The natural history of monoclonal gammopathy of undetermined significance. A 5- to 20-year follow-up of 263 cases.
Patients with monoclonal gammopathy of undetermined significance (MGUS) have a serum monoclonal component (M-component), but no evidence of multiple myeloma, macroglobulinaemia, amyloidosis or other plasma cell proliferative disease. A long-term follow-up study (median 11.5 years) has been carried out in 263 cases of MGUS, 159 males (60.5%) and 104 females (39.5%), aged 40-89 years (median 66.5 years). The actuarial probability for malignant transformation was 6.1, 15.4 and 31.3% at 5, 10 and 20 years, respectively. At the final evaluation, 157 patients (59.7%), 119 (45.3%) of whom with no increase and 38 (14.4%) with an increase in serum M-component, died of causes unrelated to MGUS and without development of any plasma cell proliferative disease; 47 patients (17.9%) were still alive without increase in M-component; 11 patients (4.1%) were still alive and at follow-up presented values of serum M-component > 30 g/l without any evidence of plasma cell proliferative or lymphoproliferative disease; 48 patients (18.3%) developed multiple myeloma (35 cases, 13.1%), solitary plasmacytoma of the bone (2 cases, 0.8%), macroglobulinaemia (4 cases, 1.6%), malignant lymphoma (3 cases, 1.2%), amyloidosis (2 cases, 0.8%), chronic lymphocytic leukaemia (1 case, 0.4%), and plasma cell leukaemia (1 case, 0.4%). The patients developing multiple myeloma, solitary plasmacytoma, macroglobulinaemia and plasma cell leukaemia had an increase in serum M-component, whereas no increase was found in malignant lymphoma, amyloidosis and chronic lymphocytic leukaemia. These findings and the data in the literature suggest that MGUS could be considered a preneoplastic condition; since no clinical and laboratory features are able to identify in advance the patients at high risk of disease progression, each patient must be followed up indefinitely.
Pasqualetti
P
P
Department of Internal Medicine and Public Health, School of Medicine and Surgery, University of L'Aquila, Italy.
Festuccia
V
V
Collacciani
A
A
Casale
R
R
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010265:Paraproteinemias / Q000503:physiopathology*; D011379:Prognosis; D012307:Risk Factors