Monoclonal gammopathy in Iceland: a population‐based registry and follow‐up

Abstract

Summary. The term monoclonal gammopathy (MG) signifies the benign or malignant clonal growth of B lymphocytes. In the present study, monoclonal gammopathy of unknown significance (MGUS) was defined as those patients with no identified haematological malignancy. A database was constructed of all 713 MG patients in Iceland between 1976 and 1997 and compared with the Icelandic Cancer Registry. The age-standardized incidence per 100 000 of MG was 10AE3 for males and 8AE6 for females, calculated for the whole period, rising steadily from 5AE8 (men) and 4AE9 (women) during the 5-year period 1976-80 to 14AE7 (men) and 12AE5 (women) during the last 5 year period. Agestandardized incidence rates were very low for subjects under 50 years of age, then increased with age from 11 and 17 per 100 000 at 50-54, to 169 and 119 per 100 000 at age 80-84, for men and women respectively. No association was detected between MG and non-haematological malignancies, neither retrospectively nor prospectively. Haematological malignancy was diagnosed in 209 (29AE3%) cases before the recorded finding of MG or within the same calendar year, leaving 504 (70AE7%) patients diagnosed with MGUS. Of these, 51 (10%) progressed to multiple myeloma or Waldenström's macroglobulinaemia after a mean interval of 3AE8 years; mean follow-up was 7AE4 years, median 6 years. The most common immunoglobulin (Ig) class was IgG (55%), followed by IgM (32%) and IgA (13%). MGUS was a highly significant risk factor for developing haematological malignancies and the risk was significantly greater for MG of the IgA class compared with either IgG or IgM.

Monoclonal gammopathy of undetermined significance in atomic bomb survivors: incidence and transformation to multiple myeloma

“…As for the transformation from MGUS to MM, a quarter of MGUS patients developed lymphoid malignancies, 66% of which were MM, within 20-35 years of onset (Gregersen et al, 2001;Kyle et al, 2002). In our study, no lymphoid neoplasms other than MM developed among MGUS patients, although other studies have reported a variety of lymphoid malignancies besides MM, including IgM lymphoma, macroglobulinaemia and chronic lymphocytic leukaemia (Kanoh et al, 1990;Blade et al, 1992;van de Poel et al, 1995;Lolin et al, 1996;Ong et al, 1997;Vuckovic et al, 1997;Colls, 1999;Gregersen et al, 2001;Kyle et al, 2002;Ogmundsdottir et al, 2002). The transformation rate in the present study, 21% at 16 years, is quite similar to that of others, for example 12% at 10 years and 25% at 20 years (Kyle et al, 2002), 8AE5% at 5 years and 19AE2% at 10 years (Blade et al, 1992), and 11% at 14 years (van de Poel et al, 1995).…”

“…The prevalence of MGUS in the general population is 2AE0% in those over 50 years old and 3AE0% in those over 70 years of age (Kyle et al, 2002), but there are a few population-based studies on the incidence of MGUS (Ong et al, 1997;Ogmundsdottir et al, 2002). Atomic bomb (A-bomb) survivors, on whom epidemiological studies have been conducted for many years to assess the effects of radiation on humans, provide a unique population for such a study.…”

Prevalence of Monoclonal Gammopathy of Undetermined Significance: A Systematic Review

“…The highest incidence rate was reported in a study of approximately 7000 atomic bomb survivors in Japan. Significantly lower incidence rates were found in retrospective registrybased studies by Ogmundsdóttir et al 25 and Ong et al 26 aGe Six studies each reported prevalence data across several age groups (Figure 1). The largest of these studies by Kyle et al 13 found the prevalence of MGUS to be 4-fold higher in those older than 80 years (6.6%) compared with those aged 50 to 59 years (1.7%) in a sample of approximately 22,000 people.…”

“…Over time, electrophoretic techniques have improved, and tests such as protein immunofixation and the serum free light chain assay have greatly increased the sensitivity of detecting M proteins in the serum. 25 The differences in sensitivities of laboratory tests used to identify M protein may influence studies' estimates of the prevalence of MGUS. 13 Furthermore, the second diagnostic criterion of MGUS requires the proportion of clonal plasma cells to be less than 10% in bone marrow.…”

Multiple myeloma: A review of the epidemiologic literature

“…8,10,335,[339][340][341][342][343][344][345][346][347] In the original Mayo Clinic series of 241 patients with MGUS, 39% developed multiple myeloma within 25 years of follow-up. 335 In a larger cohort, Kyle et al 8 reported a highly increased risk of multiple myeloma (RR 5 25.0, 95% CI: 20.0-32.0) among 1,384 residents of southeastern Minnesota in whom MGUS was diagnosed in 1960 through 1994.…”