Lancet Haematol. 2014 Oct 01;1(1):e28-e36. doi: 10.1016/S2352-3026(14)70001-8.
Clinical course of light-chain smouldering multiple myeloma (idiopathic Bence Jones proteinuria): a retrospective cohort study.
The Lancet. Haematology
Robert A Kyle, Dirk R Larson, Terry M Therneau, Angela Dispenzieri, L Joseph Melton, Joanne T Benson, Shaji Kumar, S Vincent Rajkumar
Affiliations
Affiliations
- Division of Hematology (Prof R A Kyle MD, Prof A Dispenzieri MD, Prof S Kumar MD, Prof S V Rajkumar MD), Division of Biostatistics (D R Larson MS, Prof T M Therneau PhD, J T Benson BA), and Division of Epidemiology (Prof L J Melton 3rd MD), Mayo Clinic, Rochester, MN, USA.
PMID: 25530988
PMCID: PMC4266993 DOI: 10.1016/S2352-3026(14)70001-8
Abstract
BACKGROUND: Bence Jones proteinuria is a disorder that is defined by the excretion of monoclonal light-chain protein. About 15-20% of patients with multiple myeloma secrete monoclonal light chains only, without expression of the normal immunoglobulin heavy chain, which constitutes light-chain multiple myeloma. The definition, prevalence, and progression of these premalignant phases of light-chain multiple myeloma have not been fully characterised. We aimed to identify a subset of patients with idiopathic Bence Jones proteinuria who had a high risk of progression to light-chain multiple myeloma analogous to that seen in patients with smouldering multiple myeloma.
METHODS: In this retrospective cohort study, we studied all patients seen at the Mayo Clinic (Rochester, MN, USA) within 30 days of diagnosis of idiopathic Bence Jones proteinuria between Jan 1, 1960, and June 30, 2004. Inclusion criteria were monoclonal light chain in the urine (≥0·2 g/24 h), absence of intact monoclonal immunoglobulin (M protein) in the serum, and no evidence of multiple myeloma, light-chain amyloidosis, or other related plasma-cell proliferative disorders. The primary endpoint was progression to symptomatic multiple myeloma or light-chain amyloidosis. We examined the cumulative probability of progression and the association of potential risk factors on progression rates to identify patients with a high risk of progression to multiple myeloma or light-chain amyloidosis.
FINDINGS: We identified 101 patients with idiopathic Bence Jones proteinuria. During 901 total person-years of follow-up, 27 (27%) patients developed multiple myeloma and seven (7%) developed light-chain amyloidosis. The major risk factors for progression were amount of urinary excretion of M protein per 24 h, proportion of bone marrow plasma cells, presence of a markedly abnormal free-light-chain ratio (<0·01 or >100), and reduction of all three uninvolved immunoglobulins. Based on the risk of progression, monoclonal light-chain excretion of 0·5 g/24 h or greater or at least 10% bone marrow plasma cells, or both, in the absence of end-organ damage was used to define light-chain smouldering multiple myeloma. The cumulative probability of progression to active multiple myeloma or light-chain amyloidosis in patients with light-chain smouldering multiple myeloma was 27·8% (95% CI 14·2-39·2) at 5 years, 44·6% (27·9-57·4) at 10 years, and 56·5% (36·3-70·2) at 15 years.
INTERPRETATION: Light-chain smouldering multiple myeloma as defined in this study is associated with a high risk of progression to symptomatic light-chain multiple myeloma, and this subset of patients needs careful observation and could benefit from clinical trials of early intervention.
FUNDING: Jabbs Foundation (Birmingham, UK), US National Cancer Institute, and Henry J Predolin Foundation (Madison, WI, USA).
References
- Clin Chem. 2002 Sep;48(9):1437-44 - PubMed
- Br J Haematol. 2003 Jun;121(5):749-57 - PubMed
- Blood. 2009 May 28;113(22):5412-7 - PubMed
- Lancet. 2010 May 15;375(9727):1721-8 - PubMed
- N Engl J Med. 1980 Jun 12;302(24):1347-9 - PubMed
- Acta Haematol. 1978;60(5):269-79 - PubMed
- Acta Haematol. 1980;63(5):241-6 - PubMed
- J Clin Oncol. 2013 Dec 1;31(34):4325-32 - PubMed
- Mayo Clin Proc. 2003 Jan;78(1):21-33 - PubMed
- Am J Med. 1978 May;64(5):814-26 - PubMed
- Biometrics. 1983 Mar;39(1):173-84 - PubMed
- N Engl J Med. 2007 Jun 21;356(25):2582-90 - PubMed
- N Engl J Med. 1982 Mar 11;306(10):564-7 - PubMed
- Leukemia. 2013 Aug;27(8):1738-44 - PubMed
- Am J Hematol. 2013 Mar;88(3):226-35 - PubMed
- Blood. 1992 Apr 1;79(7):1817-22 - PubMed
- Leukemia. 2013 Apr;27(4):941-6 - PubMed
- Acta Med Scand. 1974 Nov;196(5):445-7 - PubMed
- Br Med J. 1967 Sep 16;3(5567):699-704 - PubMed
- Mayo Clin Proc. 2012 Nov;87(11):1071-9 - PubMed
- N Engl J Med. 2002 Feb 21;346(8):564-9 - PubMed
- N Engl J Med. 2006 Mar 30;354(13):1362-9 - PubMed
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