox regression analyses revealed that BU staging system stage ≥ III (P=0.001, hazard ratio [HR]=5.579), ALP ≥ 187.5 IU/L (P=0.011, HR=3.563), and ITE < VGPR (P=0.002, HR=7.462) were independent significant risk factors for a poor prognosis of AL-PCMM and AL-MM. Conclusion: ALP level, which is related to cardiac amyloidosis rather than liver involvement, can be a prognostic factor for this group of patients. A BU staging system stage ≥ III, ALP ≥ 187.5 IU/L, and ITE < VGPR were independent significant risk factors for a poor prognosis of AL-PCMM and AL-MM.