Monoclonal gammopathy of undetermined significance (MGUS) are very frequent in the elderly. Its incidence is about 3% after 70 years. We have performed a retrospective study of patients aged of more than 70 years who were examined until 1995 for a MGUS.
Methods: The study included 51 patients: 24 men and 27 women. Information about evolution was obtained by medical file or by asking medical practitioner. We know the evolution of all patients until January 1st 2000. The median follow-up is 5.8 years (70 months).
Results: The MGUS remained stable for 34 patients (67%) with a median follow-up of 83 months (12 to 180 months). Nine patients (17%) developed malignant transformation of MGUS (6 multiple myeloma, 2 Waldenström macroglobulinemia, 1 malignant lymphoma). Eight (15%) developed a cancer. Twelve died without evidence of multiple myeloma or related disorder. The actuarial probability of malignant transformation at 5 years was 12%.
Conclusion: The risk of malignant transformation of MGUS doesn't decrease in the elderly. A regular and prolonged follow-up is necessary.