title: Malignant transformation of monoclonal gammopathy of undetermined significance among out-patients of a community hospital in southeastern Netherlands.
abstract: Patients with a monoclonal gammopathy without evidence of lymphoproliferative or plasma cell malignancy within a year are still at risk for malignant transformation to multiple myeloma, Waldenström's macroglobulinaemia or non-Hodgkin's lymphoma. In a prospective study performed at the Mayo Clinic, the cumulative incidence of malignant transformation was 29% in 14 years. We conducted a retrospective study to determine the frequency of malignant transformation among 334 unselected out-patients with monoclonal gammopathy of undetermined significance (MGUS) from a community hospital in Southeastern Netherlands. The cumulative incidence of malignant transformation was 11% in 14 years (95% confidence interval 6-17%). The long-term survival of patients with MGUS was slightly lower than that of the average regional population. In a nested case-control study, presence of a kappa light chain was found to be a risk factor for malignant transformation (70% of patients who developed malignant transformation compared to 30% of the control group, P < 0.01). Likewise, an initial high gamma globulin level was also found to be a risk factor (18.7 g/l v 13.7 g/l in the control group, P < 0.01). As neither risk factor has been described before, the significance of these factors for definition of a high-risk group among patients with monoclonal gammopathy remains to be determined.
authors.affiliation: Department of Internal Medicine, Catharina Hospital, Eindhoven, Netherlands.
authors.forename: M H
authors.initials: MH
authors.lastname: van de Poel
authors.forename: J W
authors.initials: JW
authors.lastname: Coebergh
authors.forename: H F
authors.initials: HF
authors.lastname: Hillen
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D002471:Cell Transformation, Neoplastic; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007145:Immunoglobulin kappa-Chains / Q000097:blood; D008228:Lymphoma, Non-Hodgkin / Q000209:etiology; D008297:Male; D008875:Middle Aged; D009101:Multiple Myeloma / Q000209:etiology; D009426:Netherlands / Q000453:epidemiology; D010265:Paraproteinemias / Q000401:mortality / Q000473:pathology*; D011230:Precancerous Conditions / Q000473:pathology*; D012189:Retrospective Studies; D012307:Risk Factors; D008258:Waldenstrom Macroglobulinemia / Q000209:etiology; D005719:gamma-Globulins / Q000032:analysis
chemical_list: D007145:Immunoglobulin kappa-Chains; D005719:gamma-Globulins