Patterns of nonhematologic malignancies in a population of African American veterans with monoclonal gammopathy of unknown significance (MGUS).

Abstract

8103 Background: Monoclonal Gammopathy of Unknown Significance (MGUS) is characterized by the presence of a monoclonal immunoglobulin in the serum or the urine with no evidence of hematologic malignancy. A possible relationship between MGUS and increased incidence of NHM has been suggested in Caucasian populations. However, data in African Americans with MGUS are lacking. Methods: Non-MGUS controls were selected randomly from patients who did not have a paraprotein detected on electrophoresis (NMGUS) and were matched 2-to-1 to MGUS cases. Descriptive statistics and comparisons are presented to compare MGUS and NMGUS groups. Results: 492 male patients with MGUS patients were matched with 984 male NMGUS patients. 451 patients had abnormal serum protein studies (91.6%) and 40 had light chain disease (8.4%). Median age at diagnosis of MGUS was 68 years (28-81). 144 MGUS patients (29.2%) and 296 NMGUS patients (30%) had 1 or more NHM. The median age of diagnosis of 1st NHM was 70 (25-94) in the MGUS group and 68.4 in the NMGUS group (34.5-94.4). 19 MGUS patients (3.8%) and 27 NMGUS patients had 2 different types of NHM (2.7%). 1 MGUS patient (0.2%) and 3 NMGUS patients (0.3%) had 3 NHM. 57 patients had MGUS before NHM (11.5%) and 69 patients were diagnosed with MGUS after the diagnosis of NHM (14%), and median differences between diagnosis of MGUS and 1st NHM were 4 years (1-12 years) and 5 years (1-38 years) respectively. Types of NHM were comparable, and prostate cancer was the most prevalent NHM in both groups (15% of MGUS patients and 17% of NMGUS patients). Median time of follow up was 49.3 months for MGUS patients and 35.2 months for NMGUS patients 140 of the MGUS patients (28.4%) and 214 non-MGUS patients (21.75%) had died at data cut-off. Conclusions: Based on these observational data, prevalence and types of NHM appear to be comparable in MGUS and NMGUS African American patients. All cause mortality appears to be higher for NHM patients if they had MGUS. This pattern will need to be verified prospectively in a larger group of patients.