A person’s risk of progressing from monoclonal gammopathy of undetermined significance (MGUS) to multiple myeloma can change over time, according to a new study published in JAMA Oncology.
 
On average, approximately 1% of patients with MGUS develop multiple myeloma annually. Doctors can currently estimate an individual’s risk of progressing soon after MGUS is diagnosed through a blood test that searches for certain blood markers. However, this new research shows that the risk can change over time, according to an article by the National Cancer Institute (NCI).
 
The researchers in the cross-sectional cohort study examined blood samples from approximately 77,469 adult participants, aged 55 to 74 years through the NCI’s Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial. They identified 187 PLCO participants who were diagnosed with multiple myeloma during the course of the trial and were found, through blood sample analysis, to have MGUS before their myeloma diagnosis.2 Investigators also identified 498 participants who were found to have MGUS that did not progress to myeloma during the trial period. 
 
The researchers then gave a risk score, low, intermediate, or high, to each blood sample based on the level of markers in blood. They found that half of those who progressed to multiple myeloma had a high risk score, whereas among those who developed multiple myeloma and had at least 3 serial blood samples available, 70% had a low- or intermediate-risk score in earlier blood samples prior to a high-risk score in subsequent samples.
 
A few of the participants who developed multiple myeloma had low- or intermediate-risk scores 1 year before diagnosis. This potentially occurred if abnormal plasma cells acquired new genetic changes that led to a progression.2
 
According to the Leukaemia Foundation, MGUS is characterized by the presence of an abnormal protein in the blood that is produced by plasma cells, those in the bone marrow that produce antibodies to fight infection. The exact cause of MGUS is unknown. Approximately 3% of people age 50 and older and 5% of people age 70 and older have the abnormal M protein in their blood. The highest incidence is among adults age 85 and older.3
 
The study authors note that the findings suggest that annual blood testing and risk assessment could lead to earlier detection of multiple myeloma.
 
 
Reference
  1. Landgren O, Hofmann J, McShane C, et al. Association of Immune Marker Changes with Progression of Monoclonal Gammopathy of Undetermined Significance to Multiple Myeloma. doi:10.1001/jamaoncol.2019.1568. https://jamanetwork.com/journals/jamaoncology/article-abstract/2738419. Published July 18, 2019. Accessed August 19, 2019.
  2. MGUS to Myeloma: Study Suggests Risk of Progression Can Change. NCI Staff. National Cancer Institute website. Published August 13, 2019. https://www.cancer.gov/news-events/cancer-currents-blog/2019/mgus-multiple-myeloma-progression-risk. Accessed August 19, 2019.
  3. Monoclonal Gammopathy of Unknown Significance (MGUS). Leukaemia Foundation website.  https://www.leukaemia.org.au/disease-information/myeloma/mgus. Accessed August 19, 2019.